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EY-CC155-WB-003

February 1983

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Document:	RSX-11M Operating System Internals Student Workbook
Order Number:	EY-CC155-WB
Revision:	003
Pages:	400
Original Filename:	http://bitsavers.org/pdf/dec/pdp11/rsx11m_s/OS_internalsCourse_1983/EY-CC155-WB-003_RSX-11M_Operating_System_Internals_Workbook_Feb83.pdf

OCR Text

EY-CC 155-WB-003

RSX-11 M Operating
System Internals
Student Workbook

EY-CC 155-WB-003

RSX-11M Operating
System Internals
Student Workbook

Prepaed by Educational Services
of
DOtal Eq..ipment Corporation

The reproduction of this material, in part or whole, is strictly prohibited.
For copy information, contact the Educational Services Department,
Digital Equipment Corporation, Bedford, Massachusetts 01730.

Printed in U.S.A.

The information in this document is subject to change without notice
and should not be construed as a commitment by Digital Equipment
Corporation. Digital Equipment Corporation assumes no responsibility
for any errors that may appear in this document.
The software described in this document is furnished under a license
and may not be used or copied except in accordance with the terms of
such license.
Digital Equipment Corporation assumes no responsibility for the use
or reliability of its software on equipment that is not supplied by Digital.

The manuscript for this book was created using DIGITAL Standard
Runoff. Book production was done by Educational Services
Development and Publishing in South Lawrence, MA.

The following are trademarks of Digital Eauipment Corporation:

~DmDDmD
DATATRIEVE
DEC
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DECset
DECsystem-10
DECSYSTEM-20

DECtape
DECUS
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DIBOL
MASSBUS
PDP
P/OS
Professional

Rainbow
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UNIBUS
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VMS
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Work Processor

2/83·15

CONTENTS
SG

STUDENT GUIDE
INTRODUCTION •
COURSE GOALS •
NON-GOALS. •
PREREQUISITES.
COURSE ORGANIZATION.
Modules..
• ••
RESOURCES. • • •

....

...

OVERVIEW OF RSX-11M
DES IGN GOALS • •
CHARACTERISTICS OF RSX-IIM • •
System Features • • • • •
Major Components of RSX-IlM. •
THE EXECUTIVE. • • • • • •
• •••
Components • • • • • • •
Use of Physical Memory •
THE FILE SYSTEM. • • • • • • • •
Design Goals •
••••••••
• • • •
Components • • • • • •
•••••• • • • • • •
• • ••
• ••••
THE UTILITIES. •

3
3
4
4
4
5

13
14
14
15

16
16
16
18
18
18
20

THE SYSTEM DATA BASE
STATIC AND DYNAMIC DATA STRUCTURES • •
The Dynamic Storage Region • • • • • • • • • • • •
TASK-RELATED DATA STRUCTURES AND LISTS •
The Task Control Block (TCB) • • •
The System Task Directory (STD) • •
The Active Task List (ATL) • • • • •
PARTITION-RELATED DATA STRUCTURES AND LISTS • • • .
The Partition Control Block (PCB) • • •
The Partition List • • • • • • • . • •
DEVICE-RELATED DATA STRUCTURES AND LISTS
The Device Control Block (DCB)
The Device List • • • • • • • • • • • • • • • • • •
Other Structures • • • • • • •
THE CLOCK QUEUE. • • • • • • • • •
The Clock Queue Control Block.
The Clock Queue • • • • • • • • •

iii

25
25
29
29

35
37
37
40
43
43

45
46
46
47

EXECUTIVE MODULES

........

OVERVIEW • • • •
PRINCIPAL EXECUTIVE MODULES. •
• • • • • • •
System Common (SYSCM)..
••••••••
System Entrance and Exit Routines (SYSXT) • • • • .
DSR Allocation Routines (CORAL) • • .
I/O Related Routines (IOSUB) • • . • • •
PLA S Ro uti n e s ( P LSUB). • • • • . . • •
Queue Manipulation Routines (QUEUE). • . • • • • •
Task Request Related Routines (REQSB). •
SST Service Routines (SSTSR) • • • • • • • • • • •
Time Dependent Scheduling (TOSCH) • .
System Initialization (INITL) • • •
DIRECTIVE MODULES. • • • • • • • • • • • • • • • • • •
Resident Directive Module (DRSUB) • • • • •
Directive Dispatches (DRDSP) • • • • • • • •
DEVICE DRIVER MODULES. • • • • •
System Device Tables (SYSTB)
RK05 Driver (DKDRV) • • • • • •

53
54
54

55
55
56
56
56
57
57
58
58

61
61
61
64
64
64

FILE SYSTEM OVERVIEW
CONCEPTS • • •
• • • • • • •
FILES-II
• • • • • • •
·
Files. • • • • ••
• ••
Retrieval Pointers • • • • • •
File Directories ••
FILES-II VOLUMES • • • • • •
The Standard riles • • • •
The Index File ••
•••.•••
The Bitmap File ••
The Master File Directory • .
•
The Badblock File • • • • • •
The System Checkpoint File •
FUNCTIONS OF THE FILE SYSTEM • •
Creating a FILES-II Volume •
Creating a File • • • • • •
Accessing a File • . • • • .
THE FILE PROCESSOR • • • • •
File Control Processors.
·
Logical Units • • • • • .
Data Structures • • • • • • • • • • •
Mounting a Volume.
Opening a File . •
s

. . . .
• • • •
•
•
· .
· .

.
•
•
•
.
.

. .
• •
• •
• •
. .
.•

71
71
73
78
80
81
81

•

82
85
86

••

•

• • • •
• • • • •

• • •
. . . . . . .
• • • • • • •

86
87
88
88
89
90
91
91
92

•

• • • ••

•

• • ••
99
• 100

SYSTEM GENERATION
OVERVIEW • • • • • • • • • •
• • • • • • • • • 107
SYSGEN Functions • • • • • ••
• • • • • • • • 107
The SYSGEN Process
• • • • ••
• 108
Types of SYSGEN. • • • • • •
• • • • • • 109
New Features for Version 4.0 •
• • • • • • • • 110
PREPARING FOR SYSGEN • • ••
• • • • • • • • • • • III
Distribution Kits.
• • • • • • • • • • • • • III
Autopatch. • • • •
•••
• III
Individual patches •
• • • • • • • • • • • 112
DETAILS OF SYSGEN.
• • •
• • •
• • • • 113
Phase 1. • ••
•••••
•••
• • • • 113
Phase 2. • • •
• • • •
• 114
Phase 3. • • •
• • • • ••
• • • • • • • 115
EXECUTIVE OPTIONS. • • • • • • •
•• •
• • • • 116
Standard Feature Executive •
• • • • 116
The Terminal Driver. • • ••
• • • • • • • • • 117
Choosing a File Processor • • • • • • • • • • • • • 118
USING VMR. • • • • • ••
• • • • • • • • • • • • • 119
OV e r vie w 0 f VMR • • • • • • ••
• • • • • • • • 119
On a Mapped System • ••
• • • • • • • • • • • 120
On an Unmapped System.
•• • • • • • •
• • 121
SAVING THE NEW SYSTEM. • • •
• • • • • • • • • 124

PHYSICAL AND VIRTUAL MEMORY
CONCEPTS • • • • • • •
•••
• • • • • • • 131
Physical Address • • • • • •
• • • 131
Virtual Addresses. •
• • • • • 131
Unmapped Systems •
• • • • 131
Mapped Systems • • • • •
• • • • • • • 133
MEMORY MANAGEMENT. • • •
• • • • • • • • 136
Overview. • • • • • • • • • • • •
• • • • • 136
••••
• 137
Memory Management Hardware •
Software Use of Memory Management. • • • ••
• 141
ALLOCATING PHYSICAL MEMORY •
• • • • • • • • • 145
Partitions • • • • • • • • • • •
• • • • 145
• 147
The Partition Wait Queue • • • • • • • •
USING PHYSICAL MEMORY.
• • • • • • • • • 149
Loading Tasks. • •
• • • • • • • • • • • • • 149
Chec kpo in ting. •
• • •
• 150
Shuffling. • • • • • • • • • • •
• • • • • 153
USING VIRTUAL MEMORY •
• ••
•• 155
Attaching. • • • • • • • • ••
•••••
• 155
Mapping. • • • •
• • • • • ••
•• 157

TASK MANAGEMENT

.....

THE TASK IMAGE
The Task Image File.
The Checkpoint Area.
The Task Header. •
• ••••
.
The Task Image • • • • • • • • •
RUNNING A TASK • • • •
•••
••••
Installing
• • • • • ••
• •••
Activating • • •
• • • • • • •
Allocating Memory. •
• ••
• •
Loading • • • • • • •
Context Switching • •
SCHEDULING A TASK. • • • • • • • • • • • • • • •
priority • • • • •
• • • •
• • • • • • •
• •
Ro und Robin. • •
Disk Swapping • •
. . . . .
. •
Clock Scheduling •
· . .
. .
AST processing •
. . . . . . .
. . . . . . . . . .
TASK TERMINATION • • •
Synchronous System Traps • • • • •
• •

•
•
•
•
.
.
.

•

SYSTEM SYNCHRONIZATION
OVERVIEW • • • • • •
• • • • •
System Synchronization Functions
Software States. • • •
Software Processes • •
The Stack Depth Indicator. • • •
Traps and Interrupts • • • •
TRAP PROCESSING. • • • • • . . • • •
The Directive Save Routine • • •
The Directive Exit Routine • • •
INTERRUPT PROCESSING • • • • • • • •
The Interrupt Save Routine.
Device Driver processing • • . •
The Interrupt Exit Routine •
FORK PROCESSING. • • • • •
The FORK Block • • • • • •
The FORK List. • • • • • • • • •
PRIVILEGED TASKS
• • • • • • •
Processing a Privileged Task.

•
•

165
• 165
• • 165
• • 167
• 168
• 170
• • 171
• • 172
• • 172
• 172
• • 174
• 177
• • 1 77
• • 177
. . 180
. . 181
. . 183
. 187
• • 188

•
•

• 195
196
• • • • • . • • 196
• • • . • 197
• •
• 198
. • • 198
•
• 200
••
• • • • • 201
• •
• • • 201
• • • •
• 205
• • • • • • • • 205
••
• • . • • 207
• • • • • 207
• • • • • 210
. • • • • 210
• • • • •
210
• •
216
••••
• 217

WRITING PRIVILEGED TASKS
OVERVIEW.
.•••••.••••
Why Write a privileged Task.
Privileged Task Structure • •
vi

227
• 227
. 228

Restrictions on privileged Tasks •
• • • •
CREATING A PRIVILEGED TASK • • • • • •
Assembling a Privileged Task •
. •
Taskbuilding a Privileged Task
••••
SAMPLE PRIVILEGED TASKS. • • • • • • • • • • •
Tracing Through System Lists • • • •
. •
Calling Executive Routines • • • • • • • • • •

.
•
•
•

230
231
231
232
233
• 233
238

SYSTEM CRASHES
CRASH PROCESSING • • • •
• • •
• 251
Causes of Crashes.
• • • • • • • • • • . . 251
Crash Sequences. •
• • • • • • • . • • . • 251
Obtaining a Crash Dump Analysis..
• • • . • • 253
CRASH DUMP ANALYSIS. • • • • • • • •
• • • . . 254
Finding the Cause of a System Crash.
• • • . • 254
Basic Information Provided in a CDA. •
.256
AN EXAMPLE • • • • • • • • . • • • • • • •
• 262

DIRECTIVE PROCESSING
THE USER TASK INTERFACE. • • • • • • •
• • • . .
Directive Parameter Block. • •
• •••.
Directive Status Word. • • •
• •••••••
THE DIRECTIVE DISPATCHER • • • •
• • . • . • •
The Directive Dispatch Table •
• • • • • . .
DIRECTIVE PROCESSING ROUTINES..
•• • • • •
•
The Interface. • • • • •
• •.••
The Directive Commons. • • • • • • •
• ••••
Send/Receive processing.
• ••••
Parent/Offspring Tasking • • • • •
•
Memory Management Processing •
• .
ADDING A USER-WRITTEN DIRECTIVE. • •
•••
•
Structuring the Directive Parameter Block.
.
Changes to the Directive Dispatcher • • • • • • • .
The Di rec ti ve Processing Rout i ne and Macros. • • .
Adding a Directive to the System • • • • • • . • •

291
291
296
297
297
301
301
303
307
309
313
315
315
316
318
320

1/0 PROCESSING
OVERVIEW • • •
• • •
Components of the I/O System • • • • • • • • • •
Initiating I/O From a User Task • • • • •
.
processing I/O Request in DRQIO. • • • • •
• • •
QIO PROCESSING • • • • • • • • • • •
Logical Units. • • • • •
•••
• •••
Processing Within DRQIO • • • • • • • • . • • • •
vi i

.
•
.
·
•
•
·

327
327
330
331
332
332
333

The ACP Function Checks.
• •
Queuing I/O Requests ••
• • •
• • • • • •
ANCILLARY CONTROL PROCESSORS •
• • • • • • • •
Types of ACPs • • • • • • • • • • • • • • • • • • •
• ••••
The FILES-II (FIIACP). • • • • • ••

334
338
339
339
343

DEVICE DRIVER PROCESSING
OVERVIEW • • • • • • • • • • • • • •
• • 349
Methods of Performing I/O. •
• 349
Design Philosophy. ••
•••••
•••
350
General Flow •
• • •
• • • • • • • • 351
DRIVER DATA BASE • • • • • • •
• • •
• • 352
Device Control Block (DCB) • • • • • • • •
352
Unit Control Block (UCB) • • • • ••
• • • • • 353
Status Control Block (SCB) • • • • • •
• 357
I/O Packet • • • • • • • • •
• 359
DRIVER STRUCTURE • • • • • • • •
• • • •
• 364
Driver Entry Points. • • • • • • • • • • •
• 364
Driver Dispatch Table..
••••
• 365
DRIVER PROCESSING. • • • • •
• • •
• • 369
Initiate I/O •
•••••
•••
• 369
Kill I/O • • •
• • •
• • • • • 370
Device Timeout.
••••••••
• 371
Po we r fa i I. • • • • • • • • • • • • • • • ••
• 372
Interrupt Processing
•••
• • • • • 372
ADVANCED DRIVER FEATURES •
• • •
• 375
Loadab1e Drivers • • •
• 375
The Interrupt Control Block.
• • • •
• 375
Resident and Loadable Data Base.
• 378
UNIBUS Mapping Registers •
• ••
• 378
Connect-to-Interrupt • • • • • • •
• 382

FIGURES
1-1
1-2

Typical Use of Physical Memory.
The File System • • • ••
••••

17
19

2-1
2-2
2-3
2-4
2-5
2-6
2-7
2-8

The List of Free Space in DSR •
Allocating DSR. • • • • •
Deallocating DSR. • • • • •
The Task Control Block • • • •
The System Task Directory • •
The Active Task List.
•••
The Partition Control Block
The Partition List • • • • • •

26
27
28
30
34
36
38
41

vii i

2-9
2-1"
2-11
2-12
2-13
2-14

Relationship Between Task and
The Device Control Block. •
The Device List • • • •
Other Data Structures • • • •
The Clock Queue Control Block
The Clock Queue •

4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-16
4-17

The File System • • • • • • • • • •
• • • 72
The File Header for a Task Image. •
• • • 75
Retrieval Pointer • • • • • • • • • ••
• ••
78
Mapping Vi rtual to Log ical Bloc ks • ••
•• • • • 79
Directory Record • • • • • • • • • • •
• ••
80
84
Structure of the Index File • • • • • • • • • • •
The Bitmap File • • • • • • • •
• ••••
85
Two Level Directory Structure • • • • •
• • • • • 86
Creating a File • • • • •
• • • • • • • • • • 89
90
Accessing a File. • • • ••
• ••••••••
The Logical unit Table. • • • • • • • • • •
• •• 93
The Volume Control Block. •
•• • • • • • • • • • 95
The File Control Block. • • • •
• • • • • • • 97
FILES-II Window Block • • • • • • • •
• • •
98
Mounting a Volume •
• • ••
• • • • • • 99
Opening a File. • ••
•••
••• •
• •• 101
Shared Access • • • • • • •
• • • 102

5-1
5-2
5-3
5-4

Partition Structure on Mapped Systems •
• ••••
Partition Structure on Unmapped 24K to 28K Systems ••
Partition Structure on Unmapped 16K to 24K Systems ••
Saved System Image • • • • • • • • • • • • • • • • • •

6-1
6-2
6-3
6-4
6-5
6-6
6-7
6-8
6-9
6-10
6-11
6-12
6-13
6-14
6-15
6-16
6-17
6-18

Typical Unmapped System
• • • • • • • • • • • 132
Typical Mapped System wi th 18-bi t Addressing..
• 134
Typical Mapped System with 22-bit Addressing • • • • • 135
Registers Used by Memory Management • • • • • • • • • 138
Active Page Registers • • • • • • • • • • • • ••
139
Page Address Registers • • • • • • • • • • • • • • • • 140
Use of Memory Management by a Nonprivileged Task • • • 142
Use of Memory Management by the Executive •
• •• 143
• 144
Use of Memory Management by a Privileged Task •
Subpartitions of a Task Partition
• • • • • • 146
148
The Partition Wait Queue. • • • • • • • • • •
Steps in Checkpointing a Task • • • • • • ••
•• 150
System Checkpoint Files • • • • • • ••
• • • • • 151
Shuffling Tasks • • • • • • • • • • • •
• 154
The Attachment Descriptor Block •
• • • • • 155
Attaching a Task to a Reg ion. •
• 156
Task Virtual Address Window Blocks. ••
• • • • • 158
Mapping a Task Address Window to a Region • • • • • • 159

Partition Structures ••
••••
•••••
• • • ••
•••
•
•

....
...
...........

42
43
44
45
46
47

120
122
123
125

STUDENT GUIDE

7-1
7-2
7-3
7-4
7-5
7-6
7-7
7-8
7-9

Task Image File •
• • • •
• • • 166
The Task Header • • • • •
• • •
• • • • • 169
The Loader Queue. •
• •••••••
• 173
Context Switching • • ••
••••
• ••
• 174
The Data Structures for an Active Task • • • •
• 176
Round Robin Scheduling ••
• 178
Time Dependent Scheduling •
• ••
• • 182
AST processing • • • • • •
• • • • • 184
SST Processing • • • • • • • • • • • • • • •
• 189

8-1
8-2
8-3
8-4
8-5
8-6
8-7
8-8
8-9
8-10
8-11
8-12
8-13
8-14
8-15
8-16
8-17

Handling Traps and Interrupts by the Hardware •
• 199
EMT Instruction Execution • • • • • • • • • •
200
The Directive Save Routine. • • • • • • • ••
•• 202
Common processing in the Directive Dispatcher •
• 203
The Directive Exit Routine. •
• • • • 204
Interrupt Processing. • • • • • • • ••
• • • • • 206
The Interrupt Save Routine. •
• • • ••
..208
The Interrupt Exit Routine. •
• 209
The FORK Block in the SCB •
• • • • • 211
The FORK List • • • • • • •
• • • • • 211
Interrupting a Task • • • • •
• • • •
• 212
Interrupt Executive Processing a Directive • • • • • • 213
Interrupt Executive Processing an Interrupt •
•• 214
In t err up t Ex e cut i ve ina n I dIe Lo 0 p • • • •
• • 21 5
privileged Task Processing. • • • • • • • ••
•• 218
Privileged Task Switches Stack and Returns. ••
• 219
System Synchronization Logic. • • • • •
• • 220

10-1
10-2
10-3

The Stack After a System Crash - lOT. • • • • ••
257
The Stack After a System Crash - EMT. • • • • • • • • 258
The Stack After a System Crash - SST. • • • • ••
259

11-1
11-2
11-3
11-4
11-5
11-6
11-7
11-8
11-9
11-10

Directive Macros. • • • . • • • • • •
The Directive Parameter Block •
• ••
. •
The Di rec t i ve Di spa tch Table.
Processing in DRDSP • ••
•.••••••
••
The Directive Commons ••
••••
• .•••
Send/Receive processing •
• • • . •
Parent/Offspring Tasking. • • • • • • • • •
•
Memory Management processing.
. • • ••
••
Directive Parameter Block for New Directive •
••
Assembling and Taskbuilding the processing Routine ••

292
295
298
299
304
307
310
314
315
321

12-1
12-2
12-3
12-4
12-5

•
The I/O Process •
••••
Logical Units . • • • •
• • • • • •
Standard ACP. •
• • • .
•
User ACP. •
• • • • • • • • • • •
. •
Foreign ACP .
• • • •
• • • • • •

329
332
340
341
342

13-1
13-2
13-3
13-4
13-5
13-6
13-7
13-8
13-9
13-10
13-11
13-12
13-13
13-14
13-15
13-16
13-17

unit Control Block for LP:. • • • • •
• ••••
unit Control Block for DK:. • • • •
• •
Status Control Block. • •
••••••••••••
I/O Packet. • • • • • • • • •
•••••
•
A Simple Configuration • • • • • • • • • • • • • • • •
A Configuration with Multiple Units.
• ••
A Configuration with Multiple Controllers • • • • • •
Driver Flow. • • • • • • • • • • • •
•••
.
Interrupt Processing - Non DMA Device •
•
Interrupt Processing - DMA Device • • • • • • • • • •
A Loadable Driver • • • • •
•
The Interrupt Control Block •
••••••••••
UNIBUS Mapping Registers. • • •
• ••••••••
Mapping Assignment Block List • • • • • • •
•
UMR Wait Queue. • • • • • • • • • • •
• ••
Connect-to-Interrupt Processing •
• ••
•
The Interrupt Transfer Block. • • • • • • • • • • • •

355
356
358
3~0

361
362
363
366
373
374
376
377
379
381
381
383
384

TABLES
2-1
2-2

Task Status Words • • • •
Partition Status Words • •

32
39

3-1
3-2
3-3

Executive Modules by Function • • • •
Directive processing Modules • •
Standard Device Drivers • • • • • • •

59
62
65

7-1

Synchronous System Traps.

9-1
9-2
9-3
9-4
9-5

Pointers to System Lists • . • • • • •
Pointers to Data Structures • • • • •
Executive Pool Routines • • • • • • •
Ex ec uti v e QU e u i n g Ro uti n e s. •
Other Executive Routines.

10-1
10-2

CDA Swi tches. •
Fault Codes for SSTs.

11-1
11-2

12-1
12-2

Function Code Dispatch vector •
• • • • • • • • • 335
Polish Routines • • • • • • • • • • • • • • • • • • • 336

13-1

Important Entries in the UCB • •

•

• 188
•
•
•
•

• • • .

• • 240

•

• • • ••

234
235
238
239

255

260
•

•

302

• • • • • 306

• 354

EXAMPLES
76
77

4-1
4-2

The File Header for a Data File • •
The File Header for a Task Image ••

9-1
9-2

Tracing Through System Lists • • •
Calling Executive Routines ••

10-1
10-2
10-3
10-4
10-5
10-6
10-7
10-8
10-9
10-10
10-11
10-12

A Sample KERNEL Stack • ••
• • • • • • • • • • • 261
CDA - volatile Registers.
• • • • 264
CDA - KERNEL Stack. • • •
• • • • • • • • 265
CDA - System Common • • • •
• • • • • • • • • 266
CDA - System Common Alphabetized Dump • • • • • • • • 269
CDA - POOL Statistics • • • • • • • • • • • • • • • • 270
CDA - Ac t i veT ask s : TT 2 •
• ••
• • • • • 27 2
CDA - Task Headers: TT2.
• • • • • • • • • • 273
CDA - POOL Dump
•••
• • • • • • • • • • • • 275
Listing of Task TT2 (DUMP). •
• • • • • • • • 277
Map of Task TT2
• • • • • • • • • • • • • • • • • 282
CDA of Task TT2
•••••••••
• • • • 283

11-1
11-2
11-3
11-4

Macro Expansions for SEND DATA. • • • • • • • • • • •
New Entry in the Directive Dispatch Table.
•
Pro c e s sin g Ro uti n e for Ne w Dire c t i ve • • • • • • • • •
Macros for New Directive. •
• ••••

13-1
13-2
13-3
13-4

• •• • • • •
A Skeleton Driver • • • • • • •
A Skeleton Driver Data Base •
• ••• • • • •
UMR Address Relocation. ••
• ••
• • • •
A Sample Connect-to-Interrupt Routine •
• • •

xii

.236
241

294
317
318
319

• 367
• 368
• 380
• 385

STUDENT GUIDE

INTRODUCTION
This course is designed for
the programmer of an RSX-llM
system.
A system programmer must troubleshoot system problems and
write needed privileged code.
As a system programmer, your
the following:

responsibilities

will

•

Determining features needed on system.

•

Performing System Generations (SYSGENs).

•

Maintaining the software by installing patches.

•

Determining the cause(s) of system crashes.

•

Providing needed privileged tasks.

•

Writing new directive code.

•

Assisting application programmers with system problems.

This course is designed to give you the knowledge and
necessary to carry out these tasks.

include

skills

COURSE GOALS
Upon completing this course, you should be able to:
RSX~IIM

Install and maintain

software.

Use output from CDA to solve system problems.

Write privileged tasks which access the system data basee

Write privileged tasks which call system routines.

Write a new directive processing routine and add the directive
to the system.

Determine system status by examining the system data base.

Use knowledge of the operating system to
of applications software.

improve

performance

STUDENT GUIDE

NON-GOALS

The following are not goals of this course:
1.

The course does not teach you how to write a device driver.

The course does not teach you how
Command Line Interpreter.

The course does not teach you how to make any modifications to
system source code. Specifically, it will not teach you how
to modify DCL in any way.

create

user-written

PREREQUISITES

You should have already taken RSX-IlM
Programming
FORTRAN/MACRO, or have equivalent experience using RSX-llM.
should also be able to read and understand MACRO-II code.

in
You

COURSE ORGANIZATION

The student workbook handout is organized into modules which
correspond to the major topics covered by the instructor during
the course. Each module is designed to support the lecture by
providing you with notes and exercises to guide your study.
A module is composed of five parts:
1.

An Introduction which provides an overview of the module.
It
explains in general terms what the module covers and how the
material within the module is related to your needs.
Often,
it introduces some of the important concepts detailed in the
module.

Objectives which list the knowledge and skills you should
obtain as a result of studying the module. Read these before
the corresponding lecture, and review them after completion of
the module and its exercises.

Resources which provide a list of reference materials for
further information about the topics of the module and related
topics. You should familiarize yourself with the reference
materials because they are your primary source of information
after you complete the course.
Your instructor may suggest selected readings as preparation
for a lecture, or for review and study after the lecture.

STUDENT GUIDE

The module text which provides brief notes on topics covered
in
the lecture, with printed copies of lists,
tables,
diagrams, etc. your instructor may use in class.
The texts
provide you with notes to review after the lecture, and
reduces somewhat the note-taking you must do during lecture.
Note that the module text is a supplement to the lecture.
It
is not intended to be tutorial
reading for learning the
material on your own.
Nor is it intended to replace the
function
of reference manuals which fully document the
software. You are strongly encouraged to supplement these
notes with notes of your own and with references to the system
documentation.

Module Exercises which are designed to help you practice and
test the knowledge acquired during lecture and study.
If you
can perform all of the written and/or lab exercises at the end
of the module, you have mastered the objectives of that
module.
Your instructor may suggest particular lab exercises to
concentrate on,
if time or equipment limitations make it
In addition,
your
impossible to perform all of them.
instructor
may
provide
additional suggestions for lab
activities.

Modules
There are thirteen modules of this course.
a brief list of their major topics:

The following

OVERVIEW OF RSX-IIM describes the
goals.

system

and

its

THE SYSTEM DATA BASE describes the most
structures and lists in the system data base.

important

data

EXECUTIVE
modules.

important

Executive

FILE SYSTEM OVERVIEW describes the structure of a
volume and the data structures needed to process it.

FILES-II

SYSTEM GENERATION describes the system generation
(For reference only; this module is optional.)

process.

PHYSICAL AND VIRTUAL MEMORY describes partitions, allocation
of memory to tasks, checkpointing, function and use of memory
management.

MODULES

describes

the

operating

most

STUDENT GUIDE
7.

TASK MANAGEMENT describes the life cycle of a task.

SYSTEM
SYNCHRONIZATION
describes
trap
and
processing, and access to the system data base.

WRITING PRIVILEGED TASKS describes
building privileged tasks.

10.

SYSTEM CRASHES uses CDA to troubleshoot system problems.

11.

DIRECTIVE PROCESSING describes the directive dispatcher, the
directive dispatch table, and directive processing routines.

12.

I/O PROCESSING describes the components
ACPs, and QIO processing.

13.

DEVICE DRIVER PROCESSING describes the driver
the structure of standard device drivers.

writing,

interrupt

assembling,

the

I/O

data

and

system,
base

and

STUDENT GUIDE

RESOURCES
1.

RSX-llM Release Notes (AA-?573G-TC)
Contains the most recent version information and should be
read
thoroughly before any system generation.
Includes
information on patching.

RSX-llM System Generation and Installation Guide
Contains complete documentation on the installation and SYSGEN
procedures.

RSX-IlM/M-Plus I/O Operations Reference Manual
Contains documentation on the FCS macros and subroutines.

RSX-llM/M-Plus Executive Reference Manual
Contains descriptions of all system directives.

RSX-llM/M-Plus Crash Dump Analyzer
Explains how to use the CDA facilities.

RSX-llM Guide to Writing an I/O Driver
Contains a detailed description of the procedures involved
writing a new device driver.

OVERVIEW OF RSX-11M

OVERVIEW OF RSX-llM

INTRODUCTION
RSX-llM is designed to support many applications
with
particular emphasis on real-time applications. For this reason, a
large number of services are provided to the programmer.
This
module presents a brief overview of these features, many of which
will be examined in detail in later modules.

OBJECTIVES
1.

List the major design goals of RSX-llM.

List the major features of RSX-llM.

List the major components of RSX-llM.

OVERVIEW OF RSX-llM

DESIGN GOALS
•

Real-time system with
8K word minimum Executive
16K word minimal system (disk based, run time only)
28K word system required for SYSGEN (version 4.0)

•

Upward compatible with RSX-llD

•

Support
All PDP-II processors
Most processor options
Full line of peripherals

•

Provide system and task synchronization not
priorities

•

Provide extensive user facilities

relying

task

Complete file system
Multiple language processors
Debugging and maintainence tools
•

Allow for any number of simultaneously executing user tasks

•

Avoid using processor priority to synchronize access to system
data base

OVERVIEW OF RSX-IIM

CHARACTERISTICS OF RSX-11 M
System Features

•

Supports multiprogramming
Several tasks can be memory-resident and
time

active

same

Improves efficiency of system
Allows quick response to events
•

Provides some user control of some system functions
Schedul ing
File access

•

Completely 'Event-Driven'
No 'monolithic monitor'
Executive entered only as a result
interrupt

•

Disk-Based
Tasks stored on disk until loaded
Allows quick task startup

•

Provides multi-tasking facilities
Dynamic task requests
Passing data between tasks
Sharing memory areas between tasks

trap

hardware

OVERVIEW OF RSX-llM

Major Components of RSX-11M
•

Executive - Contains code to perform system functions such
task scheduling, input/output operations, etc.

•

File System - Provides efficient and convenient access to data
and task files.

•

Utilities - Provide services needed
user applications.

program

and

support

OVERVIEW OF RSX-IIM

THE EXECUTIVE
Components
•

Trap and interrupt vectors - Used by hardware to provide
and interrupt service.

trap

Vectors consist of 2 words:
Word 1 - A value to go into the PC
Word 2 - A value to go into the PS
When a trap or interrupt occurs:
Current values of PC and PS are pushed onto the stack
Values in the vector are moved into the PC and PS
•

System Stack - Maintained
programs.

temporary

•

System Common - Contains pointers to important areas of system
data base.

•

Executive Code - Performs system functions.

•

Dynamic Storage Area
system data structures.

Contains

most

storage

for

dynamically

system

created

Use of Physical Memory
•

Executive contained in lowest area of memory

•

Size depends on features chosen at
20K words

•

Executive has access to I/O page in top 4K
space

•

Some device drivers may not be included within Executive

•

Some directive service routines may not be included within the
Executive

SYSGEN~

not

greater

words

than

address

OVERVIEW OF RSX-IIM

1/0 PAGE

}

TOP 4K WORDS
OF ADDRESS SPACE

~----------------------~
USER
AREA

DYNAMIC STORAGE
REGION
EXECUTIVE
CODE

EXECUTIVE
(20 K WORDS
MAXIMUM)

SYSTEM STACK
TRAP a INTERRUPT VECTORS

Figure 1-1

Typical Use of Physical Memory

OVERVIEW OF RSX-IIM

THE FILE SYSTEM
Design Goals
•

Allow programmer to organize data in a convenient manner

•

Provide protection from unauthorized access

•

Provide efficient use of disk space

Components
•

Standard structures on disk and tape volumes

•

Ancillary control processor
(ACP)
interface to file structured volumes
FllACP - For disk volumes
MTAACP - For magnetic tape volumes

•

Application-oriented software
PCS - File Control Services
RMS - Record Management Services

provide

programming

OVERVIEW OF RSX-IIM

USER
TASK
RMS/FCS
VIRTUAL BLOCKS
(VIA QIO)

.....

EXECUTIVE

FILE
PROCESSOR

(F11ACP)
LOGICAL BLOCKS

DEVICE
DRIVER

••

PHYSICAL BLOCKS

PHYSICAL
VOLUME

Figure 1-2

The File System

OVERVIEW OF RSX-IIM

THE UTILITIES
•

Tasks distributed with operating system
Perform common maintenance and development functions
Not included in memory-resident Executive

•

Four general categories of utilities
Language processors
MACRO-II
FORTRAN

Program development utilities
EDT
EDI
LBR

System maintenance utilities
BAD
CMP
VFY

PAT
File manipulation utilities
PIP

FLX
DMP

THE SYSTEM DATA BASE

INTRODUCTION
The system data base includes the data structures which
describe the current state of the system to the Executive. Every
operation within the system has its effect on the system data
base. Similarly, the state of the system data base at the time an
operation is requested determines the success and effect of the
operation.
Throughout this course, the system data base is used to
explain the mechanics of various system operations. This module
describes the most central system data structures, and how they
are related. Future modules detail the data structures and their
linkages.

OBJECTIVES
1.

Describe the major system data structures associated with task
management.

Describe the major
partition control.

associated

with

Describe the major system data structures associated with
device control.

I/O

Describe how the Executive manages the Dynamic Storage Region.

system

data

structures

THE SYSTEM DATA BASE

STATIC AND DYNAMIC DATA STRUCTURES
•

Static data structures
Created when system is built
Contained in Executive modules
Example: Data structures for standard devices selected at
SYSGEN are in the Executive module SYSTB.

•

Dynamic data structures
Created and eliminated as needed
Contained in Dynamic Storage Region (DSR)
Example: Data structures needed to define
system are in DSR.

tasks

the

maintained

The Dynamic Storage Region
•

Contains dynamic data structures

•

Space allocated and deallocated as needed

•

Allocation of DSR:
Performed by routines in module CORAL
Length is multiple of 4 bytes
Linked list
Executive

unallocated

space

No record of allocated space is kept
First-fit algorithm is used
List of preallocated I/O packets maintained
at SYSGEN

specified

THE SYSTEM DATA BASE

·SCRAVL

':!!

}
POINTER TO NEXT FREE BLOCK
SIZE OF FREE BLOCK (IN BYTESl

I"'"

ALLOCATED
SPACE

POINTER TO NEXT FREE BLOCK
SIZE OF FREE BLOCK {IN BYTES}

}
POINTER TO NEXT FREE BLOCK=O
SIZE OF FREE BLOCK (IN BYTESl

}
SIZE IN BYTES INCLUDING 2 BYTES FOR POINTER AND
2 BYTES FOR SIZE FIELD

Figure 2-1

The List of Free Space in DSR

THE SYSTEM DATA BASE

BEFORE ALLOCATION
$CRAVL

AFTER ALLOCATION

r-- $CRAVL

:::!::

POINTER TO NEXT FREE BLOCK
SIZE OF FREE BLOCK (IN BYTES)

POINTER TO NEXT FREE BLOCK ~
SIZE OF FREE BLOCK (IN BYTES)

POINTER TO NEXT FREE BLOCK=O
SIZE OF FREE BLOCK (IN BYTES)

Figure 2-2

Allocating DSR

...

THE SYSTEM DATA BASE

BEFORE DEALLOCATION

AFTER DEALLOCATION

SCRAVL

·$CRAVl

Figure 2-3

Deallocating DSR

THE SYSTEM DATA BASE

TASK-RELATED DATA STRUCTURES AND LISTS
The Task Control Block (TCB)
•

Defines task to system

•

Contains information controlling task execution
Task name
Task priority
Local event flags
Task status words

•

Contains pointers to other data structures including:
T.RCVL - Receive queue listhead
Points to linked list of data blocks queued
by the 'SEND DATA' directive.
T.ASTL - AST queue listhead
Points to linked list of ASTs queued to task.
T.UCB

- Address of data structure (UCB) identifying TI:

T.TCBL - Link word for System Task Directory
T.PCB

- Address of data structure (PCB) identifying
partition in which task executes

T.ACTL - Link word for Active Task List
•

Allows task to load and begin execution quickly
Contains pointer to task image on disk
Identifies partition in which to load task

THE SYSTEM DATA BASE

TCB

FIXED

UTILITY LINK WORD
110 PENDING COUNT

OPTIONAL

AREAL

I TASK PRIORITY

T.IOC/T.PRI

POINTER TO CHECKPOINT PCB

T.CPCB

TASK NAME
. . . .-----------------.

T.NAM

RECEIVE QUEUE
. . . .-----.-._----....

T.RCVL

IN RADSO

LlSTHEAD

AREA

(

T.lNK

QUEUE
----_ .. -AST
.........
- .... T.ASTL
LlSTHEAD

PLAS AREA

TASK LOCAL

PARENT 10FFSPRING
AREA

- - -- --- . -- -- - - - EVENT FLAGS

-. . - - -

T.EFlG

UCB ADDRESS FOR 'TI'

T.UCS

STD THREAD WORD

T.TCSl

FIRST STATUS WORD (BLOCKING BITS)

T.STAT

OTHER OPTIONS

Figure 2-4 The Task Control Block
(First Part of Fixed Area)

TCB

FIXED

FIRST STATUS WORD (BLOCKING BITS)

T.STAT

SECOND STATUS WORD (STATE BITS)

T.ST2

THIRD STATUS WORD (AnRIBUTE BITS)

T.ST3

.. . . . . . . . . . I
LBN

DEFAULT PRIORITY

T.LBN/T.DPRI

OF TASK LOAD IMAGE

UCB ADDRESS OF LOAD DEVICE

T.LDY

PCB ADDRESS OF TASK PARTITION

T.PCB

MAXIMUM SIZE OF TASK IMAGE (MAPPED)

T.MXSZ

ATL THREAD WORD

T.ACTL

SPECIFIED AST LlSTHEAD

T.SAST

T.TIO

AREA

(
OPTIONAL

AREAL

PLAS AREA
PARENT /OFFSPRING
AREA

BUFFERED 1/0 COUNT

TASK SIZE

OTHER OPTIONS

Figure 2-4 The Task Control Block
(Second Part of Fixed Area)

UNUSED

T.TKSZ

THE SYSTEM DATA BASE

TeB

- - . . A-TTACHMENT
. . - -LlSTHEAD
. . .DESCRIPTOR
- . . . . - . -- - T.ATT

FIXED
AREA

OFFSET IN PARTITION
T.SRCT EFN COUNT FOR SREF

(
OPTIONAL

AREAL

T.OFF

RESERVED

- . . . .RECEIVE·BY·REFERENCE
. . . . . - . - . - . . - . - . - T.RRFL
LlSTHEAD

PLAS AREA

. - . . . .OFFSPRING
. . . . . .CONTROL
. - . . . - . - . - T.OCBH

PARENT /OFFSPRING
AREA

BLOCK LlSTHEAD

OTHER OPTIONS

OUTSTANDING OFFSPRING COUNT

T.RDCT

EVENT FLAG MASK WORD

T.EFLM

EVENT FLAG MASK ADDRESS

~ GGEF USE COUNT I TASK HEADER LENGTH T.HDLN
Figure 2-4

The Task Control Block
(Optional Area)

THE SYSTEM DATA BASE

Table 2-1

Task Status Words

Offset

Bit

Symbol

Value

Meaning

T.STAT

15
14
13
12
8

TS.EXE
TS.RDN
TS.MSG
TS.NRP
TS.OUT
TS.CKP
TS.CKR

100000
40000
20000
10000
400
200
100

Task not in execution
I/O rundown in progress
Abort message being output
Task mapped to nonresident region
Task is out of memory
Task is being checkpointed
Task checkpointing requested

NOTE
The bits in T.STAT are called blocking
bits.
They must all be clear for the Executive to
context switch to the task.
T.ST2

15
14
13
12
11
10
9
8
7
6
5
4
3
2
1

T.ST3

15
14
13
12
11

10
9
7

6
5

T2.AST
T2.DST
T2.CHK
T2.CKD
T2.SEF
T2.FXD
T2.TIO
T2.CAF
T2.HLT
T2.ABO
T2.
T2.STP
T2.
T2.SPN
T2.
T2.WFR

100000
40000
20000
10000
4000
2000
1000
400
200
100
40
20

T 3. ACP
T3. PMD
T3.REM
T3. PRV
T3.MCR
T3.SLV
T3.CLI
T3. NSD
T3. CAL
T3.ROV

100000
40000
20000
10000
4000
2000
1000
200
100
40

4
2

AST in progress
AST recognition disabled
Task not checkpointab1e
Checkpointing disabled
Task stopped for event flag
Task fixed in memory
Task engaged in terminal I/O
Dynamic checkpoint space allocation failure
Task is being halted
Task marked for abort
Saved T2.STP on AST in progress
Task stopped
Saved T2.SPN on AST in progress
Task suspended
Saved T2.WFR on AST in progress
Task in wait for state
Ancillary control processor
Inhibit post mortem dump
Remove task on exit
Task is privileged
Task requested as external MCR function
Task is slaved
Task is a command line interpreter
Task does not allow send data
Checkpoint space allocated in task image
Task has resident overlays

THE SYSTEM DATA BASE

The System Task Directory (STD)
•

Linked list of TCBs

•

Ordered by descending default priority

•

Begins at listhead $TSKHD in System Common

•

Linked through location T.TCBL in the TCB

•

'Null Task' TCB is last entry
'Null Task' used to anchor system task lists
When 'Null Task' is scheduled, the idle loop is
until another task becomes ready to run

performed

'Null Task' TCB in System Common
'Null Task' never executes
•

TCB is inserted when task is installed

• New TCB inserted after others of same priority
• System maintains pointers (in SYSCM) to special tasks in STD
$TKTCB - Current task TCB
$TKNPT - Po inter to TCB of task termination task TKTN
$MCRPT - Po inter to TCB of MCR task
$LDRPT - Pointer to loader TCB

THE SYSTEM DATA BASE

STSKHD

SRQSCH

.....
~
.....

I T.PRI
T.TCBl
L T.OPRI
T.ACTl

248

L T.PRI

160

248

TCB OF
(TYPICALLY)
LOADER TASK

T.TeBl

I T.OPRI

160

T.ACTl

........

l T.PRI

100

T.TCBl
I T.OPRI

100

.....

STKTCB

....
--

l T.PRI
T.TCBl
I T.DPRI
T.ACTl

l T.PRI

130

........

T.TCBl
I T.DPRI
T.ACTl

I T.PRI
T.TCBL-O
T.ACTl

Figure 2-5

THIS TCB IS LOCATED IN THE
EXECUTIVE MODULE SYSCM.
IT IS THE NULL TASK'S TCB.

The System Task Directory

THE SYSTEM DATA BASE

The Active Task List (ATL)
•

Linked list of TCBs

•

Ordered by descending priority

•

Begins at $ACTHD in System Common

•

Linked through T.ACTL in TCB

•

'Null Task' TCB is last entry

•

TCB inserted when requested;

•

New TCB inserted after others of same priority

Task becomes active

THE SYSTEM DATA BASE

$TSKHD
$ACTHD

I T.PRI 248
T.TCBL
I T.DPRI 248
}
T.ACTL

.....

$RQSCH

r:::

...

........
........

I T.PRI

$TKTCB

...

.........

~
160

T.TCBL
I T.DPRI 160
I--T.ACTL

I T.PRI 100
T.TCBL
I T.DPRI 100
T.ACTL
.......
I T.PRI ~
T.TCBL
I T.DPRI 50
~
T.ACTL

......
~

TCB OF
(TYPICALLY)
LOADER TASK

......
I T.PRI
T.TCBL
I T.DPRI
T.ACTL

I T.PRI

50
......
0--

T.TCBL-O
T.ACTL-O

Figure 2-6

130

}

THIS TCB IS LOCATED IN THE
EXECUTIVE MODULE SYSCM.
IT IS THE NULL TASK'S TCB.

The Active Task List

THE SYSTEM DATA BASE

PARTITION-RELATED DATA STRUCTURES AND LISTS

The Partition Control Block (PCB)
•

Defines partition to system

•

Contains information describing partition
Partition name
Physical starting address (32 word blocks number)
Size of partition (in 32 word blocks)
Partition busy word
Partition status word
Protection word
Current UIC of owner task

•

Pointers to other data structures
If subpartition PCB, pointer to the main partition PCB
Pointer to next subpartition PCB
Pointer to queue of TCBs of tasks
partition

waiting

for

Pointer to attachment descriptor block for task
Pointer to task header of resident task

space

THE SYSTEM DATA BASE

P.lOC

LINK TO NEXT PARTITION PCB
PRIORITY OF PARTITION
PARTITION NAME

I/O COUNT

(IN RADIX-50)

POINTER TO NEXT SUB-PARTITION
POINTER TO MAIN PCB

PHYSICAL START ADDRESS OF PARTITION
SIZE OF PARTITION
PARTITION WAIT QUEUE
LIST HEAD
PARTITION SWAP SIZE (SYSTEM ONLY)
PARTITION BUSY FLAGS
TCB ADDR. OF OWNER/CURRENT UIC OF OWNER TASK
PARTITION STATUS FLAGS
POINTER TO TASK HEADER
PROTECTION WORD FOR PARTITION
ATTACHMENT DESCRIPTOR
LIST HEAD

0
2
4
6
10
12
14
16
20
22
24
26
30
32
34
36
40

P.LNK
P.PRI
P.NAM
P.SUB
P.MAIN
P.REL \P.HDR 2
P.BLKS ',P.SIZE'
P.WAIT
3
P.SWS2
P.BUSY (TWO BYTES)
P.TCB/P.OWN
P.STAT
P.HDR2
P.PR0 4
P.ATT

1. 32 WORD BLOCKS FOR MAPPED SYSTEMS
BYTES FOR UNMAPPED SYSTEMS
2. P.HDR=P.REL IN UNMAPPED SYSTEMS
3. FOR SUB-PARTITIONS OF SYSTEM CONTROLLED PARTITIONS
4. MAPPED SYSTEMS ONLY
5. MAPPED SYSTEM WITH PLAS ONLY

Figure 2-7

The Partition Control Block

THE SYSTEM DATA BASE

Table 2-2

Partition Status Word

Bit

Symbol

Value

Meaning

15
14
13
12
11
10

PS.OUT
PS.CKP
PS.CKR
PS.CHK
PS.FXD
PS.PER
PS.LIO
PS.NSF
PS. COM
PS.PIC
PS.SYS
PS.DRV
PS.DEL
PS.APR

100000
40000
2000'0
10000'
4000'
2000'
1000'
40'0'
200'

Partition is out of memory
Partition checkpoint in progress
Partition checkpoint requested
Partition is not checkpointable
Parti tion is fixed
Pari ty error in partition
Ma rked by shuffler for long I/O
Partition is not shufflable
Library or common block
Posi tion independent library of common
System controlled partition
Driver is loaded in partition
Partition should be deleted when not attached
Starting APR
Starting APR
Starting APR

8
7
6

5
4
3
2
1
0

100'
40'

20
10'

4
2
1

THE SYSTEM DATA BASE

The Partition List
•

Linked list of PCBs

•

Linked in order of increasing base address

•

Begins at location $PARHD in System Common

Linked through P.LNK in PCB

•

PCB created and inserted in list by 'SET /MAIN' or 'SET
MCR or VMR command

•

PCBs of subpartitions
Task partitions
Linked into list using P.LNK
Linked to PCB of main partition using P.SUB
System-controlled partitions
Linked to main partition PCB using P.SUB
Not linked through P.LNK

/SUB'

THE SYSTEM DATA BASE

$PARH D~

P LNK
P.SUB=O
P.MAIN

P LNK

,....-

P.SUB
P.MAIN

P LNK

,....-

P.SUB
P.MAIN

I
;:::!::

}

USER-CONTROLLED
MAIN PARTITION
WITHOUT SUBPARTITIONS

cr~
USER-CONTROLLED
MAIN PARTITION
WITH 2 SUBPARTITIONS

r--

P.LNK
P.SUB=O
P.MAIN

l..+

P.J:.~K

IoiI

P,SUB
P.MAIN

I-

P LNK=?
P.SUB
P.MAIN

...

...
-

P LNK=?
P.SUB=O
P.MAIN

SYSTEM-CONTROLLED
PARTITION WITH
2 DYNAMICALLY
CREATED SUBPARTITIONS

PCBS OF DYNAMICALLY ALLOCATED
SUBPARTITIONS ARE CHAINED ACCORDING
TO THE BASE ADDRESSES OF THEIR SUBPARTITIONS

Figure 2-8

The Partition List

THE SYSTEM DATA BASE

--..

P.SUB

I--

P.MAIN
NON· RESIDENT,

TCB t

NON·ACTIVE TASK

PCB OF
MAIN PARTITION

P.TCB=O
T.PCB

f---

P.HDR=O

't"

f4--

TCB
T.PCB

RESIDENT TASK

f4-

r-L

P.SUB

t--

P.MAIN

t-- t--

DYNAMICALL Y
CREATED PCB

P.TCB
P.HDR

TASK
HEADER

P.SUB= ?
P.MAIN
NON·RESIDENT,
ACTIVE TASK

DYNAMICALLY
CREATED PCB

TCB
T.PCB

P.TCB
~

EACH ACTIVE TASK
HAS ITS OWN
DYNAMICALLY
CREATED PCB.

P.HDR?
PCB'S OF RESIDENT
TASKS ARE CHAINED
ACCORDING TO THE
BASE ADDRESS OF
THEIR SUBPARTITION.

'--

!4-

TCB

T.PCB

P.MAIN

OTHER
RESIDENT
TASK

P.SUB=O

P.TCB

DYNAMICALL Y
CREATED PCB
(LAST)

P.HDR

TASK
HEADER

l
Figure 2-9

TK·1S1'

Relationship Between Task and Partition Structures

THE SYSTEM DATA BASE

DEVICE-RELA TED DATA STRUCTURES AND LISTS

The Device Control Block (OCB)
•

Describes physical device type

•

Contains information describing device
Generic device name in ASCII (D.NAM)
Physical units in system of this type (D. UNIT)
Device functions supported

(D.MSK)

•

Pointer to data structures describing physical units (D.UC8)

•

Pointer to entry points in device driver

(D.DSP)

LINK TO NEXT DCB

D.LNK

POINTER TO FIRST UCB OF THIS DEVICE TYPE

D.UCB

GENERIC DEVICE NAME (IN ASCII)

D.NAM

HIGHEST UNIT NUMBER LOWEST UNIT NUMBER 6

D.UNIT

LENGTH OF EACH UCB OF THIS DEVICE TYPE

10 D.UCBL

POINTER TO DRIVER DISPATCH TABLE

12 D.DSP

LEGAL FUNCTION MASK

CODES 0-15

14 D.MSK

CONTROL FUNCTION MASK

CODES 0-15

NO-OP FUNCTION MASK

CODES 0-15

ACP FUNCTION MASK

CODES 0-15

LEGAL FUNCTION MASK

CODES 16-31

CONTROL FUNCTION MASK

CODES 16-31

NO-OP FUNCTION MASK

CODES 16-31

ACP FUNCTION MASK

CODES 16-31

PCB ADDRESS OF LOADABlE DRIVER

Figure 2-10

34 D.peB

The Device Control Block

THE SYSTEM DATA BASE

The Device List
•

Linked list of DCBs

•

Ordered by inclusion in SYSTB and by order of loading

•

Begins at listhead $DEVHD in SYSCM

•

Linked through location D.LNK in DCB

po
SYSC!..-- ,.......

( SDEVHD)

....
,.....-

D.LNK
DCB FOR LP:

D.LNK
DeB FOR DB:

- DeBD.LNK OK:
FOR

"
Figure 2-11

The Device List

THE SYSTEM DATA BASE

Other Structures
•

The unit Control Block (UCB)
One UCB per physical unit of type
Size depends on device type
Contains data used to describe physical unit

•

The Status Control Block (SCB)
One SCB per controller or per line if multiplexer
Size depends on device type
Contains data needed to control I/O operations

SYSC~

( SDEVHD)

D.LNK
DCB FOR LP:
D.UCB

D.UCBL

...

r---

L-+
r---

D.LNK
DCB FOR DB:
D.UCB
D.UCBL

D.LNK
DCB FOR OK:
D.UCB

UCB FOR
LPflj:

UCB FOR
DBflj :

-.. UCB FOR
DKflj:

"
Figure 2-12

..-

SCB

UCB FOR
DB1:

D.UCBL

Other Data Structures

SCB

THE SYSTEM DATA BASE

THE CLOCK QUEUE
The Clock Queue Control Block
•

Describes time-dependent request

•

Contains eight words;

•

Five types of requests

last three depends on type of request

Mark Time
Task request with periodic rescheduling
Single shot task request
Single shot internal subroutine (two types)

C.EFN 3

POINTER TO NEXT CLOCK QUEUE CONTROL BLOCK

o C.LNK

EVENT FLAG NUMBER
(MARK TIME ONLY)

2 C.RQT

REQUEST TYPE

TCB ADDRESS OR SYSTEM SUBROUTINE ADDRESS

4 C.TCB

ABSOLUTE TIME
WHEN
REQUEST COMES DUE

LOW ORDER PART

6 C.TIM

HIGH ORDER PART

10
12

TYPE
DEPENDENT
PARAMETERS

14
16

Figure 2-13

The Clock Queue Control Block

THE SYSTEM DATA BASE

The Clock Queue
•

Linked list of Clock Queue Control Blocks

•

List ordered by increasing absolute time

•

Scanned by code in TDSCH when clock interrupt occurs

SYSCM

(SCLKHD

DSR

..-

C.LNK

...-

C.LNK

l...+

Figure 2-14

C.LNK=O

The Clock Queue

EXECUTIVE MODULES

INTRODUCTION
The Executive is composed of a number of modules.
Each
module contains code which performs a specific function or class
of related functions.
To effectively function as a systems
programmer, you must be able to locate this code. This module
provides a quick overview of the major modules in the Executive.

OBJECTIVES
1.

Recogni ze the general function of a module
directive processing, or device driver).

Locate the code which performs a given Executive function.

(i.e.,

general,

EXECUTIVE MODULES

OVERVIEW
•

Over 90 possible modules in the Executive

•

Modules conditionally assembled
[11,10]RSXMC.MAC

•

Three types of modules:

using

symbols

contained

General Executive modules
Have names which relate to function
Example:

SYSCM - System Common

Directive processing modules
Have 5 character names
First two characters are 'DR'
Last three characters indicate function
Example:
directive

DRABO

Module

for

processing

the

Device Driver modules
Have 5 character names
First two characters indicate device type
Last three characters are 'DRV'
Example:

DKDRV - Device driver for RK05 disk drives

abort

EXECUTIVE MODULES

PRINCIPAL EXECUTIVE MODULES
System Common (SYSCM)
•

Contains pointers to system lists
$CRAVL $TSKHD $ACTHD $PARHD $DEVHD $GGEF $CLKHD $FRKHD $CFLPT $UMRWT -

•

to
to
to
to
to
to
to
to
to
to

first block of free pool space
STD
ATL
Partition List
Device List
Group Global Event Flag List
Clock Queue
Fork Queue
Checkpoint File PCB List
UMR wait queue

Contains pointers to specific data blocks
$HEADR $TKNPT $SHFPT $TKTCB $RQSCH $MCRPT $LDRPT -

•

Pointer
Pointer
Po inter
Pointer
Pointer
Po inter
Pointer
Po inter
Pointer
Pointer

Pointer
Pointer
Pointer
Pointer
Po inter
Po inter
Po inter

to
to
to
to
to
to
to

header
TCB of
TCB of
TCB of
TeB of
TCB of
TCB of

of current task
TKTN
shuffler
current task
requested task
MCR
loader

General system data
$CMBEG $UMRHD $CURPR $COMEF $PWRFL $ABTIM $STKDP $INTCT $DYPMN $BTMSK $IOABM $TKPS $CXDBL -

The TCB of the null task
First UMR mapping assignment block
Current task priority
Common event flags
Power fail recovery request flag
Absolute time counter
Stack depth indicator
Clock interrupt ticks count
Days per month table
Bit mask table
I/O active bitmap
Ticks per second
Context switching disabled flag

EXECUTIVE MODULES

System Entrance and Exit Routines (SYSXT)
•

Contains routines used for entering and exiting the Executive
$DIRSV $FORK $FORKI $FORK2 $INTSV $INTSE $INTSC $INTXT $DIRXT $SWSTK -

•

Called when Executive entered by system trap
Used to create FORK process by driver
Used to create FORK process by non-driver
Used to create FORK process by CINT$ routine
Called when Exec entered by interrupt
Called when Exec entered by interrupt (Error
Logging)
Called when Exec entered by interrupt (CINT$)
Called to exit the Exec after an interrupt
Called to exit the Exec after a system trap
Called to enter the Exec from a privileged task

Contains code for the system 'idle loop'

DSR Allocation Routines (CORAL)
•

Contains routines used to allocate space in DSR
$ALOCB $ALCLK $DECLK $ALPKT $DEPKT $DEACB -

Allocates a block of specified size from DSR
Allocates a clock queue control block from DSR
Deallocates a clock queue control block
Allocates a 'send' or I/O request block
Deallocates a 'send' or Ilo request block
Deallocates a block

EXECUTIVE MODULES

I/O Related Routines (lOSUB)
•

Contains routines used in I/O-related processing
$GTPKT - Gets I/O packet from I/O queue
$.GSPKT - Gets I/O packet
$IODON - Handles common I/O completion

PLAS Routines (PLSUB)
•

Contains subroutines
Address Space (PLAS)
$SRNAM $CKACC $CRATT $SRATT $SRWND $UNMAP -

used

manipulate

Program

Logical

Searches for specified partition
Checks if desired access to region is allowed
Creates Attachment Descriptor Block (ADB)
Searches for specified ADB
Searches for specified address window
Unmaps address window

Queue Manipulation Routines (QUEUE)
•

Contains subroutines used to manipulate queues
$CLINS $CLRMV $QINSF $QINSP $QMCRL $QRMVF $QRMVT -

Inserts an entry into the clock queue
Removes an entry from the clock queue
Inserts into FIFO queue
Inserts into priority queue
Queues MCR command line
Removes from front of queue
Removes next entry with specified TCB address

EXECUTIVE MODULES

Task Request Related Routines (REQSB)
•

Contains subroutines used to handle task requests
$ABCTK - Aborts current task
$ABTSK - Aborts specified task
$BILDS - Sets up task stack and initialize task header
$ACTTK - Puts task in Active Task List (ATL)
$SETCR - Sets conditional scheduling request
$SETF - Sets event flag
$DASTT - Declares a non-I/O related AST
$QASTT - Queues an AST to a specified task
$SRAST - Searches for specified type of AST
$SRSTD - Searches STD for specified task
$ACTRM - Removes task from ATL
$STPCT - Stops current task
$STPTK - Stops specified task
$RLPAR - Releases task partition
$RLPRI - Releases specified partition
$NXTSK - Assigns next task to partition
$FNDSP - Finds space in system controlled partitions
$TSTCP - Tests if checkpoint should be initiated
$ICHKP - Initiates checkpoint of specified task
$CHKPT - Checkpoint task
$LOADT - Puts task in loader queue
$TSKRT - Requests task execution
$MAPTK - Maps task address window

SST Service Routines (SSTSR)
•

Contains routines to service Synchronous System Traps (SST)
$EMSST $ILINS SIOTRP $SGFLT $TRACE $TRP04 $SSTXT -

Non-RSX EMT instruction
Illegal or reserved instruction
lOT instruction
Memory protect violation
T-bit trap or BPT instruction
Odd address, Non-existent memory, etc.
Common SST exit routine

EXECUTIVE MODULES

Time Dependent Scheduling (TOSCH)
•

Contains routines to handle time dependent scheduling

•

Entered from clock interrupt
Updates system time and date
Manages clock queue
Checks for device timeouts
Manages Round Robin scheduling
Manages Executive level disk swapping

System Initialization (INITL)
•

Executes only for system which has not been saved
Contains the Executive transfer address location ($INITL)

•

Performs system initialization functions
writes load device and image file information into SYSCM
Initializes Processor Status Word
Initializes Memory Management registers (Mapped system)
Turns on memory management hardware (Mapped system)
Initializes Unibus Mapping Registers (11/44, 11/70)
Calculates size of physical memory
Verifies the existence of the external directive commons
Verifies the presence of the floating point processor
Verifies the presence of EIS
Verifies that all selected devices are online
Verifies the pres~nce of the watchdog timer
Sets up system clock

•

Deallocates its space to DSR

•

Values initialized by INITL are written to system image by SAV
task

EXECUTIVE MODULES

Table 3-1

Executive Modules by Function

Function

Modules

Scheduling
Task Scheduling

TDSCH - Time-Dependent Scheduling
SYSXT - Normal Scheduling

Round Robin Scheduling

TDSCH

Disk-Swapping

TDSCH

Id Ie Loop

SYSXT

Interrupt Processing
Clock Interrupts
I/O Interrupts
System Entrance
System Exit

TDSCH
XXDRV SYSXT
SYSXT

Trap Processing
Synchronous System Traps

SSTSR

'EMT' Traps

DRSUB
DRDSP

'TRAP' Traps

DRSUB
DRDSP

System Entrance

SYSXT

System Exit

SYSXT

Context Switching

SYSXT

Data Movement

BFCTL

'XX'

Indicates Device

EXECUTIVE MODULES

Table 3-1

Executive Modules by Function (Cont)

Function

Modules

DSR Allocation
For
Fo r
For
For
For

Clock Queue
FI FO Que ues
Priority Queues
eLI Messages
Error Messages

Er ro r Logg ing

CORAL
CORAL
CORAL
CORAL
ERROR
ERROR

I/O Processing
I/O Parameter Block
UMR Allocation
I/O Complet ion

IOSUB
IOSUB
IOSUB

EXECUTIVE MODULES

DIRECTIVE MODULES
Resident Directive Module (DRSUB)
•

Contains entry points for routines entered by system traps
$TRTRP - Handles TRAP instruction
$EMTRP - Handles EMT instruction

•

Contains commonly used routines
$ELGEF $DEAGF $DRDSE $DRWSE $MPXCI $MPXC2 $DRQRQ $GTUCB $OTHRI -

Eliminates Group Global Event Flag block
Deaccesses group global event flags
Declares significant event
Waits for significant event
Maps the first directive common
Maps the second directive common
Queues an I/O request and calls driver
Gets UCB address for given device and unit
Calls directive routine in second directive
common

Directive Dispatcher (DRDSP)
•

Contains code to process EMT traps

•

Determines if EMT is
Directive call
Switch to Kernel mode
Non-RSX EMT instruction

•

Contains table defining directives in system

EXECUTIVE MODULES

Table 3-2

ABRT$
ALTP$
ALUN$
ASTX$S
ATRG$
CINT$
CLEF$
CMKT$
CNCT$
CRAWS
CRGF$
CRRG$
CSRQ$
DECL$S
DSAR$S
DSCP$S
DTRG$
ELAW$
ELGF$
EMST$
ENAR$S
ENCP$S
EXIF$
EXIT$S
EXST$
EXTK$
GCCI$
GCII$
GLUN$
GMCR$
GMCX$
GPRT$
GREG$
GSSW$S
GTIM$
GTSK$
MAP$
MRKT$
QIO$
QIOW$
ReST$
RCVD$
RCVX$
RDAF$
RDXF$

Directive Processing Modules

Entry

Module

Function

$DRABO
$DRAPI
$DRASG
$DRAXT
$DRATR
$DRCIN
$DRCEF
$DRCMS
$DRCNC
$DRCRW
$DRCRE
$DRCRR
$DRCSR
$DRDSE
$DRDAR
$DRDCP
$DRDTR
$DRELW
$DRELE
$DREMS
$DREAR
$DRECP
$DREIF
$DREXT
$DREXS
$DREXP
$DRGCL
$DRCLI
$DRGLI
$DRGCL
$DRGMX
$DRGPP
$DRGPP
$DRGSS
$DRGTP
$DRGTK
$DRMAP
$DRMKT
$DRQIO
$DRQIO
$DRRCS
$DRREC
$DRREC
$DRRAF
$DRRAF

DRABO
DRATP
DRASG
DRATX
DRREG
DRCIN
DRSED
DRCMT
DRSPW
DRMAP
DRGEF
DRREG
DRCMT
DRSUB
DRDAR
DRDCP
DRREG
DRMAP
DRGEF
DRSPW
DRDAR
DRDCP
DREIF
DREIF
DRSPW
DREXP
DRGCL
DRCLI
DRGLI
DRGCL
DRMAP
DRGPP
DRGPP
DRGSS
DRGTP
DRGTK
DRMAP
DRMKT
DRQIO
DRQIO
DRRAS
DRRAS
DRRAS
DRRES
DRRES

Abort Task
Alter Priority
Assign LUN
AST Service Exit
Attach Region
Connect to Interrupt Vector
Clear Event Flag
Cancel Mark Time Requests
Connect
Create Address Window
Create Group Global Event Flags
Create Region
Cancel Time Based Requests
Declare Significant Event
Disable AST Recognition
Disable Checkpointing
Detach Region
Eliminate Address Window
Eliminate Group Global Event Flags
Emit Status
Enable AST Recognition
Enable Checkpointing
Exit If
Task Exit
Exit With Status
Extend Task
Get command for command interpreter
Get command interpreter information
Get LUN Information
Get MCR Command Line
Get Mapping Context
Get Partition Parameters
Get Region Parameters
Get Sense Switches
Get Time Parameters
Get Task Parameters
Map Address Window
Mark Time
Queue I/O Request
Queue I/O Request and Wait
Receive Data or Stop
Receive Data
Receive Data or Exit
Read All Event Flags
Read Extended Event Flags

EXECUTIVE MODULES

Table 3-2

Directive Processing Modules (Cont)

Entry

Module

Function

RPOI$
RQST$
RREF$
RSUM$
RUN$
SCAA$
SCLI$
SDAT$
SDRC$
SDRP$

$DRREQ
$DRREQ
$DRRRF
$DRRES
$DRRUN
$DRCLI
$DRCLI
$DRSND
$DRSRC
$DRSRC

DRSPW
DRSPW
DRMAP
DRRES
DRMKT
DRCLI
DRCLI
DRRAS
DRSPW
DRSPW

SETF$
SFPA$
SMSG$
SPND$S
SPRA$
SPWN$
SRDA$
SREA$
SREF$
SRRA$
STLO$
STOP$S
STSE$
SVDB$
SVTK$
ULGF$
UMAP$
USTP$
WSIG$S
WTLO$
WTSE$

$DRSEF
$DRFEX
$DRSMG
$DRSPN
$DRPUT
$DRREQ
$DRRCV
$DRREX
$DRSRF
$DRRRA
$DRSTL
$DRSTP
$DRSTS
$DRSDV
$DRSTV
$DRELE
$DRUNM
$DRUNS
$DRWSE
$DRWFL
$DRWFS

DRSED
DRPUT
DRSMG
DRRES
DRPUT
DRSPW
DRPUT
DRPUT
DRMAP
DRPUT
DRSED
DRRES
DRSED
DRSST
DRSST
DRCMT
DRMAP
DRRES
DRSUB
DRSED
DRSED

Request and pass offspring information
Request Task
Receive By Reference
Resume Task
Run Task
Specify command arrival AST
Set command line interpreter
Send Data
Send, Request, and Connect
Send data request and pass offspring
control block
Set Event Flag
Specify Floating Point AST
Send message
Suspend
Specify Power Recovery AST
Spawn
Specify Receive Data AST
Specify Requested Exit AST
Send By Reference
Specify Receive-By-Reference AST
Stop for Logical OR of Event Flags
Stop
Stop for Single Event Flag
Specify SST Vector Table for Debugging
Specify SST Vector Table for Task
Unlock group global event flags
Unmap Address Window
Unstop Task
Wait for Significant Event
Wait for Logical OR of Event Flags
Wait for Single Event Flag

EXECUTIVE MODULES

DEVICE DRIVER MODULES
System Device Tables (SYSTB)
•

Contains DCBs, UCBs and SCBs, for devices with
bases.

resident

data

•

Data bases for standard drivers are contained in SYSTB.

•

User can include other device data bases in SYSTB at SYSGEN.

RK05 Driver (DKDRV)
•

Device driver for RK05 disk drives.

•

Contains code for performing I/O to device.

•

Interrupts from RK05 drive cause entry into DKDRV at $DKINT

EXECUTIVE MODULES

Table 3-3

Standard Device Drivers

Driver

Device

DKDRV

RK05 Disk Drives

DMDRV

RK06,RK07 Disk Drives

DBDRV

RP04,RP05,RP06 Disk Drives

DRDRV

RM02,RM03,RM05,RP07,RM80

DLDRV

RL01,RL02 Disk Drives

LPDRV

Line Printer

TTDRV

Terminal

MMDRV

TU16,TE16,TU45,TU77 Magnetic Tape

MTDRV

TU10,TEI0,TS03,TMll Magnetic Tape

MSDRV

TS04 Magnetic Tape

DTDRV

TCll DECtape

DXDRV

RX01 Floppy Disk Drive

DYDRV

RX02 Floppy Disk Drive

DDDRV

TU58 Disk Cartridge

DSDRV

RS03,RS04 Disk Drives

PPDRV

Paper Tape Punch

PRDRV

Paper Tape Reader

CTDRV

TAll Cassette Tape

DFDRV

RS08 Fixed Head Disk Drive

DPDRV

RP02 Di sk Dr i ve

LKDRV

KMC-ll Line Printer, Controller

Disk Drives

FILE SYSTEM OVERVIEW

INTRODUCTION
This module introduces the FILES-II
system.
FILES-II
consists of an on-disk and in-memory data structure. The on-disk
is the same for a number of related operating systems (i.e., lAS,
RSX-IID, etc.).
The in-memory structure is RSX-IIM specific.
This structure is a cache of information which improves the
performance of the file system.

OBJECTIVES
1.

Describe the on-disk and in-memory structures of the
system.

Describe the directory structure used in FILES-II.

Describe how files are accessed on a FILES-II volume.

FILES-II

RESOURCES
1.

RSX-IIM/M-Plus I/O Operations Reference Manual

FILE SYSTEM OVERVIEW

CONCEPTS
FILES-11
•

Method of organizing data on mass-storage media

•

Common to:

RSX-IIM/M-PLUS, RSX-IID, lAS, TRAX, VMS

File system includes:
•

File processing software such as FCS or RMS
Provides easy interface
system

between

user

program

and

file

Allows access data by means of user-defined records
•

Executive code to handle queued I/O requests
Result of QIO directive
Provides synchronization of I/O operations
Determines if I/O operation is file-oriented

•

A device driver to handle primitive I/O operations
Data transfers between the device and memory

•

An ancillary
control
processor,
file-related I/O operations

ACP,

Possible conversion to driver operations

A FILES-II volume may be:
•

Any kind of disk (including floppy disks)

•

DECtape

which

performs

FILE SYSTEM OVERVIEW

PRIVILEGED I NON-PRIVILEGED

I
I
I
I
I
I
I

FCP

!
QIO
DIRECTIVE

-- - - - - ~

-r-

FCS/RMS

DEVICEINDEPENDENT

QIO
DIRECTIVE

.-..

i - - - -

-'-

QIO
DIRECTIVE
SERVICE

EXECUTIVE
I/O
SUBROUTINES

DEVICE INTERRUPT--+

t!
I/O
DRIVER

Figure 4-1

The File System

USER I/O
REQUEST

DEVICEDEPENDENT

USER STATE

- -

SYSTEM STATE

FILE SYSTEM OVERVIEW

Files
Three units of measurement of space on media:
•

Physical blocks
Physically addressable unit
Length dependent on type of media
Usually 512 bytes
RX0l - 128 bytes
RX02 - 128 or 256 bytes
Normally referenced by device driver

•

Log ical blocks
Length equal to 512 bytes
Block numbers unique for volume
Begins at logical block 0
Highest logical block equals volume size minus one
Normally referenced by the file processor (FllACP)

•

Virtual blocks
Used by programmer to access data in files
Length always equal to 512 bytes
Virtual block numbers relative to file
Begins at virtual block 1
Highest virtual block equals file size

FILE SYSTEM OVERVIEW

Files consist of two parts:
•
•

The File Header
The Fi Ie Body

T he File Header

•

Contains description of file
File name
File owner
File characteristics used by FCS and RMS
Information for mapping virtual blocks to logical blocks
on

the

•

Contains data stored by user and any control data appended
the file access method

•

Consists of a number of contiguous groups
(segments)

•

Usually one block long (512.
file processor in use

bytes);

size

depends

The File Body

logical

blocks

FILE SYSTEM OVERVIEW

FILE HEADER BLOCK
OFFSETS TO IDENTIFICATION
AND MAP AREAS
FILE ID
FILE OWNERSHIP AND PROTECTION
INFORMA TION
FILE CHARACTERISTICS
SIZE (BYTES) OF HEADER AREA

HEADER AREA

FILE NAME, TYPE AND VERSION

(DISK
BLOCK
256 WORDS)

DATES OF CREATION AND
REVISION

IDENTIFICATION AREA

SIZE (BYTES) OF IDENTIFICATION
AREA

MAPPING INFORMATION
RETRIEVAL POINTERS
CHECKSUM WORD

Figure 4-2

The File Header

MAP AREA

FILE SYSTEM OVERVIEW

Dump of DB2:r305,306]INTR01.MOD;26 - File ID 7450,60,0
Fi If:~ header
HE,~DER

AREA

H.IDOF
H.MPOF

027
056

H.FNUM!I
C1450, 60)
40:1.
1:305,306]
I:RWED,RWED,RWED,RJ
000 ....
000 --

H + F~::EGl
H.Fl..EV
H.FDWN

H+ FF'I~O
H + UCH,~

H.SCHA
H.UFAT
F • FrfYP
F.RATT
F.RSIZ
F.HIBI\
F.EFBK
F.FFBY

002
R ......'AR
O()2 -FD.CR
102 ..- 66"

H:O L..:OOOO13 .-. 1:L •
H!O L:000013 = 11 •
~~10

.... 200 •

(REST)
000000 000000 000000 000000 000000 000000 000000 000000
000000

IDENTIFICATION AREA
I.FNAM,

I.FTYF',
I • FVEF~

INTROl

I.RVNO
I.RVDT

6
14·- [I[C--8:1.

J.F~VTI

02:50:2:~

I.CRDT

15-0CT-'81
09:46:39

I.CRTI
I.EXDT
t"11~P

.MO[t;26

1:'!,f~EA

()OO

M. E~:;()N
M. EIi:VN
M.EFNlh

000

(0,0)
001
003
002 .... 2.
3:1.4 .... 204.

M.EFSO

M.CTSZ
M .I... BSZ

M.USE
M.MAX

M + F(n~V

SIZE

LBN

1. :1. •

II : 00 t

L: 1 6 ~) 7 ~j 1 = :J. 2 ~:j 9 2 9 •

CHECK~)UM

Example 4-1

The File Header for a Data File

FILE SYSTEM OVERVIEW

Dump of DB2:[305,306JSPY.TSK;16 - File ID 16104,7,0
F i 1 (~ head€-~ l'

HEf-IDER AliEA
027
056

H~IDOF

H+MPOF
H + FNUi'1,
I-L- FSECJ

( L!"d04,7)
40l
/:: 30~) 1I 306::1

H.FLEV
H.FOWN

/-I+FPRO

[RWED,IRWEDyRWEDyRJ

H~UCHA

200 ---

H" SCH(~

000 ..-

LlC -, CON

H.UFAT

F.RTYP
F+RATT

F.RSIZ
F./-IIBK
F.EFBK

F.FFBY
(t\EST ;.

001 - R.FIX
000 -1000 :::: ~)l2.
/-1:0 L:000050 - 40.
/-1:0 L:000051 = 41.

o : : o.

000000 000000 000000 000000 000000 000000 000000 000000
000000

IDENTIFICATION AREA
I • FNl~M!}

I.FTYP!I
Spy

I + FVEFt:
I. RIJNO
I. R'v'DT

14--DEC--Bl
02:50:28

I.RIFfl
I"CRDT
I.CRTI
I.EXDT
tiAr'

0~:5--JUN·--81

14:14:33

AREA
M<-ESON

000

~1 i- EF:VN

000

M. EFNl."
M,-EFSO

(0:10)
001

M+CTSl
M.LBSl

0«3
002 -- 2.
314 -_. 204.

M.USE
M + M,~X
/Vi • RTFt:'~)
~aZE

LBN

40.

H:001 L:172544 -

128356.

CHECt·:;SUM

H.CKSM

Example 4-2

133671

The File Header for a Task Image

FILE SYSTEM OVERVIEW

Retrieval Pointers
•

Defines the correspondence between logical and virtual blocks

•

Contained in the file header:
Maximum:

102 per header

One fragment per retrieval pointer
Maximum file length with 1 block per header:
•

26112 blocks

Four bytes long
One byte: number of virtual blocks in
is 256 blocks.
Three bytes:

segment;

maximum

pointer to first logical block in segment.

NO. BLOCKS - 1
STARTING LBN
( 1 ,3 ) RETRIEVAL POINTER
Figure 4-3

Retrieval Pointer

FILE SYSTEM OVERVIEW

FILE HEADER

FILE BODY
VBN

LBN
,.--------,

301

o
406
RETRIEVAL
POINTERS

302

301

11"--____1406

701

41
Figure 4-4

Mapping Virtual to Logical Blocks

701

FILE SYSTEM OVERVIEW

File Directories
•

Contains information needed to identify and locate files
File name, type and version number
File number (Relative number
file)

fil~

File sequence number (Number of times
used)
•

headers

index

file

header

Two types of directories
Master File Directory (MFD) -- One per volume
User File Directory (UFD) -- As many as desired per volume

•

Naming convention
Name of directory:

xxxyyy.DIR;l

where
xxx is a group number
yyy is a member number
Master File Directory:

000000.DIR;1

User File Directory for UIC:

[6,32]:

FILE 10

FILE SEQUENCE NO.

006032.DIR;1

I--

FILENAME

I--

(RAD50)

5
6
7

FILE TYPE (RA050)

FILE VERSION
Figure 4-5

Directory Record
80

FILE SYSTEM OVERVIEW

FILES-11 VOLUMES
The Standard Files
•

The Index File:

INDEXF.SYS

•

The Bitmap File:

BITMAP.SYS

•

The Master File Directory:

•

The Bad Block File:

•

The System Checkpoint File:

000000.DIR

BADBLK.SYS
CORIMG.SYS

FILE SYSTEM OVERVIEW

The Index File
•

Contains basic structures needed by file system.
Boot Block
Home Block
Index File Bitmap
All File Headers

•

Filespec:
[0,0]INDEXF.SYSil,
File ID/SEQ: 1/1

•

Boot Block
Contains bootstrap code for hardware booting of device
Always virtual block 1 of index file
Always logical block 0 of volume
Written by SAV command when the /WB switch is used
If volume not bootable, contains code to print the
message: THIS VOLUME DOES NOT CONTAIN A HARDWARE BOOTABLE
SYSTEM

•

Home Block
Contains information needed by file system to access
on vol ume
Volume label
Pointer to index file bitmap
Size of index file bitmap
Checksum words to validate data in home block
Always located in virtual block 2 of index file
Located in first good block in sequence
1, 400, 1000, 1400, ••••••
Checksum used to identify homeblock

data

FILE SYSTEM OVERVIEW

•

Index File Bitmap
Allows fast access to unused blocks in index file
Always located beginning in virtual block 3 of index file
One bit per possible file header in index file
Bit is set to indicate if block is in use
Bit clear if block is free
Bit is set if block is in use

•

File Headers
Contained in virtual blocks starting at block 3+n, where n
is the length of the bitmap
First 16 headers are contiguous
Virtual block of header = 2 + m + n
where
n = number of blocks in index file bitmap
m = file number

FILE SYSTEM OVERVIEW

LBN

VBN
1

BOOT BLOCK

HOME BLOCK

INDEX BIT MAP
O=FREE
1=USED

""'."
"'"

1 OR 40 o OR 1000 ...

"'"'"" ~

,."

N IS SIZ E OF INDEX
BITMAP (NO. BLOCKS)

3+N

INDEX
FILE HEADER

4+N

STORAGE BIT MAP
FILE HEADER

5+N

BAD BLOCK
FILE HEADER

.......

6+N

MASTER FILE DIRECTORY
FILE HEADER

......

7+N

CORE IMAGE CHECKPOINT
FILE HEADER

.......

""'~

8+N

......

"'" ."
USER FILE DIRECTORY
FILE HEADER

....

•

•
•
Figure 4-6

Structure of the Index File

FILE SYSTEM OVERVIEW

The Bitmap File
•

Virtual block number 1 contains allocation information used on
RSX-llD

•

Bitmap starts in virtual block number 2 of the bitmap file

•

One bit per logical block on volume

•

Value of each bit indicates status of corresponding block
Bit set - block not allocated to file
Bit clear - block allocated

•

VFY compares clear bits with retrieval pointers

•

Filespec:
[0,0]BITMAP.SYSil,
File ID/SEQ: 2/2

WORD

WORD 1

t~ ~

L BN 15

LBN a

LBN 16

LBN 31
Figure 4-7

••••

The Bitmap File

FILE SYSTEM OVERVIEW

The Master File Directory
•

Directory corresponding to UFD [0,0]

•

Contains entries for the five standard files

•

Contains entries for all UFDs on volume

•

Contains entry for system account file RSXll.SYS

•

Filespec:
[0,0]000000.DIRil,
File ID/SEQ:
4/4

The Badblock File
•

Used to keep bad blocks from being allocated to user files

•

Bad block information created by BAD or entered by the user or
manufacturer allocates blocks to file

•

Filespec:

•

No dynamic badblock handling

[0,0]BADBLK.SYSil, File ID/SEQ:

3/3

MFD

INDEXF

BITMAP

BADBLK

000000

CORIMG

GGGMMM

XXX XXX

SYS

DIR

SYS

DIR

DIR
I

I
FILE MAC

Figure 4-8

I
FILE OBJ

FILE T5K

Two Level Directory Structure

•••

FILE SYSTEM OVERVIEW

The System Checkpoint File
•

Used to checkpo int tasks

•

No space allocated when volume initialized

•

Space allocated by ACS command

•

Al wa ys contig uous

•

Filespec:
[0,0]CORIMG.SYSil,
File ID/SEQ: 5/5

FILE SYSTEM OVERVIEW

FUNCTIONS OF THE FILE SYSTEM
Creating a FILES-11 Volume
•

FILES-II volume created by INITIALIZE command

•

Home block information can be modified by the HOME command

•

Creates five standard files

•

Volume characteristics determined:
Vo 1 ume label
Number of blocks for default file extension
Size of
headers)

index

file

(number

blocks

Number of files on volume
Location of index file
Default protection for files on volume

used

for

file

FILE SYSTEM OVERVIEW

Creating a File
•

Index file bitmap searched for first free block

•

First free block used for file header

•

Bitmap file searched for required number
allocate initial file

•

Entry for new file placed in UFD

free

blocks

CREATE
FILE
HEADER

CREATE
DIRECTORY
ENTRY

ALLOCATE
BLOCKS TO
FILE BODY

MAP VIRTUAL
TO LOGICAL
BLOCKS

USE INDEX
FILE BITMAP
TO ALLOCATE
HEADER

ENTER FILE
NAME INTO
UFO

USE BITMAP
FILE TO
LOCA TE UNUSED
BLOCKS

INITIALIZE
RETRIEVAL
POINTERS

INITIALIZE
FILE HEADER

SET UP FILE
10 IN
HEADER

Figure 4-9

Creating a File

FILE SYSTEM OVERVIEW

Accessing a File
•

By file name - DBl:[10l,10l]DATA.DAT;1
MFD from device
l0ll0l.DIR

mounted

DBl:

searched

for

File ID for l0ll0l.DIR is used to find the file header
Retrieval pointers from header are used find UFD file
UFD is searched for entry for DATA.DAT
File ID for DATA.DAT is used to find the file header
Retrieval pointers from header are used to find file
File is accessed
•

If file ID is known, file header can be accessed without using
directories

INDEX FILE

VBN

-I

1 BITMAP FILE HEADER

1 BADBLOCK FILE HEADER I

-IN-D-E-X-F-I-LE-H-EA-D-E-R--

MFD
INDEXF.SYS;l

~ BITMAP.SYS;l

MFD FILE HEADER

_ _ _ _ _ _ _ _ _t-----~I BADBLK.SYS; 1

10 1 CORIMG FILE HEADER
UFO L1,1] HEADER

11
12
13

UFO [200,200] HEADER

OOOOOO.DIRj 1
CORIMG.DIR; 1
001001.DIRjl
200200.DIRj 1
005006.DIRj 1
~ 101101.DIRjl

UFO [101,101]

ID,SEa,O

A.FTNjl
DATA.DAT;l

1,1,0
2,2,0
3,3,0

0,5,0
11,1,0

4,4,0
5,5,0
6,1,0
7,1,0
0,3,0
10,6,0

~-------~I ~

UFO [101,101] HEADER I .........t - - -...
DATA.DAT;l

DATA.DAT;1 HEADER

.... .

' ... 1

USER FILE DATA

~-------~

Figure 4-10

Accessing a File

FILE SYSTEM OVERVIEW

THE FILE PROCESSOR
File Control Processors
•

Privileged system task which handles file-specific I/O

•

Processes QIO commands queued to its receive queue

•

Several file processors supplied with system
FIIACP - Used for FILES-II disk volumes
MTAACP - Used for magnetic tape volumes
NETACP - Used by DECNET

•

To speed up file operations, dedicate
volumes
)INS $FCPxxx/TASK=DBIFCP
)MOU DK0:/ACP=DBIFCP

appropriate

FCPxxn

FILE SYSTEM OVERVIEW

Logical Units
•

Tasks specify I/O devices by using logical unit numbers.

•

Each logical unit number refers to a unique I/O device.

•

Pointer to an entry of the logical unit table for the task.

•

The logical unit table is in the task header.

•

Each entry is two words long:
Word one is a pointer to the UCB for the device:
Word two is a pointer to a FILES-II window block
is open; and 0 otherwise.

•

FILES-II window block
retrieval pointers.

•

Logical unit
taskbuild.

constructed

•

Logical unit assignments can be changed by:

table

data

REASSIGN command
ALUN$ directive

structure
and

units

used

file

store

assigned

FILE SYSTEM OVERVIEW

TASK HEADER
NUMBER OF LUNs = 6

- - - - - - - - I,

POINTER TO UCB

LUN 1 ~

- - - - - - - -

POINTER TO WINDOW BLOCK IF FILE OPEN

IIiIoo.

LUN 2 ~ rIIiIoo.

POINTER TO UCB

- - - - - - - - - - - - - - - POINTER TO WINDOW BLOCK IF FILE OPEN

LUN 3 ~ r-

- - - - - -

- - - - - - - - - -

IIiIoo.

LUN 4 ~

UNIT

- - - - - - - - - - - - -

- - -

- - - - - - - - - - - - - - - -

IIiIoo.

LUN 5

....
r

LUN 6 ~

....

LOGICAL

- - - - - - - - - - - - - - - - -)
Figure 4-11

The Logical Unit Table

TABLE

FILE SYSTEM OVERVIEW

Data Structures
•

The Volume Control Block (VCB)
Created from information in home block
One VCB per mounted volume
Contains
Transaction count for volume
Logical block number of index file bitmap
Logical block number of storage bitmap
Pointers to other data structures, e.g. FCB

•

The File Control Block (FCB)
Created from file header
One FeB per open file
Conta ins
Logical block number of file header
File number and sequence numbers
File owner and protection code

•

FILES-II Window Block
One window block per accessor to file
Contains
Access privileges of accessor
Retrieval pointers (seven by default)

NOTE
Retrieval pointers in the file header use one
byte for the block count and three bytes for
the disk address; those in the window block
use two bytes for the count and four bytes
for the disk address.

FILE SYSTEM OVERVIEW

V.VCHA

VOLUME TRANSACTION COUNT

V.TRCT

V.TYPE

VOL. CHARACTERISTICS
~

~
~

- - - - - - -

VOLUME TYPE

- - - - - - VOLUME
- - - - - - LABEL
- - - - - - - -(ASCII)
- - - - - - - - - - - - - - - - (SEVEN WORDS)
- - - - - - - - -

- - - - - - - - - - - - -

- -

V.LABL

- - - -

V.PKSR
- - - (FOR ERROR LOGGING)
PACK SERIAL NUMBER

- - - - - - - - - - -

INDEX FILE WINDOW ADDRESS

V.IFWI

V.FCB
CONTROL BLOCK
- - - - - - - - - - - - - - - - FILE
LISTHEAD

Figure 4-12

The Volume Control Block
(pa rt One)

FILE SYSTEM OVERVIEW

V.IBSZ

INDEX FILE BITMAP SIZE

I- - - - - - - -

V.IBLB

INDEX FILE BITMAP LBN

V.SBCL

MAXIMUM NUMBER OF FILES

V.FMAX

V.WISZ

BITMAP FILE CLUSTER

DEFAUL T SIZE OF WINDOW

BITMAP FILE SIZE
V.FIEX

V.LRUC

DEF AUL T FILE EXTENSION

V.SBSZ

V.SBLB

VOLUME OWNER UIC

V.VOWN

VOLUME PROTECTION WORD

V.VPRO

DEFAULT FILE PROTECTION WORD

V.FPRO

- - - - - - - BITMAP FILE LBN

AVAILABLE LRU SLOTS

I - - - - - - - -

V.FRBK

NUMBER OF FREE BLOCKS ON VOLUME
V.FFNU

1ST FREE BLOCK IN INDEX BITMAPI

VOLUME STATUS

RESERVED FOR FUTURE USE

Figure 4-12

The Volume Control Block
(Part Two)

V.STS
V.EXT

FILE SYSTEM OVERVIEW

F.FSQN

POINTER TO NEXT FCB

F.LINK

FILE NUMBER

F.FNUM

FILE SEQUENCE NUMBER

F.FSEQ

FILE SEGMENT

ule OF FILE OWNER

F.FOWN

FILE PROTECTION CODE

F.FPRD

F.SCHA

SYSTEM CHARACTERISTICS
~

F.NLCK

UNUSED

I USER CHARACTERISTICS

F.UCHA

FILE HEADER

F.HDLB

LOGICAL BLOCK NUMBER OF VIRTUAL BLOCK 1

F.LBN

---------------LOGICAL BLOCK NUMBER
- - ----------- - - OF CONTIGUOUS FILE (0 OTHERWISE)

SIZE OF FILE

- - - - - - - - - - - - - - - IN- BLOCKS
NUMBER OF LOCKS
STATUS BITS

NUMBER OF ACCESSES

F.NACS

NUMBER OF WRITE ACCESSES F.STAT

DIRECTORY EOF BLOCK NUMBER

F.DREF

1ST WORD OF DIRECTORY NAME

F.DRNM

POINTER TO EXTENSION FCB

F.FEXT

STARTING VIRTUAL BLOCK NUMBER

F.FVBN

POINTER TO LOCKED BLOCK LIST

F.LKL

WINDOW BLOCK LIST

F.WIN

- - - - - - - - - - - - -OF -THIS- FILE- SEGMENT

Figure 4-13

The File Control Block

FILE SYSTEM OVERVIEW

CONTROL BITS

NUMBER OF ACTIVE MAP ENTRIES W.CTL

RESERVED

W.WISZ

I/O COUNT

W.IOC

FCB ADDRESS

W.FCB

POINTER TO LIST OF LOCKED BLOCKS

W.LKL

WINDOW BLOCK LIST LINKWORD

W.WIN

SIZE OF WINDOW

1ST VIRTUAL

- - - - - - - -

W.VBN

BLOCK MAPPED BY WINDOW

NUMBER OF BLOCKS MAPPED - 1

W.RTjR1ST RETRIEVAL

1ST PHYSICAL BLOCK

- - - - - - - - - - - - - - - -

POINTER

MAPPED BY POINTER

NUMBER OF BLOCKS MAPPED - 1
1ST PHYSICAL BLOCK

- - - - - - MAPPED
- - BY- POINTER
- - - Figure 4-14

ND RETRIEVAL

- - - -

FILES-II Window Block

)

POINTER

FILE SYSTEM OVERVIEW

Mounting a Volume
•

Volume mounted by MOUNT command
Compares the volume label with that specified in the MOUNT
command
Copies homeblock information into VCB
Associates an ACP with the volume

•

Steps in mounting a FILES-II volume:
Volume Control Block is created
VCB is linked from the UCS using U.VCB
Index file is opened
IN MEMORY

ON DISK

VCB

.....
.....

V.IFWI

V.FCB

'--:'"
:~

~DEXFIL~

.....

........

FCB

....
......

'---

...

INDEX FILE
WINDOW

FCB

INDEX
FILE

MFD

UCB

TCB

....
......
XXXACP
U.VCB
U.ACP

Figure 4-15

Mounting a Volume
99

~FDHEAD~

F.HDLB

FILE SYSTEM OVERVIEW

Opening a File
•

Steps in opening a file:
File Control Block or FCB is created.
FILES-II window block is created for file.
FCB is inserted in the FeB queue for volume.
Pointer from
initialized.

logical

unit

table

window

block

•

Shared files have only one FCB but separate window blocks.

•

File system keeps, in memory, a
recently used directories.

list

FCBs

the

This list is called the LRU.
EI iminates need to read directories from disk when file is
accessed.
Least recently used directory is
directory accessed if list is full.

flushed

when

new

Size of LRU list is determined by LRU switch on INI or HOM
command.

100

FILE SYSTEM OVERVIEW

FCB

VCB

.....
V.FCB
V.IFWI

UCB

INDEX
FILE

MFD

FCB
WINDOW BLOCK
INDEX
FILE

TCB
LUT ENTRY

FIIACP

UFO

DBO:
U.VCB
U.ACP

FCB

r-+

IN DOW BLOCK
W.FCB

Figure 4-16

Opening a File

101

....

.... A.DAT;1

FILE SYSTEM OVERVIEW

SYSTB

VCB
FCB

FCB

FCB
USER
FILE

UCB FOR
DKO:
WINDOW
BLOCK
INDEX
FILE
TASK HEADER
TASK A

WINDOW
BLOCK
USER
FILE

TASK HEADER
TASK B

WINDOW
BLOCK
USER
FILE

Figure 4-17

Shared Access

102

SYSTEM GENERATION

INTRODUCTION
The RSX-llM operating system is designed to support a large
variety
of
application
environments and possible hardware
configurations available to the PDP-II processor.
The process
used to adapt the system to these varied conditions is called
System Generation or SYSGEN.
The RSX-llM SYSGEN procedure is designed to allow customizing
of the operating system to be performed in an efficient and
accurate manner. The procedure is run under the control of
supplied indirect command files.
Facilities such as VMR and SAV
are provided to help the user set up his system quickly.

OBJECTIVES
1.

Generate a functioning RSX-IlM system.

Perform the ancillary functions, VMR and
practical system.

SAV,

produce

RESOURCES
1.

RSX-llM System Generation and Management Guide

105

SYSTEM GENERATION

OVERVIEW
SYSGEN Functions
•

Provide support for existing hardware
The processor model (e.g., PDP-ll/44)
Processor options (e.g., memory management, floating-point
processor)
Devices installed on system
Number of controllers and physical units
Vector and CSR addresses for all devices

•

Provide needed software features
Executive options (e.g., directives, 'round-robin')
File system (version of FIIACP)
Resident library support (e.g., FCPRES)
Terminal support (e.g., full-duplex)

107

SYSTEM GENERATION

The SYSGEN Process
•

SYSGEN procedure is contained in three indirect command files
SYSGEN.CMD - First phase of SYSGEN
Assembles Executive
Assembles device drivers
Creates command files to be used in phase two
SYSGEN2.CMD - Second phase of SYSGEN
Taskbuilds the Executive
Taskbuilds the device drivers
Creates needed libraries
Taskbuilds the privileged system tasks
SYSGEN3.CMD - Third phase of SYSGEN
Allows system tasks to be rebuilt

•

Between phase two and phase three, VMR should
the new system
Use VMR command file
procedure

SYSVMR.CMD

applied

the

created

SYSGEN

Can be edited to add desired partitions
Must be edited if system is unmapped
Configure the new system
Set up partitions
Load device drivers
Install system tasks

•

SYSGEN procedure creates saved answer file SYSSAVED.DAT
Contains answers to SYSGEN questions in symbolic form
File can be modified by user for use in later SYSGEN

108

SYSTEM GENERATION

Types of SYSGEN
•

SYSGEN can be performed using
distribution kit

the

base-line

system

the

Called a standalone SYSGEN
System is dedicated to SYSGEN, no other users
•

SYSGEN can be performed using an existing RSX-IIM system
Called an on-line SYSGEN
Other users can use the system during most of
process

•

the

SYSGEN

MCR commands can be inhibited during the SYSGEN process
Called a PREPGEN
Saved answer file can be corrected/modified for use
in live SYSGEN

109

later

SYSTEM GENERATION

New Features for Version 4.0
•

Autoconfigure option determines correct hardware configuration
Processor type
CSR and vector addresses

•

Standard feature Executive option produces a mapped system
Most software options
Supports all layered products

•

Improved saved answer file support
Saves responses to Phase II questions
Supports named input and output saved answer files
Can create a single saved answer file for Phase I and II

•

A minimum of 28K words of memory is required for SYSGEN

•

Directive commons increase POOL size

•

Taskbuild .CMD and .ODL files are dynamically created

•

A PLAS overlaid FCS resident library may be selected

•

Either EDI or EDT may be selected for editing SYSGEN files

•

Phase I can chain to Phase II without a break

110

SYSTEM GENERATION

PREPARING FOR SYSGEN
Distribution Kits
•

There are several different kits available
'Big Disk' distribution kit for RP04/05/06/07, RM02/03/05,
RM80 and RA80
RK06/07 distribution kit
RL0l/02 distribution kit
RK05 distribution kit

•

Distribution kit must be copied before SYSGEN using DSC
Version 3.2 DSC cannot be used unless V 4.0 patch has been
applied (see release notes)
Copy of standalone DSC supplied with kit can be used

Autopatch
•

A collection of patches to the released system
Issued at regular intervals
Also may include patches to layered products

•

Must always be applied to released
patches

•

Uses an indirect command file to generate patched system

III

version

without

SYSTEM GENERATION

Individual Patches
•

Patching source files
Used for Executive, driver and MCR patches
Use Source Language Input Program (SLP)
Create SLP command file
Invoke SLP with command file
For MACRO-II sources, output for SLP must be:
Assembled
Task-built
Integrated into system (Method
patched)

depends

component

Patching object files
Used for patching utilities
Use Object Module Patch Utility (PAT)
Create MACRO-II source file for correction
Assemble correction file
Apply correction to old object file using PAT
Output from PAT must be:
Task-built
Reinstalled into the system
•

Patching task image files
Infrequently used for operating system patches
Frequently used for patching layered products
Use Task/File Patch Program (ZAP)
Create ZAP command file
Invoke ZAP to apply patches to task image file

•

Patches supplied by DIGITAL are cumulative
Apply a patch only
previous patches

you

have

Unless the patch states otherwise,
recent version of the component
112

already
apply

applied

patch

all
most

SYSTEM GENERATION

DETAILS OF SYSGEN

Phase 1
There are seven sections in Phase 1
Setup - How SYSGEN is to be run
Target Configuration - The environment for which the
SYSGEN is being performed
Host Configuration -

The system on which SYSGEN is
being run

Executive Options - What features are desired in the new
system
Terminal Driver - Which type of terminal driver and which
features are desired
System Options - Which file processor, CLI support, and
POOL monitoring support is desired
peripheral Options -

Specification of devices, controllers
and their vectors, and CSRs

After questions have been answered, the Executive and
are assembled

113

drivers

SYSTEM GENERATION

Phase 2
There are eight sections in Phase 2
Setup - How SYSGEN Phase 2 is to be run
Library Commons Creation - Modifies SYSLIB, creates other
libraries used in taskbuilding
system tasks
Executive Taskbuild - Creates system images RSXIIM.TSK,
EXCOMI.TSK and EXCOM2.TSK
System Image Creation -

Creates RSX11M.SYS from RSX1IM.TSK

Full-Duplex Terminal Driver Taskbuild - Creates the fullduplex driver if
selected
Loadable Driver Taskbuild - Creates all drivers not built
into the Executive
Privileged Task Taskbuild - Builds privileged system tasks
System VMR - Modifies RSX11M.SYS, creating partitions,
installing tasks, etc.

114

SYSTEM GENERATION

Phase 3
•

Optional - May be performed when and as often as desired

•

Used to build optional tasks not included in distribution kit

•

Used to rebuild supplied tasks to:
Change defaults
Incorporate support
big-buffering

for

ANSI

magtape

and/or

FCS

Use a resident FCS library
•

Used to rebuild tasks after patching

•

VMR must be used to remove and install new versions
installed in the system image

115

tasks

SYSTEM GENERATION

EXECUTIVE OPTIONS
Standard Feature Executive
•

Allows the generation of
features

•

Requires a mapped system

•

Provides the following:

system

supporting

DBMS-II support
FILES-II ACP support
RMS support
Nonresident task support
Loadable task loader
Directive commons
Memory management directives
All other Executive directives
Address checking support
I/O rundown support
Multiuser support
ANSI Magtape support
Loadable driver support
AST support
20K word Executive
Error logging
Powerfail recovery
User written driver support
System controlled partitions
Round-robin scheduler and disk swapping
Software write lock support
Queue manager
Shuffler
Crash dump support
Full-duplex terminal driver
DCL and two user written CLls
POOL monitoring
PLAS resident FCS
'MIDDLE' FIIACP

116

all

standard

SYSTEM GENERATION

The Terminal Driver
•

Two possible terminal drivers:
Half-duplex driver
Full-duplex driver

•

Half-duplex driver comes in three forms:
Baseline
Tailored
Tailorable

•

The baseline half-duplex driver
Minimum terminal driver
Not available with multiuser systems

•

The tailored half-duplex driver features include:
Automatic carriage/line feed
Write with CTRL/O cancellation
Breakthrough write
CTRL/R rewrite
Get multiple characteristics
Get terminal driver options
Read after prompt
Read with no echo
Read with special terminator
CRT rubout support
User terminal input buffering

•

The tailorable driver
terminal options

allows

•

The full-duplex driver includes:

selection

all

possible

Task checkpoint during input
Passes form feeds directly to the terminal
Supports unsolicited input
character
AST
(requires
Executive AST support)
Hold screen mode
LA 3" P s u ppo r t
Device independent cursor positioning
Plus features included in the tailored half-duplex driver
•

Full-duplex driver requires
driver support

117

mapped

system

with

loadable

SYSTEM GENERATION

Choosing a File Processor
•

Several different versions of FllACP available

•

Versions differ in amount
internal buffers

number

•

See discussion in module 'I/O processing' for descriptions
available ACPS

118

overlaying

and

SYSTEM GENERATION

USING VMR
Overview of VMR

•

Can perform many of the same tasks as MCR
Define partitions
Load drivers
Install tasks

•

Commands operate on system image file

•

Used to perform system initialization for needed features
Set up partitions
Load standard drivers
Install system tasks and utilities

119

SYSTEM GENERATION

On a Mapped System
•

SYSGEN generates a VMR command file which should be edited
produce the system desired

•

All needed partitions are defined

Driver partition
Directive commons
All leftover space goes in GEN
•

Commands for partitions needed by application
added to the command file

•

All DEC-supplied drivers are loaded

•

All important system tasks are installed

tasks

GEN
FCPPAR
FCSRES
SYSPAR

321400
275400
242700
232600

DRVPAR
TTPAR
LDRPAR
EXCOM2
EXCOM1

206200
146200
143400
134500
120000

EXECUTIVE
Figure 5-1

Partition Structure on Mapped Systems
120

must

SYSTEM GENERATION

On an Unmapped System
•

Modification of SYSVMR.CMD recommended on unmapped system
It is not possible for SYSVMR.CMD
partition structure

•

create

optimal

For unmapped 16K to 24K systems, VMR:
Creates partition GEN and installs all tasks into it
Length is always 40000 bytes
Creates partition SYSPAR
Length is 1000 bytes if FCPMIN chosen
Length is 1200 bytes if FCPSML chosen
Creates partition SPLPAR if PRT chosen
Length is 10400 bytes

•

For unmapped 24K to 28K systems, VMR:
Creates partition GEN and installs all tasks into it
Length is always 40000 bytes
Creates partition SYSPAR
Length is 1000 bytes if FCPMIN chosen
Length is 1200 bytes if FCPSML chosen
Creates partition PAR14K
Length is 70000 bytes
Creates partition SPLPAR if PRT selected
Length is 10400 bytes

121

SYSTEM GENERATION

SPLPAR

SYSPAR

130000

PAR 14K ~ - - - - - - - - - 100000
GEN
-..

40000

EXECUTIVE

Figure 5-2

Partition Structure on Unmapped 24K to 28K Systems

122

SYSTEM GENERATION

SPLPAR

__________~100000

SYSPAR
GEN

__________~40000
EXECUTIVE

________________~O

Figure 5-3

Partition Structure on Unmapped 16K to 24K Systems

123

SYSTEM GENERATION

SAVING THE NEW SYSTEM
•

Copies the current system image into
from which the system was booted

the

system

image

•

Used to make a system hardware bootable

•

System must be saved before compressed by DSC or BRU

•

Requirements for saving a system

file

SAV must run from CO:
Error logging is not active
All tasks are installed from LB:
No checkpoint files are active
No volumes are mounted except the load device
The load device can be successfully dismounted
No tasks have outstanding I/O
No task is connected to interrupts
All drivers, active tasks and fixed
the saved area of memory
•

tasks

reside

Saving a system
Lowest part of memory copied into buffer in SAV task
Secondary bootstrap program loaded into low memory
Special driver used to load system to and from disk
Cannot use interrupts
Same special drivers used by SAV and BOOT

124

within

SYSTEM GENERATION

Can create a bootstrap program within the volume bootblock
Reads in first block in system image file
Transfers control to secondary bootstrap in block just
loaded into memory
Before writing system image to
block number in TCB into file ID

disk,

converts

When system booted, file IDs in TCBs converted
logical block number

logical

back

SPECIAL DRIVER

SAVE
TASK

-------

STACK

2010

SYSTEM IMAGE
BOOTSTRAP

------SPECIAL DRIVER
------o

Figure 5-4

Saved System Image

125

into

PHYSICAL AND VIRTUAL MEMORY

INTRODUCTION
The most important resource managed by an operating system is
physical memory.
To manage memory, an operating system must
define subdivisions of memory, allocate space to tasks, and
optimize memory use.
This module examines the data structures
used to perform these tasks.
Since the PDP-II uses l6-bit words, only 32K words of
physical memory can be addressed unless some form of address
relocation is provided.
On the PDP-II, the
memory
KT-ll
management hardware provides the mechanism for relocation. This
module also explains the hardware and processing used.

OBJECTIVES
1.

Diagram the data structures used by the Executive
physical memory.

List the steps in checkpointing a task.

Describe the memory management hardware.

129

control

PHYSICAL AND VIRTUAL MEMORY

CONCEPTS
Physical Addresses
•

A contiguous series of word addressable hardware locations

•

Defines main memory and peripheral device registers

Virtual Addresses
•

Set of addresses used within a task

•

Program counter is a l6-bit register
User task can reference addresses
octal

between

Virtual addresses are local to a task

Unmapped Systems
•

32K words of addressing space

•

Maximum physical memory is 28K words

•

Programs built for specific memory location

•

No memory protection

131

and

177777

PHYSICAL AND VIRTUAL MEMORY

177777

160000

1/0 PAGE

USER
AREA
28K
WORDS

000000

EXECUTIVE
(20K WORDS
MAXIMUM)
Figure 6-1

Typical Unmapped System

132

32K
WORDS

PHYSICAL AND VIRTUAL MEMORY

Mapped Systems
•

KT-ll hardware is present

•

Two types of mapped systems
18-bit addresses
128K words of addressing space
124K words of physical memory
22-bit addresses
2048K words of addressing space
1920K words of physical memory

•

16-bit virtual address converted to
addresses

•

Virtual addresses range from 0 to 32767

•

Relocation and memory protection provided

133

18-

22-bit

physical

PHYSICAL AND VIRTUAL MEMORY

777777
760000

I/O PAGE

USER
AREA
124K
WORDS

000000
Figure 6-2

128K
WORDS

EXECUTIVE
(20K WORDS
MAXIMUM)
Typical Mapped System with IS-bit Addressing

134

PHYSICAL AND VIRTUAL MEMORY

17777777

17760000
17757777

16760000

I/O PAGE
UNIBUS MAPPING
REGISTERS
(124K WORDS)

2048K

USER
AREA

WORDS

1920K
WORDS

00000000
Figure 6-3

EXECUTIVE
(20K WORDS
MAXIMUM)

Typical Mapped System with 22-bit Addressing

135

PHYSICAL AND VIRTUAL MEMORY

MEMORY MANAGEMENT

Overview
•

Basic functions
Perform memory relocation/mapping
Provide extended memory addressing capability

•

Task is mapped in pages
Page length is from 1 to 128 memory blocks
Memory block is 32 words in length (100 octal bytes)

136

PHYSICAL AND VIRTUAL MEMORY

Memory Management Hardware
•

Several sets of relocation registers:
(APRs)

•

Each APR consists of two 16-bit words

Active

Page

Registers

Page Address Register (PAR)
Contains a physical memory address
in units of 32
words memory blocks
Used to relocate 4K words of virtual memory (one page)
Page Descriptor Register (PDR)
Contains the size of the virtual memory
relocated
Provides control of access rights

block

•

Every mapped system contains at least two sets of eight APRs
KERNEL Mode APRs
USER Mode APRs

•

Larger processors have more APRs
APRs for KERNEL and USER mode Instruction and Data space
Supervisor mode Instruction and Data space APRs

•

The Processor Status Word

•

Four memory management registers (MMR0, MMR1, MMR2, and
control processor use of memory management

(PS) determines the APRs in use

MMR0 - Error flags
Page number whose reference caused error
Other status flags
MMR1 - Only on 11/44 and 11/70
Records any autoincrement/decrement of
general purpose registers
MMR2 - The Virtual Address Program Counter
MMR3 - Only on 11/44 and 11/70
Enables/disables
Use of D space APRs
22-bit mapping
UNIBUS mapping

137

MMR3)

PHYSICAL AND VIRTUAL MEMORY

ABORT -NON RESIDENT
ABORT -PAGE }
LENGTH ERROR

t J

••

•

A•

. .

ABORT -READ ONLY}
ACCESS VIOLATION
TRAP-MEMORY MANAGEME NT
NOT USED - - - - NOT USED - - - - ENABLE MEMORY MANAGEM ENT TRAP
MAINTENANCE MODE - INSTRUCTION COMPLETED
PAGE MODE - - - - PAGE ADDRESS SPACE I/O
PAGENUMBER--------------------------------------~

ENABLE RELOCATION - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -....

MEMORY MANAGEMENT REGISTER #0 (MMRO)

AMOUNT CHANGED
(2'S COMPLEMENT)

MEMORY MANAGEMENT REGISTER # 1 (MMR 1)

I I I

MODE

IMMR3
17772516

ENABLE UNIBUS MAP - - - - - - - -....
ENABLE 22-BIT MAPPING
KERNEL

SUPERVISOR - - - - - - - - - - - - - - - - - - - - -.....
USER

------------------------~

MEMORY MANAGEMENT REGISTER #3 (MMR3)
Figure 6-4

Registers Used by Memory Management

138

PHYSICAL AND VIRTUAL MEMORY

15
PAGE ADDRESS FIELD (PAF)

THE PAGE ADDRESS REGISTER
APR
15 14

PA,GE

~EN~TH ~IEL~ (P~F) I A I w I

I I A~F I
ED

THE PAGE DESCRIPTOR REGISTER
ACF - ACCESS CONTROL FIELD
ED - EXPANSION DIRECTION

~ } - ACCESS INFORMATION BITS
PLF - PAGE LENGTH FIELD
Figure 6-5

Active Page Registers

139

PHYSICAL AND VIRTUAL MEMORY

PHYSICAL MEMORY

4K WORDS 473400
PAR
NUMBER

VIRTUAL
ADDRESSES

PARs

7
6
5
4
3
2
1
0

160000-177777
140000-157777
120000-137777
100000-117777
060000-07",777
040000-057777
020000-037777
000000-017777

002300
002100
000000
000166
000000
003242
004734
004534

4K WORDS 453400

4K WORDS 324200

4K WORDS 230000
4K WORDS 210000

4K WORDS 16600

Figure 6-6

Page Address Registers

140

PHYSICAL AND VIRTUAL MEMORY

Software Use of Memory Management
•

RSX-llM uses KERNEL and USER instruction space APRs

•

KERNEL APRs are loaded so that
APRs 0 through 3 or 4 point to Executive code and data

4 APRs for 16K word Executives
5 APRs for 20K word Executives
APR 7 points to the I/O page
Other APRs are dynamically mapped as needed
•

User tasks are mapped using USER APRs
If task does not map to the Executive
APRs are used consecutively starting at APR 0
If task maps to the Executive
APRs 0 through 3 or 4 are the same as the KERNEL
APRs 0 through 3 or 4
APR 7 points to the I/O page
Other USER APRs a.re used to map the user task

141

PHYSICAL AND VIRTUAL MEMORY

LIBRARY

---USER PARs

7
6
5
4
3
2
1
0

004000
005622
005422
000000
000000
003142
002742
002542

COMMON
(POSITION
INDEPENDENT)

}

4K
WORDS

TASK

---IMAGE

----

Figure 6-7

6K
WORDS

(NON-POSITION
INDEPENDENT)

12K
WORDS

Use of Memory Management by a Nonprivileged Task

142

PHYSICAL AND VIRTUAL MEMORY

{001600 - 16-BIT
007600 - 18-81T
177600 - 22-81T
I/O PAGE

}

4K
WORDS

KERNEL PARs

6
5
4

000000
000000

000600
000400
000200
0000

2
1

4K WORDS

16K WORD
EXECUTIVE

{
Figure 6-8

20K
WORDS

OOOOOO - 16K EXECUTIVE
001000 - 20K EXECUTIVE

Use of Memory Management by the Executive

143

PHYSICAL AND VIRTUAL MEMORY

I/O PAGE

KERNEL
PARs

7
6 ....----1....------1
5
4 ....-+-t-------1
3
2

~~t-------+~

USER
PARs
PRIVILEGED
TASK

- - - -r--I-------J..-----J 5

4
3
t--------t
2
t--------i
1

t--------t

7
6
t---------I

~------t

~-------'

'----Io+---~

EXECUTIVE

COPIED FROM USER PARs
WHEN TASK SWITCHES TO KERNEL MODE

Figure 6-9

Use of Memory Management by a privileged Task

144

PHYSICAL AND VIRTUAL MEMORY

ALLOCATING PHYSICAL MEMORY
Partitions

Task Partitions
•

Controlled by user

•

May be divided into subpartitions

•

May be built to run
subpartitions

•

Controlled by busy word P.BUSY in the PCB of the main partiton

main

partition

one

the

Common Partitions
•

Used for shared data or code

•

Linked to task statically by taskbuilder
using memory management directives

dynamically

Device Partitions
•

Pseudo-areas whose addresses overlay the I/O page

•

Allow nonprivileged tasks to access the I/O page

System-Controlled Partitions
•

Used to hold executable tasks,
regions

•

Space allocated as needed by the Executive

•

Tasks loaded into dynamically created subpartitions

145

device

drivers,

and

dynamic

PHYSICAL AND VIRTUAL MEMORY

PCB OF 1ST
sUBPARTITION

PCB OF
MAIN PARTITION

P.sUB

P.SUB

I-+01010000)10000000 P.BUSY

PCB OF 2ND
sUBPARTITION

P.MAIN
01000000101000000 P.BUSY

PCB OF 3RD
sUBPARTITION

P.SUB
P.MAIN

00000000100100000 P.BUsy

P.sUB = 0
P.MAIN
00010000100010000 P.BUSY

V
MAIN PARTITION
NOT BUSY

2ND SUBPARTITION
NOT BUSY

1ST SUBPARTlTlON
BUSY

Figure 6-10

V
3RD SUBPARTITION
BUSY

Subpartitions of a Task Partition

146

PHYSICAL AND VIRTUAL MEMORY

The Partition Wait Queue
•

Linked list of TCBs of tasks waiting for space in partition

•

Ordered by descending task priority

•

When TCB is placed in wait queue of
partition, subpartition PCB is created
partition list

•

First task in queue is allocated space before others

147

system controlled
but not linked to

PHYSICAL AND VIRTUAL MEMORY

-=-

P.LNK
P.SUB
P.MAIN

--.......

P.WAIT

I .........

--....

.........

P.LNK

,..-

----

P.SUB=O

T.LNK

T.LNK=O

.....

T.PCB

WAIT QUEUE OF A
USER CONTROLLED
MAIN PARTITION
WITH ONE
SUBPARTITION

T.PCB

P.MAIN

T.LNK

T.PCB

L..

T.LNK

-=r
. T.LNK=O

P.LNK

...

P.SUB
P.MAIN
~ P.WAIT-

...- - •
~

..
-.

P.SUB=O
P.MAIN

.. ..
~

T.PCB

P.SUB=O
P.MAIN

T.PCB

P.SUB=O
P.MAIN

•
P.LNK=?
P.SUB=O
P.MAIN

""=

V-

TCB'S OF WAITING TASKS ARE CHAINED ACCORDING
TO THE RUNNING PRIORITY OF THE TASKS IN
DESCENDING ORDER

Figure 6-11

The Partition Wait Queue

148

WAIT QUEUE OF A SYSTEM
CONTROLLED PARTITION
WITH ONE TASK
ALREADY RESIDENT

PHYSICAL AND VIRTUAL MEMORY

USING PHYSICAL MEMORY

Loading Tasks
•

Task TCB placed in loader queue after space allocated

•

Loading performed by loader task, LOADR

•

Loader task uses loader queue to decide
next

which

task

load

Utility link word, T.LNK, used to link TCBs in queue
Location T.RCVL in the loader TCB is the queue listhead
•

Steps in loading:
Executive places TCB of task to be loaded
queue (LOADRs receive queue)

the

loader

Executive unstops the loader
Loader scans queue and loads task
When queue is empty, loader calls $STPCT to stop itself

149

PHYSICAL AND VIRTUAL MEMORY

Checkpointing
•

Task is copied from memory to space on a disk volume
Allows a higher priority task to execute
Copied either to a reserved area in task image file or
a system checkpoint file

files

are

Reserved area only used if
full
•

system

checkpoint

Steps in checkpointing a task
Test to see if task should be checkpointed
Initiate the checkpoint operation
Allocate checkpoint space and write the task to disk

TEST IF TASK SHOULD
BE CHECKPOINTED

r~----------~,I\-~------------~

......

INITIATE
CHECKPOINT

WAlT FOR
1/0
COMPLETION

DON'T
CHECkPOINT
TASK

ALLOCATE SPACE
IN SYSTEM
CHECKPOINT FILE

r-:-Lr-:I

~~
PLACE TCB
IN LOADER
QUEUE

Fig ure 6-12

UNSTOP
LOADER

Steps in Checkpointing a Task

150

CHECKPOINT
TASK

PHYSICAL AND VIRTUAL MEMORY

POINTER TO NEXT CHECKPOINT PCB

o P.LNK

UCB ADDRESS OF CHECKPOINT DEVICE

2 P.PRI
4 P.NAM

LBNOF CHECKPOINT FILE

6
POINTER TO NEXT CHECKPOINT SUBPARTITION CB

10 P.SUB

POINTER TO CHECKPOINT MAIN PARTITION CB

12 P.MAIN

RELATIVE BLOCK NO. WITHIN CHECKPOINT FILE

14 P.REL

SIZE OF CHECKPOINT TASK (IN DISK BLOCKS)

16 P.SIZE

CHECKPOINT PARTITION CONTROL BLOCK
Figure 6-13

System Checkpoint Files:

151

The Checkpoint PCB

PHYSICAL AND VIRTUAL MEMORY

SCF LPT~
--.

P.LNK

P.SUB
P.MAIN

...
--.

P.SUB
P.MAIN

CHECKPOINT FILE
WITH 2 CHECKPOINTED

TASKS IN IT

T.CPCB

~ P.LNK=O

---

P.SUB=O
P.MAIN

Figure 6-13

CHECKPOINT FILE
CURRENTLY NOT USED

System Checkpoint Files:

152

PCB Linkages

PHYSICAL AND VIRTUAL MEMORY

Shuffling
•

Consolidates holes in a system-controlled partition

•

Shuffling performed by shuffler task -

•

Performed in two passes over a system-controlled partition

SHUFL

Shuffler Pass One

•

Partition list searched, from
partition

•

If task is
in wait queue of
shuffle operation is initiated

•

Shuffle operation:
Find next hole

$PARHD,

for

system-controlled

partition,

(first?)

Find region following hole
Determine if region is shufflable
If shufflable, checkpointable and stopped, or
MCR BLOCK command, task is checkpointed

blocked

If shufflable, move region and contents to bottom of hole
When all regions have
reallocate space
•

been

shuffled,

invoke

$NXTSK

Nonshufflable regions
Loaded device drivers
Tasks connected to interrupt vectors
Tasks fixed for parity errors
Tasks with long outstanding I/O (did not complete
second)

1/2

found

and

Dynamic regions
If nonshufflable region is found, next hole is
process continues
•

If pass one completes and the
empty, pass two is invoked.

153

partition

wait

queue

not

PHYSICAL AND VIRTUAL MEMORY

Shuffler Pass Two

•

Attempts to gain space by finding a contiguous
holes and lower priority checkpointable tasks

•

Checkpoint operations initiated by calls to $ICHKP

•

When checkpointing is complete, pass one is rerun

BEFORE
SHUFFLING
SYSTEM
CONTROLLED
PARTITION

sequence

AFTER
SHUFFLING

SHUFFLABLE
TASK

FREE

FREE
SHUFFLABLE
TASK

FREE
NON-SHUFFLABLE~

______________. .~

TASK

FREE
SHUFFLABLE
TASK

FREE

FREE
SHUFFLABLE
TASK

FREE
SHUFFLABLE
TASK
Figure 6-14

Shuffling Tasks

154

PHYSICAL AND VIRTUAL MEMORY

USING VIRTUAL MEMORY

Attaching
•

Makes region available to attaching task

•

Steps in attaching to a region:
An Attachment Descriptor Block (ADB)

is created

ADB is linked to the PCB for the region using A.PCB in the
ADB, and P.ATT in the PCB
ADB is linked to the TCB for the task using A.TCB
ADB, and T.ATT in the TCB
ADB is linked into the ADB list for
A.PCBL in the ADB

A.IOC 1

A.MPCT 7

the

partition

using

ADB is linked into the ADB list for the task using
in the ADB

A.TCBL

PCB ATTACHMENT QUEUE THREAD WORD

o A.PCBl

1/0 COUNT THROUGH THIS DESCRIPTOR

the

PRIORITY OF ATTACHED TASK

A.PRI

TCB ADDRESS OF ATTACHED TASK

A.TCB

TCB ATTACHMENT QUEUE THREAD WORD

A.TCBl

MAPPING COUNT OF TASK THROUGH THIS DESCRIPTOR

1 STATUS BYTE

PCB ADDRESS OF ATTACHED TASK

ATTACHMENT DESCRIPTOR BLOCK
BIT

MASK

AS.DEL - TASK HAS DELETE ACCESS (1=YES)

AS.EXT - TASK HAS EXTEND ACCESS (1 =YES)

AS.WRT - TASK HAS WRITE ACCESS (1=YES)

AS. RED - TASK HAS READ ACCESS (1 =YES)

A TT ACHMENT DESCRIPTOR STATUS BITS
Figure 6-15

The Attachment Descriptor Block

155

10 A.STAT
12

A.PCB

PHYSICAL AND VIRTUAL MEMORY

....

TCB
T.PCB
-

T.ATT

TASK
HEADER
WINDOW
BLOCK 0

::
...:..

ADB

A.TCBl

ADS

-----

PCB
OF
TASK
REGION
-

PCB
OF
CREATED
REGION

WINDOW
BLOCK 1
Figure 6-16

P.ATT -

Attaching a Task to a Region

156

PHYSICAL AND VIRTUAL MEMORY

Mapping
•

Task virtual address window block contains information
to load APRs to allow access to physical region

•

Task is mapped to a region if a window
needed access information for the region

block

needed

contains

the

Pointers to the PCB and ADB for the region
High and low virtual address limits for the region
Window size and offset in the physical region in
blocks

word

Number of APRs needed for the window and PDR information

157

PHYSICAL AND VIRTUAL MEMORY

POINTER TO NUMBER OF WINDOW BLOCKS

....
.......

NUMBER OF WINDOW BLOCKS

r ~----------PCB ADDRESS

W.BPCB

LOW VIRTUAL ADDRESS LIMIT

W.BLVR

~----------HIGH VIRTUAL ADDRESS LIMIT

~----------WINDO
BLOCK

ADB ADDRESS

H.WND

~-----------

------------

W.BHVR
W.BATT

WINDOW SIZE (32 WORD BLOCKS)

W.BSIZ

OFFSET INTO PARTITION (32 WORD BLOCKS)

W.BOFF

;;;-

~ N~;;;
- ;;;S-:;:-;D~~;;;
- W.BNPD/W.BFPD
....
_ _ _P;;S
_,
...1..
______

>
WINDO
BLOCK

CONTENTS OF LAST PDR

W.BLPD

'Figure 6-17

Task Virtual Address Window Blocks

158

PHYSICAL AND VIRTUAL MEMORY

TCB
T.PCB
I--

T.ATT -

ADB

A.TeBl

TASK
HEADER
WINDOW
BLOCK 0

-=.

ADB

-- --~

PCB
OF
TASK
REGION

1= L.
-

WINDOW
BLOCK 1

Figure 6-18

---

---..

P.ATT -

PCB
OF
CREATED
REGION
~

P.ATT -

Mapping a Task Address Window to a Region

159

TASK MANAGEMENT

INTRODUCTION
The basic unit of executable code under RSX-lIM is the task.
Most tasks are user written, but some are system-supplied, such as
the task-loader, MeR, etc.
The Executive must manage
the task
scheduling and allocate needed
resources
to requesting tasks.
This module describes the techniques used to manage tasks.

OBJECTIVES
1.

Describe the content and functions of the
and task header.

task

label

blocks

Diagram the data structures used to manage task scheduling.

Describe the process of task termination.

RESOURCES
1.

RSX-I1M System List and Data Structures

RSX-11M/M-PLUS Executive Reference Manual

163

TASK MANAGEMENT

THE TASK IMAGE
The Task Image File
•

Created by the taskbuilder

•

Includes: label block group, checkpoint area (optional), task
header, and task image

The Label Block Group
•

Label block 0
Task and resident library data
Used to set up TCB and task addressing windows in header

•

Label block 1
Table of LUN assignments for LUN 1 through LUN 128
Used to create Logical Unit Table(LUT)

•

in header

La bel b 10 c k 2
Continuation of Table of LUN
through LUN 255 (if needed)

assignments

for

LUN

129

Used to create LUT in header
•

Label block 3
Segment load list (optional)
Resident libraries that contain memory resident overlays

The Checkpoint Area
•

Used to provide checkpoint space when no
the system checkpoint files

•

Size equal to size of header plus the task image

165

space

available

TASK MANAGEMENT

LABEL BLOCK 0 - TASK AND
RESIDENT LIBRARY DATA
LABEL BLOCK
GROUP

LABEL BLOCK 1 - TABLE OF
LUN ASSIGNMENTS
LABEL BLOCK 2 - TABLE OF
LUN ASSIGNMENTS (OPTIONAL)
LABEL BLOCK 3 - SEGMENT
LOAD LIST (OPTIONAL)

CHECK POINT
AREA

TASK HEADER FIXED PART
TASK HEADER VARIABLE PART
ROOT SEGMENT

TASK HEADER

SEGMENT TABLE
AUTOLOAD VECTOR

TASK IMAGE
OVERLAY SEGMENTS
(TASK-RESIDENT
OVERLA Y DATA BASE)

REGION DESCRIPTOR
WINDOW DESCRIPTORS
SEGMENT DESCRIPTORS

Figure 7-1

Task Image File

166

TASK MANAGEMENT

The Task Header
•

Consists of two parts:

•

Fixed part contains

fixed and variable

Event Flag mask word and address
Initial values for PS, PC and SP
Low-Core context: $DSW, and inpure storage area addresses
for FCS, FORTRAN, etc.
Pointers to specific areas within the variable part
•

Variable part contains
Window blocks
Logical unit table
Task context

•

Window Block
Describes task mapping
Associates window with region
Contains pointer to PCBs of regions used by task
Pointers loaded at task installation
Used to load APRs for task
Initialized when task is installed

•

Logical Unit Table
Contains a two word entry for each logical
the task

unit

used

Word one: address of the UCB of the device assigned
to the logical unit
(UCB address loaded at task
installation)
Word two:
open file

address of the FILES-II window block of

167

TASK MANAGEMENT

The Task Image
•

Task code

•

Overlay information
Autoload vectors
Region and window descriptors for memory-resident overlays
Segment descriptors

I
I
I

I
I

ADDRESS OF EVENT FLAG CONTEXT
ADDRESS OF FLOATING-POINT CONTEXT
POINTER TO NUMBER OF WINDOW BLOCKS

H.DSW}

DIRECTIVE STATUS WORD
ADDRESS OF FCS IMPURE STORAGE
ADDRESS OF FORTRAN IMPURE STORAGE
TASK HEADER FIXED PART

ADDRESS OF OVERLAY IMPURE STORAGE
ADDRESS OF IMPURE VECTORS
MAILBOX LUN

T ASK HEADER ,VARIABLE PART

1 SWAPPING PRIORITY

UNUSED
RESERVED
RESERVED
RESERVED
HEADER GUARD WORD POINTER
NUMBER OF LUNS

Figure 7-2

The Task Header:

168

40 H.EFSV
42 H.FPSA
44 H.WND
46
50 H.FCS
52 H.FORT LOW-CORE
CONTEXT
54 H.OVLY
56 H.VEXT
60 H.SPRIIH.NML
62
64
66
70
72 H.GARD
74 H.NLUN

Fixed Part

TASK MANAGEMENT

H.LUN

TASK HEADER FIXED PART

I LUN TABLE (2 WORDS PER LUN)
NUMBER OF WINDOW BLOCKS

OFFSETS

PARTITION CONTROL BLOCK ADDRESS

W.BPCB

LOW VIRTUAL ADDRESS LIMIT

W.BLVR

HIGH VIRTUAL ADDRESS LIMIT

W.BHVR

ADDRESS OF ATTACHMENT DESCRIPTOR

W.BATT

WINDOW SIZE (IN 32-WORD BLOCKS)

W.BSIZ

OFFSET INTO PARTITION (IN 32-WORD BLOCKS)

W.BOFF

NUMBER OF PDRS TO MAP

W.BNPD/W.BFPD

FIRST PDR ADDRESS

W.BLPD

CONTENTS OF LAST PDR

••
•

TASK HEADER VARIABLE PART

Figure 7-2

The Task Header:

Beginning of Variable Part

•
•
•
TASK HEADER FIXED PART
TASK HEADER VARIABLE PART

~
Figure 7-2

CURRENT PS
CURRENT PC
CURRENT R5
CURRENT R4
CURRENT R3
CURRENT R2
CURRENT R1
CURRENT RO
HEADER GUARD WORD

The Task Header:

169

INITIAL VALUES
RELATIVE BLOCK NUMBER OF HEADER
IDENT. WORD #2
IDENT. WORD # 1
TASK NAME WORD #2
TASK NAME WORD # 1
PROGRAM TRANSFER ADDRESS

End of Variable Part

TASK MANAGEMENT

RUNNING A TASK
•

Performed by MCR RUN command
Directives
RUN$
RQST$
SPWN$

•

If task not installed, use MCR command
Task is installed with name equal to terminal, TTnn
Task is executed
Task is removed on exit

•

Two types of requests:
Immediate request - is executed as soon as possible
Time-dependent request
Executed at a specified time
Rescheduled to run periodically

•

Steps in running a task
Task is installed
Task is activated
Memory is allocated to task
Task is loaded
Task is scheduled
Task is terminated

170

TASK MANAGEMENT

Installing
•

Task is installed by MeR command
Permanent installation by INS command
Temporary installation by RUN command

•

TCB is created and initialized

•

Location T.PCB in TCB points to:
The PCB of the partition or subpartition for which it
built (if partition is user-controlled)
The PCB of the main
system-controlled)

partition

(i f

partition

was
is

•

Locations T.LDV and T.LBN point to the load device and logical
block number of the task image file

•

Access rights to resident commons and libraries are checked

•

Task TCB is inserted into the STD by routine $QINSP in
QUEUE

•

Window blocks in header are initialized from the label blocks

•

LUT is initialized from the label blocks and UCB addresses are
loaded

171

module

TASK MANAGEMENT

Activating
•

Task placed in the Active Task List (ATL)

•

If task not installed and not privileged,
installed

Allocating Memory
•

Partition wait-queue used to schedule memory use
Ordered by task priority
Linked using T.LNK, the utility link word
Starts at P.WAIT in PCB

•

TCB placed in partition wait-queue
When task is requested
When task is checkpointed

Loading
•

Task placed in loader queue
Utility link word, T.LNK, links TeBs in queue
Location P.WAIT in PCB is queue listhead

•

In mapped system, task header copied into DSR
Executive updates copy in DSR
$DSW only data in task copy that is updated

172

temporarily

TASK MANAGEMENT

.....
TCB OF
LOADER
TASK

T.RCVL -

LJ ...

T.LNK

f--+

T.LNK

__________________

T.LNK=O

_________________J

TCB'S OF TASKS TO BE LOADED OR ROLLED OUT/IN
ARE CHAINED ACCORDING TO THE RUNNING PRIORITY
OF THE TASKS IN DESCENDING ORDER.
TS.CKP

TS.OUT

INVALID

INITIAL LOAD

CHECKPOINT WRITE

CHECKPOINT READ

LOADER QUEUE
TK-1813

Figure 7-3

The Loader Queue

173

TASK MANAGEMENT

Context Switching
•

Current task's context stored in task header

•

Task context includes:
General registers (R0 - R5)
Processor Status Word
Stack pointer (R6)
Program counter (R7)
Floating-point registers

•

Mapping context for current task is not saved

•

New task's context is loaded from its header

•

Mapping context for new task created using window
PCBs

blocks

GPRs

}NEW
TASK

HEADA

FPRs

...

} OLD
TASK

HEADR

}DSR

APRs

SYSCM

} EXEC

CODE

SA VING CONTEXT
Figure 7-4

LOWCR

Context swi tching :
174

Sav ing Context

and

TASK MANAGEMENT

GPRs

NEW
} TASK

HEADA
WINDOW BLOCKS

HEADA

OLD
} TASK

TCB OF

-~ NEW TASK
SYSCM

-~ STKTCB::

LOADING CONTEXT
Figure 7-4

LOWER

Context Switching:

175

Loading Context

TASK· MANAGEMENT

PCB FOR
GEN

P.SUB

TCB

•
I

PCB FOR

UCB
TASK
HEADER

[.TASK PARTITION

••
UCB

T.ACTL
P.MAIN
T.PCS
P.HDA
WINDOW BLOCK 0

T.ATT

'----v----J
IN MEMORY

Figure 7-5

The Data Structures for an Active Task

176

TASK MANAGEMENT

SCHEDULING A TASK
Priority

•

Scheduling request sets value in $RQSCH

•

Value can be:
The beginning of the ATL (e.g., after a significant event)
Address of particular
scheduling request)

TCB

(e.g.,

after

conditional

•

Scheduling algorithm scans the ATL beginning at the TCB
address is in $RQSCH

•

System chooses:

whose

First resident unblocked task
First task with a pending AST
Round Robin

•

Tasks of the same priority share the CPU

•

Is a SYSGEN option

•

Parameters set at SYSGEN
Round robin scheduling time interval
Priority range for round robin

•

For each priority in priority range
Sublist of tasks of that priority is scanned
TCBs of blocked, suspended or waiting tasks are skipped
TCB of first eligible task is placed last in list of tasks
with same priority

177

TASK MANAGEMENT

TASK X
(BLOCKED)
PRIORITY 100

TASK A

•

CURRENT TASK

1
TASK B
(BLOCKED)

INTERVAL #1

1
PRIORITY=50

TASK C

1
TASK D

1
TASK E
(BLOCKED)

1
TASK Y
PRIORITY =30

Figure 7-6

Round Robin Scheduling:

178

Interval #1

TASK MANAGEMENT

TASK X
(BLOCKED)
PRIORITY= 100

1
TASK B
(BLOCKED)

!
TASK C

CURRENT TASK

1
PRIORITY=50

TASK D

INTERVAL #2

I
TASK E
(BLOCKED)

1
TASK A

1
TASK Y
PRIORITY=30

Figure 7-6

Round Robin Scheduling:

179

Interval #2

TASK MANAGEMENT

Disk Swapping
•

Allows tasks of similar priority to share memory

•

Is a SYSGEN option

•

Parameters set at SYSGEN
Swapping priority
Time interval for swapping

•

Steps in disk swapping
When task loaded, swapping priority is set
the task header
At the end
decremented

each

swapping

H.SPRI is not decremented
swapping priority

beyond

interval,
the

H.SPRI

negative

the

For checkpointing, H.SPRI is added to the running priority
When task is checkpointed,
swapping priority

180

H.SPRI

set

back

the

TASK MANAGEMENT

Clock Scheduling
•

Provides facility for tasks to run
At specific times
After specific time intervals

•

When clock interrupt occurs, the clock queue is scanned

•

Types of time dependent requests
Mark time request
Task request with periodic rescheduling
Single shot task request
Single shot internal subroutine

181

TASK MANAGEMENT

INC~UIt.NT

ItojTERRUP'
COLNT

CRUTE
FORK
PROCESS

UPDATE

TIME AND
DATE

TIMf
DEPENDENT
SCHEDULlfliG

ROUND
ROliN

DEVICE

TIMEOUT

DISK
SWAPPltiG

YES

Figure 7-7

Time-Dependent Scheduling

182

TASK MANAGEMENT

AST Processing
•

AST is used to notify a task when an
occurred

•

Three phases in processing an AST

asynchronous

event

has

Specifying the AST
Allocate an AST control block
Fill in the type of AST at A.CBL
Link the block to the TCB at T.SAST
Declaring the AST
Queue the AST control block to the AST queue at T.ASTL
Scheduling the AST
Conditional schedule request is made
After context switch to task, RESCH in SYSXT
to dequeue an AST
Stopped task is activated to
stopped again

•

process

the

When an AST is scheduled
Necessary data is pushed onto the task stack
AST executes before return to task code

183

attempts
AST,

then

TASK MANAGEMENT

I/O LIST FOR

CLOCK QUEUE

CLOCK
..
QUEUE..
-----4~~ CONTROL
----~~~
III"'" BLOCK F O R ' "
MARKTIME

DB9J:
..

1/0

PACKET

III"'"

Tee
T.ASTL=O

T.SAST

Figure 7-8

AST
CONTROL
BLOCK
FOR
RECEIVE
DATA

AST Processing:

184

Sources of ASTs

TASK MANAGEMENT

I/O LIST FOR

CLOCK QUEUE

CLOCK
QUEUE...
-----4~~ CONTROL r~----~~~
,.. BLOCK F O R ' "
MARKTIME

DB91:

...

I/O
PACKET

,..

TeB
~
T.ASTL
~---------

T.SAST

Figure 7-8

,......

--..,...

.....

,..

AST
CONTROL
BLOCK
FOR
MARKTIME

AST
CONTROL
BLOCK
FOR
RECEIVE
DATA

AST Processing:

185

MARKTIME EXPIRES

Marktime Expiration

,..

TASK MANAGEMENT

I/O LIST FOR

DB(iJ:
1/0

PACKET

TeB

T.ASTL

... - - - - - - - - -

....

...

AST
CONTROL
BLOCK
FOR
MARKTIME

....

...

AST
... CONTROL

T.SAST

BLOCK
FOR
RECEIVE
DATA

AST
CONTROL
BLOCK
FOR
RECEIVE
DATA

,If

DATA RECE IVED BY TASK
Figure 7-8

AST Processing:

Completion of a Receive Data

I/O LIST FOR

DB9J:

...

- - - 4...~

1;0
PACKET

TeB

...

........
....

----------

...
...

AST
... CONTROL

... BLOCK

T.ASTL

FOR
MARKTIME

AST
CONTROL
BLOCK
FOR
RECEIVE
DATA

--.

AST

CONTROL
... BLOCK

FOR
1/0
COMPLETION

T.SAST=O

I/O REQUEST COMPLETES
Figure 7-8

AST Processing:

Completion of an I/O Operation
186

TASK MANAGEMENT

TASK TERMINATION
•

Normal termination
Task issues an exit directive

•

Abnormal termination
Another task issues an abort directive
Task is aborted by an MCR abort command
Task is aborted because of an SST

•

Actions performed at task termination
Halt task
Cleanup system database
Cancel mark time requests
Break links to offspring tasks
Disconnect interrupt vectors, if any
If T3.REM = 1, deallocate TCB
Deallocate header in pool if mapped system
If abnormal exit, run TKTN
Declare a significant event

•

I/O Rundown
Kill all I/O on each assigned LUN
Detach all attached devices
Close all files opened by task

187

TASK MANAGEMENT

Synchronous System Traps
•

Trap vector for each type

•

System response to SST
Kernel mode: Crash system
User mode:

Abort task if no user SST vector
Execute user-supplied routine if
user SST vector

Table 7-1

Trap
Vector

Synchronous System Traps

Trap
Service
Routine Routine

Cause

$TRP04

Odd or nonexistent memory address error

250

$SGFLT

Memory protect violation

$TRACE

T-bit or 8PT instruction

$IOTRP

rOT instruction

$ILINS

Reserved instruction

$EMTRP

$EMSST

Non-RSX EMT instruction

$TRTRP

$TRrrRP

TRAP

244

$FPPR8 $FPPR8
(or $FPPR7)

instruction

Synchronous floating-point exception

188

TASK MANAGEMENT

YES
RETURN
DIRECTIVE
STATUS

CRASH
SYSTEM

YES
SET UP STACK
FOR RETURN TO
USER SST
ROUTINE

ABORT

TASK

Figure 7-9

SST processing

189

SYSTEM SYNCHRONIZATION

INTRODUCTION
A large number of activities are in progress at any given
time while an RSX-IIM system is in use. System synchronization is
the term given to the system processing which keeps these
activities from interfering with each other.
One important
activity which must be controlled is access to the system data
base.

OBJECTIVES
1.

Describe how a software trap is processed by the system.

Describe how a hardware interrupt is processed by the system.

Describe FORK processing.

Describe how a privileged task gets access to the system
base and code.

data

RESOURCE
1.

RSX-IIM System Lists and Data Structures

193

SYSTEM SYNCHRONIZATION
OVERVIEW

•

Executive is driven by interrupts and traps
Idle until interrupt or trap occurs

•

System operation
Executive booted into memory by ROM
ROM starts Executive by initializing PS and PC
Executive initializes the environment
Enables memory management unit
Turns on clock
Drivers called at powerfail entry points
,.~ x e cut i v e

d r 0 ps in t 0 i dIe loop and wa its for in t err n p t s

Command typed in at a terminal
Interrupt occurs
Command passed to MCR or DCL
MCR or DCL runs a task
Task may issue traps
Clock may interrupt functions

195

SYSTEM SYNCHRONIZATION

System Synchronization Functions
•

Provides serial access to system database
Process accessing system database 'owns' the
until finished

database

'Race' conditions are avoided
•

Provides orderly method of allocating CPU use between user
and system

Software States
•

User State
User code executing
Processor in USER mode
Processor fully interruptable - Hardware priority is 0

•

System State
Only state in which the shared system database
be accessed

should

Processor in KERNEL mode
Processor fully interruptable - Hardware priority is 0
•

Interrupt Service State
Used to perform critical operations after an interrupt
Processor in KERNEL mode
Processor not fully interruptable - Hardware
between 4 and 7

196

priority

SYSTEM SYNCHRONIZATION

Software Processes
•

Process - A stream of code in
complete logical job

KERNEL

mode

performing

Can be in the Executive or in a privileged task
•

There are
Executive

three

types

processes

contained

the

Trap process
Services a software trap
Performed in system state
Interrupt Process
Services a hardware interrupt
Performed in interrupt service state
FORK Process
Allows process or task to
database
Performed in system state

197

get

access

system

SYSTEM SYNCHRONIZATION

The Stack Depth Indicator
•

One word' at location $STKDP in the Executive module SYSCM

•

Indicates software state and number
have occurred in KERNEL mode

interrupts

which

Value of +1 indicates processing in user state
Value of 0 indicates processing in system or interrupt
service state
Trap or interrupt occurred from user state
Negative value
service state

indicates

processing

interrupt

Trap occurred from system state
•

Each time trap or interrupt occur, $STKDP is decreased

•

Each time a trap or interrupt process completes, $STKDP is
increased by 1

Traps and Interrupts
•

CPU hardware performs following steps
New program counter and processor status are
from the vector
Current program counter
pushed onto current stack

and

processor

obtained

status

are

Current stack is KERNEL stack if mapped system
Current stack is USER stack if unmapped system
•

New program
routine

counter

contains

•

New processor status causes

address

Processor to change to KERNEL mode
Processor priority to change to level 7

198

trap

service

SYSTEM SYNCHRONIZATION

PHYSICAL
MEMORY

$STACK::
~

SYSTEM
STACK

OLD PS

",-_____---,1 PC

OLD PC

...
r

'"-_ _ _ _ _......." PS
NEW PS

VECTORS ~

NEW PC

"'-

Figure 8-1

••••••
Handling Traps and Interrupts by the Hardware

199

SYSTEM SYNCHRONIZATION
TRAP PROCESSING

Trap caused by execution of a
'trap'
instruction
synchronous system trap detected by the Executive

Each type of trap corresponds to a unique two word
low memory

Most common trap is 'EMT 377', the result of a directive call

EMT instructions

vector

Cause a transfer to location $EMTRP in module DRSUB
Processing
Dispatcher

occurs

module

$DRDSP,

Directive

the

DRSUB
$EMTRP::
JSR R5, $DIRSV

LOWCR

MOV $XCOM1, KlSAR5
JMP$DRDSP

SYSXT
$DIRSV::

DRDSP
$DRDSP::

CALL (R5)
BR $DIRXT

CALL - - - -

$DIRXT::

EMT TRAP
VECTOR

RETURN

....--t RETURN

Figure 8-2

EMT Instruction Execution

200

RTI

SYSTEM SYNCHRONIZATION

The Directive Save Routine
•

Code begins at label $DIRSV in module SYSXT

•

Called by trap processing routine upon entry

•

Processing in directive save routine
Stack depth indicator is decremented to 0
R5 is saved on current stack by JSR instruction
R4 is saved on current stack
On unmapped system, loads R6 with pointer to system stack
R3, R2, Rl and R0 are saved on system stack
Performs coroutine call back to DRSUB

The Directive Exit Routine
•

Code begins at label $DIRXT in module SYSXT

•

Raises processor priority to 7 to lock out interrupts

•

Checks for waiting FORK process
If so: maps driver using KERNEL APR 5
transfers control to next FORK process

•

Increments $STKDP (Should now be +1)

•

Restores general purpose registers

•

Executes RTI instruction to return to USER mode

201

SYSTEM SYNCHRONIZATION

SAVE
R4

ONLY UNMAPPED
SYSTEM
DECREMENT
$STKDP

SAVE STACK
POINTER

.-- --,
I

LOWER
LOAD SYSTEM
PROCESSOR
STACK POINTER ~....~ PRIORITY TO 0

L.. _ _ _ _ _ _ ..J
SAVE
REGISTERS
R3,R2,R1,RO
COROUTINE
CALL BACK
TO DRSUB

Figure 8-3

The Directive Save Routine

202

SYSTEM SYNCHRONIZATION

GET 'EMT'
INSTRUCTION

PROCESS
DIRECTIVE

Figure 8-4

Common processing in the Directive Dispatcher

203

SYSTEM SYNCHRONIZATION

LOCK OUT
INTERRUPTS

EXECUTE
FORK
ROUTINE

RESTORE
REGISTERS
RO,R1,R2,R3

INITIATE
TASK
EXIT

UNMAPPED ONLY

--,I

RELOAD
USER STACK

POINTER

...b~1
...

RESCHEDULE

INCREMENT
SSTKDP

RESTORE
R4,R5

L _ _ _ _ _ _ .J

Figure 8-5

The Directive Exit Routine

204

SYSTEM SYNCHRONIZATION
INTERRUPT PROCESSING

•

Interrupt caused by hardware event

•

Device driver allows interrupt by
bit device register

•

Each device controller has its own 2-word interrupt vector
low memory

setting

'interrupt-enable'
in

The Interrupt Save Routine

•

Code begins at label $INTSV in module SYSXT

•

Entry is with processor priority at level 7 to lock out
interrupts

•

Called by interrupt service routine upon entry

•

Processing in interrupt save routine

other

Stack depth indicator is decremented by one
R5 is saved on the current stack by JSR R5,$INTSV
R4 is saved on the current stack
On unmapped system, SP is loaded with the address
system stack if entry is from user mode

the

Processor priority
interrupting device

the

Performs coroutine call
routine
•

lowered

priority

back

the

interrupt

service

Several versions of this routine are available in module SYSXT
$INTSV - Used by devices without error logging
$INTSE - Used by devices with error logging
$INTSC - Used by connect-to-interrupt routines

205

SYSTEM SYNCHRONIZATION

SYSXT

DRIVER

LoweR

$XXINT::

$INTSV::

CALL (RS)
$INTX1::

INTERRUPT
VECTOR

RETURN

Figure 8-6

Interrupt Processing

206

RTI

SYSTEM SYNCHRONIZATION

Device Driver Proces~ing
•

Usually divided into three processing sections

•

Processor Status Word in vector causes
service routine at priority 7

entry

into

interrupt

All interrupts are blocked
Usually $INTSV is called and lowers priority
•

Critical processing is performed at the priority of the devic~
For a terminal, the last input character is processed and
the interrupt-enable bit is set for the next character
If the system data base must be accessed, a
is created

•

FORK

process

A device driver can access the system data base only as a FORK
process
A FORK process executes at processor priority 0

The Interrupt Exit Routine
•

Code begins at label $INTXI in the module SYSXT

•

Raises processor priority to 7 to lock out interrupts

•

Checks for waiting FORK process
If one: lowers priority to 0
saves R0 - R3 on system stack
executes the $DIRXT routine

•

Increments $STKDP

•

Restores general registers

•

Executes RTI instruction to return to USER mode

207

SYSTEM SYNCHRONIZATION

SAVE
R4

DECREMENT
$STKDP

SAVE
CURRENT SP

r--I
I
IL___

--,
I
__.J

COROUTINE
CALL TO

DRIVER

UNMAPPED

ONLY
Figure 8-7

The Interrupt Save Routine

208

SYSTEM SYNCHRONIZATION

LOCK
INTERRUPTS

.>-....~ GO TO 10$ IN
$DIRXT

GO TO 5$ IN
$DIRXT

ALLOW
INTERRUPTS

SAVE
REGISTERS
RO,R1,R2,R3

Figure 8-8

The Interrupt Exit Routine

209

SYSTEM SYNCHRONIZATION
FORK PROCESSING
•

Provides serial access to the system data base
Processes needing access are queued
No process gains access until the
finished with the system data base

current

process

•

Usually process is part of a device driver, but any privileged
task can create a FORK process

•

Created by routines in module SYSXT
$FORK

- Used by device drivers

$FORK0 - Creates FORK process wi thout saving R4 and R5
$FORKI - Creates FORK process saving R4 and R5
$FORK2 - Used by connect-to-interrupt routines
The FORK Block
•

Four word block containing
Link word for FORK list
Saved PC
Saved R5
Saved R4

•

FORK block for device driver contained in the SCB

The FORK List
•

FORK blocks are linked into FIFO queue called FORK list

•

Begins at list head in SYSCM at location $FRKHD

210

SYSTEM SYNCHRONIZATION

S.PKT
POINTER TO NEXT FORK BLOCK

S.FRK

SAVED PC
SAVED R5

SAVED R4

KISAR5
Figure 8-9

The FORK Block in the SCB

SYSCM
$FRKHD

....

B -

FORK
BLOCK

Figure 8-10

211

.......-

FORK
BLOCK

The FORK List

--~

FORK
BLOCK

SYSTEM SYNCHRONIZATION

PR7
CPU
PRIORITY

CALL

SDIRSV

$INTSV

PR6
PR5
PR4

CALL
$FORK

RETURN
TO $DIRXT

PRO

RETURN

1 TO $OIRXT

250.
TASK
PRIORITY

010

SYSTEM STACK
STACK DEPTH
INDICATOR

INTERRUPT
AT BR4

(TRAP)

$STACK::
$STKDP::

DO
CKJ
+1

Figure 8-11

$DIRXT
RO
R1
R2
R3
R4
RS

CKJ

PC
PS

$INTX1

DO-......,;.p...;;c~

PC
PS

R4
RS

SDIRXT
RO
R1
R?
R3
R4
RS

Interrupting a Task

212

SYSTEM SYNCHRONIZATION

CALL
$DIRSV

PR7

CALL
$INTSV
RETURN
TO$INTX1

PR6
PR5
PR4

CPU
PRIORITY

RETURN
TO $DIRXT

PRO
250.
TASK
PRIORITY

INTERRUPT
AT BR6

010
(TRAP)

SYSTEM STACK
STACK DEPTH
INDICATOR

$STACK::
$STKDP::

Figure 8-12

c:::£LJ
+1

PC
PS
$DIRXT
RO
R1
R2
R3
R4
RS
PC
PS

$DIRXT
RO
R1
R2
R3
R4
RS
PC
PS

$INTX1
R4
RS
PC
PS
$DIRXT
RO
R1
R2
R3
R4
RS
PC
PS

$DIRXT
RO
R1
R2
R3
R4
RS
PC
PS

I1
....._-..;..1-,I 1.....____0___1I + 1

Interrupt Executive Processing a Directive

213

SYSTEM SYNCHRONIZATION

PR7
CPU
PRIORITY

CALL
$INTSV

RETURN
TO $INTXI

PR6
PR5
PR4

RETURN
TO $INTXI

PRO

INTERRUPT
AT
BRS

250.
TASK
PRIORITY

STACK DEPTH
INDICATOR

INTERRUPT
AT
BR4

PC
PS
$INTXI SINTX
R4
R4
RS
RS
PC
PC
PS
~ PS

ISINTX
R4
RS
PC
~ PS

aLl

SYSTEM STACK

$STACK::
$STKDP:: 1""-+~1""'11

Figure 8-13

CALL
$INTSV

aLl

II +1 II +1 II o II

[$INTX
R4
RS
PC
PS
$INTX
R4
RS
PC
PS

ISINTX
R4
RS
PC
PS

II -1 II

Interrupt Executive Processing an Interrupt

214

II +1

SYSTEM SYNCHRONIZATION

CALL
$INTSV

PR7
PR6
PR5
PR4

CPU
PRIORITY

PRO

CALL
$FORK

RETURN
TO$DIRXT

TASK
EXIT
(TRAP)

250.
TASK
PRIORITY

EXECID LE
INTERRUPT
AT BR4

SYSTEM STACK
STACK DEPTH
INDICATOR

SSTACK::
SSTKDP::

Figure 8-14

RO
R1
R2
R3
R4
RS
PC
PS

PC
PS
RO
R1
R2
R3
R4
RS
PC
PS

o II

$INTX1

R4
RS
PC
PS
RO
R1
R2
R3
R4
RS
PC
PS

-1

$DIRXT

RO
R1
R2
R3
R4
RS
PC
PS

Interrupt Executive in an Idle Loop

215

SYSTEM SYNCHRONIZATION

PRIVILEGED TASKS

•

Privilege bit is set in second status word in TCB
Task can use privileged directives
Task can perform privileged I/O functions
Task can perform logical block transfers
volumes

•

Task is built
taskbuilding

privileged

using

the

to/from

/PR

mounted

switch

when

/PR:0 creates privileged task whose mapping is the same as
that of a nonprivileged task
/PR:n creates privileged task which maps to the Executive
n = 4 if Executive is 16K words
n = 5 if Executive is 20K words

216

SYSTEM SYNCHRONIZATION

Processing a Privileged Task
•

Privileged task must switch to KERNEL mode
data base

•

Switch to KERNEL
instruction

CALL

mode

performed

access

system

$SWSTK,LABEL

CALL macro translates this to EMT 376
CALL macro is in SY:[11,10]RSXMC.MAC
LABEL is a location in the privileged task to return
leaving KERNEL mode

when

•

In module DRDSP, a jump to location $SWSTK in module SYSXT
executed

•

The routine $SWSTK
Moves the contents of USER mode APRs 5
mode APRs 5 and 6

and

KERNEL

Moves the address of LABEL to location SP+16 on the stack

217

SYSTEM SYNCHRONIZATION

LOW CR

EMT TRAP
VECTOR

DRSUB

$EMTRP::
DIRSV$

~-@ ®
JMP $DRDSP

®
USER PROGRAM
CALL $SWSTK,
LABEL

RETURN
LABEL:

.... II-

•

SYSXT
$DIRSV::

I. . .

$DRDSP::

CALL (R5)
$DIRXT::

---

JMP $SWSTK-

EXIT$S

RTI

---

$SWSTK::

.. CALLR @(SP)+

®
®
Figure 8-15

Privileged Task Processing

218

SYSTEM SYNCHRONIZATION

CPU
PRIORITY

CALL
$DIRSV

PR7
PR6
PR5
PR4
PRO

CALL
$DIRSV

RETURN
TO $DIRXT

250.
TASK
PRIORITY

SYSTEM STACK
STACK DEPTH
INDICATOR

$STACK::
$STKDP::

Figure 8-16

010
(TRAP)

SWITCH
STACK
(TRAP)

DO
l2!:J
+1

$DIRXT
RO
R1
R2
R3
R4
R5
PC
PS

___ DO
l2!:J
II

$DIRXT
RO
R1
R2
R3
R4
R5
PC
PS

Privileged Task Switches Stack and Returns

219

SYSTEM SYNCHRONIZATION

CALL TRAP
ROUTINE

(

SDIRSV

FORK
PROCESS

....-_ _ _..,.4~

REMOVE FORK
LIST ENTRY
RESTORE
R4.RS

SAVE RS-RO ON
THE STACK
DEC $STKDP

RESTORE
RO-R3

INC$STKDP
RESTORE
R4,R5

.........(

SELECT
NEW TASK
AND SWITCH
CONTEXT

IDLE
LOOP

POWER

Figure 8-17

System Synchronization Logic:

220

$DIRSV

Rli

)

SYSTEM SYNCHRONIZATION

SAVE R3-RO ON
KERNEL STACK

(

$FORK

SAVE PC, R5
IN FORK BLOCK
LINK BLOCK INTO LIST
YES

SAVE R5, R4
ON THE
STACK
DEC $STKDP

INC $STKDP
RESTORE
R4,R5

CALL INTERRUPT
SERVICE ROUTINE

Figure 8-17

System Synchronization Logic:
and $INTSV

221

$DIRXT, $FORK,

WRITING PRIVILEGED TASKS

INTRODUCTION
In many practical environments, it is often necessary to
write tasks which must interact with the Executive in ways not
planned by the designers of the operating system. The tool used
in these situations is the privileged task.
(In this module,
"privileged task" refers to a task which maps to the Executive.) A
privileged task has access to both the system data base and
Executive code and can therefore act as an extension of the
operating system.
To write and use privileged tasks, the programmer must
understand the operating system, the system data base and the
methods that the Executive uses to synchronize access to the
system data base.
The previous modules, together with this
module, provides that understanding.

OBJECTIVES
1.

Assemble and taskbuild privileged tasks.

Use a privileged task to access the system data base.

Use Executive routines to perform tasks.

RESOURCES
1.

RSX-llM System Lists and Data Structures

225

WRITING PRIVILEGED TASKS

OVERVIEW
Why Write a Privileged Task
•

To acquire the privileged attribute
Allows task to issue privileged directives
Allows access to any file without protection checks
Allows task to issue logical block I/O to a mounted volume

•

Tasks which map to the Executive have access to:
Routines contained in the Executive
Executive data base including
System Common (SYSCM)
System device tables (SYSTB)
Dynamic Storage Region (POOL)
The I/O Page
Device registers
Memory management registers

227

WRITING PRIVILEGED TASKS

Privileged Task Structure
•

Consists of at least three sections
First section
Executes in USER mode
Contains the transfer point of the task
Contains code for processing
system state

before

transferring

Second section
Executes in KERNEL mode
Contains code which accesses Executive data
Thi rd section
Executes in USER mode
Contains return location from KERNEL mode
Contains code for processing data
Executive in the second section

•

obtained

from

the

USER Mode APRs
For system with 16K word Executive
APRs 0 - 3 are used to map the Execut i ve
APRs 4 - 6 are used to map the privileged task
APR 7 is normally used to map the I/O page but can map
an added 4K words of the task if needed
Privileged task can be
12K words if I/O page is needed in USER mode
16K words if I/O page is not needed in USER mode

228

WRITING PRIVILEGED TASKS

•

For system with 20K word Executive
APRs 0 - 4 are used to map the Executive
APRs 5 and 6 are used to map the privileged task
APR 7 is normally used to map the I/O page but can map
added 4K words of the task if needed
privileged task can be
8K words if I/O page is needed in USER mode
12K words if I/O page is not needed in USER mode

229

WRITING PRIVILEGED TASKS

Restrictions on Privileged Tasks
•

Parameter Passing
User state to system state
Values can be passed in registers R0 - R5
Values can be passed in memory locations
System state to user state
Values can only be passed in
registers are restored

•

memory

locations

Time spent in system state should be minimal
Interrupt processing affected since the FORK queue is
serviced
No other user task can execute

•

No trap can occur in system state
No directives can be executed
Traps in system state cause a system crash

•

since

Privileged instructions should be used with care

230

not

WRITING PRIVILEGED TASKS

CREATING A PRIVILEGED TASK
Assembling a Privileged Task
•

To assemble a privileged task to map to the Executive:
)MAC File,File=[1,1]EXEMC/ML,[11,10]RSXMC/PA:l,[USER UIC]File

•

EXEMC.MLB
Contains
Macros defining offsets
Bit values for all system data structures
Not needed if no reference is made to these structures

•

RSXMC.MAC
Contains
Conditional assembly symbols defining the system
Several commonly used macros such as CALL and CALLR
Always needed to interpret CALL $SWSTK

231

WRITING PRIVILEGED TASKS

Taskbuilding a Privileged Task
•

The following command is needed to taskbuild a privileged task
which maps to the Executive
)TKB File/PR:n=File,[l,l]EXELIB/LB,[l,54]RSXllM.STB

•

EXELIB.
Executive object library
Contains global symbols for resolving
structures not resolved during assembly

•

offsets

data

symbols

used

RSXllM. STB
Executive symbol table file
Allows resolution of
privileged task

Executive

232

global

WRITING PRIVILEGED TASKS.

SAMPLE PRIVILEGED TASKS
Tracing Through System Lists

•

Function of privileged task
Calculate and display size of free pool

•

The pointer $CRAVL is used to access the
blocks

•

$SWSTK is used to switch to system state

•

Time spent in system state is minimal

list

free

pool

System data accessed in system state
•

I/O performed in user
No traps in system state

•

Size of free pool is saved before return to user state
Registers cannot be used to pass data from system to
state

233

user

WRITING PRIVILEGED TASKS

Table 9-1

Pointers to System Lists

Pointer*

System List

$LOGHD

Logical device assignment list

$CRAVL

Free pool block listhead

$ACTHD

Active task list listhead

$CFLPT

Pointer to first checkpoint file PCB

$FRKHD

FORK queue listhead

$CLKHD

Clock queue listhead

$PARHD

Pointer to partition list

$TSKHD

Pointer to system task directory

$GGEF

Pointer to group global event flags list

$ERHEA

Error logging message queue listhead

$PKAVL

Pointer to list of preallocated I/O packets

$UMRHD

Mapping assignment block listhead

$UMRWT

UMR wait queue listhead

$MOULS

Mounted device listhead

*All pointers are located in SYSCM

234

WRITING PRIVILEGED TASKS

Table 9-2

Pointers to Data Structures

Pointer*

Description

$HEADR

Pointer to current task header

$TKNPT

Pointer to TKTN TCB

$SHFPT

Pointer to shuffler

$MCRPT

Pointer to MCR TCB

$TKTCB

Pointer to current task TCB

$LDRPT

Pointer to loader TCB

*All pointers are located in SYSCM

235

Tee

MACRO M1200

POOlA

29-DEC-81 13:54

PAGE 3
.TITLE

1
2
3
4

;** - POOlA - DISPLAY POOL SIZE

l\..)

w
0'\

6
7
8
9
10 000000
11 000030
12 000032
13
14 000053
15
16 000120
17 000120
18 000122
19 000126
20 000132
21 000136
22 000140
23 000142
24 000144
25 000150
26
27
28
29 000152
30 000156
31 000162
3'" 0()0166
33 000172
34 0()0176
35 000204

124
000045

005001
012700
066001
011000
001374
006201
010167
000207

117

OOOOOOG
000002

177660

124

THIS TASK WIll CALCULATE AND DISPLAY THE TOTAL SYSTEM
DYNAMIC STORAGE REGION SIZE

.MCAll
.NlIST
OUTaIO: aIOW$
ARGlST: .BlKW
OUTMES: .ASCIZ
BUFFl
OUTBUF: .BlKB
.EVEN
START:
ClR
MOV
CAll
10$:
ADD
MOV
BNE
ASR
MOV
RETURN

aIOW$,EXIT$S,DIRS
BEX
IO.WVB,1,1",,(OUTBUF,0,40>
; ARG lIST FOR SEDMSG
1
ITOTAl POOL = ~D.I
.-OUTMES+20.
BUFFl
Rl
tSCRAVl,RO
$SWSTK,30$
2(RO),Rl
(RO),RO
lOS
Rl
R1,ARGlST

; FOR TOTAL FREE SPACE
; POINT TO FIRST DSR PACKET
; SWITCH TO SYSTEM STATE
; ; ADD IN SIZE OF THfS PACKET

; ; GET LINK TO NEXT PACKET
; ; IF NE NOT END OF lIST
; ; CONVERT TO WORDS
; ; SAVE SIZE OF DSR
; ; RETURN TO USER STATE

FORMAT AND PRINT OUTPUT
;

012700
012701
012702

000053'
000032'
000030'

010167

177620

'"0

POOlA

000120'

Example 9-1

30$:

MOV
MOV
MOV
CALL
MOV
DIR$
EXITSS
.END

tOUTBUF,RO
SET OUTPUT STRING
tOUTMES,Rl
AND INPUT STRING
tARGlST,R2
AND ARGUMENT LIST
; FOR EDIT MESSAGE
SEDMSG
R1,OUTQIO+Q.IOPl+2 ; UPDATE MESSAGE SIZE
; WRITE OUT MESSAGE
touTaIO
; AND EXIT FROM PROGRAM
START

Tracing Through System Lists
(Sheet 1 of 2)

POOL A
MACfW M1200
SYMBOl. TABL.E

N
W
-.....J

29··-DEC ..··81 13:54

ARGl.ST 00003Mi:
A"CHK:::: 000000
A"CLI== 000020
A"CNT:: 000000
A"CPS:: 000000
A"NSI:: 000000
A"PRI= O()OOO()
A$$TfW:: 000000
nUFFL ..- O()()045
C"CDA= ()OOO02
C"CKp:: 000000
C$'INT:: O()()OOO
C'~;ORF:: OOl,OOO
C"HSH:: 177564
C,$/WN::: 000000
[1"1-111= 000003
D"IAG:: 000000
n'$ISK:: 000000
n$$Ll1= 000001
D"Mll:: 000003
[I"PAR:: ()O()() 00
[I"SHF= 000000
n"WCK= O()OOOO
D'$YNC= 000000
n"YNM= 000000
[I"ZMD:: O()OOOO
D"Zl1:: 000001
E$,DVC== 000000
E$,NSI:: 000000
E"PER= 000000
E"XPR== 000000
F$$LPP= 000000
F'$LVL= ()()OOOl
G"TPP= OO()()OO
G$,TSS:: 000000

ASS.

EI~RORS

000000
000212
DETECTED:

PAGE:

~5-1

G"TTK:::: 000000
H"raZ:::: 000074
IO.WVB=
GX
1$$CSZ:::: 000200
I"RAR::: 000000
l"RDN:: 000000
K$'CNT:::: 1.77546
K"CSR::: 177546
K'$DAS= 000000
~~"IEN:::: 000115
K"l.DC""" 000001
K"TF'S= 0()0074
000000
l.D'CO
000000
L[r'DII
LD'[r[r
000000
000000
LD'[rK
L[r'[rL..
000000
000000
L..D'DM
LD$Dr<
000000
000000
LD'DS
LD$DT
000000
OO()OOO
LD'DY
LD,l.F'
000000
LD,MM
000000
000000
LD'NL
LD$RD
()OOOOO
l.[r'TT
000000
000000
LD'VT
LK.SPN== 000002
LK.WAT= 000010
L"ASG::: 000000
L.."[rBG== 000000
l.$,DRV:::: 000000
L'$L[rf.::::: 000000
L"PTO= 000170

L"P 11 "-, 000002
L"l1.R:::: 000000
M"CRB:: 000124
M$$CRX~-:: 000000
M"EXT:::: 000000
M$'FCS:: 000000
M"MGE""" 000000
M"MUF':::: 000000
M$$NET= 002627
M"OVR:::: 000000
M"XLN:::: 000400
N'$LDV:::: 00000:1.
N"MOV::.' 000041
N"UMR".:: 000030
OUTBUF 0OOO53R
OUTMES 000032Fi:
OUTOIO OOOOOOF;:
P$,D70:::: 000000
P"GMX= 000000
P'$LAS== 000000
P"MAX= 000400
P$'OFF:::: 000000
P'$OOl.= 000000
P"P45= 000000
F"'RFL:::: 000000
P"RTY= 000000
P"SRF::: 000000
P"WND= 000000
(U'OPT= 000005
O. rOAE::::: 00OO1.~:.~
o. rOEF:::: 000006
O.IOFN:: 000002
0.10LU:: 000004
O. HIPL:::: 0000:1.4
O. J:(IPR::: 000007

******

0.10SB= 000010
f<"CON=: OOOOO()
R"DER::: ()()OOOO
R"DSF'::: 000000
R$'EIS:::: 000000
R$'EXV:::: 000000
R'$HDV== 000000
R$'Hll= 000004
R'$JP1::: 000004
R'$JS1:::: 000004
R"K11:: 000001
R"l.KL= 000001
R"Lll:: 000001
f.:$'MPL= 000000
f.:"Mll:::: 000004
R"NDC:::: 000006
f.:"NDH::: 000226
R"NDL:::: 000001
R$'SND= 000000
r':$$X21= 000001
R$$11M:::: 000000
R,,611'"' 000001
START
000120R
S"ECC:::: 000000
S"HDW= 000000
S"LIB:: 000000
S"NM1= 042513
S"NM2= 046522
S,'NM3= 052111
S"OPT:::: OOOO()O
S"UBD= 000000
S"WPC::: 000036
S"WPR::: OOOOO~5
S$$WRG:: 000000
S"YSZ= 044000

000
001
0

VIRTUAL MEMm\:y USED:
11375 WORDS ( 45 PAGES)
DYNAMIC MEMORY:
:1.2692 WORDS ( 48 PAGES)
ELAPSED TIME: 00:OO!12
YPOOLA~LB:[2,54]RSXMC/PA:l~[1,1]EXEMC/ML,DB2![305,306]POOlA

Example 9-1

Tracing Through System Lists
(Sheet 2 of 2)

T"[lTW:::: 000000
T"CCA::: 000000
T"COM:::: 000000
T$'CON= 000000
T"CTR:::: 000000
T"CUp::: 000000
T"Cl,l::: 000001
T"ESC::: 000000
T$'GMC:::: 000000
T"GTS::: 000000
T"KMG:::: 000000
T$'LWC:::: 000000
T"M03::: 000002
T"RED:::: 000000
T"RNE:::: 000000
T"RPR:::: 000000
T"RST:::: 000000
T"FWB:::: 000000
T"SMC:::: 000000
T"UTO::: 0000:36
T"U58::: 000001
U"DAS::: 000000
U"MHI= ()OOOOO
U,'MLO:::: 140000
U"MRN::: 170230
V"CTR::: 000774
V$'TL[r= 000120
V"TLM::: 00020::'i
V'$TRM::: 000000
X"DBT::: 000000
X$'HDR::: 000000
'CRAVl.:::
GX
'EDMSG:::
GX
"'ARG::: 000003
"'OST:: 000014

******
******

::0
H

t-3
H

to
::0
H

<:
H

t-t
tzl

tzl

t:1

t-3

::,;;:

WRITING PRIVILEGED TASKS

Calling Executive Routines
•

Function of privileged task
To simulate issuing an MCR command from a terminal

•

Privileged task must construct MCR command block
Terminal UCB is located by searching device list
MCR command block (84 bytes) is
using routine $ALOCB

allocated

from

pool

Block is queued to MCR by using routine $QMCRL
Block is deallocated on I/O error by calling $DEACB
•

Time spent in system state is minimized by returning
state to perform calculations, etc.

Table 9-3

user

Executive Pool Routines*

Entry
Point

Description

Inputs

Outputs

$ALOCB

Allocates a variable
length core buffer

Rl = Size of
buffer

C-bit = 0 Block allocated
C-bit = I Insufficient spacE
R0 - Address of block
Rl - Length of block

R0 = Address
of block
Rl
Block
si ze

None

First fit
Length in multiples
of four bytes
$DEACB

Deallocates a variable
length core buffer

*AII routines are in Executive module CORAL

238

WRITING PRIVILEGED TASKS

Table 9-4

Executive Queueing Routines*

Entry
Point

Description

Inputs

Outputs

$QINSF

Inserts entry at end
of FIFO queue

Address of
listhead
Rl = Address of
new entry

None

(Same as $QINSF)

None

Saves R0, Rl
$QINSP

Inserts entry in a
priority ordered
queue

Saves R0, Rl
$QINSB

Inserts entry at
beginning of queue

(Same as $QINSF)

All registers are
saved
$QRMVF

Removes entry from
beginning of queue

R0 = Address of
listhead

C-bit = 0 Entry removed
C-bit = 1 Empty list
Rl - Address of entry

R0 = Address of
listhead
Rl = TCB address

C-bit = 0 Entry removed
C-bit = 1 Entry not found
Rl - Address of entry

Saves R0
$QRMVT

Removes entry with
a specifed TCB address

$QMCRL

Queues a command line
Rl
to eLI of issuing terminal

None
of
= Address
command line

*All routines are in Executive model QUEUE

239

WRITING PRIVILEGED TASKS

Table 9-5

Other Executive Routines

Entry
Point

Description

Inputs

Outputs

$SRSTD

Searches STD for
specified task

R3 == Address of
RAD50 task
name

C-bit = 0 Task found
C-bit == 1 Task not found
R0 = TeB address of task

RJ == Address of
RADS0 name

C-bit = 0 Partition found
C-bit == 1 Not found
R2 == PCB address

Ret = Event flag
number
RS = TCB address
of task

R0 ==
Rl ==

Module: REQSB
$SRNAM

Search the partition
11st for a named
partition
Module: PLSUB

$CEFI

Converts an event
flag number to an
event flag address
Module: EXESB

240

Mask word
Event flag address

TERM

MACRO M1200

22-0CT-81 12:40

PAGE 3
.TITlE

1
2
3
4
5
6
7

THIS TASK ASKS THE USER FOR A TERMINAL NUMBER AND A
COMMAND lINE.
IT THEN PASSES THE COMMAND TO MCR
AS IF HAD ORIGINATED AT THE SPECIFIED TERMINAL. IT
PERFORMS THIS TASK BY USING SYSTEM SUBROUTINES, $ALOCB
AND $QMCRL, TO ALLOCATE A BLOCK FROM POOL AND PASS IT
TO MCR.

9
10
11
12
13
14
15
16
17
18
19
20
21

THE TASK MUST BE BUILT PRIVILEGED AND MAP TO THE EXECUTIVE.
TO ASSEMBLE:
>MAC

>TKB

EXIT$S,QIOW$S,DCBDF$

TERMINAL MESSAGES

TERM/PR:5~TERM,[1,54]RSXIIM.STB/SS

.MCALl
DCBDF$

23 000000
24

~
~

TERM~[1~1]EXEMC/ML,[11,10]RSXMC/PA:1,[(YOUR

TO BUILD:

26
27 000000
000003
000006
000011
000014
000017
000022
000025
000030
28
29 000033
000036
000041
000044
000047
000052
000055
000060
30
31 000062
000065
000070
000073
000076
000101
000104
000107
000112
000115
000120
32

TERM

;

012
116
122
040
122
116
040
115
122
000033
105
105
101
117
101
040
122
103
000027
116
102
040
040
124
103
114
124
040
101
041
000037

015
124
040
124
115
101
116
102
072

105
105
101
105
111
114
125
105
040

116
122
040
115
116
106
040
122

124
040
103
115
104
117
115

125
105
111
116
040
124
054
122
101
111

115
122
123
117
117
101
040
131
107
116

PRMT:

.ASCII

<12><15>/ENTER A TERMINAL NUMBER: I

PlEN
MES1:

.ASCII

.-PRMT
;LENGTH OF PROMPT
IENTER A COMMAND FOR MCRI

lENTl
MESS1:

.ASCII

.-MESl
INUMBER IS NOT OCTAL, TRY AGAIN!I

lENI

Example 9-2

.-MESSl

Calling Executive Routines
(Sheet 1 of 5)

UIC)]TERM

TERM

N
~

MACRO M1200
33 000121
000124
000127
000132
000135
000140
000143
34
35 000144
000147
000152
000155
000160
000163
36
37 000166
000171
000174
000177
000202
000205
000210
000213
000216
38
39
40
41
42
43 000220
44 O()0224
4~j 0()0230
46 000232
47 O()O234
48 OOO:~36
49 000240
~)() 000242
~_) 1 O()O244
~:52 000246
53
54

22-0CT--Sl 12:40

124
115
101
116
040
125
041
000023
116
120
114
126
114
114
000022
111
040
122
040
040
115
116
111
125
000032

105
111
114
117
106
116

122
116
040
124
117
104

117
117
040
101
101
105

040
117
101
111
102
041

057
105
117
117
103
115
104
116
124

117
122
122
116
117
101
040
120

PAGE 3-1
ERMES:

.ASCII

ITERMINAL NOT FOUND!I

ERL
POOL:

.ASCII

INO POOL AVAILABLE!I

PL
IOERR:

• ASCII

.-POOL
!I/O ERROR ON COMMAND INPUT!

.-ERMES

::c

H
~
H

Z
Cl
."

.-IOERR

IOL

jMAKE SURE OF WORD BOUNDARY

.EVEN

124
177777
000000
000000
000000
000000
000000
000000

124

.BLI(B
.BLKW
.ASCII
.WORD
.WORD
.WORD
.WORD
.WORD
.WORD
.WORD

4
2

ITTI
--1
0
0
0
0
0
0

1:"'1

;BUFFER FOR TERMINAL NUMBER
;rIO STATUS BLOCK
jTERMINAL NAME
;ERROR INDICATOR
;ADDRESS OF COMMAND LINE IN POOL
jADDRESS OF POOL BLOCK
jSAVED UCB ADDRESS
;SAVED [rCB ADDRESS
;SAVED LOW UNIT NUMBER
;SAVED HIGH UNIT NUMBER

BEGINNING OF CODE

£:"t:"

.J.J

56 000250
57 OO()322
~)8 O()()374
~)9 O()0400
60 000404
61 000406
62
63
64 O()()412
6~:; O()0414
66 000416
67 O()O422
60 000426
69 O()O432
7() 000434

TERM:
016703
012700
005002

005702
001402
000167

177626
000220'

TST
BE(~

000436
CONT:

012700
011000
001422

CHClWSS
CHOWS5
MDV
MOV
CL.R
CALL__

OOOOOOG
L.t:

Example 9-2

JMP
CALL.
MIJV
MOV
BEO

PROGRAM DATA
;
BUF:
IOSB:
NAM:
ERRCNT:
COMM:
PLACE:
UCB:
DCB:
LOW:
HIGH:

::c

;PROMF'T
tIO.WVB,t5,tl",,<tPRMT,tPLEN,t40>
tIO.RVB,t5,tl"tIOSB,,<tBUF,t4> ;GET 'TT' NUMBER
;SAVE CHARACTER COUNT
I (lSB'" 2 , F~3
;SET UP FOR CALL TO CONVERSION
:JBUF ,FW
ROllTINE - FROM ASCII TO
R2
BINAF~Y (OCTAL)
SCOTB
; Rl WILL CONTAIN CONVERTED NUMBER
j R2 WILL CONTAIN TERr.INATOR
;TE5T FOf< Er<ROR
F\2
HF NOT CONTINUE
CONT
;GO TO ERROR ROUTINE
ERR1
;;SWITCH TO SYSTEM STATE
SSWSTI\,BACK
; ;F'ICK UP LISTHEAD FOR DCB LIST
t$DEVHD,RO
(RO) , RO
;;GO TO NEXT DCB
;; IF NONE FINISH UP
GO

Calling Executive Routines
(Sheet 2 of 5)

[z]

Cl
[z]

0
~

):1/

(J)
~
(J)

TERM

l\.)

.e:a
w

MACRO M1200
71 ()O04~36
72 000444
7~5 000446
74 OO()454
n'i 000462
"76 O()O466
"77 O()O470
713 000474
79 O()()502
BO O()()504
131 O()0504
132 O()0510
13:~ O()()~:i 12
04 ()()0516
135 OOO!:'i2::~
Elb ()()()~)2b
137 O()O530
BEl
89 000534
90 O()0540
91 ()()0542
'n 000544
'1~5 O()0550
94 OOO!:i56
'l~j O()()562
'16 0005M)
97 000572
913 000574
'1'1 OO()600
lO() ()()0604
101 ()()()60b
l.O::! OOObOb
1.03 000612
104 000614
10~) O()0620
106 O()O624
107 O()06~~O
lOB O()()634
109 O()O636
1:10 O()()644
1:L1 O()O652
112 O()()724
1:L3 000730
1.14 O()()7~~4
11~.) O()1006
1:L6 ()()1010
117 O()1014
111:1 001020
:L:L'1 O()1 022
120 ()():L026
l:~ 1. ()()1. 0~32
122 ()()1 03b
123 O():L044
1:~4 O()1050
:L25 ()()1052
126 O()1052
127

22·-0CT··.. 8:J. :J.2:40

026760

1 "7"7561.>

000004

000006
000007
177560

1.775b4

PAGE 3,,-2
CMF'
BNE
MOVB
MOVB
CMF'

001:~"72

llb06"7

116067
020167
003361
010067
062767
0057b7
001402
000167
016700
01b002
()101()4
166704

BIH

17"7546
000001

17ni30

GO:
BACK:

177522
000430
17"n"'i20
000002

1$:

1,7"7510

01b005
070504
060502
010267
012767

000010

0127()1

000124

103404
005267
01()067

177432
177432

177470
17"7777

005767
001402

177420

0001b7

00040b
000124
177406
00O()40

012700
01.b701
1.12721077003
016767

17"7!7i"70

Ob2"7b7

177374
000004

005067
005067

177274
177'272

1 ()30()2
000167
105"767
002002
000167

000272
177204
0002bO

Olb701
016761

1.77200
1"7"7176

177454

NONE:
BACK2:

1$:
2$:
177:~70

177~3b2

3$:
4$:
O()()()O:;?

MOV
ADD
r~ETURN

TST
BEU
.JMP
MOV
MOV
MOV
SUB
MIN
MUL
ADD
MOV
MOV
CALL
MOV
CALL
BCS
INC
MOV
RETURN
TST
BEQ
.JMP
MOV
MOV
MOVB
SOB
MOV
ADD
rHOW$S
CLR
CI...R
rnOW$S
£ICC
JMP
TSTf.f
BGE
JMF'
CALL
MClV
MDV
CALL
Ii:ETUr~N

BACI\3:
EXIT$S

Example 9-2

v; LOOK FOR 'TT' DCB
99IF NOT 'TT' GET NEXT nCB
9; GET LOW UNIT NUMBER
; 9GET HIGH UNIT NUMBER
;,COMPARE INPUT WITH HIGH
,;IF INPUT LARGER GET NEXT DCB
;;SAVE DCB ADDRESS
;;INDICATE NO ERROR HERE
; ; r~ETURN TO USER STATE
;NOW IN USEF~ STATE
;TEST FOR EF~ROR
ERRCNT
;CONTINUE IF OK
1$
;GO TO ERROF~ ROUTINE
ERR2
;GET DCB ADDRESS
DCB,RO
;GET ADDRESS OF FIRST UCB
D.UCB(RO),R2
;MOVE FOR CALCULATIONS
Rl,R4
;FIND THE NUMBER WITHIN UCBS
1.0W,R4
; FOR CURRENT DCB
;GET UCB LENGTH
D.UCBL (RO) , r~5
;CALCULATE OFFSET FOR UCB
R4, f~5
;CALCULATE BEGINNING OF UCB
R5,R2
;SAVE UCB ADDRESS
R2,UCB
;RESET ERRor~ COUNT
t:--1 , ERRCNT
;;SWITCH TO SYSTEM STATE
$SWSTK,BACK2
; ;SET {fLOCK SIZE
t84. ,R1
;;ALLOCATE BLOCK FROM POOL
$ALOCB
HNO ROOM IN POOL
NONE
;;INDICATE NO ERROR HERE
ERRCNT
;;SAVE ADDRESS OF POOL BLOCK
RO,PLACE
; ; RETURN TO USER STATE
;BACK IN USER STATE
;CHECK FOR ERRor~
ERRCNT
1$
;CONTINUE IF OK
;GO TO ERROR ROUTINE
Efm~5
;SET LENGTH OF BLOCK
t84.,fW
;GET ADDRESS OF BLOCK
PLACE,Rl
;PLACE BLANKS IN BLOCK
t40, cru >+
;LOOP UNTIL nmOUGH
RO,2$
;CALCULATE LOCATION OF COMMAND
PLACE,COMM
; LOCATION IN BLOCK
t4,COMM
;PROMF'T FOR COMMAND
tIO.WVB,15,t1",,<tMES1,tLENT1,t40>
IOSB
IOS£I+2
;INPUT COMMAND
tIO.RVB,t5,t1"IOSB,,<COMM,t80.>
;CONTINIJE IF OK
3$
;BRANCH IF aIO ERROR
ERR4
;CHECK FOR I/O ERr~OR
IOSH
;CONTINUE IF OK
4$
;BRANCH IF ERROR
ERR4
;;SWITCH TO SYSTEM STATE
$SWSTI" ~ BACK~3
;; GET ADDRESS OF BLOCI"
PLACE, r~ 1
;;PLACE UC£! ADDRESS IN BLOCK
UCFh2(R1 )
; ; aUEUE BLOCK TO Mcr(
$UMr.RL
;,LEAVE SYSTEM STATE
;BACK IN USER STATE
;[XIT

NAM,[I.NAM(RO)
L1
D.UNIT(RO),LOW
D.UNIT+1.(RO),HIGH
R1,HIGH
1.1
RO,DCB
t1.,ERRCNT

Calling Executi ve Routines
(Sheet 3 of 5)

::0

t-3

C')

'"0

::0
H

<
H
r

tzl

C')

tzl

t1
t-3

(I)

::,;;:

(I)

TERM

MACRO M1200
128
129
130 001060
131 001132
132 001136
1~53 001140
1:34 001142

22-0CT-81 12:40

PAGE 3-3
ROUTINE TO HANDLE BAD TERMINAL NUMBER
;

ERR1:
012700
005020
077302
000167

000220'
CLEAR:
177102

CUOWSS
MOV
CLR
SOB
~JMP

tIO.WVB,t5,tl",,<tMESS1,tLEN1,t40>
;PRINT MESSAGE
tBUF,RO
;GET INPUT BUFFER ADDRESS
(RO)t
;CLEAR BUFFER
R3,CLEAR
;R3 CONTAINS CHARACTER COUNT
TERM
;TRY AGAIN

13~)

136
137
138 001146
139 001220

ROUTINE TO HANDLE NON-EXISTENT TERMINAL
;

ERR2:

QIOWSS
EXITSS

tIO.WVB,t5,tl",,<tERMES,tERL,t40>
;EXIT

;PRINT MESSAGE

140

141
142
143 001226
144 001300
145
146
147
148
149 001306
150 001360
151 001364
152 001370
l~j3 001374
1:'54 001400
155 001402
1~56 001402
157

ROUTINE TO HANDLE POOL ALLOCATION FAILURE
ERR3:

;

ERR4:
016700
012701

176646
000124

QIOWSS
EXITSS

QIOWSS
CALL
MOV
MOV
CALL
RETURN
EXITSS
.END

Example 9-2

;PRINT MESSAGE

ROUTINE TO HANDLE 1/0 ERRORS ON COMMAND INPUT
THE POOL BLOCK MUST BE DEALLOCATED!

FIN:
0002::iO'

tIO.WVB,t5,tl",,<tPOOL,tPL,t40>
;EXIT

tIO.WVB,t5,tl",,<tIOERR,tIOL,t40>
;PRINT MESSAGE
SSWSTK,FIN
;;SWITCH TO SYSTEM STATE
PLACE,RO
;;GET ADDRESS OF BLOCK
t84.,Rl
;;SET BLOCK LENGTH
SDEACB
;;DEALLOCATE BLOCK
;;LEAVE SYSTEM STATE
;BACK IN USER STATE
;EXIT
TERM

Calling Executive Routines
(Sheet 4 of 5)

MACI:W M1200
TERM
GYMBOL. TABLE

22 ..··0CT ..··81 1.2:40

A$$BIO::::
A$$BRT::
A$$CHK::
AS$eL!::
A$$CPS::
A$SNSI":

I\J
~

U'1

D.MnK
ft.NAM
[I.PCB
D.UCB
D.UCBL
[I.UNIT
II. VCAN::
D.VDEB:=
[I.VINI===
[I.VOUT:::
D. VPWF=-"

000000
000000
O()OOOO
000004
000000
000000
A$$PI~I::: 000000
A$$THp:: 000000
[IACI,
0OO504F:
O()0606R
BACK2
001052R
BACK3
BUF
0OO220R
B$$LV1:: O~5()463
B$$LV2:: 020040
001136R
CLEAR
C()MM
000234R
O()0422R
CIlNT
C$$CDA:: 000002
C$$CHE:: 000000
C$$CKp:: 000004
C$$CSR::: 177404
C$$INT== 000000
C$$ONS:: 000001
C$$ORE": 002022
C$$OTM:: 000000
C$$H!JH:: 177564
C$$RUN:: 000000
C$$SMT=: 000000
C$$TTY:: 1.77564

DeB

OOO:~42R

D$$Hll::
D!.$IAG::
[I$$ISK=
[I$~;t_:l.1 ::
D$$Ml1::
[I$$PAR::
D$$SHF::
U$.WCK::
[I$$YNC=
D$$YNM:"
D.DSF'
D.LNK

000001
000000
000000
000002
O()()OOI
000000
O()OOOO
000000
O()()OOO
000000
000012
OOO()OO

ABS.

EI~I;:Of~S

000036
001410
DETECTED:

EI~l.

ERMES
ERRCNT
ERR1
ERR2
ERR3
ERR4
E$$ACT::::
E$$DVC>:
E$$LOG::::
E$$XPR==
FIN
F$$l.Pp::::
F$$l.VL"""
GO
G$$EFN::
G$$TPP:::
G$$TSS=
G$$TTK=
HIGH
H$$RTZ::
IOEI~R

IOL
rOSB
IO .I~VB=
IO.WVB=
I$$RAR:::
I$$RDN::::
K$$AST=
K$$CNT=
K$$CSR:::

PAGE 3,,-4
K$$IEN:::: 000 l.l. ~5
K$$LDC:::: 000144
K$$TP8:: 000144
LD~;CO
000000
LD$IIn
000000
LD$[lK
000000
LD$DL
000000
l.D$DM
000000
000000
LD$DF~
LD$DS
000000
LD$DT
000000
LD$LP
000000
l.D$MM
000000
l.D$TT
000000
000027
LENT1
000037
LENl.
000244R
l.OW
L$$ASG=: 000000
L$$DRV::: 000000
L$$LDR= 000000
L.. $$PTO= 000036
L$$P11= 000001
000432R
L1
MESS1
000062R
0OOO33R
MES1
M$$CRB= 000124
M$$CRX= 000000
M$$EIS= 000000
M$$EXT= 000000
M$$FCS= 000000
M$$MGE= 000000
M$$MIJP"" 000000
M$$OVR= 000000
OOO:~~~OR
NAM
0006()4R
NONE
N$$LDV::: 000001
N$$MOV= 000041
N$$UMR:: 0000~~4
000022
PL
PLACE
000236R
PLEN
000033
POOL
0OO144F~

O()OO1.4
000004
0000:~4

000002
000010
000006
000002
1.77776
000000
000004
OOO()()6
000023
000121R
000232R
001060R
001146R
001226R
001306R
000000
000000
000000
000000
001402R
000000
000001
000502R
000000
000000
000000
000000
000246R
000074
0OO166R
000032
000224R

****** GX
GX
******
000000
000000
000000
:1.72542
172540

PRMT
P$$BPR::::
P$$CTL::::
PSSFRS::::
P$$GMX~-::

P$$HIL::
P$$LAS=
P$$LOL::::
P$$OFF=
P$$P45:::
P$$RFL::::
P$$RTY=
P$$SRF==
a$$OPT=
R$$DER==
R$$EXV=
R$$JS1=
R$$Kll::::
R$$LKL=
R$$Lll=
R$$MOF=
R$$Mll=
R$$NDC=
R$$NDH=
R$$NDL=
R$$F'OI=
R$$SND=
R$$llM=
R$$60F:::
R$$611=
S$$ECC=
S$$NM1=
S$$NM2:::
S$$NM3=
S$.TIM::
S$$TOF'=
S$$WLK=
S$$WF'C=
S$$WF'R=
S$$YSZ=
TERM
T$$ACR==

OOOOOOR
000063
000000
000310
000000
003100
000000
001130
000000
000000
000000
000000
000000
000005
000000
000000
000001
000001
000001
000001
000000
000001
000005
000226
000001
000000
000000
000000
000000
000001
000000
051522
030530
046461
000000
000000
000000
000036
000005
022000
000250R
000000

000
001
0

( 40 PAGES)
10113 WORDS
VIRTUAl. MEMORY USED:
( 62 PAGES)
161.20 WORDS
DYNAMIC MEMDRY:
00:00:14
ELAPSED TIME:
lERM,TERM/-SP=[1.,lJEXEMC/ML~[11,10JRSXMC/PA:1.,[7,1.JTERM

Example 9-2

Calling Executive Routines
(Sheet 5 of 5)

T$$BTW== 000000
T$$BUF::: 000000
T$$CCA:: 000000
T$$CCO== 000000
T$$CPW:::: 000000
T$$CTR== 000000
T$$CLJP::: 000000
T$$C11::: 000001
T$$E8C:::: 000000
T$$GMC::: 000000
T$$GTS= 000000
T$$HFF== 000000
T$$HLD::: 000000
T$$J16= 000001
T$$KMG::: 000000
T$$LWC= 000000
T$$RED::: 000000
T$$RNE= 000000
T$$RPR::: 000000
T$$RST= 000000
T$$RUB= 000000
T$$SMC= 000000
T$$SYN::: 000000
T$$TF~W::: 000000
T$$UTB== 000000
T$$UTO= 000170
T$$U58::: 000001
T$$VBF= 000000
T$$30F'= 000000
UCB
000240R
IJ$$MHI:: 000000
U$.MLO= 160000
U$$MRN::: 170234
V$$CrR= 000400
V$$RSN::: 000040
X$$[JItT= 000000
$ALOCB=
GX
$CorE! =
GX
$[lEACE!=
GX
$[JEVH[I=
GX
$aMCRL=
GX
$$$ARG::: 000002

******
******
******
******
******

:tJ
H

'tJ

:tJ
H

<
H
t:'"'
tzl

tzl

0
~

(f)
~
(f)

SYSTEM CRASHES

INTRODUCTION
Only certain carefully defined SSTs are allowed in ~ystem
state.
System crashes occur when a software fault is recognized
within system state. The processor trap mechanism signals the
system crash.
CDA is a SYSGEN option which aids the system
programmer in tracing system faults. When a fault occurs, the
Executive trap handling facility saves the register context in
memory, then passes control to the crash routine, which dumps the
memory to a disk or tape. The CDA utility may be used to format
the dump information into a convenient report.

OBJECTIVES
1.

To analyze a report generated by CDA to determine the cause of
a system crash.

RESOURCES
1.

RSX-IIM/M-PLUS Crash Dump Analyzer

RSX-IIM System Lists and Data Structures

249

SYSTEM CRASHES

CRASH PROCESSING
Causes of Crashes
•

Processor traps in system state
Powerfail and parity error traps do not cause crash
Other processor traps cause system crash
System automatically crashes

•

Processor HALTs or enters infinite loop
System must be manually crashed

•

Manually crashing the system
Physical location 40 contains the instruction JMP $CRASH
Processor halted
Address 40 loaded
Processor restarted

Crash Sequences
•

Three different crash sequences
Initiated by lOT
Initiated by EMT or TRAP
Initiated by other trap
Odd address
Illegal instruction
Memory management fault
Floating-point fault/PIRQ

251

SYSTEM CRASHES

Crash Sequences
•

lOT
Used when system detects an inconsistent system state
Sequence:
lOT trap vectors to the module SSTSR
R0 - R5 are not saved
Only PS and PC are pushed onto the stack
Jump to $CRASH in module CRASH is executed
Executive issues lOT only in modules DRDSP and SSTSR

•

EMT or TRAP
Results from EMT or TRAP attemp in system state
Sequence:
Directive save operation is performed
Executive issues lOT
Continue as with the lOT

•

Other Traps
Traps vector to module SSTSR
Directive save operation is performed
If Memory Management Fault, the status registers SR0, SRI,
and SR2 are pushed onto the stack
One word fault code is pushed onto the stack
Byte count of the information saved
stack
Executive jumps to $CRASH

252

pushed

onto

the

SYSTEM CRASHES

Obtaining a Crash Dump Analysis
•

If XDT is present, respond with X to continue with crash

•

Registers are printed on
halts

•

Mount crash dump volume and press the continue switch

•

After memory contents is saved, boot the system

•

Run CDA to produce the analysis

the

console

printer;

the

system

Inputs: The copy of memory created at the crash or by a
previous execution of CDA
The symbol definition file for the system
Outputs: A listing file containing the analysis of the dump
A binary file which is a copy of the contents of
the crash dump volume
•

Command Format:
)CDA <CR)
CDA) [1 istf i le/sw] , [binaryf i le/sw] =symbol f i le/STB,
crash-input [/sw]

•

Two types of switches can be used
Analysis switches
applied to the input

determine

which

CDA

Function switches - provide control options

253

routines

are

SYSTEM CRASHES

CRASH DUMP ANALYSIS
Finding the Cause of a System Crash
•

Usually requires
Output from the CDA utility
Map of the operating system
Listings and maps of relevant tasks

•

Common steps in interpreting a crash dump
Get KERNEL stack pointer
Examine KERNEL stack and $STKDP
(i.e., traps and interrupts)

for

sequence

events

Find PC and PS when trap occurred (from KERNEL stack)
Determine APRs in use and find which
instruction at which the crash occurred
Use the Memory Map
region

locate

the

APR

proper

Use the listing and map of the code occupying
to locate the instruction
•

System data base may have been
occurred

corrupted

long

'Current Task' may not have caused crash

254

mapped

the

partition

the

region

before

crash

SYSTEM CRASHES

Table

l~-l

CDA Switches

CDA Analysis Switches
/ACT

Lists the TCBs for active tasks

/CLQ

Lists the contents of the clock queue

/DEV

Lists the information on all devices in the system

/HDR

Lists the headers for all resident tasks

/PCB

Lists the PCBs

/POOL

Lists the contents of POOL

/STD

Lists the contents of the STD

/ALL

Lists the output of all analysis routines

/DUMP:a:b
Lists the contents of memory between the 18-bit
addresses a and b
/TASK=name:a:b
Lists the virtual space of task 'name' between the
16-bit address a and b
Note:

All analysis switches are used with the crash-input

CDA Function Switches
/LIMIT:n

Limits output listing to n pages
Used on the list file

/MEMSIZ:n

Saves nK words of memory in a binary file
Used on the binary file

/STB

Identifies the symbol definition file
Used on the STB file for the system

255

SYSTEM CRASHES

Basic Information Provided in a CDA
The KERNEL Stack and $STKDP

•

The KERNEL stack provides a record
since system state was entered

the

system

entrances

•

Each trap and interrupt causes task context to be saved on the
KERNEL stack

•

$STKDP indicates how many times context has been saved

•

Contents of stack can be partitioned by locating the saved PSs
Each PS indicates the start of context saved by a trap
an interrupt

PS on stack located by position on stack
First entry
interrupt

stack

from

first

trap

Next PS will be nine words further on stack if trap or
fork occurred
Next PS will be five
interrupt occurred

words

Context pushed because SST
extra trap specific words

further

contains

on
11

stack
words

if
plus

If an SST occurred, it is always the last context on stack
Contents of the APRs

•

Determines mapping between virtual and physical addresses
KERNEL APRs show mapping when crash occurred
USER APRs show mapping of current user task

256

SYSTEM CRASHES

•

PC
PS

$STA CK
Figure 10-1

The Stack After a System Crash -

257

rOT

SYSTEM CRASHES

•

PC
PS
RETURN TO $DIRXT
RO
R1
R2
R3
R4
R5

PC
PS
$STA CK
Figure 10-2

The Stack After a System Crash - EMT

258

SYSTEM CRASHES

•

BYTE COUNT
FAULT CODE
TRAP SPECIFIC
DATA
RETURN TO SDIRXT
RO
R1
R2
R3
R4
R5
PC
PS

SST ACK

Figure 10-3

The Stack After a System Crash - SST

259

SYSTEM CRASHES

Table 10-2
Code

Number of Bytes

Fault Codes for SSTs
SST Trap

Traps through vector 4 (Odd address,
etc .)

Segment fault

Trace or break-point instruction

lOT instruction

Illegal or reserved instruction

Non-RSX EMT trap instruction

Floating-point exception

260

(11/4~)

SYSTEM CRASHES

KERNEL Stack Pointer

= 000562

Location

Contents

000556

024552

- PC at Crash

000560

000010

- PS at Crash

000562*

000004

- Number of bytes

000564

000000

- SST Code

000566

003120

- Addr of $DIRXT

000570

000001

- R0

000572

070514

- Rl

000574

074460

- R2

000576

053204

- R3

000600

144000

- R4

000602

000000

- R5

000604

121204

- PC

000606

030000

- PS

000610

003126

- ADDR of $DIRXT

000612

000000

- R0

000614

070514

- Rl

000616

074460

- R2

000620

053200

- R3

000622

144000

- R4

000624

000000

- R5

000626

121206

- PC

000630

170000

- PS

Example 10-1

SST Information

Context at SST

Context at Trap

A Sample KERNEL Stack

261

SYSTEM CRASHES

AN EXAMPLE
Situation

•

Privileged task TT2 is executing.
Task prompts for terminal number.
User enters terminal number.
System crashes.
CDA prints message:
Pool link error at
Size = 001736

~~~~40

262

-- FWD ptr = 000167

SYSTEM CRASHES

Output from CDA

•

Current task = RMDEMO
Error indicates
Error caused by another task
Other task corrupted list of free pool blocks

•

Contents of KERNEL stack indicate crash caused by rOT
Consistent with pool pointer = 000167
Note that 000167 is JMP instruction and 001736 is location
of $CRASH

•

Any recently or currently active
caused crash

privileged

tasks

may

have

•

Examination of listing of task TT2 shows that
and uses a block of pool

task

allocates

Address of pool stored at location PLACE in task
Task map indicates address of PLACE is 121430
•

Dump of task obtained from binary crash file
Value of 054100 stored in PLACE

•

Examination of pool dump indicates
Value 000040 entered in 84 words starting at 054100
Allocated block started at 054100 and contained 84 bytes
Error at location 000630 in task:

263

MOV should be MOVB

SYSTEM CRASHES

RSX-11M CRASH DUMP ANALYZER
VOLATILE REGISTERS

V4.0

1-NOV-81

SP(U)=121164

AFTER CRASH:

PS=000340

SP(K)=000660

BEFORE CRASH:

PC=141362

PS=030000

RO=137034
MMRO=OOOOOl

Rl=137034

R2=131120

MMR1=000000

R3=000000

MMR2=002326

S P ACE

PAR
000000
000200
000400
000600
001000
004732
005132
177600

S f' ACE

MMR3=000060

S P ACE

PItR
000000
000000
000000
000000
000000
000000
000000
000000

PAR
000000
000000
000000
000000
000000
000000
000000
000000

F\5=137014

R4=000167

PAR
000000
000000
000000
000000
000000
000000
000000
000000

SUP E R V ISO R
PUR
000000
000000
000000
000000
000000
000000
000000
O{){)OOO

S P ACE

F'DR
000000
000000
000000
000000
000000
000000
000000
000000

PAR
000000
000000
000000
000000
000000
000000
000000
000000

K ERN E L

S P ACE
PAR
077506
000000
077506
000200
077506
000400
077406
000600
077506
001000
0"77506
004732
077406
005132
077506
177600

Example 10-2

It
S P ACE
PItR
PAR
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000

CDA - Volatile Registers

264

MAP

~30

00000000
00020000
00040000
00060000
00100000
00146200
00166200
17000000
17000000
17000000
17000000
17000000
17000000
17000000
17000000
17000000
17000000
1"7000000
17000000
17000000
17000000
17000000
17000000
17000000
1700000()
17000000
17000000
1700000()
00045100
17760()OO

;:H

001 O:7j 1 00

1
2
3
4

5
6
7

8
9

10
11
12
13
14
15
16
17
18
:L 9

20
21
'")'")

A.. ....

23
24
:~5

PDR

PAGE 1

U NIB U S

USE R
PUR
077506
077406
077406
077406
077406
0"77506
033006
077406

11:16

26
27
28
29

SYSTEM CRASHES

V4.0

RSX --11 M CRASH DUMP ANALYZER
STACK

1-NOV-81

11:16

PAGE 2

KEf~NEL

KERNEL STACK:
000400

000000

000420

000000

000440

000000

000460

000000

000500

000000

000520

000000

000540

000000

OOO~:)60

000000

131514

131534

133054

133036

123156

001662

000600

006110

133304

044000

025312

132602

030000

026304

001000

OO()620

()263()4

001000

131542

1,oSOO20

133040

010024

011604

124670

000640

000000

000002

000144

000000

036154

137014

141362

030000

000660

003236

000000

136256

131120

000000

136320

134554

142576

000700

170000

Example 10-3

CDA - KERNEL Stack

265

SYSTEM CRASHES

RSX-11M CRASH DUMP ANALYZER
SYSTEM COMMON

V4.0

CRASH OCCURRED AT 11:12:27

1-NOV-81

CURRENT TASK

RMDEMO

TCB ADDRESS = 052110

$SYSID

$EXSIZ

120000

$STKDP ::: 000000

$COMEF:

SYSTEM NAME = RSX11M
LOAD DEVICE

DRO

EXT
MUP
EXV
DRV
PLA
CAL
PKT
EXP
OFF
FDT
DYM

$SYSIZ = 9216./288K

(33-48) 000000

LBN = 00135325

DPR
IRR
GGF
RAS
RBN
SWP
STP

MEANING
22-BIT EXTENDED MEMORY SUPPORT
MULTI-USER PROTECTION SUPPORT
20K EXEC SUPPORTED
LOADABlE DRIVER SUPPORT
PLAS SUPPORT
DYNAMIC CHECKPOINT SPACE ALLOCATION
PREALLOCATION OF I/O PACKETS
EXTEND TASK DIRECTIVE SUPPORTED
PARENT/OFFSPRING TASKING SUPPORTED
FULL DUPLEX TERMINAL DRIVER
DYNAMIC MEMORY ALLOCATION SUPPORTED

= 167400

MEANING
DIRECTIVE PARTITION SUPPORT
INSTALL, REQUEST, AND REMOVE TASK SUPPORT
GROUP GLOBAL EVENT FLAG SUPPORT
RECEIVE/SEND DATA PACKET SUPPORT
ROUND ROBIN SCHEDULING SUPPORTED
EXECUTIVE LEVEL DISK SWAPPING SUPPORTED
EVENT FLAG MASK IS IN THE TeB

SYSTEM FEATURE MASK (THIRD WORD)
BIT SET
CLI
EIS
STM
AST

496.

= 013377

SYSTEM FEATURE MASK (SECOND WORD)
BIT SET

(49-64) 000000

FILE SIZE

= 025214

MEANING
MULTIPLE CLI SUPPORT
SYSTEM REQUIRES THE EXTENDED INSTRUCTION SET
SYSTEM HAS SET SYSTEM TIME DIRECTIVE
SYSTEM HAS AST SUPPORT

Example 10-4 CDA - System Common
(Sheet 1 of 3)

266

PAGE 3

$SYUIC = [1,54]

$NTUIC = [1,54]

SYSTEM FEATURE MASK (FIRST WORD)
BIT SET

11:16

SYSTEM CRASHES

l-NOV-81

V4.0

RSX-llM CRASH DUMP ANALYZER
SYSTEM COMMON DUMP

010110 $f'RIHL 003100
$PRILL 001130
$PFRSZ 000310
$f'OLBP 000063
$POLFL 000000
$PARPT 017320
$CLKHD 045716
$COPT 043630

010250

000000
000000
000000
000000
000000
000000
000000
000000

007770 $TKNPT
$SHFPT
$CKCNT
$CKCSR

010130 $f'ARHD 117734
$LDRPT 117510
$TSKHD 117510
$XCOMl 001200
$XCOM2 001345
$GGEF 000000
$GFTCB 010150
$GEFPT 010150

010270

000000
000000
000000
000000
000000
000000
000000
$ERBAF 000000

()tOOl. 0 $PWRFL 000000

010150 $GEFDM
$IDLCT
$IDLPT
$DYPMN

000254
000001
170017
020035
020037
020037
017440
017440

010310

000000
000000
000000
000000
000000
000000
000000
000000

VALUE

007750

010316
000207
$HEADR 052654
160400
$COMEF 000000
000000
$SYSID 030463
020040
110610
111040
172542
172540
!~CKLDC 000144
$SYUIC 000454
000000
!~EXSIZ 120000

$SIGFL 000000
$L.OGHD 000000
$MCRCB 000000
$LSTLK 000000
000003
$CRAVL 046464
000000

LABEL

VALUE

ADDR

L.f-IBEL

LABEL

PAGE 4

VALUE

ADDR

11:16

010030 $ACTHD 117510
$ItICSV 001037
$TKTCB 052110
$LBUIC 000454
$ABTIM 041233
$RQSCH 000000
$STKItP 000000
$DEVHD 040746

010170

020040
$BTMSK 000001
000002
000004
000010
000020
000040
000100

010330

000000
000000
000000
000000
000000
000000
000000
000000

010050 $RNDCT 000005
$SWF'CT 000036
$ERRPT 000000
$CFLf'T 050740
000000

010210

000200
000400
001000
002000
004000
010000
020000
040000

010350

000000
$ERFID 000000
000000
000000
000000
000000
$PRMOD 000106
$SYSIZ 022000

010230

100000
$ERHEA 000000
010232
$ENTSQ 000000
$ERRSQ 000000
$ERFLA 000000
000000
000000

010370

000000
135325
051104
000760
177777
000015
000037
000030

026~~54

$INTCT 177777
$FRKHD 000000
010070

010066
$FMASK 013377
167400
025214
$HFMSK 000003
$PTTCB 112314
$PRISZ 033364
$POLST 000401

Example 10-4 CDA - System Common
(Shee t 2 of 3)

267

$DPM

SYSTEM CRASHES

RSX-11M CRASH DUMP ANALYZER
SYSTEM COMMON DUMP
ArtDR

V4.0

1-NOV-81

11:16

ADDR

000074
000074
000144
000121
000013
000001
000013
000014

010470 $PKAVL 054034
$PKNUM 002403
$MXEXT 177777
$UMRHD 000000
$UMRf'T 170200
000034
$UMRWT 000000
010504

010550 $MCRPT 111750
050712
000000
000040
003404
005015
000076
005015

010430

000033
$TTNS 000063
$TLMTS 000200
000000
000014
000001
000000
000001

010510 $TEMPO 111750
$TEMP1 052514
$TEMP2 130562
$TEMP4 000000
$AVRHD 000000
$MOULS 047064
$CXDBL 000000
$SYSNM 051522

010570

010450

000027
000000
000073
000000
000073
000000
$TIKLM 000143
000000

010530

010410
$TKPS

LABEL

030530
046461
$CLICQ 000000
010534
$CPTBL 010550
052464
000000
000000

Example 10-4 . CDA - System Common
(Sheet 3 of 3)

268

ADDR

LABEL

VALUE

LABEL

VALUE

PAGE 5

041515
037122
000000

SYSTEM CRASHES

RSX-11M CRASH DUMP ANALYZER
SYSTEM COMMON ALPHABETIZED DUMP

V4.0

1-NOV-81

11:16

PAGE 6

$ABTIM 041233

$ERLOF

000

$MOULS 047064

$STKDP 000000

$ACTHD 117510

$ERRPT 000000

$MXEXT 177777

$SWPCT 000036

000000

$ERRSa 000000

$NTUIC 000454

$SYSIZ 022000

$CFLF'T 050740

$EXSIZ 120000

$PARHD 117734

$SYSNM 051522

$CKCNT 172542

$FMASK 013377

$PARPT 017320

$SYUIC 000454

$CKCSR 172540

$FRKHIt 000000

$PFRSZ 000310

$TEMPO 111750

000144

$GEFDM 000254

$PKAVL 054034

$TEMP1 052514

$CL.ICQ 000000

$GEFPT 010150

$PKMAX

005

$TEMP2 130562

$CLKHD 045716

$GFTCB 010150

$PKNUM

003

$TEMP4 000000

$COPT

043630

$GGEF

000000

$POLBF' 000063

$TKNf'T 110610

$CPTBL

0105~)O

$HEADR 052654

$f'OLFL 000000

$TKPS

!~Cf:;:AVL

046464

$HFMSK 000003

$POLST 000401

$TKTCB 052110

~;CUI:;:PR

341

$IDLCT

001

$f'RIHL 003100

$TSKHD 117510

$CXDBL

000

$IDLFL

000

$PRILl. 001130

$TTNS

000063

$DEVI-ID 040"746

$IDLF'T 170017

$F'RISZ 033364

$UMF~HD

000000

$[lICSV 001037

$INTCT 177777

$PRMOD 000106

$UMRPT 170200

$DF'M

000037

$LBUIC 000454

$PTTCB 112314

$UMRWT 000000

!~ENTSQ

000000

$LDRF'T 11]510

$F'WRFL 000000

$WTCSI~

$ERBAF

000

$LOGHD 000000

$RNDCT 000005

$WTDUM 017320

$ERFID 000000

$LSTLK 000000

$RQSCH 000000

$XCOM1 001200

$ERFLI~

000

$MCRCB 000000

$SHFPT 111.040

$XCOM2 001345

~;ERHEA

000000

$MCRPT 111750

$SIGFL 000000

$AVI~HD

~iCKLDC

Example 10-5

CDA

- System Common Alphabetized Dump

269

000144

017320

SYSTEM CRASHES

Pool link error at 000040 -- FWD ptr
POOL SIZE (BYTES)

PAGE 7

1-NOV-81

V4.0

RSX-11M CRASH DUMP ANALYZER
POOL STATISTICS

000167

Size

= 21376.

LARGEST FREE BLOCK (BYTES) - 36.

= 144.
NUMBER OF FRAGMENTS = 13.

TOTAL FREE BYTES

MINIMUM BLOCK SIZE (BYTES)

PODL. BITMAP (CONSTRUCTED FROM LINKED POOL, BLOCK FREE IF BIT SET) :

000000
000000
000000
000000
000000
000000
017740
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000

O()OOOO
000000

000000
001400
000000
000000
000000
170000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000

060000
000000
000000
000000
000000
000037
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000

002014
000000
000000
000000
007600
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000

000000
000000
000000
000000
002000
003400
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000

000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000

000200
000000
000001
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000

Example 10-6 CDA - POOL Statistics
( Sheet 1 of 2)

270

001000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
OOO()OO

001736

SYSTEM CRASHES

RSX-llM CRASH DUMP ANALYZER
POOL STI~TISTICS
000000
000000
000000
000000
000000

000000
000000
000000
000000
000000

V4.0

000000
000000
000000
000000
000000

1--NOV-81

11:16

000000
000000
000000
000000
000000

000000
000000
000000
000000

Exarnp1 e 10-6 CDA - POOL Statistics
(Sheet 2 of 2)

271

PAGE 8

000000
000000
000000
000000

SYSTEM CRASHES

1'-NOV--81

11:16

= GEN

PCB ADDRESS

= 055174

LOAD DEVICE

SYO:

RSX-llM CRASH DUMP ANALYZER
ACTIVE TASKS

V4.0

PAGE 19

TT2

= 054440
LOAD ADDRESS = 00440400
TCB ADDRESS

PIU = 50.

MAX SIZE

1/0 COUNT

000031

PAR

= 1.

UIC

EVENT FLAGS

= [7,377]

= <1-16) 000000

LBN = 00117403
TI

= TT2:

<17-32) 000000

T.STAT:
-CHK

WFR

T.ST3:

-PMD

REM

T.TIO:

000000

PRV

MCR

TeB DUMP:
000000
000020
000040
000060
000100

000000
054456
000062
000031
054536

000462
000000
117403
047102
000000

000000
000000
046166
047102
000001

Example 10-7

100100
044256
055174
000000
054462

000000
007754
000031
000000
000000

000000
000000
111404
000000

CDA - Active Tasks:

272

054452
020001
000000
054532

TT2

000000
074000
000000
000000

SYSTEM CRASHES

V4.0

RSX-11M CRASH DUMP Al'fALYZER
TASK HEADERS
000040
000060
000100
000120
000140
000160

000000
000376
000000
000000
132277
000000

000000
000000
042360
046116
046430
177777

055102
000000
000000
000000
000123
044000

1-NOV-81

11:16

126202
000000
000000
000000
000612
000056

000000
055144
046166
000001
051006
120533

000001
000000
043630
046072
000000
000000

PAGE 30

000000
000007
000000
053654
1700()O
000000

000000
046072
046072
120000
124636

TT2
HEADER ADDRESS == 054554
PS==170000

TCB ADDRESS

054440

PC=122200

RO==OOOOOO

R1=054350

R2=044336

R3==000001

R4==000001

R5=000060

INITIAL PS == 170017

INITIAL PC == 121442

INITIAL SP = 121172

HEADER SIZE

NO. OF WINDOWS == 1.

NO. OF LUNS ::: 6.

122.

CURRENT UIC

SP==121172

DEFAULT UIC == [7,377]

054702

H.GARD

DSW == 000001

054744

H.VEXT

000000

H. SF'I:n

._.,J •

H.FCB ::: 000000

H.FORT

000000

H.OVLY

000000

C:O

LOGICAL UNIT TABLE:

DEV

WINDOW

-_._---

SYO:
SYO:
SYO:
SYO:
rIO:
CLOt

2
3
4

c.-

W.CTL

W.FCB

F.FNUM

--_._ .... -

F.FSEQ
_ 0 _ _ _ _ _ ••

F.STAT

NAC

_............ _..- .....

NLCK

000000
000000
000000
000000
000000
000000

WINDOW BLOCKS:
PAR

VIRT LIMITS

ATT DESC

WND SIZE

OFFSET

1ST PDR

NO.

LAST PDR

GEN

120000 123077

047074

000031

000000

177612

014006

003777

HEADER:
000000

121172

000172

Example 10-8

053254

135600

CDA - Tasks Headers:
(Sheet 1 of 2)

273

170017

TT2

121442

SYSTEM CRASHES

RSX-11M CRASH DUMP ANALYZER
TASK HEADERS
000020
000040
000060
O()O100
000120
O()0140
O()0160

1211.72
000000
000373
000000
000000
000031
000001

000000
000000
000000
046166
046116
000000
044336

Example 10-8

V4.0

000000
054702
000000
000000
000000
000612
054350

000000
000001
000000
046166
000001
014006
000000

1····NOV-81

11:16

000000
000000
000000
000000
055174
l700()()
000000

000000
000000
054744
046166
1.20000
122200

CDA - Tasks Headers:
(Sheet 2 of 2)

274

PI~GE

000000
000000
O()0006
OOO()()()
123()T7
O()()()60

TT2

000000
O()OO()O
046166
046072
047074
O()OOOl

SYSTEM CRASHES

RSX-IIM CRASH DUMP -ANALYZER
POOL DUMP
053260
053270
053300
OS:3310
053320
OS3330
053340
0~)3350

053360
053:~70
O~53400

053410
0:'53420
053430
0~5:S440
0~53450

053460
()~534 70
053500
053:510
O~53~'j20

053530
0~53540
()~53~55()
O~):~~)60
()53~'j70

053600
0536:LO
053620
053630
0:53640
()53650
0536<SO
05:3670
()~53700
()~)37:LO

053720
05~5730
()~)374()

053750
053760
0~53770
()~)4000

054():L0
0~34020
0~)4()30

054040
0~)4()50

054060
054()70
054100

1-NOV-S1

V4.0

114250
000001
115404
** 053276
** 000000
000106 * 114250 * 000000
115404 * 000000 * 001000
* 000401
* 000000
000016 * 121350 * 000000 *
** 000401 ** 000000 ** 000000 000000
* 000000
114730
* 000000
* 121246
* 066117
131574
000000 * 000000
* 000000 * 000000 * 000000
** 000033
053640 * 000044 * 111404 * 041740
000000
000001
000000
111426
000000
000000
000024
053640
000000
053640
000010
000403
000000
000000
120412
000212
000000
000454
000454
143107
120750
120412
170017
000000
000000
000000
000000
000000
000000
000000
000000
000000
053552
000002
143030
000000
14:3142
000000
000373
000000
000000
000000
000000
053634
000006
046166
000000
043630
000000
041006
000000
046166
000000
046072 * 000000
046116
000000 * 0000()2
046674
120000
144277
052360
000243
000000
001212
021006
115404
160000
175577
053270
000156
000147
000616
066402
170000
121016
000000
000000
1.43107
000060
000060
1.20431
000000
000000
054224
000014
000000
000000
000403
000000
054374
000062
026226
000000
055174
115274
004076
000123
000000
000123
000000
111404
000050
054750
000000
046430
046430
000000
000000
000062
000000
131574
007537
000000
053732 * 000000
05:~736
177776
000001
044000
054440
100400
020000
050000
000062
142440
046142
115274
000306
054440
000000
000000
000306
000000
054002
000000
000000
000000
054012
000000
000000
000003
053742
05401.6
000000
000000 + 055240 + 000044
+ 000020 + 000000 + 044416 + 000400
+ 135154 + 005103 + 140054 + 000000
+ 005077 + 140:L44 + 000070 + 000000
+ 000000 + 000000 + 000000 + 000000
000040
000040
000040
000040

*
*
**
*
*
*
*
*
**
*
**

*
*
**
*
**
*
*
*
*
*
*
**
*
*
*
*
*
**
*
*
*
*
*
**
*
*

*
*
**
*
**
*
**
*
*
*
***
*
*
*
*
*
**
*
**
**
*
*
*

*
**
*
**
*
*
*
*
*
*
*
**
*
*

*
**
*
**
*
*
*
*
*
*
**
*
*

**
**
*
**
*
*
**
*
**
*

11:16

PAGE 82

!XQ

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2
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NJP TYX ED2 L2
! Y
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AJ lUX LH4 XOL !2 EbL<
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! !? d@S
AYW 01L AP
!!
2
2
2
2! !
F LIN
JVV
LG4

[ABOVE LINE REPEATED 9. TIMES]
054220
054230

000040
* 000040
* 000040
000040

000040
000040

2
2

Example 10-9 CDA - POOL Dump
(Sheet 1 of 2)

275

F
{

2
2

2! !
2! !

SYSTEM CRASHES

RSX·-l1M C/:;:ASH DUMP ANALYZER
F'OOL DUMP
054240
O~54250

054260
054270
0~54~500

054310
()~54~52()

0~)4330
0~54340
0~)4350
()54~560

0543}0
0~:;4400
()~5441 0

054420
0~34430
0~:;4440

054450
054460
O~544 70
0~54500
054~)l0

054520
054~:;30

054~540
0~54550
054~560

054570
054600
054610
0~:;4620

054630
054640
0~54650

054660
054670
()54700
()~54710

054720
0~:;47~50

054740
054750
05476()
0~'j477()

() ~5 ~.)() 0 0
()~.:;~5()10

05~5020
0~)~5030

() ~5 ~:i 0 40
()~550!50

055060
0!5~50"70
()~.'i~j:l. 00
055110
055:1.20

()~5~5 130

**
**

*
*
*
**
**
*
*
*
*
*
**
*
**
*
*
*
*
*
*
*
*
*
*
**
*

*
*

*
*
**
*
*
*
*
*
*
**
*
*
*
*

000040
000040
000040
000040
000040
000040
000040
000040
000040
000040
000040
000040
000040 * 000040 *
000040 * 000040
000040 * 000040 *
170000
125200
000004
130034 *
000000 * 000000
111404 * 055050
121246 * 004110
000005
140111
100000
000000
000000
000462
000000
000000
054456
000000
007754
000000 *
000062 * 117403
000031
111404
000031
047102
000000
000000
0545:36
000000
000000 * 001000 *
053254
135600
170017
121442
000000
000000
000000
000000
054702 * 000001
000000 * 000000
000000 * 000000
000006
046166 *
000000 * 046166 *
000000
046072
000000
000001
123077 * 047074 *
000612
014006
000060 * 000001
0543:':iO
000000 *
1.20::'i02
000176
000454
000454
120506
000000
000000
000000
000000
000000
126202
000000 *
000376
000000
000000
055144
000000
042360
000000
046166
000000
046116 *
000000
000001
132277
046430
000612
051006 *
O()()OOO
17777?

**
*

**
**

*
*

*
*
**
*

*
*
*
*
*
*
*
*
*
*
*
*
*
*

*
**

*
*
**
*
*
*
*
*
*
***
*
**
*

l-NOV-81

V4.0

**
*
**

*
**
*

*
*
**
*
*
*
*
**
**
*
*
*
*
*

**
**

000040
000040
000040
000040
000040
000040
000040
000040
000040
000040
000040
000040
000040 * 000040
000040
000040
000040 * 000040
127542 * 000000
131100 * 000110
000000
000773
000540
044000
140046
000000
000056
000000
053654
000000
000000 * 100100
054452
000000
000000
044256
074000
020001
046166 * 055174
000000
000000
047102
000000
054532 * 000000
000001
054462
121172
000172
003777
003777
121172
000000
000000
000000
000000 * 000000
000000 * 000000
000373
000000
000000
054744
000000
046166
000000
046166
000000
046116
055174
120000
000031
000000
170000 * 122200
000001
044336
000000
120424
140354
135600
1"7001.7 * 121"714
000000 * 000000
000000
000000
055102
000001
000000 * 000000
000000 * 000000
000007
046072
000000
0436:~0
000000 * 046072
000000 * 046072
053654 * 120000
000000
000123
170000
124636
044000
000000

**
**
*

**
..
*
*
*
*

*
*
*
*
*
*
*

*
**
***
*
*
*
*
*
*
*

*
**
*

2
2
2
2
2
2
2
2
2

2
2
2
2

2
2
2
2
!
2
,sp $KH
! II .GD

2
2
2
2
2
2
2
2
2
.BR
.T2

2!
2!
2!
2!
2
2
2
2
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p *bl
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Example 10-9 CDA - POOL Dump
(Sheet 2 of 2)

276

PAGE 83

11:16

,
,

DUMP

MACRO M1200

01-NOV-81 11:09

PAGE 3
.TITLE

DUMP

3
4
5
6
7

THIS TASK ASKS THE USER FOR A TERMINAL NUMBER AND A
COMMAND LINE.
IT THEN PASSES THE COMMAND TO MCR
AS IF HAD ORIGINATED AT THE SPECIFIED TERMINAL.
IT
PERFORMS THIS TASK BY USING SYSTEM SUBROUTINES, $ALOCB
AND $QMCRL, TO ALLOCATE A BLOCK FROM POOL AND PASS IT
TO MCR.

9
10
11

THE TASK MUST BE BUILT PRIVILEGED AND MAP TO THE EXECUTIVE.

TO ASSEMBLE:

13
14
15
16
17

)MAC TERM=[1,lJEXEMC/ML,[11,10JRSXMC/PA:1,[(YOUR UIC)JTERM
TO BUILD:

~
~
~

19
20
21
22
23 000000
24
25
26
27 000000
000003
000006
000011
000014
000017
000022
000025
000030
28
29 000033
000036
000041
000044
000047
000052
000055
000060
30
31 000062
000065
000070
000073
000076
000101
000104
000107
000112
000115
000120
32

>TKB TERM/PR:5=TERM,[1,54JRSXIIM.STB/SS
.MCALL
DCBDF$

TERMINAL MESSAGES

;

012
116
122
040
122
116
040
115
122
000033
105
105
101
117
101
040
122
103
000027
116
102
040
040
124
103
114
124
040
101
041
000037

015
124
040
124
115
101
116
102
072

105
105
101
105
111
114
125
105
040

116
122
040
115
116
106
040
122

124
040
103
115
104
117
115

125
105
111
116
040
124
054
122
101
111

115
122
123
117
117
101
040
131
107
116

EXIT$S,QIOW$S,DCBDF$

PRMT:

.ASCII

<12>(15)/ENTER A TERMINAL NUMBER: I

PLEN
MES1:

.ASCII

.-PRMT
;LENGTH OF PROMPT
IENTER A COMMAND FOR MCRI

LENTl
MESS1:

.ASCII

.-MESl
INUMBER IS NOT OCTAL, TRY AGAIN!I

LENl

Example 10-10

.-MESSI

Listing of Task TT2
(Sheet 1 of 5)

(DUMP)

DUMP

MACRO M1200
33 000121
000124
000127
000132
000135
000140
000143
34

35 000144
000147
000152
000155
000160
000163
~36

-.J
00

37 000166
000171
000174
000177
000202
000205
000210
000213
00()216
38
39
40
41
4'1
...
43 000220
44 O()O224
4~j OO()230
46 000232
47 OO()234
48 O()O236
49 000240
50 000242
~H 000244
~j2 O()0246

01---NOV--81 11:09

124
115
101
116
040
125
041
000023
116
120
114
126
114
114
000022
111
040
122
040
040
115
116
111
125
000032

111
114
117
106
116

122
116
040
124
117
104

117
117
040
101
101
105

040
117
101
111
102
041

057
105
117
117
103
115
104
116
124

117
122
122
116
117
101
040
120

10~i

PAGE 3--1
ERMES:

.ASCII

/TERMINAL NOT FOUND!/

ERL
POOL:

.ASCII

/NO F'OOL AVAILABLE!/

PL
IOERR:

.ASCII

.-POOL
!I/O ERROR ON COMMAND INPUT!

.-ERMES

(f)

t<
(f)

1-3
IOL

[%l

.-IOERR
.EVEN

;MAKE SURE OF WORD BOUNDARY

PROGRAM DATA

1.24
177777
000000
000000
000000
000000
000000
000000

124

BUF:
.BLKB
IOSB:
.BLKW
.ASCII
NAM:
ERRCNT: .WORD
COMM:
.WORD
PLACE:
.WORD
UCB:
.WORD
DCB:
.WORD
LOW:
.WORD
HIGH:
.WORD

4
2
/TT/
--1
0
0
0
0
0
0

:tJ
;BUFFER FOR TERMINAL NUMBER
;I/O STATUS BLOCK
;TERMINAL NAME
;ERROR IN[lICATOf~
;ADDRESS OF COMMAND LINE IN POOL
;ADDRESS OF POOL BLOCK
;SAVED UCB ADDRESS
;SAVED DCB ADDRESS
;SAVED LOW UNIT NUMBER
;SAVED HIGH UNIT NUMBER

::)~5

BEGINNING OF CODE

~)~)

56 000250

000322
~_'i8 O()O374
~j9 000400
60 000404
61 000406
(l2

TERM:

~j;1

016703
012700
005002

177626
000220'

OIOW$S
(HOW$S
MOV
MOV
CLR
CALL

6:~

64 000412
6~5 000414
66 0OO4Ul
67 000422
613 0OO42b
b9 000432
70 000434

005702
001402
000167

000436
CONT:

0127()0
011000
001422

OOOOOOG
L1 :

Example 10-10

TST
BEO
.IMP
CALL
MOV
MOV
BEO

tIO.WVB,t5,tl",,<tPRMT,tPLEN,t40>
;PROMPT
IIO.RVB,t5,tl"tIOSB,,<tBUF,t4> ;GET 'TT' NUMBER
;SAVE CHARACTER COUNT
IOSB+2,R3
tBlIF,RO
;SET UP FOR CALL TO CONVERSION
R2
ROUTINE - FROM ASCII TO
$eOTB
BINARY(OCTAL)
; Rl WILL CONTAIN CONVERTED NUMBER
; R2 WILL CONTAIN TEr~MINATOR
R?
;TE8T FOR ERROR
;IF NOT CONTINUE
CONT
;GO TO Ef~ROR ROUTINE
ERRl
; ;SWITCH TO SYSTEM STATE
$SWSTK,BACK
; ;PICK UP LIsniEAD FOR DCB LIST
t$DEVHD,RO
(RO) ,RO
;;GO TO NEXT DCB
;; IF NONE FINISH liP
GO

Listing of Task TT2
(Sheet 2 of 5)

3:
()

(DUMP)

(f)

::c

[%l
(f)

DUMP

MACr·W M1::>'OO
71 0004::S6

000444
73 O()O446
74 O()()454
ni 000462
76 OO()466
77 000470
7B OO()474
7'J 000502
flO 000504
131. 000504
82 OOO~i:LO
B:~ OO()512
134 O()()516
13""., 000522
136 000526
87 0005:30

01·_·NOV--B1 1.1.:09

026760
OOUP2
116067
11.6067
O~~O167

17n)66

000006
000007
177560

PAGE :3-··2

000004

CMF'
BNE
MOVB
MOVB
CMF'
BGT
MOV
ADD
RETURN

l.T7!570
177~)64

OO::~:361

010067
062767

177!:-I46
OOOOOl

OO~i767

17752:~

00:L402
00()167
016700
016002
010104
166704

177530

000430
177520
000002

GO:
BACK:

TST
£lEO
JMF'
MOV
MOV
MOV
SUB

1$:

1.77510

I'V
-....J
1...0

139 O()()534
90 000540
'71 000542
9') 000544
9::S 000550
'/4 000556
9~i O()O562
96 O()0566
97 000572
'JI3 O()O574
99 OO()6()0
:LO() 000604
lO1 000606
10:~ 000606
10:5 ()()06:1.2
:L04 0006:1.4
l O~i O()()620
106 000624
107 0006:30
lOB 0006:54
109 O()063t.1
110 000644
Hl 000652
1.:I.::! OOO?24
1.l.3

ooono

:L:l4 000"734
:1.15 001006
:1.16 O()1010
117 O()10:l.4
111:1 ()O1020
1.1.9 ()O102~~
120 001026
121 OO:t032
1.22 0010:·56
12:5 001044
:1.24 001050
l2~5 0010S:;!
126 001052
127

016005
070504
060502
010267
012767

000010

012701

000124

177470
1.77777

177454

10~~404

005267
010067

1.77432
177432

NONE:
BACK2:

TST
BEll
JMF'
MOV
MOV
MDV
SOB
MDV
ADD
OIOW$S
CLR
CLR
OIOW$S
BCC:
JMP
TSTB
BOE
JMF'
CALL
MOV
MOV
CALL
RETURN

17742()

005767
001402
000167
01270()
016701
012721
0'7'7003
016'767
062767

1773"74
000004

005067
OOS067

177274
177272

103002
000167
:1.05767
002002
00016"7

000272
177204
000260

016701
0:1.6761

1 '7'7200
177176

00040tl
000124
17740tl
000040

MOV
MUL
ADD
MOV
MOV
CALL
MOV
CALL
BCS
INC
MOV
RETURN

1$:
2$:

1. '7'73"70
17"7362

3$:
4$:
000002
BACK::~:

EXIT$S

Example 10-10

NAM,[I.NAM(RO)

;;LOOK Fem 'TT' DCB
;;IF NOT 'TT' GET NEXT DCB
; ;GET LOW UNIT NUMBEF~
D.UNIT(RO),L..OW
; ;GET HIGH UNIT NUMBER
D.UNITt1(RO),HIGH
; ; COMPAF~E INPUT WITH HIGH
R1,HIGH
;;IF INPUT LAF~GER GET NEXT DCB
L.1
; ;SAVE DCB ADDRESS
I;:O,DCB
;;INDICATE NO EFmOR HERE
tt ,EI;:RCNT
; ; F~ETlJRN TO USEF~ STATE
;NOW IN USEf~ STATE
;TEST FOR ERROf~
ERRCNT
1$
;CONTINUE IF OK
;GO TO EFmOR fWUTINE
ERR2
;GET DCB ADDRESS
DCB,RO
D.UCB(RO),R:?
HiET ADDRESS OF FIRST UCB
R1,R4
;MOVE FOR CALCULATIONS
;FlND THE NUMBER WITHIN UCBS
LOW,R4
; FOR CURF~ENT DCB
D.UCBl.(RO),R5
;GET UCB LENGTH
R4,R5
;CALCULATE OFFSET FOR UCB
R5, f~2
;CALCULATE BEGINNING OF UCB
;SAVE UCB ADDRESS
R2,UCB
;RESET ERROR COUNT
t-1,ERRCNT
; ;SWITCH TO SYSTEM STATE
$SWSTK,BACK2
; ;SET BLOCK SIZE
tB4.,f~1
;;ALLOCATE BLOCK FROM POOL
$ALOCB
HNO ROOM IN POOL
NONE
;;INDICATE NO ERROR HERE
ERRCNT
; ;SAVE ADDRESS OF POUL_ BLOCK
Ii:O,PLACE
v;RETURN TO USER STATE
;BACK IN USER STATE
;CHECK FOR EHROR
EHRCNT
1$
;C:ONTINUE IF OK
;00
TO ERROF~ FWlJTINE
ERR3
;SET LENGTH OF BLOCK
t84.,RO
;OET AIr[lf~ESS OF BLOCK
F'LACE,Rl
t40, (R1)t
;F'LACE BLANKS IN BLOCK
RO,2$
; LOIJF' UNTIL THROUGH
;CALCULATE LOCATION OF COMMAND
PLACE,COMM
; LOCATION IN BLOCK
t4,COMM
;PROMF'T FOR COMMAND
tIO.WVB,t5,t1",,<tMES1,tLENT1,t40>
;CLEAR THE 110 STATUS _. WORD 1
IOSB
;
- WORD 2
WSBt2
;INF'UT COMMAND
tIO.RVB,t5,t1"IOSB,,<COMM,t80.>
~:S$
;CONTINUE IF OK
pBRANCH IF tHO ERROR
E:f~R4
;CHECK FOR I/O ERROR
lCISB
4$
;CONTINUE IF OK
;BRANCH IF ERROR
ERR4
; ;SWITCH TO SYSTEM STATE
$SWSTK , BACK::~
; ;GET ADDRESS OF BLOCK
PLACbR1
;;PLACE (JCB ADDRESS IN BUICK
UGB,2(Rl)
; ; (WEUE BLOCK TO MCR
$OMCRL
;;LEAVE SYSTEM STATE
;BACK IN USER STATE
;EXIT
L1

Listing of Task TT2
(Sheet 3 of 5)

( DUMP)

(f)

t<
(f)

...:3
t:tJ

3:
()

::0

(f)

:c
t:tJ

(f)

DUMP

MACRO M1200

01-NOV-81 11:09

PAGE 3-3
ROUTINE TO HANDLE BAD TERMINAL NUMBER

128

129
130 001060
1:31 001132
132 001136
133 O()1140
134 001142

ERR1:
012700
005020
077302
000167

000220'
CLEAR:
177102

aIOW$S
MOV
CLR
SOB
JMP

tIO.WVB,t5,tl",,<tMESS1,tLEN1,t40>
iPRINT MESSAGE
tBUF,RO
;GET INPUT BUFFER ADDRESS
(RO>t
iCLEAR BUFFER
R3,CLEAR
iR3 CONTAINS CHARACTER COUNT
TERM
;TRY AGAIN

13~j

ROUTINE TO HANDLE NON-EXISTENT TERMINAL

136
137
138 001146
13'i'

;

EfI:R2:

aIOW$S
EXIT$S

ERR3:

aIOW$S
EXIT$S

O()l :~20

140
141

tIO.WVB,t5,tl",,<tERMES,tERL,t40>
;EXIT

i Pf\l NT MESSAGE

ROUTINE TO HANDLE POOL ALLOCATION FAILURE

14::!

143 001226
144 001300

tIO.WVB,t5,tl",,<tPOOL,tPL,t40>
;EXIT

iPRINT MESSAGE

14~5

ROUTINE TO HANDLE I/O ERRORS ON COMMAND INPUT
THE POOL BLOCK MUST BE DEALLOCATED!

146
1.47
lAO

149

001:~06

1~50 001.360
151 001364
152 001370
1~53 001374
1.~.i4 001400
l!'.'j5 001402
156 001402
157

ERf~4

016700
012701

176646
000124

IHDW$S
CALL
MOV
MOV
CALL
RETURN

FIN:

EXIT$S
.END

000250'

Example 10-10

tIO.WVB,t5,tl",,<tIOERR,tIOL,t40>
;PRINT MESSAGE
$SWSTK,FIN
;;SWITCH TO SYSTEM STATE
iiGET ADDRESS OF BLOCK
PLACE,RO
tB4.,Rl
;iSET BLOCK LENGTH
$DEACB
iiDEALLOCATE BLOCK
iiLEAVE SYSTEM STATE
iBACK IN USER STATE
iEXIT
TERM

Listing of Task TT2 (DUMP)
(Sheet 4 of 5)

DUMP
MACRO M1200
!:iYMBOL TABL.E

ex>
I-'

01 .... NOV .. ·B:I. :l.1!09

A$$BIO:::: 000000
(~$$BHT:: O()()OOO
AHCHK:: 000000
(.1~5$CLI": 000004
A!J$CPf:i:: 000000
AUNSI:: 000000
A$$PRI:: OO()OOO
A!~$TfW::: 000000
0005041;;
BACK
BACK2
0OO606R
0010521;;
BACK3
0OO220R
BUF
[I$$I...V:I.::: 030463
B$$LV2:: O:W040
CLEAR
001136f.:
0OO234R
CIJMM
000422R
CONT
CHCDA:: 000002
C!J~~CHE:::: 000000
C!51iCKP:: 000004
CHCSH:: 177404
C$$INT:: 000000
C$$l1NS:: 000001
CHORE:: 002022
CHOTM:: 000000
CUHSH:: 177564
CUR UN:: 000000
CUSHT:: 000000
CUTTY:: 177564
DCI)
0OO242R
DUHll== 000001
DUIA":: 000000
[I!.$IBK": 000000
D$$L1.:I.:: 000002
[lll$Ml :1:: O()OOOl
D$$F'AI;;:: 000000
[I!.~iSHF:: OO()OOO
DUWCK:: 000000
I)$$YNC:: 000000
D$$YNM:: 000000
I).DSP
000012
I).LNK
000000

ABS.
EJ~I~()RB

000036
00:1.410
DETECTED!

D.MSK
D.NAM
D.PCB
[I.UCH
D.UCBL.
[I.UNIT
D.VCAN:::
D.VDEB::
D. VIN!::::
D.VOUT::::
D.VPWF::o
EI;;1...
ERMES
ERRCNT
ERRl
ERR2
ERR3
ERR4
E$$ACT=
EUDVC::::
E$$LOG=
E$$XPR::
FIN
F$$l..Pp::::
F$$LVL::::
GO
G$$EFN::
G$$TPP::::
G$$TSS::::
G$$TTK;:::
HIGH
H$$RTZ"
IOERR
101...
IOSB
10. RVB";:
IO.WVB:::
I$$RAR::;:
I$$RDN::
I,UAST::
KUCNT=
K$$CSR=

PAGE 3-.. -4

000014
OO()O04
0000]4
000002
000010
000006
000002
1"7"7776
000000
000004
000006
00002:~

0OO121R
000232R
001060R
001146R
001226f.:
00n06R
000000
000000
000000
000000
001402R
000000
000001
00050:m
000000
000000
000000
000000
000246H
0000"14
000166R
0000~52

000224R
GX
****** OX
******
000000
000000
000000
172542
172540

K$$IEN:::
K$$L..DC:::
K$$TPS::::
LD$CO
L.D$DD ....
LD$DK
LD$DL
LD$DM
LD$DR
LD$DS
L[I$DT
LD$L.P
LD$MM
LD$TT
LENTl
LENl
LOW
L$$ASG=
L$$DRV=
L$$LDR::::
L$$PTO:::
L$$P11=
L1
MESSl
MESl
M$$CRB=
M$$CRX=
M$$EIS:::
M$$EXT=
H$$FCB::::
M$$MGE:::
M$$HUf'":
M$$OVR::::
NAM
NONE
N$$LDV:;;
N$$MClV:::
N$$UMH=
PI...
PLACE
PLEN
POOL..

000113
000144
000144
OOO()OO
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000027
0000:37
000244R
000000
000000
000000
000036
000001
0004]2R
0OO062R
0OO03]R
000124
000000
000000
000000
000000
000000
000000
000000
000230H
000604R
000001
000041
000034
000022
0002~i6R

000033
000144R

PRMT
P$$BPf~::

P$$CTL=
P$$FRS:::
P$$GMX=
P$$HIL=
PULAS=
P$$LOL=
PUOFF=
P$$P45::
P$$RFL::::
PURTY=
P$$SRF=
Q$$OPT=
RUDER::::
R$$EXV::
R$$JS1=
R$$K11=
R$$LKL=
R$$L11=
R$$MOF=
R$$Mll=
R$$NDC=
R$$NDH::
R$$NDL==
RUPOI=
f<$$SND::::
H$$11M::
R$$60F==
RU611=
S$$ECC=
S$$NM1=
S$$NM2=
S$$NM3=
S$$TIM=
S$$TOP=
S$$WLK=
S$$WPC=
S$$WPR==
S$$YSZ=
TERM
T$$ACR=

OOOOOOR
OOO()63
000000
000310
000000
003100
000000
001UO
000000
000000
000000
000000
000000
000005
000000
000000
000001
000001
000001
000001
000000
000001
000005
000226
000001
000000
000000
000000
000000
000001
000000
051522
030!:'i30
046461
000000
000000
000000
0000~56

000005
022000
000250R
000000

000
001
0

( 40 PAGES)
VH.:TlJAL MEMORY USED!
101n WCJRDS
( 62 PAGES)
DYNAMIC MEMORY!
161 ~!O WORDS
ELAPSED TIME!
00!OO:13
DUMP,DUMP/-BP=[1,:l.JEXEMC/ML,[11,10JRSXMC/PA:l,[7,3"17JDUHP

Examp1 e 10-10

Listing of Task TT2
(Sheet 5 of 5)

(DUMP)

T$$BTW::::
T$$f:/UF""
T$$CCA:::
T$$CCO:::
T$$CPW=
T$$CTR:::
T$$ClJP=
'I"$$Cll=
TUE~)C:::

000000
000000
000000
000000
000000
000000
000000
000001
000000
000000
000000
000000
000000
000001
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000000
000170
000001
000000
000000
000:;!40R
000000
160000
170234
000400
000040
000000

TUGMC:::
1'$$G1"8:::
1'$$HFF:::
T$$HL[I:::
T$$J16:::
T$$KMG=
TULWC=
T$$RED=
TURNE=
T$$RPR=
TURST=
T$$RUB=
1'$$SMC=
T$$SYN::
T$$TRW:::
T$$UTB=
T$$UTO=
T$$U58=
T$$Vf.lF::::
T$$301='=
UCH
U$$HHI=
U$$HLO::::
U$$HRN::::
V$$CTR::
V$$RSN:::
X$$DBT::::
$ALOCH==
$COTB .$I)EACB:::
$DEVHD:::
$QMCRL=
$$$ARG= 000002

****** GX
****** GX
****** GX
****** GX
****** GX

t-<:
Ul

t1:J
~

()

::0

>
Ul
::r:
t1:J

Memors allocation map
1. -··NOV-.. O:l.

Page 1

TKB M39.7D
11: 09

Partition name : GEN
Identification : M4.0
Task
UIC
[7,377J
Stack
limits: 120172 121171 001000 00512.
PI:W ;;fT' ai..kff'f:~Sf:): 121442
Task attributes: PR
Total address windows: 1.
Task
ima~e
size
800. words
Task address limits: :1.20000 123007
R-W disk blk limits: 000002 000005 000004 00004.

*** Root segment: DUMP
R/W mem limits: 120000 123007 003010 01544.
Disk blk limits: 000002 000005 000004 00004.
Memory allocation synopsis:
N

Title

Ident

File

121172 001504 00836.
121172 001410 00776. DUMP
122676 000112 00074.

M4.0

DUMP.OBJ;2

Si?C~t j. on

ex>
N

IO.RVB 010400

ICl.WVB O:L1000

$ALClCB 011346

$DEACB 011614

*** Task builder statistics:
Total wOT'k f i Ie r€·!ff? rf~nces: 850.
Work fi IE')
rpad!;;: ().
lJoT'k f:il€~ wr:i.t(,~s: O.
!;;L~(? of CClT'(,' pool:
20506. words (80. pages)
Sizc:') of work file: 768. words (3. pages)
Elapsed time:OO:00:04

Example 10-11

Map of Task TT2

$DEVHD ()1()046

$QMCRL 021432

SYSTEM CRASHES

V4.0

RSX-11M CRASH DUMP ANALYZER
TASI"~ DUMP

1-NOV-81

11:39

PAGE 9

TASK DUMP OF TT2

TCB ADDRESS

054440

HEADER ADDRESS

054554

WINDOW BLOCKS:
PAl:;:

VIRT l.IMITS

ATT DESC

WND SIZE

OFFSET

1ST PDR

NO.

LAST PDR

GEN

120000 123077

047074

000031

000000

177612

014006

WINDOW =1=1 ..__. TASK VIRTUAL l.IMITS 120000--123077

---------------------------------------------PHYSICAL STARTING ADDRESS

_. 00440400

1.20000
:1.20010
120020
120030
120040
1200:'50
120060
120070
1201.00
120110
1201.20
1.201:30
120140
1.20150
120160
:L20170

053254
170017
000000
000000
054702
000000
000000
000006
000000
000000
000000
123077
000612
000000
100100
000000

-----------------------------------000000
003777
121172
000000
000000
000000
000000
000000
000000
000000
000000
115274
000031
004070
053254
000000

0001.72
003777
000000
000000
000000
000000
000000
054744
046166
046166
046116
1.200()0
000000
000001
000000
000000

135600
121442
000000
000000
000000
000000
000000
046166
046166
046072
000001
000000
014006
135600
000000
000000

lAKG
lY94

CB M4. 0
8PO ZDB

,V ;
p.=I=

A~~G

z·
NNR

NOL
F
LIN
LIN
LHN
.XOL YX ZW9
!
Y
14
!ALX
A
!M4+
TT2

BY
dY
vL
vL
NL

LIN.
LIN
LG4
A
.:::

C30
0

vL
vL
:L

?&
; !

(!?

[ABOVE LINE REPEATED 60. TIMES]
1.21140
121150
121160
121170
121200
121210
121220
121230
121240
1212~)0

000000
000001
000120
000000
020122
047111
042502
051105
040515
046440

006003
000000
000000
006412
020101
046101
035122
040440
042116
051103

010400
000000
000000
047105
042524
047040
042440
041440
043040
052516

000005
054104
000000
042524
046522
046525
052116
046517
051117
041115

A65 B.2
A
B
BCR LT7
lEF4 EFO KC.
lLUA LHA LT
!KCJ IMJ ~~BP
!MFU JP2 J/X
!J07 J7F KH2
lLMX MFS MY8

Example 10-12 CDA of Task TT2
(Sheet 1 of 4)

283

E
ND6

[IX
P

ENTE
KC.
LN4 R A TERM
LN7 INAL NUM
MSV BER: ENT
LN1 ER A COM
MFl .MAND FOR
JXM 1 MCRNUMB

SYSTEM CRASHES

RSX····11M el:~ASH DUMP ANALYZER
lASI, DUMP
1212bO
:1.21270

051105
020124

044440
041517

12L~00

0~)2()4()

0~:)4522

121310
121320
12:L3:30
:L 2 1:340
121350
121360
121:370
1.214()0
1214:1.0
121420

047111

052041
020114

:L:~14]0

121440
:L21450
1214t')O
:1.21470
:L21500

040!7i16

04712~.';

020~504

O~5()040

047517
()40514
020:1.17
047117
042116

020114
046102
051105
041440
044440
000000
O()()OOO
044212
00::=;046
012746
005046
OOOOOl
011000
005046
012746
005046
112716
0:1.2746
104377
121412
005702

044501
020:L22
04051:;
052:L25
000000
0::i4l00
00002:1.
012746
()12746
005046
O()()OO!7i

121~)10

0060():~

:1.21520
1.21530
121540

005046
012746
121416
012746
()12746
177626
004767
000167
O:L2700
026760
116067
000007
00:3:3b1
000001
177!522
()16"7()()
0101()4
000010
177470
104376
004767
177432

:l.2:L~i50

12:L5.S0
121570
:1.21600
12161.0
1.2:l,'S20
12:1.630
l21b40
121650
121660
121670
1.21"700
:1.21"71.0
121720
1.21730
121"740
121750
1.21760
1.21l"70

1.22000
1.2201()
:I.::!2020
122030
:1.22040
:1.22050
:1.22060
122070
:1.22100
122:1.10
:1.22120
:1.221:30
1.22140
1.2:~15()

020123
040524
040440
051:1.05
047516

047506
02·7!7i11

00006:~

052124
044336
00~3046

000()40
121172
112716
012746
104377
005046
121412
005046
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006003
012700
001004
0004:36
010046

1··NOV···B1

V4.0

04751t')

026114
040507
044~)15

020124
047516
053101
020505
047522
046517
()~jO:l.16

000000
054104
000002
005046
000033
005046
012746
0:1.2746
005046
000004
012746
0000()1
010400
016703
005002
0():L402

10437t')

121b76

001422
001372
116067
177560
062767

000406
:1.77406
016767
000004
005046
000027

O:L27b"7
122000
0.-S7362
O:L0067
17"7420
012700
01272:1.
177374
177362
012746
012746

011000
000004
177570
020167
177546
000207
000167
016002
17"7510
060502
177777
01270:1.
103404
177432
001402
000124
000040
177370
005046
000040
1.21225

0()~)o46

00~7;046

11271b

012746
012746
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0()5046
000120
016746

OOOOO:i
()06003

012746
104377
177272
005046
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005046

00~;"76"7

177::=i66

000()()6
17n)64

()10067
177530
001402
177520
166704
()70~i()4

00~)()67

005046
O:L6746
177242

00~;767

000430
000002
()16005
010267
17"7454
000124
005267
000207
000167
016701
077003
062767
005046
012746
()0~;046

000001
01.1000
005067
00~j046

012746
OO~)04b

11271.6

11 ::39

!MFU K.
EFS L$V! ER IS NO!
!EF6 J01 .JRD GeT! T OCTAL., !
!MRP NKZ JP2 .J[~ 1 ! TRY AGA!
!UJA MRO MFlJ K/E! IN!TERMI!
!.J08 EF. I... $V EF6! NAL NOT !
!L..$N LUM EL.6 L..$V FOUND!NO!
1L..22 L..$W EF. M2A
POOL AV!
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!GVY EFl MFU L..$Z liD ERRO!
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! ,J07 ,J7F ~~
L..:~8
MAND INP
MSI AK
.UT3
M<:'
rr DX
ND6
ND2 KIN KXJ
B !@X'·'H H
& & &
0 Axe AX8 AX8
$ !f
f
crF
2 CTF
crr Y94 AX8 AX8 !f ZM& &
AX8 W80
A eTF !& N
f
f
f
E ClF B5H erF I
!A65 U61 AX8 AX8
& &
!AX8 AX8 eTF
D & & f
!CrF ZCR AX8 CTF f
t& f
!ZCV AX8 W80
A
t& N
!CTF
E CTF B.2 f
f
!ClF A65 U61 DOS f
C !
@ t
! 50 CSH ZCR AXB
!AWl L6 A5J SJ w
If
! B9 GF U60 ZG8 w
'" >t!
!CSH BWN B5H SZ .@ &
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48
D SB ! p···v
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t w p !
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! 2Z BWl 2Z CD! ! 7
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w
@ T A
! FV CSH BD [I()Q
(~
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[I lZ AX8 AXO
r"'& 8.
f
!AX8 CTF
2 eTF
& f
M&
I
f
W erF Z U AX8
!AX8 AX8 W80
A & & N
f
!CTF
f
E err B5H
7
!CTF A65 U61 AYO f
! OL.. AYO
O.J Axe .<N7 :N&
!AX8 AX8 AX8 eTF !& & & f
! B D1N 0 AX8, !F- f 0"'&
!D1N IZ AXB W80! 'f .N& N I
~)

CDA of Task TT2
( Sheet 2 of 4)

Example 10-12

284

PAGE 10

SYSTEM CRASHES

CRASH DUMP ANAL.YZER
TASK DUMP

V4.0

012746
012746
000167
002002
122244
177176
000207
005046
000040
121254
112716
012746
1.04377
077302

000005
006003
000272
000167
016701
000002
012746
005046
012746
005046
000001
011000
012700
0001.67
005046
000023
005046
012746
012746
000463
005046
000022
005046
012746
012746
000463
005046
000032
005046
012746
012746
122574
000124
012746
000012
004567
:L22705
000011
120502
004767
112005
000207
005000
066600
000415
005001
103402
000002
010446
000006
012605
000000
000000
000000
000000
000000

F~SX-11M

122160
122170
122200
122210
122220
:1.22230
122240
1.::.?22~iO

:1.22260
:L22270
122300
122310
122320
:L22330
122340
:1.22350
:1.22360
1.22370
122400
122410
:1.22420
1.22430
122440
:1.22450
122460
122470
:1.22:500
:l.22~~i1.0
122~)20

122530
122~j40

122~i~)0

122!560
122~PO
1.22.~OO

1.22610
1.22620
122630
:J. 22tAO

122650
122660
122670
122700
122710
:1.22720
122730
122740
122750
122760
1227"70
123000
123010
l23020
123030
1.23040
123050

000001
010400
103002
177204
104376
0:1.6761
077170
104377
012746
012746
005046
000005
006003
00~)020

0()5046
000040
121313
:1.1.2716
012746
104377
00504c)
000040
1.21336
112716
012746
104377
OO!5046
000040
121360
112716
012746
10437"7
1.76646
067022
10437"7
01.2702
OO~-:;OO1

001774
1627()5
010004
0104()0
116002
012746
006001

00::'j046

01.2746
005046
000001
011000
012746
005046
012746
005046
000001
011000
0:1.2746
00:7j046
012746
005046
00000:1.
01.1.000
104376
01.2701
000207
012702
0000:1.0
11200::=j
122705
000060
010200
060::=i01
177777
000021
103002

00~5316

003:~:71

000020
001.)101

010146
02011.6
005366
000207
016605
012604
000000
000000
000000
000000
000000

00~i200

022626
010546
012603
000000
000000
000000
000000
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l-NOV-81

012746
104377
105767
000260
177200
004767
000463
005046
000037
005046
012746
012746
121412
177102
012746
012746
005046
000005
006003
104377
012746
012746
005046
000005
006003
104377
012746
012746
005046
000005
006003
016700
004767
000463
000402
000144
000040
001771
103010
000016
000764
010046
006000
000002
012746
006300
161601
003367
010346
004736
000207
000000
000000
000000
000000
000000

11:39

f
f
A CTF
E eTF
B.2 eTF A65 U61
f
uaz B9 DZ VOl
w
w
w 0
.6 YZ B9 DP ! N
U60 ZM .. Doa .. 2 ! N $$A
D1Y .0
B AWl !Q NN w
TIP eo eTF G$ !. ~.~N f 3
& & &
U61 AX8 AX8 AX8
eTF
2 eTF
1. f
f
CTF ZAD AX8 AX8 f , • & &
A eTF & N
f
AX8 W80
f
f
E eTF B5H eTF
@
it
.A65 U61 eSH zeR
BNw BN
AXP TKJ B9 $J
AX8 AX8 AX8 eTF & & & f
S eTF
f
f
2 eTF
ZA5 AX8 AX8 AX8 KM& & &
of
W80
A eTF
E N
eTF B5H eTF A65 f
f
U61 eTF G$ U61
f 3
AX8 AX8 AX8 eTF & & & 'f
R eTF
f
f
2 eTF
ZBN AX8 AX8 AX8 "'M& & &
f
W80
A eTF
E N
f
eTF B5H eTF A65. f
f 3
U61 eTF G$ U61
AX8 AX8 AX8 eTF & & & f
f
f
Z eTF
2 eTF
ZB2 AX8 AX8 AX8 pM& & &
W80
f
A eTF
E N
f
eTF B::'jH eTF A65 f
:%@
U61 U60 ZSD DOP.
&}A T w
WN eSl BD AWl
f 3
aXR eo eTF G$
n
FR
B
U61 eSJ
J
w d
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H ATW BT B
2
E%
AXA W$M ZT7
ya
E% 'd
I
YT ZT7
60U AH Y2B ua2 EeO B!
BVT BYX AWl
N
w
Aa t
B+2 ova W$M LT.
&
X8R 80 eo BWN
a AX A62 f
eTF
B
ITI
A63 U(~Z aT2
A/F ADY FI eTF N 'd
f
@
f
P BX8 AXA BAX
A8(1 EFO UXB 6PA !A N
c!
.A$H AOF
w !
B ADW
v
!F V CO B/O B.F ! /. & f
F AWF
f
!BlN D.7
!eO$ co. COl eo

Example 10-12 CDA of Task TT2
(Sheet 3 of 4)

285

PAGE 11

SYSTEM CRASHES

R5X-llM CRASH DUMP ANALYZER
TASK DUMP
123060
1.23070

000000
000000

1-Nov···a1

V4.0

000000
000000

[END OF ANALYSIS OUTPUT]

Example 10-12 CDA of Task TT2
(Sheet 4 of 4)

286

PAGE 1.2

11:39

!!
, !

DIRECTIVE PROCESSING

INTRODUCTION
Many tasks require activities, such as I/O, which cannot be
easily performed within a user task. To provide the facilities
for these activities without requiring privileged tasks and
extensive knowledge of the inner workings of the operating system,
RSX-IIM provides a set of system services called Executive
directives.
Executive directives provide a simple interface to these
services.
This interface is through system macros for the
MACRO-II programmer and system subroutines for the
FORTRAN
programmer.
The interface also provides a completion code fo r
error checking.

OBJECTIVES
1.

List the steps in processing an Executive directive.

Perform the steps necessary to add a user written directive to
the system.

RESOURCES
1.

RSX-IIM System Lists and Data Structures

RSX-IIM/M-PLUS Executive Reference Manual

289

DIRECTIVE PROCESSING

THE USER TASK INTERFACE

•

MACRO-II task uses macros to invoke directives

•

Three types of macros
$-form
$C-form
$S-form

•

FORTRAN tasks call subroutines

•

Directive Parameter Block (DPB) used to pass data to system

•

Result of directive execution indicated by
Directive Status Word (DSW)
Processor Status Word
Set to indicate failure
Clear to indicate success

Directive Parameter Block

•

Data structure contained within the user task

•

Contains parameters needed to execute the directive
Directive identification code (DIC)
Other parameters as needed
Length depends on DIC, can be variable

•

Location of DPB
In task data area
In user selected PSECT
In PSECT $DPB$$
On task stack

•

Directive identification code always odd whole number

291

DIRECTIVE PROCESSING

TASK
} HEADER
....

TASK
STACK

ADDRESS OF OPS (EVEN VALUE)

OPS: SOATS ___________
[OPS FOR DIRECTIVE]

BlA NK

)

DATA AREA

CODE

PS ECT

OIRS -OPS

SO PBSS
PSE CT

{

Figure 11-1

Directive Macros:

'$' Form

} TASK
HEADER
SP

JII

OP B

OPB SIZE AND ole (ODD VALUE)

.""
>

TASK
STACK

1-<

DATA AREA
BlA NK
PS ECT

SOATSS

$0 PBSS

PSE CT

------------

}

CODE

{

Figure 11-1

Directive Macros:

292

'$S' Form

DIRECTIVE PROCESSING

TASK
} HEADER

.......-:

ADDRESS OF DPB LEVEN VALUEI

TASK
STACK
DATA AREA

BlA NK

PSE CT

SDAT$C

------------

)

CODE

$0 PB$$
PSE CT

[DPB FOR DIRECTIVE]
~

Figure 11-1

Directive Macros:

293

'$C' Form

DIRECTIVE PROCESSING

'$' FORM
SEND:

'SCI

SDAT$

TASKB,BUF,5

DIR$

ISEND,ERR

SEND:

71.,5
/TASKB/
BUF
5
ISEND,-(SP)
377
.+6
PC, ERR

.PSECT

$DPB$$

FORM

$$$
SDAT$C

'sst

.BYTE
.RAD50
.WORD
.WORD
MaV
EMT
BCC
JSR

TASKB,BUF,5,PROG1,ERR

.BYTE
.RAD50
.WORD
.WORD
.PSECT
MOV
EMT
BCC
JSR

71.,5
/TASKB/
BUF
5
PROG1
I$$$,-(SP)
377
.+6
PC, ERR

.RAD50

/TASKB/

MOV
MaV
MOV
MaV
MaV
.BYTE
EMT
BCC
JSR

i5,-(SP)
tBUF,-(SP)
TASKB+2,- (SP)
TASKB,- (SP)
(PC)+,-(SP)
71.,5
377
.+6
PC, ERR

FORM

TASKB:

.RAD50

SDAT$S

TASKB:

/TASKB/

tTASKB,tBUF,i5,ERR

Example 11-1

Macro Expansions for SEND DATA

294

DIRECTIVE PROCESSING

DPB SIZE
IN WORDS

ole

PARAMETER 1
PARAMETER 2

PARAMETER N
Figure 11-2

The Directive Parameter Block

295

DIRECTIVE PROCESSING

Directive Status Word

•
•
•

Executi ve returns a status code in the DSW
In general, success is denoted by a status of +1
The Set/Clear Event Flag directives use

" to indicate success and flag clear
2 to indicate success and flag set

•

An error is indicated by a negative status

•

Value stored at location $DSW in the task header
(in task region)

•

In FORTRAN, value returned in calling argument

296

DIRECTIVE PROCESSING

THE DIRECTIVE DISPATCHER

•

EMT trap causes entry to module DRSUB at $EMTRP

•

Module DRDSP is mapped using KERNEL APR5 and control passes to
module DRDSP at $DRDSP

•

Routine $DRDSP distinguishs between directive calls, calls
$SWSTK and non-RSX EMT traps

•

For directive calls

KERNEL APR6 is used to map
WDB or RDB if PLAS directive
DPB otherwise
Directive processing routine is called
•

To process a request to switch to kernel mode, a jump
Executive routine $SWSTK is executed

the

•

For non-RSX EMT traps, a jump to $EMSST in SSTSR is executed

The Directive Dispatch Table
•

Contains entry for each directive
Address of service routine
'Flags byte'
Length in words (For variable length = 0)

•

Assembled in one of two possible forms
Single table form
Two words per possible directive
Double table form
One byte per possible directive
Two words per existing directive

•

The form which uses the least space is automatically chosen
If less than 75 percent of directives exist, use
table structure
If 75 percent or more of the
use the one table structure
297

possible

directives

the

two

exist,

DIRECTIVE PROCESSING

010$

OIOWS

GLUNS

ALUNS

ALTPS

ADDRESS OF SDROIO
FLAGS BYTE
I DPB LENGTH
ADDRESS OF SDROIO
FLAGS BYTE
I DPB LENGTH
ADDRESS OF SDRGLI
FLAGS BYTE
I DPB LENGTH
ADDRESS OF SDRASG
FLAGS BYTE
I DPB LENGTH

0
ROSTS

11.

UNUSED

13.

ADDRESS OF SDRREO
FLAGS BYTE
I DPB LENGTH

0
0

UNUSED

15.

RUNS

17.

ADDRESS OF $DRRUN
FLAGS BYTE
I DPB LENGTH

UNUSED

19.

0
SRRAS

21.

MRKTS

23.

ADDRESS OF ~ DRRRA
FLAGS BYTE
I OPB LENGTH
ADDRESS OF ~ DRMKT
FLAGS BYTE
I DPB LENGTH

2.
4.
6.
8.
10.
12.
14.
16.
18.
20.
22.
24.
26.
28.
30.
32.
34.
36.
40.
42.
44.
46.
50.
52.

Single Table Form

TABLE 1
010$

2.
6.
10.
14.
0
18.
0
0
22.
0
26.
30.
34.
38.
42.
46.
50.

OIOWS
3.
GLUNS
5.
ALUNS
7.
ALTP$
9.
ROSTS 11.
UNUSED 13.
UNUSED 15.
RUNS
17.
UNUSED 19.
SRRAS 21.
MRKTS 23.
CSROS 25.
CMKT$ 27.
EXSTS
29.
CLEF$
31.
SETFS
33.

TABLE 2
....
.....

~
~

ADDRESS OF $DROIO
FLAGS BYTE
1 DPB LENGTH=12.
ADDRESS OF $DROIO
FLAGS BYTE
I DPB LENGTH= 12.
ADDRESS OF $DRGLI
FLAGS BYTE
I DPB LENGTH=3.
ADDRESS OF $DRASG
FLAGS BYTE
I DPB LENGTH=4.
ADDRESS OF $DRREO
FLAGS BYTE
I DPB LENGTH=7.
ADDRESS OF $DRRUN
FLAGS BYTE
I DPB LENGTH= 11.
ADDRESS OF $DRRRA
FLAGS BYTE
I DPB LENGTH=2.
ADDRESS OF $DRMKT
I DPB LENGTH=5.
FLAGS BYTE

8.
10.
12.
14.
16.
18.
20.

22.
24.
26.
28.
30.
32.

I
Double Table Form
Figure 11-3

4.
6.

The Directive Dispatch Table
298

DIRECTIVE PROCESSING

ADDRESS CHECK
RDB/WDB

CONVERT
EVENT FLAG

YES

(

YES

-ERROR

)

Figure 11-4 processing in DRDSP
(Sheet 1 of 2)

299

CALL ROUTINE

DIRECTIVE PROCESSING

RO=TCB
ADDRESS OF
CURRENT TASK

CALL
SSRSTD

~~_N_O-c

____E_R_R_OR
_____

R1=TASK
STATUS WORD

ERROR

Figure 11-4 Processing in DRDSP
( Sh e e t 2 0 f 2)

300

DIRECTIVE PROCESSING

DIRECTIVE PROCESSING ROUTINES

The Interface
•

Directive processing routine is called with
as in Table 11-1

registers

•

Flag byte in directive dispatch table determines processing
ACHKDB - Address PLAS definition block
CEFNCL - Convert the event flag
GEFUSE - Do not increment group global use count
CEFNMT - Event flag must be specified
DFCTSK - Task name defaults to current task
MUPCHK - Perform multi-user protection check
SRSTCL - Call $SRSTD to find TCB in STD

•

Bits set in flag byte determine contents of R0 and R1
If CEFNCL specified
R0 - Event flag mask word
R1 - Address of event flag
If SRSTCL specified
R0 - TCB address of specified task
R1 - Address of status word in TCB

301

loaded

DIRECTIVE PROCESSING

Table 11-1
Register

Contents

Address of the TeB of the current task

Address of the header of the current task

Address of the next word in the DPB

Address of the second task status word of
the current task

Depends on directive

302

DIRECTIVE PROCESSING

The Directive Commons
•

Most directive processing code removed from Executive
Increases available DSR

•

Two directive commons, EXCOMI and EXCOM2
Existence of commons determined at SYSGEN
Kernel I-space APR 5 used to map directive commons
Location of processing routine indicated by low order
of address of routine in DDT

•

Module DRSUB
Is in the Executive
Always mapped
Contains the location $EMTRP
Calls $DIRSV
Maps to DRDSP which is in EXCOMI
Contains coroutines $MPXCI and $MPXC2 which are
used to map EXCOMI and EXCOM2

303

bit

DIRECTIVE PROCESSING

I/O PAGE
KERNEL ACTIVE
PAGE REGISTERS

USER TASK

== ==

APR#7
APR#6
APR#5
APR#4
APR#3
APR#2
APR#1
APR#O

OPB

EXCOM2
EXCOM1

EXECUTIVE

EXECUTIVE MAPPING
Figure 11-5

The Directive Commons:

304

Standard Executive Mapping

DIRECTIVE PROCESSING

I/O PAGE
KERNEL ACTIVE
PAGE REGISTERS

USER TASK

APR#7
APR#6
APR#5
APR#4
APR#3
APR#2
APR#1
APR#Q

_ _- r - -

==OPB ==
EXCOM2
EXCOM1

EXECUTIVE

Figure 11-5

The Directive Commons:

305

Mapping to Reference EXCOM1

DIRECTIVE PROCESSING

Table 1'1-2

Directive Processing Modules

Module

Location

Routines

DRABO
DRASG
DRATP
DRATX
DRCIN
DRCLI
DRCMT
DRDAR
DRDCP
DRDSP
DREIF
DREXP
DRGCL
DRGEF
DRGLI
DRGPP
DRGSS
DRGTK
DRGTP
DRMAP

EXCOMI
EXCOM2
EXCOM2
EXCOMI
EXCOM2
EXCOM.l
EXCOMl
EXCOM1
EXEC
EXCOMI
EXEC
EXCOM2
EXeO""l
EXCOM2
EXCOMI
EXCOMI
EXCOMl
EXCOMI
EXCOM2
EXCOM2

$DRABO
$DRATX

DRMKT
DRPUT
DRQIO
DRRAS
DRREG
DRRES
DRSED

EXCOMI
EXCOMI
EXCOMI
EXCOMI
EXCOM2
EXCOMI
EXCOMI

DRSMG
DRSPW
DRSST
DRSUB

EXCOM2

$DRCIN, $DISIN
$DRCLl, $STCLI, $STCLI
$DRDAR,
$DRDCP,
$TRTRP,
$DREIF,
$DREXP
$GRGCL,
$DRCRE,

$DREAR
$DRECP
$DRTRP, $EMTRP, $DRDSP, $DRATP
$DREXT, $DREX1
$RLMCB, $RLCIB
$DRELE, $UNLCK, $GTGEF

$DRGLI

$DRGPP
$DRGSS
$DRGTK

$DRGTP
$DRCHW, $DRELW, $DRMAP, $DRUNM, $DRSRF, $DRRRF
$DRGMX
$DRM.KT, $DRRUN
$DRREX, $CAAST, $DRFEX, $DRPUT, $DRRRA, $DRRCV
$DRQIO
$DRRCS, $DRREC, $DRSND
$DRUNS, $DRRES, $DRS'l'P, $DRSPN
$DRCEF, $DRRAF, $DRSEF, $DRSTS, $DRSTL, $DRWFL
$DRWFS

EXCOMI
EXCOMI
EXEC

$DRSDV, $DRSTV
$ELGEF, $DEAGF, $SRGEF, $DRDSE, $TKWSE, $DRWSE
$MPXCl, $MPXC2, $DETRG, $CITFR, $DRQRQ, $SRCCQ
$GTUCB, $STCLI, $FNCLI, $TRTRP, $EMTRP, $OTHR1
$DRATP

306

DIRECTIVE PROCESSING

Send/Receive Processing
•

Used to transfer a 13-word data packet to a specified task

•

Routine $DRSND in module DRRAS used to send data

•

Routine $DRREC in module DRRAS used to receive data

•

Steps in sending/receiving
An 18-word send/receive data block is allocated in DSR
Link word for receive queue
Sender name in RADS0
13-word data area
UCB of TI: of sender
Current UIC of sender
A 13-word buffer in sender task is copied into DSR block
A IS-word buffer in user task
data

receives

sender

name

and

DSR
TASK B

15 WORD

TeB

BUFFER

T.RCVL

18 WORDS

{

SEND/RECEIVE
DATA BLOCK

~----

13 WORD
BUFFER

Figure 11-6

TASK B

Send/Receive Processing:
307

Send from TASK A

TASK A

DIRECTIVE PROCESSING

DSR
TASK B

TASK B
15 WORD

TCB

BUFFER

T.RCVL

18 WORDS {

SEND/RECEIVE
DATA BLOCK

13 WORD

TASK A

BUFFER

Figure 11-6

Send/Receive Processing:

308

Receive by TASK B

DIRECTIVE PROCESSING

Parent/Offspring Tasking
•

Connecting TASKA to TASKB
TASKB passes a one-word status back to TASKA when
TASKB exits
TASKB emits status
TASKA is the parent task, TASKB is the offspring task

•

TASKA spawns TASKB
TASKA requests TASKB
TASKA connects to TASKB

•

Steps in connecting
A l4-word offspring control block is allocated in DSR
OCB is linked to the TCB of the offspring task at T.OCBH
When offspring exits or emits status, status moved to
placed into first word in 8-word status area

OCB

Status automatically moved into parent status buffer
Parent task specifies event
flag
and/or
AST
notification of the offspring's return of status

309

for

DIRECTIVE PROCESSING

OCB liNK WORD

O.lINK

ADDRESS OF MCR COMMAND liNE

O.MCRl

PARENT TCB ADDRESS

O.PTCB

EXIT AST ADDRESS

O.AST

EXIT EVENT FLAG

O.EFN

EXIT STATUS BLOCK VIRTUAL ADDRESS

O.ESB

O.STAT

16
20
EXIT STATUS
BUFFER
(8 WORDS)

22
24
26
30
32

Figure 11-7

Parent/Offspring Tasking:

310

Offspring Control Block

DIRECTIVE PROCESSING

TCB OF
PARENT TASK

.....

T.RDCT=1

...

::...

TCB OF
OFFSPRING
TASK

O.LNK=O
O.PTeB

-T.OCBH-

TCB OF
CONNECTING
TASK

T.RDCT=O

Figure 11-7

parent/Offspring Tasking:

311

Spawning a Task

DIRECTIVE PROCESSING

TCB OF
PARENT TASK

.......

T.RDCT=1

.....

TCB OF
OFFSPRING
TASK

O.LNK

•

O.PTCB

I--

O.LNK=O
O.PTCB

~T.OCBH-

TCB OF
CONNECTING
TASK

........

T.RDCT=1

Fig ure 11-7

Parent/Offspr ing Tasking:

312

Connecting ·to· a Task

DIRECTIVE PROCESSING

Memory Management Processing
•

User task specifies information for creating/attaching
region in a Region Definition Block (RDB)

•

Information in RDB used to initialize PCB for subpartition
dynamic partition

•

User task specifies information for creating/mapping
addressing window in a Window Definition Block (WDB)

•

Information in WDB used to initialize
header

313

window

block

task

DIRECTIVE PROCESSING

REGION DEFINITION
BLOCK

PARTITION CONTROL
BLOCK (PCB)
LINK TO NEXT PARTITION PCB

REGION 10

I PRIORITY OF PARTITION

I/O COUNT=O
SIZE OF REGION

~---------

(32W BLOCKS)

PARTITION NAME
(IN RADIX-50)

---------~

POINTER TO NEXT SUB-PARTITION

SIZE OF PARTITION

PARTITION WAIT QUEUE

LIST HEAD
~
PARTITION SWAP SIZE (SYSTEM ONLY)

REGION'S MAIN PARTITION NAME

PARTITION BUSY FLAGS

(RAD50)

TCS ADDR. OF OWNER/CURRENT UIC OF OWNER TASK

.....----------------f,,/'A
REGION STATUS WORD
....._______________________
-f A

PARTITION STATUS FLAGS
POINTER TO TASK HEADER

PROTECTION WORD FOR REGION

REGION PROTECTION WORD

,,/'

~------

ATTACHMENT DESCRIPTOR
LIST HEAD

------~

CREATING A REGION

WINDOW DEFINITION
BLOCK
BASE APR

WINDOW ID

VIRTUAL BASE ADDRESS (BYTES)

TASK ADDRESSING
WINDOW BLOCK

PCB ADDRESS
LOW VIRTUAL ADDRESS LIMIT

WINDOW SIZE (32W BLOCKS)

HIGH VIRTUAL ADDRESS LIMIT

REGION ID

ADDRESS OF A TT ACHMENT DESCRIPTOR

OFFSET IN REGION (32W BLOCKS)

SIZE OF WINDOW IN 32. WORD BLOCKS
PHYSICAL MEMORY OFFSET IN 32. WORD BLOCKS

LENGTH TO MAP (32W BLOCKS)

NUMBER OF
APRS TO MAP

WINDOW STATUS WORD

1 FIRST(LOW
PDR ADDRESS
BYTE)

CONTENTS OF LAST PDR

SEND/RECEIVE BUFFER ADDRESS (BYTES)

CREATING AND MAPPING A WINDOW
Figure 11-8

Memory Management Processing

314

DIRECTIVE PROCESSING

ADDING A USER-WRITTEN DIRECTIVE

•

Interface to the directive processing
Structure of Directive Parameter Block must be determined
Entry for new directive must be added to the DDT
Directive processing routine must be written
Macros to invoke directive must be written
Directive processing routine must be built into the system
Macros must be added to the system macro library

Structuring the Directive Parameter Block

•

Information needed to execute directive

•

Choose an unused DIC

•

Choose order for necessary parameters
If event flag is first parameter,
CEFNMT

specify

CEFNCL

and/or

If task name is first
SRSTCL

specify

DFCTSK

and/or

parameter,

DIC=161

SIZE=4

TASK NAME
IN RAD50
EVENT FLAG NUMBER
Figure 11-9

Directive Parameter Block for New Directive

315

DIRECTIVE PROCESSING

Changes to the Directive Dispatcher
•

DDT determines
Which directive processing routine to call
What processing to perform in DRDSP
Size of DPB
Where the module is to be located (directive commons)

•

Each directive is represented by a line
defined in the module DRDSP

•

Format of line in DIREC macro is
MAC

the

DIREC

macro

DIC,DPBSIZ,DIRADR,MASK,COND,SECOND

Where
DIC
DPBSIZ
DIRADR
MASK
COND
SECOND

Directive Identification Code
Size of the DPB
Address of the Directive Processing Routine
Directive Processing Control Mask
Conditional Assembly Parameters which must
be defined if the directive is supported
Conditional assembly parameters which if
defined require that the directive have a
variable length DPB

Example:
MAC

55.,2.,$DRCRR!PAG,<ACHKDB),P$$LAS

This is the 'create region' directive.
PAG is set to 1 if directive common support is
desired, 0 otherwise. The service routine will be
placed in EXCOM2.

316

DIRECTIVE PROCESSING

Place the following in the Directive Dispatch Table
MAC

l6l.,4.,$DRFLG!PAG,(DFCTSK!SRSTCL)

DIC
Size of DPB
Processing Routine
Force to EXCOM2
Default to current task
Call $SRSTD to find TCB
Example 11-2

New Entry in the Directive Dispatch Table

317

DIRECTIVE PROCESSING

The Directive Processing Routine and Macros
•

Routine should be written to make use of the standard register
usage in DRDSP

•

Assembly with EXEMC and RSXMC

•

Provide only macros needed by applications
• TI TL.E
.IDENT

DF~Fl.G

/1.0/

** - SDRFLG - SET TASK'S LOCAL EVENT FLAG
THIS DIRECTIVE INSTRUCTS THE SYSTEM TO SET A SPECIFIED TASK'S l.OCAl.
EVENT FLAG.
DF'B FDr~MAT:
~Jrr.

WD .. 0.1
WD. 02
WD.

0:3

DIC (161.), DPB SIZE (4.)
FIRST HALF OF TASK NAME (RAD50)
SECOND HALF OF TASK NAME (RAD50)
EVENT FLAG NUMBER (1-32.)

,
;

INPUTS:
RO - TCB ADDR. OF TARGET TASK
R1 - ADDR. OF FIRST TASK STATUS WORD
R2 - ADDR. OF SECOND TASK STATUS WORD
R3 - ADDR. OF NEXT WORD IN DPB
R4 - ADDR. OF HEADER OF CURRENT TASK
R5 - ADDR. OF TCB OF CURRENT TASK

OUTF'J...ITS:
IF DIRECTIVE IS SUCCESSFULLY COMPLETED
DIRECTIVE STATUS D.RS22 IS RETURNED IF EVENT FLAG IS
ALREADY SET
DIRECTIVE STATUS D~RSOO IS RETURNED IF EVENT FLAG WAS
CLEARED
C - 1 IF DIRECTIVE IS REJECTED
DIRECTIVE STATUS D.RS97 IS RETURNED IF IL.LEGAL EVENT
FLAG
C = 0

,
;
;
,
;
,

y .•.

.FNABI...

LSB

t"iOV

RO,R5
$CEFN

mDf~FL.G: :

CAl... I...

BeS
BIT
BE[~
DI:~f:)TS

:I.()~~:

HIS
rl/:~STS

20!~ :

DRf:;TE;
.. END

;ADDR OF TARGET TASK TeB
;CONVERT TO EVENT FLAG MASK
20$
;Il.LEGAL EVENT FLAG
RO,(Rl) ;EVENT Fl.AG ALREADY SET?
10$
;NO, IF EQUAL
D.RS22 ;RETURN STATUS
RO,(Rl) ;SET THE EVENT FLAG
D.RSOO ;RETURN STATUS
D.RS97 ;ILLEGAL EVENT FLAG STATUS

Example 11-3

Processing Routine for New Directive
318

DIRECTIVE PROCESSING

y+
$

FORM OF MACRO FOR $DRFLG

• Mf~CRO
.BYTE

SL.EF$ TN,EFN

R50$

.WORD
.ENDM

EFN
SL.EFt

16:1.• v4

SC FORM OF MACRO FOR $DRFLG
~.

.MACRO
<-PSECT

SLEF$C TNvEFN,ERRyPST
$DPB$$

.BYTE
R5()$
.WDRD

EFN

.PSECT

PST

MOV
EMT

IS$$v-(SP)
.... O<~3??>

IF NB

Bec

;

:J.b:J.• ,,4

EI~~I~

.+6

..J81~

PC"ERR

.ENDC
.ENDM

SL.EF$C

$8 FDRM OF MACRO FOR SDRFLG

!J .-

MOV$

SL.EFtS TN,EFN,ERR
EFN

I~~FA$

+ MACI~O

MDt..'

(PC)ty-(SP)

.BYTE
DII:~~;

:1.1.>:1..,4
, ERF~

.ENDM

SLEFtS

Example 11-4

Macros for New Directive

319

DIRECTIVE PROCESSING

Adding a Directive to the System
•

Directive can be included in the Executive or in EXCOM2
In the Executive if
Directive commons not chosen at SYSGEN
Not enough room in EXCOM2
Otherwise in EXCOM2

•

To include in the Executive
Build with the Executive during SYSGEN

•

To include in EXCOM2
Build with EXCOM2 during SYSGEN

•

Macros included in system macro library RSXMAC.SML

320

DIRECTIVE PROCESSING

MAC DRFLG=LB: [1,1] EXEMC/ML,SY: [11,10] RSXMC,DRFLG

+
:

LBR LB: [1,24] RSX11M/IN :DRFLG

LB:[1,24]RSX11M/LB:DRFLG

TKB @RSXBLD

ASSEMBLE
DIRECTIVE
ROUTINE

I
I

t
I
I
I
I
I
I

ADD OBJECT
MODULE TO
LIBRARY

ADD LINE
TO TASK BUILD
COMMAND FILE

+
I
I
I
I
I
I
I
I
I

TASK BUILD

Figure 11-10

Assembling and Taskbuilding the Processing Routine

321

I/O PROCESSING

INTRODUCTION
Any modern operating system must provide a complete I/O
system.
Besides providing basic I/O device handling software, it
must also provide a convenient file system.
Device drivers handle primitive I/O functions under RSX-IIM.
These drivers are tailored to individual devices and optimized to
provide maximum performance. They are invoked by means of the QIO
mechanism.
RSX-IIM uses the FILES-II file system. There are two levels
of software support in the operating system for FILES-II. The
more visible level includes the file access systems, FCS, and RMS.
These systems provide all features needed in any application under
RSX-IIM. A more primitive level, in the form of ACPs (FIIACP),
forms the interface between FCS/RMS and device drivers.

OBJECTIVES
1.

Diagram the flow in the I/O system.

List the types of ACPs and their differences.

List the steps in processing an I/O request within DRQIO.

RESOURCES
1.

RSX-IIM System Lists and Data Structures

RSX-IIM Guide to Writing an I/O Driver

RSX-IIM/M-PLUS I/O Operations References Manual

325

I/O PROCESSING

OVERVIEW
Components of the I/O System
•

The File System
Used to structure data for convenient use in applications
Provides software for easy manipulation of data
Consists of:
FILES-II structures
File Control Services (FCS)
Record Management Services (RMS)

•

QIO directive
Used to request I/O service from the Executive
Can be used directly in user task
All file-system I/O requests converted into QIOs

•

Device Drivers
Used to control physical devices and perform actual I/O
One required for each device type
Carry I/O requests to transfer data

327

I/O PROCESSING

•

Ancillary Control Processor (ACP)
Performs functions subordinate to those of the driver
Provides a file system for user tasks
Handles protocols needed by a communications network
Converts I/O requests into one or more request to a device
driver
Manipulates I/O parts of the system data base
Three ACPs provided with RSX-IIM
FIIACP:

Files-II

MTAACP:

Magtape I/O ACP

NETACP:

DECNET ACP

328

I/O PROCESSING

USER STATE

: SYSTEM STATE

I
USER TASK
010 -

UOIO
......- - - - - - - -... 1

DROIO

UOIO

CD
AOIO

DRIVER

0@
(IN I)

UOIO

~---.....j CALL SGTPKT

NOTE: UOIO: USER ISSUED 010
AOIO: ACP ISSUED 010

Figure 12-1

I
The I/O Process

329

I/O PROCESSING

Initiating I/O From a User Task
•

Use QIO directives
Harder to use than other methods
Can be the most efficient method of I/O
For file I/O, use virtual block transfers
For non-file I/O, use logical block transfers

•

Use high-level language I/O commands
Easier to use than QIOs, but less efficient
Language processor may
FCS/RMS commands

•

convert

QIOs

convert

form

natural

Use FCS/RMS to perform file system I/O
Allows data to be
application

accessed

File processor converts to QIOs

330

the

I/O PROCESSING

Processing 1/0 Request in ORQIO

•

All I/O performed as a result of QIO directives

•

QIO directive parameters are
returned

•

Parameters used to create I/O packet

•

I/O packet is queued to a device driver or to an ACP

•

If ACP function, a
queuing I/O packet

number

checked;

331

checks

directive

are

status

performed

before

I/O PROCESSING

010 PROCESSING
Logical Units
•

Logical Unit Numbers (LUNs)
is to be performed

identify the device to

which

•

LUN determines a unique entry in the task's Logical Unit Table
(LUT) in the task header

•

Each entry in the LUT is two words long

•

When a task is installed, the first word of each LUT entry
initialized with the UCB address of the device

•

When a file is opened on a volume, the second word
corresponding LUN points to a FILES-II window block

the

TASK
HEADER

USER TASK
UCB

QIO -,3, ...

Figure 12-2

Logical Units

332

I/O

I/O PROCESSING

Processing Within DROIO
•

Locates the UCB for LUN
Calls $MPLUN in module EXESB

•

Checks to see if driver resident
Location D.DSP in the DCB

•

Clears specified event flag

•

Clears I/O status block if specified

•

QIO directive is now successful
DSW shows success
Any errors are reported as I/O errors in the IOSB

•

Allocates space for I/O packet in POOL
Calls $ALPKT in module CORAL

•

Increments I/O request count in the TCB

•

Copy data from DPB to I/O packet

•

If function is IO.KIL, go the routine $IOKIL in module IOSUB

•

Check if task has privileges to perform I/O

•

Check function code against function masks in DCB

•

If not legal function,

•

If control function, queue I/O packet to driver

•

If 'no-op'

•

If ACP function to mounted device, perform ACP function checks

return I/O error

function, return successful status

333

I/O PROCESSING

The ACP Function Checks
•

Implemented by a collection of primitive routines

•

Each ACP requires a different group of these routines

•

A two-level dispatch table, the Polish
is used

•

First level table, the Function Code Dispatch vector,
at FCDSP in DRQIO

Interpreter

Database,
resides

Each entry corresponds to a unique function code
Each entry is a vector which
dispatch table
•

points

second

level

Second level dispatch table contains primitive routines to
called

334

I/O PROCESSING
Table 12-1

Function Code Dispatch vector

Function
Code

Dispatch
Table

Function

FCIFC

Illegal function

FCPKT

Find file name in directory

UNLCK

Unlock Block

FCPKT

Remove file name from directory

FCPKT

Enter file name in directory

FCACC

Access file for READ

FCAce

Access file for READ and WRITE

FCACC

Access file for READ, WRITE, and EXTEND

FCDAC

De ace e s s

FCRVB

Read Virtual Block

FCWVB

Write Virtual Block

FCEXT

Extend file

FceRE

Create file

FCDEL

Mark file for DELETE/TRUNCATE file

FCPKT

Read file attributes

FCPKT

Write file attributes

FCPKT

User magtape control function

FCWVB

Transmit process message

FCRVB

Receive process message

FceON

Connect to process

FeDIS

Disconnect from process

FCNCT

Network control process

FCIFC

I11egal

FCIFC

Illegal function

f i 1e

function

335

I/O PROCESSING

Table 12-2

Polish Routines

Table

Routine

Function

FCIFC

IEIFC

Set illegal function status

FCACC

CKDMO
CKALN
CKMOU
CKACP
BDPKT
CKRLK

Check if volume marked for dismount
Check if file already accessed on LUN
Check volume mounted this user
Set flag to queue to ACP
Build an I/O packet
Synchronize access and exit

FCDAC

CKNLN
CKQMT
BDPKT
CKRLK

Check if file accessed on LUN
Queue to MTAACP if ANSI
Build an I/O packet
Synchronize and exit

FCRVB

CKNLN
CKRAC

Check if file accessed on LUN
Check read access and exit

FCWVB

CKNLN
CKWAC

Check if file accessed on LUN
Check write access and exit

FCCRE

CKDMO
CKALN
CKPKT

Check if volume marked for dismount
Check if file accessed on LUN
Join common ACP and check mount

FCDEL

CKTRN
CKACP
CKMOU
BDPKT
CKXIT

Check if really truncate
Set flag to queue to ACP
Check volume mounted by this user
Build an I/O packet
Exit

FCPKT

CKACP
CKMOU
BDPKT
CKXIT

Set flag to queue to ACP
Check volume mounted by this user
Build an I/O packet
Exit

FCEXT

CKPND

Increment window pending count for extend

UNLCK

CKNLN
UNLXT

Check if file accessed on LUN
Set registers and exit

FCCON

CKDMO
CKALN
CReON
CKRLK

Check if volume marked for dismount
Check if process already connected on LUN
Address check connect buffer
Interlock LUN usage and exit

336

I/O PROCESSING

Table 12-2

Polish Routines (Cont)

Table

Routine

Function

FCDIS

CRNLN
CRDIS
CRRLR

Check if process connected on LUN
Check buffer and copy parameters
Interlock LUN usage and exit

FCNCT

CKDMO
CRCON
CKXIT

Check if volume marked for dismount
Address check buffer
Exit

337

I/O PROCESSING

Queuing 1/0 Requests
•

I/O request packets are queued by
DRSUB

•

Processing in $DRQRQ

routine

$DRQRQ

module

loaded

into

Bit UC.QUE in U.CTL in the UCB is checked
If set, packet queued to driver
Contents of KERNEL APR 5 is saved on stack
If driver loadable, base address
KERNEL APR 5

driver

The driver is called to initiate I/O
When driver exits
Control returns to $DRQRQ
Original contents of KERNEL APR 5 are restored

338

I/O PROCESSING

ANCILLARY CONTROL PROCESSORS
Types of ACPs

•

Stand a rd ACPs
Known to the Executive
Executive includes special code for support
Follow rules used by DEC in writing FllACP and MTAACP

•

User ACPs
Not known to the Executive
Known only to the driver which uses their services
UC.QUE set in U.CTL to
DRQIO

prevent

ACP

function

checks

Driver does preprocessing and queues requests to ACPs
No change to the Executive code is necessary
•

Fo re ign ACPs
Between standard and user ACPs
Known to the Executive
No special services provided to support ACP
Identified by foreign bit US. FOR in the UCB

339

I/O PROCESSING

USER
TASK
~ QIO

CHECK FOR LEGALITY
CONSTRUCT I/O PACKET
SPECIAL ACP PROCESSING
QUEUE TO ACP IF SPECIFIED

$DRQIO

t JMP
QUEUE I/O PACKET
CALL DRIVER INITIA TOR

$DRQRQ

t JSR
CALL $GTPKT

DEVICE DRIVER

~ JSR

GET I/O PACKET
DETERMINE ACP FUNCTION
:

$GTPKT

~ JSR

QUEUE PACKET TO ACP
REQUEST ACP
Figure 12-3

Standard ACP

340

$EXRQP

I/O PROCESSING

USER
TASK

t QIO
CHECK FOR LEGALITY
CONSTRUCT 1/0 PACKET
COpy 1/0 PARAMETERS

$DRQIO

t JMP
CALL DRIVER INITIATOR

$DRQRQ

t JSR
SPECIAL ACP PROCESSING
QUEUE TO ACP
,

DEVICE DRIVER

JSR

QUEUE 1/0 PACKET TO ACP
REQUEST ACP

Figure 12-4

User ACP

341

$EXRQP

I/O PROCESSING

USER
TASK

+ QIO
CHECK FOR LEGALITY
CONSTRUCT I/O PACKET
COpy I/O PARAMETERS
QUEUE TO ACP IF UC.QUE=O

$DRQIO

t JMP
CALL DRIVER INITIATOR

$DRQRQ

t JSR
SPECIAL ACP PROCESSING
QUEUE I/O PACKET
CALL $GTPKT
~ JSR
GET I/O PACKET
DETERMINE ACP FUNCTION

DEVICE DRIVER

$GTPKT

~ " JSR
QUEUE PACKET TO ACP
REQUEST ACP
Figure 12-5

Foreign ACP

342

$EXRQP

I/O PROCESSING

The FILES-11 (F 11 ACP)

•

Implements the FILES-II structure for disks

•

Provides needed file primitives (open, close, etc.)

•

Converts file primitives to driver primitives
Open file requires several driver operations:
Locating the file which may require several
directory records and headers

reads

Creating the FCB from the file header
Creating the window block from the retrieval pointers

Versions available at SYSGEN

•

MINIMUM Version
Not recomended for general use
Runs in 2K words of memory
Heavily overlaid
No internal buffers for storing data
Mapped and unmapped systems

•

SMALL Version
Provides limited performance optimization
Requires 10 to 100 times more I/O
and file opens than larger ACPs

for

Heavily overlaid
Runs in 2.5K words of memory
Mapped and unmapped systems
Default version for unmapped systems

343