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Document:	VAX/VMS System Dump Analyzer Reference Manual
Order Number:	AA-J526A-TE
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VAX/VMS
System Dump Analyzer
Reference Manual
Order No. AA-J526A-TE

March 1980
This document describes how the VAX/VMS System Dump Analyzer works
and how to use it.

VAX/VMS
System Dump Analyzer
Reference Manual
Order No. AA-J526A-TE

SUPERSESSION/UPDATE INFORMATION: This is a new document for this release.
OPERATING SYSTEM AND VERSION:

VAX/VMS V02

SOFTWARE VERSION:

VAX/VMS V02

To order additional copies of this document, contact the Software Distribution
Center, Digital Equipment Corporation, Maynard, Massachusetts 01754

digital equipment corporation . maynard, massachusetts

First Printing, March 1980
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 only be used or copied in accordance with the terms of such
license.
No responsibility is assumed for the use or reliability of software on
equipment that is not supplied by DIGITAL or its affiliated companies.

@ 1980 by Digital Equipment Corporation

The postage prepaid READER'S COMMENTS form on the last page of this
document requests the user's critical evaluation to assist us in
preparing future documentation.
The following are trademarks of Digital Equipment Corporation:

DIGITAL
DEC
PDP
DECUS
UNIBUS
COMPUTER LABS
COMTEX
DDT
DEC COMM
ASSIST-11
VAX
DECnet
DATATRIEVE

DECsystem-10
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DECSYSTEM-20
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MASSBUS
OMNIBUS
OS/8
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RSX
TYPESET-8
TYPESET-11
TMS-11
ITPS-10
SBI
PDT

CONTENTS

Page
v

PREFACE
CHAPTER

INTRODUCTION TO SDA

1-1

CHAPTER

THE SYSTEM DUMP FILE

2-1

2.1
2.2

SETTING THE SYSTEM DUMP FILE SIZE
SAVING SYSTEM DUMP FILES

2-1
2-2

RUNNING SDA

3-1

3.1
3.2
3.3
3.4
3.5
3.6

INVOKING SDA WITH THE RUN COMMAND
INVOKING SDA AS A FOREIGN COMMAND
EXAMINING THE RUNNING SYSTEM
READING THE SYSTEM DUMP FILE
BUILDING THE SDA SYMBOL TABLE
INVOKING SDA IN THE SITE-SPECIFIC START-UP
PROCEDURE

3-1
3-2
3-2
3-2
3-3

SDA COMMAND STRINGS

4-1

4.l

GENERAL FORMAT
EXPRESSIONS

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

CHAPTER

4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
CHAPTER

Radix Operators
Unary Operators
Binary Operators
Special Operators
Symbols

3-3

5-1
5-2
5-3
5-5
5-6
5-10
5-11
5-14
5-15
5-17
5-18
5-19
5-21
5-24
5-29
5-33
5-3n
5-39
5-46
5-49
5-51

SDA COMMANDS
COPY
DEFINE
EVALUATE
EXAMINE
EXIT
FORMAT
HELP
READ
REPEAT
SET OUTPUT
SET PROCESS
SHOW CRASH
SHOW DEVICE
SHOW PAGE TABLE
SHOW PFN DATA
SHOW POOL
SHOW .PROCESS
SHOW STACK
SHOW SUMMARY
SHOW SYMBOL

iii

CONTENTS

Page
CHAPTER

CHAPTER

ANALYZING SYSTEM FAILURES -- GUIDELINES AND
EXAMPLES

6-1

6.1
6.2
6.2.1
6.2.2
6.3
6.3.1
6.3.2
6.3.3
6.3.3.1
6.3.3.2
6.3.4
6.3.4.1
6.3.4.2
6.3.4.3
6.4

GENERAL PROCEDURE FOR SOLVING SYSTEM FAILURES
FATAL BUGCHECK CONDITIONS
Fatal Exceptions
Illegal Page Faults
DEBUGGING A SYSTEM FAILURE
AN EXAMPLE
Identifying the Bugcheck
Identifying the Exception
Locating the Source of the Exception
Finding the Driver Using the DPT List
Calculating the Offset into the Driver
Finding the Problem within the Routine
Stepping through the Routine
Checking the Values of Key Variables
Identifying and Fixing the Defective Code
INDUCING A SYSTEM FAILURE

6-1
6-2
6-2
6-5
6-6
6-6
6-6
6-9
n-9
6-10
6-10
6-12
6-12
6-13
6-15

SDA ERROR MESSAGES

7-1

7.1
7.2

INITIALIZATION ERROR MESSAGES
OPERATIONAL ERROR MESSAGES

7-1
7-1

INDEX

Index-1

FIGURES
Figure

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

System Region Memory
System Crash Information
Device Data Block List for Dn Devices
Controller Data Structures for DB Devices
Device Unit Data Structures for Device DBAl
System Page Table
PFN Data Base
Paged Dynamic Storage Pool
Process Information
Working Set List
Process Section Table
Program Region Memory
Current Operating Stack (Kernel)
Summary of Active Processes
Global Symbols
Interrupt Stack and Vectors
Page Table Display Showing Invalid Location
80069EOO
Linked List of Driver Prologue Tables
Location of Instruction in Driver Routine
Location of Defective Code in Driver Routine

5-9
5-23
5-27
5-27
5-28
5-32
5-35
5-38
5-42
5-43
5-44
5-45
5-48
5-50
5-52
n-6

6-8
6-9
n-11
6-14

TABLES
Table

5-1

Summary of SDA Commands

5-1

PREFACE

MANUAL OBJECTIVES
The VAX/VMS System Dump Analyzer Reference Manual contains information
useful in determining the cause of a VAX/VMS operating system failure.

INTENDED AUDIENCE
This reference manual is intended for users who possess extensive
knowledge of VAX/VMS data structures. It assumes that the audience
for this manual includes VAX/VMS developers and DIGITAL Software
Support Specialists, as well as DIGITAL customers familiar with
VAX/VMS internal design.
In addition, system programmers who are writing device drivers may
need to use SDA. The system manager should also become familiar with
SDA, usually to produce SDA listings after each crash and, more
importantly, to save the system dump file for later analysis.

STRUCTURE OF THIS DOCUMENT
This reference manual consists of seven chapters:
•

Chapter 1 provides an introduction to SDA and
operations.

•

Chapter 2 describes the system dump file that SDA analyzes.

•

Chapter 3 explains how to run SDA to analyze a
examine the running system.

•

Chapter 4 details the SDA command format.

•

Chapter 5 describes the SDA commands, in alphabetical order.

•

Chapter n gives guidelines for analyzing system
steps through a sample system crash.

•

Chapter 7 lists and
operation.

explains

the

messages

summarizes

dump

file

failures

SDA

and
SDA

ASSOCIATED DOCUMENTS
This document has the following prerequisites:
VAX-11/780 Hardware Handbook
VAX/VMS S~-~marx_P~-5-~E_!pt~_?.~~-and Glossa
The following documents are associated with this manual:
VAX-11 Run-Time Library Reference Manual
VAX/VMS Guide to Writing a Device Driver
VAX/VMS system Manager 'sGliTae··----VAX/vMs sys~m-~er-~ce=~~=~~:ference Manual
For a complete list of all VAX-11 documents, including
brief
descriptions of each, see the VAX-11 Information Dir_:_ec_~~¥. ..-~~9 ___!_nd~~·

CONVENTIONS USED IN THIS DOCUMENT
The following conventions are used in this document.
Convention

Meaning

SHOW CRASH

Uppercase words and letters, used
in
examples, indicate that you
should type the word or letter
exactly as shown.

symbol-name

Lowercase words and letters, used
in format examples, indicate that
you are to substitute a word or
value of your choice.

SET PROCESS

name
/INDEX = nn
/SYSTEM

Square brackets indicate that the
enclosed
argument
is optional,
except
for
brackets
used
in
directory specifications.
Braces are
from which
chosen.

used to enclose lists
one element is to be

A vertical ellipsis indicates that
not all of the statements in an
example or figure are shown.

SHOW SYMBOL TEN
TEN :::: 000000:1.0

In examples of commands you enter
and SDA responses, all output lines
and prompting characters that SDA
prints or displays are shown in
black letters.
All the lines you
type are shown in red letters.
A symbol with a 1- to 3-character
abbreviation
indicates that you
press a key on the terminal.

CHAPTER 1
INTRODUCTION TO SDA

The System Dump Analyzer (SDA) is a VAX/VMS utility
determining the cause of an operating system failure.

that

aids

When an internal error occurs that interferes with normal operations,
the operating system writes information concerning its status at the
time of the system failure to a predefined system dump file.
SDA
examines and formats the contents of this file.
With the help of the SDA commands, you can display parts of the
formatted system dump file on a video display terminal, or you can
create hard copy listings.
SDA performs the following operations:
•

Assigns a value to a symbol

•

Examines memory of any process

•

Formats block of data

•

Displays device data structures

•

Displays memory management structures

•

Displays a summary of all processes on the system

•

Displays the SDA symbol table

•

Copies the system dump file

•

Sends output to a file or device

•

Reads symbols from any object module

In addition to analyzing the system dump file, SDA can perform the
operations listed above on a running system without interrupting that
system's operation.
While SDA provides a great deal of information, it does not analyze
all
the various control blocks and data contained in memory.
Therefore, in the event of system failure, it is extremely important
that customers send a copy of the system dump file to DIGITAL along
with a Software Performance Report (SPR).

1-1

CHAPTER 2
THE SYSTEM DUMP FILE

Before the VAX/VMS operating system can write information to the
system dump file, the system parameter DUMPBUG must be set. Normally,
this parameter is enabled by default; to reset DUMPBUG, as well as
other system parameters, consult the VAX/VMS System Manager's Guide.
If the DUMPBUG parameter is set and the operating system fails, the
system writes the contents of the ~rror log buffers, processor
registers, and physical memory to the contiguous file SYSDUMP.DMP.
SDA analyzes this file and produces formatted displays of its
contents.
SYSDUMP.DMP is furnished as an empty file in the VAX/VMS software
distribution kit. It is located in the system directory [SYSEXE] and
its file size is initially small.

2.1

SETTING THE SYSTEM DUMP FILE SIZE

To preserve the continuity of the error log file and save all of
physical memory, it is important to make sure that the dump file's
size in blocks matches the individual system configuration.
To change the size of SYSDUMP.DMP, the system manager (or a user with
similar privileges) runs a command procedure in the directory [SYSUPD]
called SWAPFILES.COM. The command line is:
S @[SYSUPDJSWAPFILES
The command procedure prompts you for paging, swapping, and dump file
sizes.
You can enter a new file size or simply press
~ •
If you
enter a new file size, the command procedure creates a new system dump
file.
This new file will not be used by the operating system until
after a system reboot.
To calculate the correct dump file size for
the formula:
blocks

your

configuration,

use

= physical-memory-size-in-pages + 4

The four additional blocks store hardware context and error log
buffers.
You can also use the table provided in the VAX/VMS System
Manager's Guide to find the correct size.
This
table
lists
recommended sizes for the three files affected by the SWAPFILES
command procedure. The system manager's guide also gives detailed
information on SWAPFILES.COM and on changing dump file size.

2-1

THE SYSTEM DUMP FILE
2.2

SAVING SYSTEM DUMP FILES

Every time the operating system writes information to SYSDUMP.DMP, it
writes over whatever was previously stored in the file. For this
reason, the system manager should save the contents of SYSDUMP.DMP
after a system failure has occurred. One way to accomplish this is to
copy the file to another directory. Use the DIGITAL Command Language
(DCL) command COPY, as shown in the following example:
$

COPY SYSSSYSTEM:SYSDUMP+DMP;l [SYSERRJSAVEDUMP.DMP

SDA also provides a COPY command. This command can be included in the
series of SDA commands in the site-specific start-up procedure.
Section 3.6 discusses the start-up procedure in more detail. The COPY
command is explained in Chapter 5.

2-2

CHAPTER 3
RUNNING SDA

SDA can analyze a dump file or examine the running system.
possible for SDA to read the dump file, you need:
•

Read access to SYSDUMP.DMP

•

Read access to a copy of the system symbol table

•

Enough virtual space for SDA to map
file

the

entire

To make it

system

dump

To ensure that SDA has the correct amount of virtual address space,
the running system must have the system parameter VIRTUALPGCNT equal
to the size of the dump file plus 1000 pages. In addition, your page
file quota (PGFLQUOTA in the user's authorization record created by
running the User Authorization Program) must be at least the size of
the dump file plus 1000 pages. See the VAX/VMS System Manager's Guide
for information on system parameters and the User Author1zat1ori
Program (AUTHORIZE).

3.1

INVOKING SDA WITH THE RUN COMMAND

If the above conditions are satisfied, you can invoke
the following DCL command:
$

SDA

typing

RUN SYSSSYSTEM:SDA

When you issue this command, SDA will
system dump file you want to examine:

prompt

for

the

name

the

Enter name of dump file >
To examine the most recent system dump (SYS$SYSTEM:SYSDUMP.DMP), press
~
in response to the prompt. SDA will search the system directory
(logical name SYS$SYSTEM) for SYSDUMP.DMP. To examine an older dump
file, enter its file specification:
Enter name of dump file > CWIZARDJACPCRASH.DMP
The default file specification for the system
dump
file
is
SYS$DISK: [default-dir]SYSDUMP.DMP where SYS$DISK and [default-dir]
represent, respectively, the device and directory specified by the
last SET DEFAULT command.
(See the VAX/VMS Command Language User's
Guide for a description of the SET DEFAULT command.)

3-1

RUNNING SDA
If you want to examine the running system, type an asterisk (*)
in
response to the dump file prompt.
See Section 3.3 for further
details.

3.2

INVOKING SDA AS A FOREIGN COMMAND

You can also invoke SDA
assignment statement:
t

SDA

foreign

command

using

the

DCL

:= SSDA

A foreign command is a command not known to the command
that can be executed by entering a command string.

interpreter

The dollar sign ($) indicates to DCL that the expression is a foreign
command. Now you can specify a file or the asterisk as a parameter to
the SDA command:
$

SDA [DUMPSJBADUCB

Defining SDA as a foreign command abbreviates SDA initialization
because it eliminates the need to respond to the dump file prompt.
For further information on the foreign command feature of DCL, see
Appendix A of the VAX/VMS Command Language User's Guide.
You can also invoke SDA from the site-specific start-up
Section 3.6 describes this method of calling SDA.

3.3

procedure;

EXAMINING THE RUNNING SYSTEM

Occasionally, VAX/VMS encounters an internal problem that hinders
system performance without generating a system failure. By allowing
you to examine the running system, SDA provides the means to search
memory for the solution to the problem without disturbing the
operating system.
To examine the running system, invoke SDA as described in Section 3.1.
SDA automatically sets the process context to your process.
(See the
description of the SET PROCESS command in Chapter 5 for a discussion
of process context.)
To analyze the system dump file, SDA maps the entire file.
By
contrast, when SDA examines a running system, it retrieves only the
information necessary to process a given command.
Because of the system's dynamic nature, use extreme caution when
examining the running system. Although you can safely reference most
locations, accessing certain portions of memory, such as I/O address
space or nonresident process header pages that the current process
does not own, causes the system to fail.

3.4

READING THE SYSTEM DUMP FILE

When you invoke SDA and specify the name of a dump file
(or press
) SDA gathers the data needed to create the displays from that
dump file. Under certain conditions, the contents of general purpose
or processor registers may not be saved in SYSDUMP.DMP.

3-2

RUNNING SDA
For example, during console
restart bugchecks,
such as HALT,
the
VAX-11 LSI-11 console program destroys the contents of all the general
purpose registers except the program counter and the processor status
longword.
SDA indicates in the SHOW CRASH display that the registers
wer~ wiped out by the console.
Processor registers may also be lost
if the error log buffers
in
memory
are
full.
When the operating system writes data to
SYSDUMP.DMP, it creates an error log entry in the error log buffer
that stores the contents of the processor registers.
If the buffers
are full, the contents of the registers are lost because the operating
system cannot create an error log entry for them.
Again, SDA prints a
message in the SHOW CRASH display indicating that an error log entry
for the registers does not exist.
Although the system dump file must be contiguous for the operating
system to write information to it successfully, the file need not be
contiguous for SDA to read it.
Thus, if your copy of the system dump
file is not contiguous, you will still be able to run SDA.

3.5

BUILDING THE SDA SYMBOL TABLE

After locating and reading the system dump file, SDA next attempts to
read the system symbol table file.
This file, named SYS.STE, contains
all the global symbols used by the operating system.
SDA's ability to
read global symbols makes it easier to analyze a dump because you can
examine locations by symbol rather than by virtual address.
SDA first looks for SYS.STE in the directory and device containing the
system dump.
If the file is not there, SDA looks for it in the system
directory SYS$SYSTEM.
Once SDA finds SYS.STE, it copies the file's
contents to the SDA symbol
table.
If SDA cannot find the system
symbol table file, it will not run.
When SDA finishes building its symbol table, it prints out
identifying itself and the immediate cause of the crash:

message

VAX/VMS Shlstem dumP analszer
Dump taken on 28-Feb-1979 01:22:58+43
MTXCNTNONZY Mutex count nonzero at s~stem service exit
SDA>
The SDA> prompt indicates that the utility is
ready to accept SDA
commands.
You
can
now use SDA interactively,
send selected
information to a file,
or print selected information on a
line
printer.
Refer to the description of the SET OUTPUT command in
Chapter 5 for directions on setting up output files.

3.6

INVOKING SDA IN THE SITE-SPECIFIC START-UP PROCEDURE

Because an SDA listing is an important tool in determining the general
nature of a system failure, it is a good idea to make sure that one is
produced after every crash.
The system manager can ensure the
creation of an SDA listing by modifying the SYSTARTUP.COM file in
[SYSMGR] to invoke SDA when the system is booted.

3-3

RUNNING SDA

When called by the start-up procedure, SDA scans the system dump file
for a flag that indicates whether SDA has processed the file. This
flag is cleared each time the operating system writes to SYSDUMP.DMP,
except in the case of an emergency shutdown (OPCCRASK.EXE). If the
flag is clear, SDA executes the commands designated in the command
procedure and sets the flag. If, however, SDA finds that the dump
file flag is set, it exits without performing any of the specified
commands. Thus, SDA will execute only if the system just failed.
To allow you to run SDA from the site-specific start-up procedure, the
system parameter PQL DPGFLQUOTA must equal the size of the system dump
file plus 1000 pages-:- See the VAX/VMS Syste_~t:1_9_!!.~~-~-.r' s Guide for more
information on system parameters.
the
The example below shows commands that might be added to
site-specific start-up procedure to produce an SDA listing after each
crash.
$
$
$

Print dump listing if system just failed

$ RUN SYS$SYSTEM:SDA
SYS$SYSTEM:SYSDUMP.DMP
COPY SYS$SYSTEM:SAVEDUMP.DMP
SET OUTPUT LPAO:SYSDUMP.LIS
SHOW CRASH
SHOW STACK
SHOW SUMMARY
SHOW PROCESS/PCB/PHO/REG
SHOW SYMBOL/ALL
EXIT

3-4

Save dump file
Create listing file
Display crash
information
Show current stack
List all active
processes
Display current process
Print system symbol
table

CHAPTER 4
SDA COMMAND STRINGS

The following sections describe the SDA command format and
of expressions SDA uses within commands.

4.1

the

types

GENERAL FORMAT

SDA uses a command string format similar to that of the DIGITAL
Command Language (DCL) interpreter. You issue commands in the general
format:
command [parameter] [/qualifier]

[!comment]

command
The name of an SDA command that tells the utility to perform a
certain function. Commands can consist of one or more words, and
can be abbreviated to the number of characters that make the
command unique.
For example, SH stands for SHOW and SE stands
for SET.
parameter
The target of the command. For example, SHOW PROCESS GORK
SDA to display the process GORK.

tells

When a parameter is a file specification, the current
device and directory are represented as listed below.

default

Default

Meaning

SYS$DISK

Device specified in the
SET DEFAULT command

most

recent

[default-dir]

Directory specified in
the
recent SET DEFAULT command

most

See the VAX/VMS Command Language User's Guide for
of the DCL command SET DEFAULT.

description

/qualifier
The name of a command qualifier that modifies the action of an
SDA command.
A qualifier is always preceded by a slash (/).
Multiple qualifiers can follow a single parameter but must be
delimited by slashes. Qualifiers can be abbreviated as long as
they remain unique.

4-1

SDA COMMAND STRINGS
!comment
A comment. SDA ignores the exclamation point and all
appearing after it on the same line.

4.2

characters

EXPRESSIONS

Certain SDA commands allow expressions
create expressions, you can use:

command

parameters.

• Radix operators
• Unary operators
• Binary operators
• Special operators
•
4.2.l

Symbols

Radix Operators

Radix operators determine which base SDA uses to evaluate expressions.
You can use one of three radix operators to specify the radix for a
numeric value.
Operator

Radix

Example

Hexadecimal
Octal
Decimal

"'XlO
"'030
"'Dl6

The default radix is hexadecimal.
SDA displays hexadecimal
with leading zeros and decimal values with leading spaces.

4.2.2

values

Unary Operators

SDA recognizes the following unary operators:
Operator

Function

Assigns positive value
Assigns negative value
Uses contents of location
Adds 80000000 to value
Adds 7FFEOOOO to value

The unary operator G corresponds the first virtual address in system
space, while the unary operator H corresponds to a convenient base
address in a process's control region.

4-2

SDA COMMAND STRINGS
4.2.3

Binary Operators

SDA performs integer arithmetic on 32-bit
indicating arithmetic operations are:
Operator

Function

Addition
Subtraction
Multiplication
Division
Arithmetic shift

operands.

The

characters

SDA carries out multiplication, division, and arithmetic shift before
addition and subtraction. In division, SDA does not round integers,
nor does it retain a remainder.

4.2.4

Special Operators

SDA uses parentheses as special operators.
Expressions enclosed in
parentheses are evaluated first. In the case of nested parenthetical
expressions, SDA evaluates from innermost to outermost.

4.2.5

Symbols

Symbols are composed of l to 31 alphanumeric characters that
include the special characters dollar sign ($) and underline(_).

can

SDA copies symbols into its symbol table from the SYS.STB file.
can also be created by the DEFINE and READ commands.

They

In addition, SDA provides the following special symbols:
Symbol

Meaning
Current location

80000000

7FFEOOOO
General purpose registers
Argument Pointer
Frame Pointer
Kernel Mode Stack Pointer
Executive Mode Stack Pointer
Supervisor Mode Stack Pointer
User Mode Stack Pointer
Program Region Base Register
Program Region Length Register
Control Region Base Register
Control Region Length Register
Program Counter
Processor status longword

RO-Rll
AP
FP
KSP
ESP
SSP
USP
POBR
POLR
Pl BR
Pl LR
PC
PSL

The register symbols correspond to the registers saved in the hardware
context of the current process (see the description of the SET PROCESS
command in Chapter 5). For example,

SDA> EXAMINE @USP
This command displays the first longword on the user mode stack.

4-3

CHAPTER 5
SDA COMMANDS

Table 5-1 lists the SDA commands and gives a brief explanation of
their
functions.
The
underlined characters represent command
abbreviations.
Table 5-1
Summary of SDA Commands
~----------~-----------------·--··-,,·-------,.----

Command

Function

~-----------+-----------

-------------··-····-

COPY

Copies the dump file

DEFINE

Defines symbols and their values

EVALUATE

Performs computations

EXAMINE

Examines memory locations

EXIT

Exits from the display or from SDA

FORMAT

Formats data blocks

HELP

Prints help files

READ

Copies object module symbols

REPEAT

Repeats the last command

SET OUTPUT

Sets output to
specification

the

SET PROCESS

Sets the
process

context

SHOW CRASH

Displays crash information

SHOW DEVICE

Displays I/O data structures

SHOW PAGE TABLE

Displays the system page table

SHOW PFN DATA

Displays the PFN data base

SHOW POOL

Displays dynamic memory

SHOW PROCESS

Displays specific process information

SHOW STACK

Displays process/interrupt stacks

SHOW SUMMARY

Displays a summary of all processes

SHOW SYMBOL

Displays the symbol table

process

device
to

! . -_ _ _ _ _ _ _ _ _ __..___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - · · --

5-1

or
a

file

specific

SDA COMMANDS

COPY
Each time the system fails, new information is written over the
contents of SYSDUMP.DMP. The COPY command allows you to preserve the
contents of SYSDUMP.DMP by copying it to another file.
{The resulting
copy does not have to be a contiguous file;
see Section 3.4.)
In most cases, the system manager will include the COPY command in the
SYSTARTUP.COM command procedure so that each time the system fails,
SDA will copy the system dump file to another file.
Format
COPY output-file-spec
Defaults
None

None

Parameters
output-file-spec
The device, directory, and file name to which SDA copies the
system
dump
file.
The
default
file
specification is
SYS$DISK: [default-dir]SYSDUMP.DMP.
See the
VAX/VMS
CQ~ma~J!
information about file
Language __fL~~!.' ~ -·· __ G~-~~~for
more
specifications.

Examples

SDA> COPY SYSSSYSTEM:SAVEDUMP
The COPY command takes the SYSDUMP.DMP file and copies it to the
system device and directory SYS$SYSTEM under the file name
SAVEDUMP.DMP.

5-2

SDA COMMANDS

DEFINE
The DEFINE command assigns a value to a symbol.
SDA evaluates the
expression before assigning it to the symbol.
If the symbol is
already defined, the new value simply replaces the old one.
Although both DEFINE and EVALUATE perform computations, DEFINE adds
symbols used for temporary computations to the SDA symbol table, while
EVALUATE simply performs the computation.
Format

DEFINE symbol

l l

Qualifiers

Defaults

None

expression

Parameters

symbol
A 1- to 31-alphanumeric character symbol you designate to
represent a value. See Section 4.2.5 for a discussion of valid
SDA symbols.
expression
An expression to be defined by the symbol. You can separate
expression from the symbol by a space or by an equal sign.
Section 4.2 for a discussion of SDA expressions.

the
See

Examples

SDA> DEFINE BEGIN = 80058EOO
SDA> DEFINE END = 80058E60
SDA> EXAMINE BEGIN:END
In this example, DEFINE delimits a range of address space.
A
subsequent EXAMINE command can then easily examine that section
of memory locations. The symbols serve as reference points in
memory.

SDA> DEFINE NEXT = @PC
SDA> EXAMINE NEXT
00000454 :
1FDAF812

••• +

The temporary symbol NEXT defines the address contained in the
program counter.
SDA represents nonprinting characters by a
period (.) and puts quotation marks around ASCII text. Refer to
Section 4.2.5 for a discussion of SDA symbols.

SDA> DEFINE VEC SCHSGL_PCBVEC
A symbol VEC has been assigned to a global symbol. Now you can
access the memory location or value represented by the global
symbol by specifying the symbol VEC.

5-3

SDA COMMANDS

SDA> DEFINE COUNT = 4
SDA> DEFINE RESULT = COUNT*COUNT
SDA> EVALUATE RESULT
Hex

= 00000010

Decimal

The value 4 is symbolically
arithmetic expression.

5-4

defined

and

then

used

SDA COMMANDS

EVALUATE
The EVALUATE command computes the value of any SDA expression
displays the results in hexadecimal and decimal format.

and

Format
EVALUATE expression
Qualifiers

Defaults

None

Parameters
expression
The expression to be evaluated.
See
description of valid SDA expressions.

Section

4.2

for

hexadecimal

and

Examples
1.

SDA> EVALUATE .... :J.
Hex :::: FFFFFFFF

Dc·:·~c :i. ma 1

EVALUATE prints the values
decimal.
2.

:::: .... :I.

negative

SDA> DEF I NE TEN :::: A
SDA> EVALUATE TEN
He~·{

:::: OOOOOOOA

Dc·~c i ma 1

====

:I. 0

EVALUATE computes and displays the value of the symbol TEN.
In
this example, the character "A" could also be a symbol. When SDA
encounters a quantity that can either be a symbol or
a
hexadecimal expression, SDA first treats the quantity as a symbol
and looks for it in the symbol table. If SDA cannot locate the
quantity in the symbol table, it evaluates the quantity as a
hexadecimal expression.
3.

SDA> EVALUATE ( <TEN*6>+<·-1/4) >+<2+4>

Hex

= 00000042

Decimal = 66

The EVALUATE command evaluates a complex expression and prints
the result as hexadecimal and decimal values. See Sections 4.2.2
through 4.2.5 for a discussion of the expressions used in this
example.

5-5

SDA COMMANDS

EXAMINE
The EXAMINE command displays the contents of a location
locations in physical memory.

range

You can use location parameters to examine specific locations or you
can use qualifiers to display entire process and system regions.
There are two ways to examine a range of locations:
1) designate
starting and ending locations separated by a colon, for example,
80000040:80000200; or 2) specify a location and a byte length,
separated by a semicolon, for example, 80000400;16.
If at any time you omit the location parameter from the EXAMINE
command, SDA takes the location you last examined, increases it by 4
(one longword) and examines the resulting location.

Examining Specific Locations
A location can be represented by any valid SDA expression.
When you
use the EXAMINE command to look at a location, SDA displays the
location, its symbolic representation (if possible), and its contents,
in hexadecimal and ASCII formats.
SDA initially sets the current location to -4 (decimal) in the program
region (PO) of the process.
To examine memory locations in other
processes, you must use the SET PROCESS command.

Examining Memory Regions
You can dump an entire region of virtual memory by adding one or
qualifiers to the EXAMINE command.

SDA formats the dump into columns of longwords, 4 for an 80-column
device and 8 for a 132-column device, and prints the ASCII value of
the longwords on the right side of the display.
The final column
contains the address of the first longword in each line. You read the
dump display from right to left.
If a series of virtual addresses does not exist in physical memory,
SDA prints a message specifying the range of addresses that were not
translated:
Virtual locations locl : loc2 are not in

Ph~sical

memor~

In this message, locl and loc2 represent the starting and ending
addresses of the range.
This message also appears if you try to
examine a single location that has not been mapped into physical
memory.
If a range of virtual locations contains only zeros,
message:
Zeros suppressed from locl to loc2

5-6

SDA

prints

the

SDA COMMANDS
Format
EXAMINE

[location]

[:locationll
[;length] \

Qualifiers

Defaults

/PO

None

/Pl
/SYSTEM
/ALL

Parameters
location
Expression that specifies the address in virtual memory at
data is stored.

which

length
Expression that
display.

specifies

the

number

bytes

you

want

Qualifiers
/PO
Prints the entire program region for a given process.
The
default for this qualifier is the PO region of the current
process; you must use the SET PROCESS command to examine other
processes' PO regions.
/Pl
The
Prints the entire control region for a given process.
default for this qualifier is the Pl region of the current
process; use the SET PROCESS command to examine different Pl
regions.
/SYSTEM
Prints portions of the writeable system region.
/ALL

Prints both the entire program and control regions for
process, and portions of the writeable system region.

given

Examples
1.

SDA> EXAMINE 80000200
SYS$SETEF : 8FBC003C

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

The system virtual address is defined b¥ a global symbol.
The
information stored at this address is given in hexadecimal and in
ASCII formats. SDA represents nonprinting characters by a period
(.) and puts quotation marks (" ") around ASCII text.

5-7

SDA COMMANDS
2.

SDA> EXAMINE PC
PC :

80008E22

SI:tA> EXAMINE @F'C
EXE$FWNDWN+o~·59

•• • • •

6l.l'72065

•e wa•

SDA examines the program counter and
program counter.

th~

address contained in the

SDA> EXAMINE 80000008;11
SDA displays a range of bytes starting at address 80000008 and
ending at 80000027.
SDA displays byte ranges in units of lo
{decimal) bytes. In this case, SDA displays two lines of lo
bytes even though a value of 17 {11 hexadecimal) was given.

SDA> EXAMINE/SYSTEM

Figure 5-1 shows a
command.

portion

5-8

the

display

produced

this

~AX/VHS

Svatem

21-~AV•1q7q

2.0 •• Svatem Dump Ana1vais
memorv

0P~0P000

P0~0~?03

8P05f8eP 80PP0848
4t4244P3 02313146
8P0~3qA8

r~P0~000
~0~1~0r1

~~e~e~~q
~00~0PP~
8~0b0408

8~0bVSC3
000~~~00

~~~C?~P0
~~P00P0~

~~~"0~52
0~000000
~2P~0501
~~00181~
8~n~3B8C
P0~~20~P

~P0~vPVP

p~n0pp~p

~~prppp~

4tS~gF~3

~P0P~P0P
~pp~~VP~

80~~2Q~4
P~P~0P52

P0~~0?~3

~0?0~012

~PPPP~PA

7FFEEAF4

~00P00P8
8~00087C

8p00pq48

~0060~34

0~~0P011

0~~~4328
000~0002
80001~46

00e213q3

• I •• +C ••••• I

~000001A
80~6q0q~

••••• ' •••••••••••••••••• H •• I • • • •

~0~1}0~1

~JP~0~P~

4556Uq52 44424408 ~PP000~0 0~000000 00000000
8P017C00 8006~868 0a1000cc 80003qA8
1C4040~8 80062qAP 80068EB0 00000~00 80000848
P0~0~000 03150P2A 80078230 000~0000 800008BC
7-CPC~rPP PP3~~8~8 nb00P000 8P11402C ~~00e0co
~P~0~1~r 0~0~00~0 0PEE~FAA 1PPP0P0P 0P0532BE
r~PP~~~p 0P0PP00P 0PP?P0P0 0n030p0r e0000000
~gPb?P34 8P0PnQ7C 8Pa00A88 00000000 ~0000000
aFsaa1s2 455P4FP8 P0P3P0Pn P~0~PP0P 00P0PP0P
02~~PV1Q ~P0PP?Pn sn~P2420 081~PeAC 8PP03qAp

a000~q8(

~8PP~2A~

0P842042

~Cr4~V07

p~~~~~0e

0~P0P00?

00PP~00e

~~0~r~2~
0~0~P~V0
000~rP~b

rPPQ9477

~P?PPF0~
~02r~r~p
P0~V~P~r

0~1a~00r
0~0P~0~P
P?0~FFFF

80~7A030

000PPP00 Are00qac

VP250001
0PP27BBA

8~06B6C0

rP~~?00~

~~~~~~!~
8~er2Apq
v~000rbC

EF1b3FFP ?P?PP000

ppprp~r,1

rPPS~vaa

0P~P0~~0

~0P~r0PP

8P05EH2P
800P~PfC

032F1316
0P026h!7 pppqqqFq

80003qA8
800P~A2~

pp~pr~0~

800178~0

~0~0pqa8

0PP0P~~0

8007~7PP 8P06F160
0aer.p?Ae A00e8420
8~~eJbEE ~rr0111F 8~001606 ~PP00e~r r00rrr0r 80r01cC0 8~0PPAbC 0PP00CAB
800ieq7r 0rr010r0 02P9PPIC 0PPP~P?P ~r0~er~r ~rr0rAbC 000P0C~3 EF163FBB
4t5844P3 03313146 p~~~2A4~ rr"6PV34 A~~~PABC 8~r0eBEU 8~P~~AAC 80e00A8C
BP~~3qA5 ~r~prer~ ~~er~rs2 a5564q52 ua584a~s Pe~00000 0P0~0n0e 0P00e000

'°

1413711& 0 88

~eQion

8000~A2~

~~~~~e2~

FFF~pp~~

80~P2C6D

~~0P0~P?

80~02AA7

~810~128

800~3qAe

8P00~AFC

?eaor11A

~2~rer~1

\C?Daera

8~?62CAr

~0~~PAA0

0~PA0~00

~P00~A88

~0~~kP?A

r0~r~022

~004181~

?e~~~P0P

03140000

~0~78820

000~0001

80~00AFC

000~~~vr

~~~~~Pr~

~0r~~~~p

~e~~er~0

r0e~P8~8

~~rP~PAC

8PAAD418

~P0PP0CC

~7PP0PPP

0P~PP00~

?~~1P0PF

0~P~PPP0

f5ESESES
FSF5ESE5
E5F5ESES
E5F5F5f5
~0?P127C PA06~A34 8P00?Cqp
~~~H0P52 45Sbaq52 444240?8
,0P0PP14 eP~?V0AP 00000000
081S~P?1 ~~000000 8000pCQ0

E5ESESES
E5E5E5E5
E5E5E5E5
E5ESE5E5
8P000D78

0?P001EE
00e0e000
ESESESE5
E5E5ESES
F.5ESESES
ESE5ESE5

0P~~P1E5

8P~Pieca

8,•r~eB&U

E5ESE5t5
E5ESF5f5
E5E5t5E5
F5ESE5E5

E5E5E5E5 E5~5ESE5 fSE5E5ES
F5E5E5F5 ~5E5F5E5 f5E5F5F5
f5ESE5E5 F5ESE5E5 F5E5E5E5
E5E5E5E5 E5E5F.~E5 E5E5E5E5

000~00~0

E5E5t5f5
f5f5F5ES
f5E5E5E5
F5E5E5F5
414?40?3

8000~c1c
8P~~eEFC
800~pC5C
~00e~0P?

r~00013~
00?1~P~1
~000?0~~
~~0~~A00

~0P~PP00
eAP~FF.FF
~lP~epA~
P~010~1~

000?~0F~

0810J074

8~000CQ0

~P0~~V0~

0AP~PP~P

P~P~PPPl

R??e~(qp

PH~?rA~P

800~PDP4 ~r~0~0er A000eBE4 Rrr00fFC 0r010004
8007PD?? ~~~~P?A1 A00rrCD~ R0?rrrD0 0000000~
00B~r~~c 0AP000r~ 00000000 PA00~6FA Ae0r0000
FF~FFFFF v.~00r.01a 00PP00A~ 0P~A~~0A 08100074

~t0~0~Ap

~c1s~0v1

0~00~00~

~er~2P5r.

~000000r

~001r11P

00~~0000

~~080002

~~r7742P

000P00~2

8P0PPDAC 8000r.E20 ~00~0?0? PeC00r00 00000000
444C4Er8 ~nr.00200 n,0P?0er0 ~~~00err 414r4E03
~00~rz00 00v0000r. 0a1~e01a 0?r.00r00 e0000~00
000~e0~0 P0V000AA 0~0~0P0~ 8~00PD78 80000EFC
3008r0e1 00~0~0n0 R~P0000~ 8~P~0DEC 8~~~~DEC
0~0~v~rr

000~00PP

000~~~~~
0000r0~0

~0P~000P
00V0~P~0

00P000~P

P0~00?0e

0P0~P~0Q

800~tEq8

544S4E03 0054454E 8~001648
P00000C8 ~PP000ee 00005245
0~010001 eee00rr0 000~0000
8Pe0efQA ~0000P0~ 00000000 0c1c2~~0

000e.000e

0P~0000r

0~0~0000

0~00001r

000000~0

V.00~00C0

A0P~0000

00000~00

8000~EZ~

a0~00EFc

000~0000
0R10?~7U
0~0n0000
0~0P0P0P

~00000~0

8P000c1c
~e~rPBEU

~000~0P0
@e000csc
0000r0e0 000d~000 ?000?000
FFPFFFFF 0000001u 0000000~
0100p0A0 PCtS0~e1 00000000
A0A10110 00~00000 00080~06
80?00004 80000004 ~0000000
~~~00RE4 8~0~0EFC 00P10004
80000044 A00e0n4u 00e00000
0?0000~0 0~0PP434 0000000A
00000000 80001608 00000034
0000~000 00000052 45S6aqs2
00P1P0~1 0pn00000 00000000

V000~000

00~a00A0

0C1s~001

~0000000

0000~010

r0r~0000

00060034 80000E58 80~e3260
S&aq5244 S4454E0q 00000000
0000p000 000e0000 08100080
80r&AC30 000~0000 0~000000
000~0000 ~000~001 000P0000 00000000
00000000 00000000 00000000 00000000

Figure 5-1

••• I

•••••••• I

•• I. I

••

F 101 H,,,1 1 • • 4., 1 1 1 0 0 F11 00 0BA
•••••••••••••OBORIVER 1 0 0 0 1 0 1 0 q 01
,q,,,,,,k,,,.1 •••••••••••••• •••
H,,,,,,,,, 1 , 1 ) , , , • , . . , , , 11 ,,l, 1 , 1 ,
•••••••• 0 ••• * •••••••••••••••• f,,
0001

•••• , •••••• ,.,> •••••• , ••••••••••

. 2................... . ........ .

................................
,,,,,,,,,,,,1,,,4,,,d),,,,,,,QPA
•••••••••••••O?ERATQR 1 1 0 0 0 0 1 0 q 00

,Q,,,,,.-s •••••••••••••••••• c •••
H • , , • • , , , , •, • , , , , , , 1 B
et et 1 1 t
I

, , •,, •,., •
0 t t t e t t t t I t t t e t f Wt t t ( I t t

e e I I I I I 8 8

'I I I I

I I et 1 I I

t I,.. I t I I I I I I I I

91 t I ( I I I I I I I I t t , I t I I I I I' t I I I

.... ,.......................... .
I I t I I I I I t I I I I I IQ I

I I It I I I I I 8 I? I I

.?, ••••• 1 ••••••••••••••••••• 1•••
••••••••••••••••"•••'*•1F1t,,DXA

•••••••••••••OXDRIVER, 011 , 01 ,q, 0
• q •• c ••••

* •••••• ""'...... • •• c•••

........ ............... " ...... .
• • • • • • • • • • • • • , • • • • • • ' • • • • • M •• I

••

································
................................
•••••••••••• -•••••• ,,d,.,d ••• ••••

I It e It It I I I e I I I I I t

t t

I It I I I It I It I

,,,,:w:,,,,,,,4,,,t,,,, •• ,.~BA,,,,
0 1 1 1 0 1 0 0 0 MBDRIVER 0 6,, 001 6 1 • 1 0 1 0 •

............
............... ' .. ..
..............................
............................ ...
············'···················
.... '*............ ....... ...... .
t

e 1 t

t t t t t t e I I e t I I I I I I I I I I I I I I I I I

\
•••••••••••••••••••••••• t • ••••••
e e I et I I I I I 8 I I e I I t

I e I I I I I I I t

e •I I I

ltfltlllllllttt••ea11tll911tlt1S

• • '• • • • • • '• • • ' ' • P+ •' • ' • • • •' • • • ' '
t It 0 t It 0 t t 1 et t t
t t t t I It t t It t It I

•

u,,, 11 , 11 , , 1 ,NLA,.,,,, 1 , 1 1,.,NLD
RIVER,,,, 1 ,,,,,,.,,,t, 1 1 , , , , , , , ,
I It I It t

I I I I t

I t e I 1C I e t • t

I I I t I I t I I I

................................
I I I I I I I I It e It I I It et I I I It I I I t I It I

~2 •• x ••• a ••• H•• ,NET,,NET ••••••••

01100

NETORIVER 0 1 0 0 1 1 1 1 • 1 1 1 1 1 , 011

1 1 I I I I• I I f I I I I I I I I It I

......... ..................... .
1 t t t

t tat

0 I It t

t • t

t t

It I t I e I

It I

I It I I It t It I

t t t I I I I I I I I e t e I t '1 I t e I I I I I I I I I I I

System Region Memory

80000800
80000820
80000840
80000800
80000880
800008&0
800008C0
800008E0
80000q00
80000q20
80000q40
80000qo0
80000qe0
80000qA0
80000qc0
8000iitqE0
800ei0A00
80000A20
80000A41i!!
80000A60
8121000•80
811100000
80000AC0
80000AE0
8l'!000B00
80000820
80000640
80000B60
8111000080
80000BA0
80000BC0
B0000BE0
8000111C00
8111000c20
80000C40
80000C60
80000C80
80000CA0
80000cc0
80000CE0
80000000
80000020
80000040
800000&0
80000080
8011100040
800111eJOC0
80000DE0
8Ql000E00
80000E20
8011100E411l
80000!60
80000E80
80000E40
80000EC0

C/)

(")

3
3

>
z
0

C/)

SDA COMMANDS

EXIT
The EXIT command performs two functions:
it discontinues SDA displays
and exits from the utility. During interactive sessions, if a display
has more than one page and is being shown on a video display terminal
such as a VTlOO, SDA will issue the following message each time it
reaches the bottom of a page:

Press RETURN for

more~

If you want to discontinue the current display, type EXIT at the
prompt.
(On hard copy terminals, SDA does not prompt at the bottom of
each page.) If you do not type EXIT at the screen overflow prompt and
simply execute another command, SDA will accept the command as if you
had exited from the display.
To stop SDA, type EXIT in response to the SDA prompt.
Format

EXIT
Qualifiers

Defaults

None

Parameters

None

5-10

SDA COMMANDS

FORMAT
The FORMAT command displays a formatted list
specific block. It attempts to:

the

contents

•

Characterize a range of locations as a block

•

Assign a symbol to each item of data within the block

Most VAX/VMS blocks contain a byte that indicates the block type.
This byte is stored at offset 10 (decimal) from the first address of
the block. The FORMAT command examines the byte stored at this offset
as a block type. If the byte represents a valid block type, SDA tries
to find its corresponding symbols. If the byte does not represent a
valid block type, SDA issues the message:
invalid block

t~Pe

in sPecified block

Not every block contains a block type byte at offset 10. If this byte
is absent, you must designate a block type at command level by using
the qualifier /TYPE in order to format the block.
The display produced by FORMAT shows, from left to right, the virtual
address of each item within the block, its symbolic name, and its
hexadecimal representation.
Format
FORMAT location
Qualifiers

Defaults

/TYPE=

None

Parameters
location
The starting location of the block you want
location can be any valid SDA expression.

format.

The

Qualifiers
/TYPE=block-type
The symbolic prefix that corresponds to the type of block
structure you want to format. SDA finds all symbols containing
the specified prefix in the form:
block-type$field-type_field-name
The

~ield

L
W
B
Q
T
C

types accepted by SDA are:
longword
word
byte
quadword
counted ASCII string (0 through 31 characters)
constant

5-11

SDA

COMMANDS

You can define your own block types and use the READ command to
include them in the SDA symbol table. Thus, a valid block type
is one that SDA can find in the symbol table. If SDA cannot find
the symbols associated with the block type you have ~ndicated, it
will issue the message:
No "block-type"

s~mbols

found to format this block

Examples
1.

SDA> FORMAT @SCH$GL_CURPCB
aoo6<1~.=;~;o

PCB!l>L .... SC~FI...

BOOO~!F4B

800695~)4

PCB$1....... SC~BI...
PCB$W .... SIZE
PCB!~B .... TYPE

80002F4B
OO'?C

B0069~5~:;a

B006<.»::5~iA

SDA takes the address pointed to by the
the block type, and formats the block.
2.

global

symbol,

obtains

$ HUN SYS$SYSTEM: SDA

SDA> 1:~EAD GLOBALS. STB
SDA> FOl=<MAT

(~I OC!~GL ... DEVL.. I ST

DDB$L .... I... INK
DDB$1... .... UCB
DDB$W .... S I ZE
DDB!l>B .... TYPE

BOOOOf:MB
BOOOOB4C
B00008::=iO

nooooa::52

B0000</4B

flOOOOB'lC
()() :54
Of.>
()()

800008~;;]

DDB~>l... .... DDT
DDB$l.. .... ACF'D
DDB!I> T .... NAME

B00008::=;4
B00008:58
800008~iC

BOOf.,040B
02~5:1.:5:1.46
II

DBA u

() () () () () () () ()

00000860
00000064
00000868

DDB$ T .... n1:~vNAME
SDA> FOFmAT fd.

8000086C

()()()()()()()()
()()()()0000
H DBDI:~ I VE!=~ ff

SDA> r~EPEAT

This example illustrates the use of SDA commands to format a list
of blocks. The steps followed in the example are listed below:
•

Invoke SDA.

•

Use the READ command to read the DOB symbol definitions
from GLOBALS.STB into the SDA symbol table.
For a
further discussion of object module files, see the
description of the READ command.

•

Use the FORMAT command to format the location pointed to
by the global symbol TOC$GL DEVLIST. When SDA finishes
formatting this block, it sets the current location to
the first byte of the block.
5-12

SDA COMMANDS

•

Use the FORMAT command again to format the next block in
the device list.
Most blocks contain a pointer to the
next block in a linked list. This pointer is usually the
first longword in the block. In this step, the FORMAT
command causes SDA to format the contents of the current
location (the first longword of the block).

•

Repeat the FORMAT command to format the next entry in the
list.
In this way, you can step through the entire
device list, formatting each block.

SDA> READ SYMDEF
SDA> FORMAT G10ACOO/TYPE=PHD
80 :I. OACOO
8010AC04
80 :I. OACOB
BO :I. OACOA
80 :I. OACOC
BO :I. OACOE
BO:l.OAC:l.O
80:1.0r~C:l.2

BO :I. OAC :I. 4
00:1.0AC:l.B
BO :I. OAC :l.1~
no :1. or.~c :1. c
BO :I. OAC20
B010AC22
BO:l.OAC24
BO :I. OAC26
BO :I. OAC:?B
BO :I. OAC2C
BO :I. OAC:-30
BO:l.OAC34
no :I. OAC3B
BO :I. OAC3<r
00:1.0AC::~l

no :I. OAC3C
80 :I. OAC40
n 0 :I. 0 AC 4 2
BO :I. OAC44
BO :I. OAC4t.)
BO :I. OAC4B
BOlOAC4A
BO:I. OAC4C
BO :L OAC~:50
80 :I. OAc:=.)4
80 l oAc:=m

PHD~>C~ .... PI:~ I VMSI'\

00:3osnos
00000000

PHD~t>W .... WSI... I ST

0046
042[1

PHD~~W .... WSAUTH
PHD~~W .... WSl...OCI'\

()()~::;:I.

00~:5 :I.

PHD~l>W .... WSDYN
PHD~t>W .... WSNEXT
PHD$W .... WSl...r~~:;T
PH Dii> 1....... 1:( E FE F( FI... T
PHD~~W .... V.JSC~UOTA
PHD~~W .... DFW~:>CNT
PHD~t>l... .... PAGF I 1...
PHD~t>B .... PAGF I 1...
PH:O~~W .... P~:>T
PHD~l>l... .... Pf>TBA~:>OFF

OOC9

OODB
00000000
04211
OODB
0:·3 ()()() 0 ()()
0600
()()()()

PHD~t>W .... PSTl... AST
PH D~t> t,..J .... P ~:; T F 1:;: EE

FFDfl
()()()()

PHD~t>l... .... FF~EPOlJA
PH r:i ~I> I... .... FF~ E PT EC NT
PHD~l>l... .... Fl:~EP :I. l.,JA
PHD~>l... .... PGFl...CNT
PHD~l>B .... DFPFC
PHD~l>B .... PGTBPFC
PHD~t>W .... Fl...r.~GS
PHD$1... .... CPUT IM
PHD~>W .... C~l.JANT
PHD!l>W .... Pl:~Cl...M
PHD~t>W .... ASTl...M
PHD$W .... PHV INDEX
PHD!l>W .... BAK
PHD~~W .... WSL.X
PHD$W .... PSTBASMAX
PHDil>L .... PAGEFLTS
PHD$1... .... D I OCNT
PHDi~L. .... B I DCNT
PHD$1... .... CPUI... IM

000Ar~200

0000 :I. 9"7B
/FFD9000
002/0B2D
?F

02
0006
000224/:1.
FFF/
0008
00:1.0
OOOF
o~:i26
o~=rno

00064~'.) :I. c
0 0 0 0 ~.=; 6 ;·5 :I.
00009C2B
0000000()

This example shows the use of the qualifier /TYPE=.
The READ
command is issued to move PHD symbols to SDA's symbol table (see
the description of the READ command for details on command
syntax).
Then, the FORMAT command can identify the process
header block that starts at location 8010ACOO.

5-13

SDA COMMANDS

HELP
The HELP command lists information about the SDA utility,
its
operation, and its command format. HELP has three command parameters.
If you do not specify a parameter, HELP gives a brief description of
SDA operations and lists SDA commands.
Format
HELP

[command-name]!
[EXPRESSION]
[OPERATION]

Qualifiers
--.........

Defaults

None

--~.-- ........

Parameters
command-name
Specifies the SDA command for which you need information.
EXPRESSION
Prints a description of SDA expressions.
OPERATION
Describes how to operate SDA at your
site-specific start-up procedure.

5-14

terminal

and

through

the

SDA COMMANDS

READ
The READ command lets you extract global symbols from any object
module file and insert the definitions automatically into SDA's symbol
table.
The object module file can be the output of a compiler or assembler or
the output of the linker qualifier /SYMBOL_TABLE.
It is important to note that the READ command recognizes global
symbols but ignores local symbols; hence, only global symbols are
copied into the SDA symbol table.
The program below shows some sample definitions of global symbols •
• TITLE

GLOBALS, GLOBAL SYMBOLS FOR SYSTEM DUMP ANALYZER

Note: the macros in this program must use the
argument GLOBAL. This argument defines them as
globals so that they will be automatically carried
into the object file. Without the GLOBAL argument,
the macros would be local and SDA would not be
able to read them.
$PHDDEF GLOBAL
$DDBDEF GLOBAL
$UCBDEF GLOBAL
$VCBDEF GLOBAL
$ACBDEF GLOBAL
$IRPDEF GLOBAL

PROCESS HEADER DEFINITIONS
DEVICE DATA BLOCK
UNIT CONTROL BLOCK
VOLUME CONTROL BLOCK
AST CONTROL BLOCK
I/O REQUEST PACKET

(more macros can be inserted here)
.END
Use the following DCL command to generate an object module file with
the file type STB that contains the global symbols defined in the
sample program GLOBALS.MAR, as shown above:
$

MACRO GLOBALS+SYS$LIBRARY:LIB/LIBRARY /OBJECT=GLCBALS.STB

Now you can invoke SDA and use the READ command to copy
into the SDA symbol table, as shown in Example 1 below.

the

symbols

Format
READ file-spec
Qualifiers

Defaults

None

Parameters
file-spec
The device, directory, and file name of the file whose symbols
you want copied to SDA. The default file specification for this
parameter is SYS$DISK: [default-dir]filename.STB.

5-15

SDA COMMANDS
Examples

SDA> READ GLOBALS
SDA searches for the file specification
current device and directory.

s-10

GLOBALS.STB

the

SDA COMMANDS

REPEAT
The REPEAT command repeats execution of the last command issued. This
command is primarily used to step through a linked list of data
structures or to examine a sequence of memory locations. On terminal
devices, you can use the escape key ( ~:§:Cl ) to perform the same
function as the REPEAT command;
®Q
provides a faster means of
executing the command.

Format
REPEAT
Qualifiers

Defaults

None

Parameters
None

Examples
1.

SDA> FORMAT @SCH$(3Q_LEFWQ

800631EO
800631E4
800631E8
800631EA
800631EB

80062[18()
8()0()30[1()

PCE1$L-~mFL.

PCB$L .... SC~BI...
F'CB$W .... SIZE

F'CB$B.... TYF'E

007C

PCB$B .... Pl:~I

:1.8

PCB~l>l... .... SC:~FL..
PCB$1....... SC:~BI...
PCB~>W .... S I ZE
PCB~t>B .... TYPE
PCB~>B .... PF~ I

80062FBO
B006:5 :I. EO
007C

80062FBO
80062FEi4

PCB~l>l... .... S(~FI...

aooo:·5ono

PCB~l>l... .... S(~BI...

noo6::.~riao

B0062FBB
B0062FBA

PCB~l>~J .... S I :Z.E

8001.>2FBB

PCB~t>B .... PI:~ I

SDA> FOF~MAT @.
800621:18()
80062Df.M
80062[188

80062DBA
80062I:tf.lB

SDA> REPEAT

PCB~t>B .... TYPE

007C

In this example, the FORMAT command is used to examine the local
event flag wait queue. The first process control block (PCB) in
the wait queue is formatted, then the rest of the queue can be
examined by using REPEAT (or by pressing
~
)•

5-17

SDA COMMANDS

SET OUTPUT
The SET OUTPUT command writes the output of SDA commands to a file or
device of your choice.
If you set output to a file, SDA creates a
table of contents that identifies the displays you selected.
When you set SDA output to a file or device, SDA stops displaying
commands at your terminal. If you finish directing SDA commands to an
output file and wish to return to interactive display, you can issue
another SET OUTPUT command using your terminal device as the file
specification. You can also exit from SDA and then recall the
utility.
Format
SET OUTPUT file-spec
Qualifiers

Defaults

None

Parameters
file-spec
The device, directory, and file to which
written.
The
default
file
SYS$DISK: [default-dir]SYSDUMP.LIS.

SDA output will
specification

be
is

Examples
1.

SDA> SET OUTPUT BROKEN
SDA> SHOW CRASH
SDA> SHOW PROCESS/ALL
~:>DA> SHOW SUMMARY

SDA> EXIT

SDA stores the displays produced by the commands following SET
OUTPUT on the current device and directory in a file called
BROKEN. LIS.

5-18

SDA COMMANDS

SET PROCESS
The SET PROCESS command moves process context to a specific process.
This command allows you to examine the data structures associated with
any given process.
When you invoke SDA and specify a dump file, process context, that is,
the virtual memory you will see upon executing SDA commands, defaults
to the process that was executing when the system failed.
If you are
examining the running system, process context defaults to your
process.
When you issue a SET PROCESS command, process context changes to the
process you specify. Many of the SDA commands, for example, EXAMINE,
SHOW PROCESS and SHOW STACK, operate on tRe current process, that is,
the context of the process specified in the last SET PROCESS command.
SET PROCESS locates the information needed for the particular
but produces no output.
You must specify one of the three SET PROCESS parameters or
generate a syntax error.

process
SDA

will

Format
SET PROCESS

J;~:~EX=nnl

l/SYSTEM
Qualifiers

Defaults

None

Parameters
name
A 1 to 31 character alphanumeric string assigned to the process.
The dollar sign ($) and underline ( ) characters can be included
in the string.
/INDEX=nn
The index to the software process control block (PCB). The index
number
(nn)
is composed of the last four hexadecimal digits of
the process identification (PID).
/SYSTEM
The system process control block. The system PCB and process
header
(PHD)
are dummy structures that are located in system
space and contain the system working set, global section table,
global page table, and other system-wide data.

5-19

SDA COMMANDS
Examples
1.

SDA> SET PROCESS/ I NDEX=4:3
SDA> EXAMINE/f:•o

SDA locates the process by means of the index number and displays
the contents of its program region.
2•

SDA> SET PROCESS SM I TH
SDA> SHOW STACK

Setting the process to SMITH causes the SHOW STACK command to
default to SMITH rather than to the currently executing process.

5-20

SDA COMMANDS

SHOW CRASH
The SHOW CRASH command displays fundamental information concerning the
operating system and the currently executing process. The display can
be divided into three sections:
•

Operating system and process information

•

General and special register contents

•

Processor and hardware maintenance register contents

Operating System and Process Information
The first section of SHOW CRASH lists:
•

Date and time of the crash

•

Name and version number of the operating system

•

Name of the currently executing process

•

File specification of the image executing in
context (left blank if no image is executing)

•

Interrupt Priority Level (in decimal) of the processor

the

process

General and Special Register Contents
The second section of the SHOW CRASH display lists the contents of the
general purpose and special registers.
•

RO through Rll

•

Argument Pointer (AP)

•

Frame Pointer (FP)

•

Stack Pointer (SP)

•

Program Counter (PC)

•

Processor Status Longword (PSL)

Process and Hardware Maintenance Register Contents
The third section of the SHOW CRASH display lists the contents of
three sets of registers. The first set includes registers that store
the vital statistics of the currently executing process, as well as
registers that contain information used by the operating system. The
second set of registers are the stack pointers for the processor
access modes plus the interrupt stack. The third set of registers are
used in hardware maintenance.
The process and system registers are:
POBR
POLR
PlBR
PlLR
SBR
SLR
PCBB
SCBB
ASTLVL
SISR

Program Region Base Register
Program Region Length Register
Control Region Base Register
Control Region Length Register
System Region Base Register
System Region Length Register
Process Control Block Base Register
System Control Block Base Register
Asynchronous System Trap Level
Software Interrupt Summary Register
5-21

SDA COMMANDS
The stack pointers are:
ISP
KSP
ESP
SSP
USP

Interrupt Stack Pointer
Kernel Mode Stack Pointer
Executive Mode Stack Pointer
Supervisor Mode Stack Pointer
User Mode Stack Pointer

The hardware maintenance registers are:

recs
!CR
TOOR
ACCS
SB IFS
SBISC
SB I MT
SBIER
SB I TA
SBIS

Interval Clock Control/Status Register
Interval Count Register
Time-of-Day Register
Accelerator Control and Status Register
SB! Fault/Status Register
SB! Silo Comparator Register
SB! Maintenance Register
SB! Error Register
SBI Timeout Address Register
SBI Silo Register

Format
SHOW CRASH
Qualifiers

Defaults

None

----------

Parameters
None
Examples

SDA> SHOW CRASH
Figure 5-2 shows the display produced by this command.

5-22

SDA COMMANDS
VAX/VMS 2.0 -- System Dump Analysis
System crash information

21-MAY-1979 14:42:49.46

Time of system crash: 21-MAY-1979 10:57:48.99
Version of system: VAX/VMS VERSION 1.50
Reason for BUGCHECK exception: PGFIPLHI, Pagefault with IPL too high
Process currently executing: GALCHER
Current image file name: 082: [F4V2.TOOL]BLISS32.EXE;43
Current IPL: 7

(decimal)

General registers:
RO
R4
R8
AP
PSL

0019CCAB
8006BACO
7FFDB998
7FFEEBC4
00070000

Rl
R5
R9
FP

00000000
7FFDFEOO
00019108
7f'FEEB7C

R2
Rfi
RlO
SP

000081100
OOlFFFBC
0000255C
7FFEEB38

R3
R7
Rll
PC

8010CSOC
00000200
7FFEfiC10
80006074

Processor registers:
POBR
POLR
Pl BR
PlLR
SBR
SLR

8010C400
000003EE
7F914400
001FFEC9
OOlFCOOO
00001000

ISP
KSP
ESP
SSP
USP

8007C200
7FFEEB38
7FFEFOOO
7FFEF828
7FFDB65C

PCBB
SCBB
ASTLVL
SISR

recs

ICR
TODR

Figure 5-2

0012C678
001D6AOO
00000004
00180000
800000Cl
FFFFF88F
585540BA

ACCS
SB IFS
SB I SC
SBIMT
SElI ER
SB I TA
SBIS

00008001
00040000
00000000
00200200
00008002
00075CD8
00000000

System Crash Information

5-23

SDA COMMANDS

SHOW DEVICE
The SHOW DEVICE command displays a
structures associated with a device.
divided into three sections:
•

Device data block lists

•

Controller data structures

•

Device unit data structures

formatted list of all data
The display for each device is

For a detailed explanation of I/O data structures displayed by SDA,
consult Appendix A of the VAX/VMS Guide to ~-E.!_ting __ ~ __I?~vi__ce Driver.
Device Data Block (DOB) List
The DDB list shows information common to all devices associated with a
single controller. It shows:

• Address of the controller status register (CSR)
• Name of the controller
•

Name of the ancillary control process (ACP)

• Name of the I/O driver
• Address of the driver prologue table (DPT)
• Length of the I/O driver and DPT
Controller Data Structures
SDA displays the contents of the
associated with each controller:
•

following

four

data

structures

Device Data Block (DDB)
points to the driver dispatch
table, the channel request block, and the first unit control
block connected to the controller

Request Block (CRB)
• Channel
arbitrate requests between

stores information used to
devices attached to a single

controller
•

Interrupt Dispatch Block (IDB) -- contains controller status
information used to dispatch interrupts to the proper driver

•

Driver Dispatch Table (DDT) -- points to routines that process
the I/O request

Device Unit Data Structures
The final section of the SHOW DEVICE display itemizes the contents of
the Unit Control Block (UCB) for each device. If the device is
handling file-structured requests, the display lists the Volume
Control Block (VCB) and the ACP queue as well.

5-24

SDA COMMANDS
Unit Control Block (UCB) - SDA organizes the data stored in the UCB
into a list of items. Heading the list are the address of next UCB,
the status of the device, and the longword whose bits express various
characteristics of the device.
Following the heading, SDA lists pointers to other block types:
I/O Request Packet (IRP) address
Channel Request Block (CRB) address
Volume Control Block (VCB) address
The next six items on the list concern the fork block for
driver:

the

device

Fork Queue Forward Link (FQFL)
Fork Queue Backward Link (FQBL)
Fork Interrupt Priority Level (IPL)
Fork PC, R3, and R4
The UCB contains device status

infor~ation:

Device class
Device type
Device buffer size (DEVBUFSIZ)
Device dependent data (DEVDEPEND) longword
Device status (DEVSTS) longword
Device IPL
Reference count
Operations count
The final items detailed concern mailboxes
from the I/O request packet:

and

information

obtained

Associated Mail Box (AMB) address
System Virtual Page Number (SVPN)
System Virtual Address of Page Table Entry (SVAPTE)
Byte Off set (BOFF)
Byte Count (BCNT)
Error Retry Count (ERTCNT)
Error Retry Maximum (ERTMAX)
Error Count (ERRCNT)
Owner UIC
Process Identification (PID)
SDA also formats all the I/O request packets queued to the UCB.
The
packet currently being processed is flagged by an asterisk (*).
Information contained in each I/O request packet is listed in the
following order across the page:
Channel number (CHAN)
Function value (FUNC)
Window Control Block (WCB)
Event flag number (EFN)
Asynchronous system trap (AST)
I/O status block (IOSB)
Status flags (STATUS)
If the request queue is empty, SDA issues the message:

*** I/O reauest aueue is emPtw ***

5-25

SDA COMMANDS
Volume Control Block and ACP Queue - If a volume was mounted on the
device SDA reads and displays the contents of the volume control block
(VCB) and the ancillary control process queue block (AQB).
The VCR
identifies the volume and contains counts and quotas concerning files
on that volume.
The ACP queue block contains information about the ancillary control
process (ACP) associated with the volume. SDA reads the AQB and lists
its contents in readable format.
If the request queue is empty, SDA prints the message:

*** ACP reGuest Gueue is empt~ ***
Format
SHOW DEVICE [device-name]
Qualifiers

Defaults

None

Parameters
device-name
The name of a device whose data structures you want
The device name takes the form:

display.

devcu
where
dev = 2-alphabetic character device code
c
I-alphabetic character controller designator
u
= 1- or 2-digit device unit number
You can display information about several devices by specifying a
device code or a device code and controller. For example, SHOW
DEVICE D lists all devices with device code Dn, where n
corresponds to the second letter of the device code. SHOW DEVICE
DBA lists all devices with device code DB and controller A.
To
display a single unit, specify the entire device name: SHOW
DEVICE DBAl displays the device associated with device name DBAl.
If you do not specify a device name, SDA lists the data
structures of every device on the system.
Examples
1•

S DA> SHOW ItEV I CE

Figure 5-3 is a sample Device Data Block list of all the devices
attached to the system whose device codes start with D. This is
an example of the first section of the display produced by SHOW
DEVICE.

5-26

SDA COMMANDS
VAX/VMS 2.0 -- System Dump Analysis
I/O data structures

18-DEC-1979 11:38:52.7ti

DOB list
Address
80000848
8009A4CO
8009ADOO
8009C560
8009Cfi20

Controller

ACP

Driver

DPT

DPT size

DRA

1"11ACP
FllACP
FllACP
FllACP
FllACP

DRDRIVER
DMDRIVER
DYDRIVER
DBDRIVER
DBDRIVER

80080410
800821EO
80082ECO
80087640
800871140

0814
08FO
011FO
OliFO
OfiFO

OMA
DYA

OBA
DBB

Figure 5-3

Device Data Block List for Dn Devices

SDA> SHOW DEVICE DBA
Figure 5-4 shows information on the data structures associated
with DB device controller A. This is an example of the second
section of the display produced by SHOW DEVICE.

VAX/VMS 2.0 -- System Dump Analysis
I/O data structures

ln-AUG-1979 lfi:34:54.81

Controller: OBA
Device Data Block (DOB):
DDT address
First UCB address
CRB address

800fi0408
8000087C
8005EB20

Channel Request Block (CRB) :
UCB reference count
Channel allocation mask
Secondary CRB address
IDB address
Controller init. routine
Unit init. routine
Unit start routine
Unit disconnect routine

11
00
00000000
80075E40
80001271
800609DE
00000000
00000000

Interrupt Dispatch Block (IDB):
CSR address
Owner UCB address
Number of units
ADP address

80017800
00000000
8
8005EBl10

Driver Dispatch Table (DDT):
Start I/O routine
Unsol. interrupt routine
Function Decision table
Cancel I/O routine
Register dump routine
Diagnostic buffer size
Error buffer size

00000102
00000637
0000007A
8000A869
00000592
0080
OOAE

Figure 5-4

Controller Data Structures for DB Devices

5-27

SDA COMMANDS

SDA> SHOW DEVICE DBAl
Figure 5-5 shows an example of the last section of the display
produced by SHOW DEVICE. The display lists the UCB, VCB, and AQB
for the device DBAl.

VAX/VMS 1.0 -- System Dump Analysis
I/O data structures

15-AUG-1979 17:10:0n.n8

DB Al
UCB address:
Device status:
Characteristics:
IRP address
CRB address
VCB address
FQFL
FQBL
Fork IPL
Fork PC
Fork R3
Fork R4

80074830
1810
1C4D4008

80089350
80068520
80076140
80003A48
80003A48
8
80074831
80019C80
80019800

online,valid,unload

Device class
01
Device type
05
DEVBUFSIZ
512
DEVDEPEND
032Fl3Hi
DEVSTS
0000
Device IPL
21
Reference count
0
Operation count
837f!i5
AMB address
00000000

SVPN
SVAPTE
BOFF
BCNT
ERTCNT
ERTMAX
ERRCNT
Owner UIC
PID

00000217
8009835C
0000
0200
8
8
l
[
1, 11
00000000

*** I/O request queue is empty ***
Volume: VMSWORK2
Status: 80
system
AQB address
Rel. Volume #
Transactions
Mount count
Window size
Default extension

800f!iE4AO
2
3
1
7
5

Cluster size
Reserved files
Maximum files
Free blocks
Record size
RVT address

3
9

25000
19791
0

8008C820

ACP for volume: DRASACP
PID
ACP type
ACP class
Status
Mount count
AQB linkage

00010042
3
0

def sys

00000000

*** ACP request queue is empty ***

Figure 5-5

Device Unit Data Structures for Device DBAl

5-28

SDA COMMANDS

SHOW PAGE_TABLE
The SHOW PAGE TABLE command displays a formatted list of system page
table entries-which are used to map virtual pages to physical pages.
T'h e d i s p 1 a y can be d iv i de d i n to 1 e ft and r i g ht sect i on s •
The 1 e ft
section contains virtual page information. The right section contains
physical page information.
Virtual Page Information

The left section of the display describes virtual pages using
information contained in the system page table. Each line of this
display lists characteristics of a particular virtual page as well as
locations needed for address translation. The values listed are:
•

ADDRESS -- system virtual address that marks
virtual page

•

SVAPTE -- system virtual address of the page table entry
maps this virtual page

•

PTE -- page table entry;
virtual page

•

Type -- type of virtual page;
VALID
TRANS
DZ ERO
PG FIL
STX
GPTX
IOPAGE

•

longword

that

the

base

describes

that
system

there are seven types:

Valid page (in main memory)
Transitional page (between main
memory and page lists)
Demand-allocate-zero-fill page
Paging file page
Section table index page
Global page table index page
I/O address space page

PROT -- protection; a code derived from bits in the PTE that
designate the type of access (read and/or write) granted to
processor access modes
(Kernel, Executive, Supervisor, or
User).

-- letter(s)
representing the value of a bit or a
• Bits
combination of bits in the PTE;
indicates certain aspects of
a page.

The bit codes are:

M
L

K,E,S or U

Modify bit
Locked into working set
Access mode of owner of page
(only one letter will appear)

5-29

SDA COMMANDS
Physical Page Information
If the virtual page has been mapped to a physical page, the right
section of the display includes information from the Page Frame Number
(PFN) data base. Otherwise, the section is left blank. SDA organizes
the 18 bytes of PFN data into nine categories:
•

PAGTYP -- type of physical page;
PROCESS
SYSTEM
GLOBAL
PPGTBL
GPGTBL
GBLWRT

•

there are six page types:

Process page
System page
Global section page
Process page table page
Global page table page
Global writeable section page

LOC -- location of page in system;
ACTIVE
MDFYLST
FREEL ST
BADLST
REL PEND
RD ERROR
PAGEOUT
PAGE IN

there are eight locations:

In working set
In modified page list
In free page list
In bad page list
Release pending
Read error
Paging out
Paging in

•

STATE -- byte that describes the state of the physical page.

•

TYPE -- byte that describes the
PAGTYP).

•

REFCOUNT -- reference count; word indicating the presence of
a reference to this PFN.
If the value of REFCOUNT is
non-zero, the page is used in at least one working set.
If
the value is zero, the page is not used in any working set.

•

BAK -- backing store address;
which pages can be written

•

SVAPTE -- virtual address associated with this page frame.
The two SVAPTEs indicate a valid link between physical and
virtual address space.

•

FLINK -- forward link within PFN data base;
share count of a global section.

also acts as

the

•

BLINK
backward link within PFN data base;
index to the working set list.

also acts as

type

virtual

location on a

disk

page

device

SDA indicates pages that cannot be accessed with the message:
-------- n NULL PAGES

where n represents the number of inaccessible pages.

5-30

(see

SDA COMMANDS
Format
SHOW PAGE TABLE
Qualifiers

Defaults

/GLOBAL
/SYSTEM
/ALL

/ALL

Parameters
None
Qualifiers
/GLOBAL
Lists the global page table.
/SYSTEM
Lists the system page table.
/ALL
Lists both the global and
default for the command.

system

page

tables.

This

the

produced

this

Examples

SDA> SHOW PAGE-TABLE/SYSTEM
Figure 5-6 shows
command.

one

page

5-31

the

display

ADDRESS

U'I

w
!\..)

8000DOOO
8000D200
8000D400
8000D600
8000D800
8000DAOO
8000DCOO
8000DEOO
8000EOOO
8000E200
8000E400
8000E600
8000E800
8000EAOO
8000ECOO
8000EEOO
8000FOOO
8000F200
8000F400
8000F600
8000F800
8000FAOO
8000FCOO
8000FEOO
80010000
80010200
80010400
80010600
80010800
80010AOO
80010COO
80010EOO

SVAPTE

PTE

801F91AO 78000B7A
801F91A4 F80004E9
801F91A8 78000134
801F91AC F80009E5
801F91BO F8000DB2
801F91B4 F80001DD
801F91B8 F80001E9
801F91BC F8000257
801F91CO F800098E
801F91C4 F8000A5B
801F91C8 F800049A
801F91CC F8000844
801F91DO F8000075
801F91D4 78000088
801F91D8 F800020A
801F91DC F8000270
801F91EO F8000A4C
801F91E4 78000096
801F91E8 FA00067B
801F91EC 780001E5
801F91FO F800031A
801F91F4 F800029A
801F91F8 7800098C
801F91FC 7C40FFF8
801F9200 F80002DC
801F9204 78000159
801F9208 7C40FFF8
801F920C 7C40FFF8
801F9210 7C40FFF8
801F9214 7C40FFF8
801F9218 7C40FFF8
801F921C F80009F7

TYPE

PROT

BITS PAGTYP

TRANS UR
VALID UR
TRANS UR
VALID UR
VALID UR
VALID UR
VALID UR
VALID UR
VALID UR
VALID UR
VALID UR
VALID UR
VALID UR
TRANS UR
VALID UR
VALID UR
VALID UR
TRANS UR
VALID UR
TRANS UR
VALID UR
VALID UR
TRANS UR
STX
UR
VALID UR
TRANS UR
STX
UR
STX
UR
STX
UR
STX
UR
STX
UR
VALID UR

K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K SYSTEM
K
K SYSTEM
K SYSTEM
K
K
K
K
K
K SYSTEM

LOC STATE TYPE

REFCNT

BAK

SVAPTE

FLINK

BLINK

801F91AO
801F91A4
801F91A8
801F91AC
801F91BO
801F91B4
801F91B8
801F91BC
801F91CO
801F91C4
801F91C8
801F91CC
801F91DO
801F91D4
801F91D8
801F91DC
801F91EO
801F91E4
801F91E8
801F91EC
801F91FO
801F91F4
801F91F8

01E5
0000
053E
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
ODB9
0000
0000
0000
0909
0000
0000
0000
0000
02BA

0742
0046
0654
0062
0058
0057
OOA6
007C
007D
OOA3
004E
0094
0068
0394
005C
0058
0060
0585
0072
OB7A
006C
OOA9
0159

801F9200
801F9204

0000
098C

0087
094D

FREELST 00
ACTIVE 07
FREELST 00
ACTIVE 07
ACTIVE 07
ACTIVE 07
ACTIVE 07
JI.CT IVE 07
ACTIVE 07
ACTIVE 07
ACTIVE 07
ACTIVE 07
ACTIVE 07
FREELST 00
ACTIVE 07
ACTIVE 07
ACTIVE 07
FREELST 00
ACTIVE 07
FREELST 00
ACTIVE 07
ACTIVE 07
FREELST 00

01
01
01
01
01
01
01
01
01
01
01
01
01
01
01
01
01
01
01
01
01
01
01

0
1
0
1
1
1
1
1
1
1
1
1
1
0
1
1
1
0
1
0
1
1
0

0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8
0040FFF8

ACTIVE 07
FREELST 00

01
01

1
0

0040FFF8
0040FFF8

801F928C 94100010
801F9290 94100030
801F9294 90100031
801F9298 90100032
801F929C 90100033
801F92AO 94100034
801F92A4 94100035
801F92A8 90100036
801F92AC 90100037
801F92BO 941009FO
801F92B4 901009Fl
801F92B8 901009F2
801F92BC 901009F3
801F92CO 941009F4
801F92C4 901009F5
801F92C8 901009F6
801F92CC 901009F7

IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW
IOPAG KW

M
M

>
z

(/)

ACTIVE

K
K
K
K
K
K
K
K
K
K
K
K
K
K
K
K
K

Figure 5-6

3
3

-------- 27 NULL PAGES
80014600
80014800
80014AOO
80014COO
80014EOO
80015000
80015200
80015400
80015600
80015800
80015AOO
80015COO
80015EOO
80016000
80016200
80016400
80016600

C/)

System Page Table

0040FFF8

801F921C

0000

0083

SDA COMMANDS

SHOW PFN_DATA
The SHOW PFN DATA command displays a formatted list of values
contained in the page lists and in the PFN data base that can be used
to translate physical pages to virtual pages.
There are four data
physical memory:

structures

concerned

with

the

management

•

Free Page List -- pages available for use

•

Modified Page List -- pages to be written to disk

•

Bad Page List

pages containing data errors

•

PFN Data Base

all pages in physical memory

To display a particular physical page, specify its page frame number
(PFN).
To list the pages of one or more data structures, use the
qualifiers. If you do not specify a parameter or a qualifier, SDA
will dump all the page lists and the entire PFN data base.
The format used to display physical page data is the same for each
data structure.
Figure 5-7 shows a page of the display produced by
the command SHOW PFN DATA/SYSTEM. SDA organizes the information for
each page under the following headings:
•

PFN -- page frame number;
physical memory

the

absolute

•

PTE ADDRESS -- Page Table Entry address; the virtual address
of the Page Table Entry (see the description of the SHOW
PAGE_TABLE command for more details).

•

BAK -- backing store address;
which pages can be written

•

REFCNT
reference count; a word whose value signals whether
a page is part of a working set

•

FLINK -- forward link;
forward link within the PFN data
(also used as share count of a global section)

base

•

BLINK -- backward link; backward link within the PFN
base (also used as an index to the working set list)

data

•

TYPE -- type of page that was mapped into physical memory (see
the description of the SHOW PAGE TABLE command for a list of
the different types)

location on a

current state of the page in
• STATE
description of the SHOW PAGE TABLE
~-

states)

5-33

page

number

disk

within

device

the system (see the
command for a list of

SDA COMMANDS

Format
SHOW PFN DATA [number]
Qualifiers

Defaults

/FREE
/MODIFIED
/BAD
/SYSTEM
/ALL

/ALL

Parameters
number
The number of the physical page you want to display.

Qualifiers
/FREE
Displays the free page list.
/MODIFIED
Displays the modified page list
/BAD
Displays the bad page list.
/SYSTEM
Displays the PFN data base in order of PFN starting at page frame
zero.
/ALL
Displays all of the above memory management
This is the default for the command.

data

structures.

Examples
1.

SDA> SHOW F'FN .... DATA/SYSTEM

Figure 5-7 shows
command.

one

page

5-34

the

display

produced

this

SDA COMMANDS
VAX/VMS 2.0 -- System Dump Analysis
PFN data base
PFN

PTE ADDRESS

BAK

0000
0-001
0002
0003
0004
0005
0006
0007
0008
0009
OOOA
OOOB

00000000
800A3Cl0
80174EAO
8010CEEO
801F7F70
8010CEB4
80174CAC
8016D200
8010CE2C
801COC58
801FB890
801FC6BC
00000000
801F03EO
801F0474
8010CF1C
80101040
801FD524
8017C900
80113F88
8011F480
801F0464
80-lOCfilO
801'503BC
80085008
80160338
801FB774
80160254
801020D8
801F'D5FO
8010A808
801F060C
80110848
8010CFEO
801B59D4
00000000
80174CA4
00000000
8010CE34
801FCB6C
8010CA28
8010CC98
801601F4
8010C604
8016D348
80160204
801A28 38
00000000
801FD2E8
00000000
8010C7C4

00000000
03000000
03000000
033FFFFF
03000000
033FFFFF
03000000
0300E351
0300E20E
03000000
03000000
03000000
00000000
0040FFB8
0040FFAO
033FFFFF
033FFFFF
0040FF90
03000000
0300E2C6
03000000
03000000
0040FFE8
03000000
03000000
03000000
03000000
033FFFFF
033FFFFF
0040FF90
03005305
0040FF70
033FFFFF
0 33FFF1''F
03000000
00000000
03000000
00000000
0300E2EO
03000000
0040FFE8
033FFFFF
03008FF2
0040FFE8
03000000
0300E352
0300861C
00000000
0040FFDO
00000000
0040FFE8

oooc

0000
OOOE
OOOF
0010
0011
0012
0013
0014
0015
OOH
0017
0018
0019
OOlA
0018
OOlC
0010
OOlE
OOlF
0020
0021
0022
0023
0024
0025
0026
0027
0028
0029
002A
002B
002C
0020
002E
002F
0030
0031
0032

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

21-MAY-1979 15:00:04.82

REFCNT

FLINK BLINK

0
1
1
1
1
1
1
0
0
1
1
1
0
1
0
1
1
1
1
1
1
1
0
1
1
1
1
0
1
1
1
1
1
1
1
0
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1

0895 OAAF
0000 0053
0000 007C
0000 01A2
0000 OOC9
0000 018D
0000 OOCE
0020 0498
0006 095F
0000 OOOB
0000 0054
0000 004B
05n6 08Bl
0002 0000
03FB ODll
0000 0084
0000 008C
0002 0000
0000 0047
0000 014B
0000 0088
0000 OOnB
0001 0195
0000 OOFE
0000 0050
0000 0143
0000 004E
018E 0634
0000 0084
0002 0000
0000 0175
0001 0000
0000 0002
0000 OODC
0000 0046
020C 025B
0000 oocc
0A2E 08CB
0590 0423
0000 004F
0000 DOCS
OA25 occs
0000 0058
07AC ODIE
0000 0135
0401 0007
0000 0007
0840 OB03
0003 0000
093A 08CD
0000 017A

Figure 5-7

5-35

TYPE

STATE

----------

00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
04 PPGTBL
04 PPGTBL
00 PROCESS
02 GLOBAL
02 GLOBAL
00 PROCESS
00 PROCESS
02 GLOBAL
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
04 PPGTBL
00 PROCESS
00 PROCESS
02 GLOBAL
00 PROCESS
02 GLOBAL
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
04 PPGTBL
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
00 PROCESS
02 GLOBAL
00 PROCESS
00 PROCESS

00 FREEL ST
87 ACTIVE
87 ACTIVE
87 ACTIVE
07 ACTIVE
87 ACTIVE
07 ACTIVE
00 FREEL ST
81 MDFYLST
07 ACTIVE
07 ACTIVE
87 ACTIVE
00 FREEL ST
07 ACTIVE
00 FREEL ST
87 ACTIVE
87 ACTIVE
07 ACTIVE
07 ACTIVE
07 ACTIVE
07 ACTIVE
07 ACTIVE
00 FREELST
07 ACTIVE
07 ACTIVE
07 ACTIVE
87 ACTIVE
81 MDFYLST
87 ACTIVE
07 ACTIVE
87 ACTIVE
07 ACT IVS
87 ACTIVE
87 ACTIVE
07 ACTIVE
00 FREEL ST
07 ACTIVE
00 FREEL ST
81 MDFYLST
87 ACTIVE
07 ACTIVE
81 MDFYLST
87 ACTIVE
00 FREEL ST
07 ACTIVE
00 FREEL ST
87 ACTIVE
00 FREEL ST
07 ACTIVE
00 FREEL ST
07 ACTIVE

PFN Data Base

SDA COMMANDS

SHOW POOL
The SHOW POOL command displays the contents of the I/O Request Packet
(IRP) pool, the nonpaged dynamic storage pool, and the paged dynamic
storage pool. This data is organized into blocks;
SDA attempts to
identify each block by its block type.
SHOW POOL displays only
allocated blocks, that is, blocks that are (or were) currently in use
by the system.
The information contained in each of the three pools is shown in the
same format. From left to right, the contents of the display are:
•

Block type -- the type of information contained in the block.
SDA tries to define the block type. If it is unable to do so,
the message UNKNOWN is printed instead of the name of the
block type.

•

Starting address -- the virtual address that marks
of the block.

•

Block size -- the number (decimal) of bytes of nonpaged memory
allocated to the block. The block size is fixed at 80 in the
IRP pool and is variable in the paged and nonpaged pools.

•

Contents (hexadecimal)
the contents of the block
longwords. The contents are arranged four columns across.

•

Contents (ASCII) -- the contents of the block in ASCII format.

the

start

Format
SHOW POOL
Qualifiers

Defaults

/!RP

/NON PAGED
/PAGED
/SUMMARY
/ALL

/ALL

Parameters
None
Qualifiers
/!RP
Prints the I/O request packet pool. Formats all blocks currently
allocated (in use) within this pool.
/NON PAGED
Prints the nonpaged dynamic storage pool currently in use by
system.

5-36

the

SDA COMMANDS

/PAGED
Prints the paged dynamic storage pool currently
system.

use

the

/SUMMARY
Prints a summary of the pools selected by the above qualifiers.
/SUMMARY displays the different block types present and lists the
total number and bytes used of each in decimal.
This qualifier
also prints the total number of bytes used in each pool.
/ALL

Prints IRP, nonpaged, and paged dynamic storage pools.
the default for the command.

This

Examples

SDA> SHOW POOL/PAGED
Figure 5-8 shows a page of the display produced by this command.

5-37

SDA COMMANDS
VAX/VMS 2.0 -- System Dump Analysis
Paged dynamic storage pool
GSD

80056FAO

21-MAY-1979 16:21:47.68

48
00010004 00150028 80056FDO 80056810 • k ••• o •• ( •••••••
5F424D53 5452500A 80056870 FFC8AOOO •••• ph ••• PRTSMB
00000000 00000000 00000000 00313030 001 •••••••••••• -:

GSD

80056FDO

48
00010004 00150028 80057000 80056FAO .o ••• p •• ( •••••••
59414C50 53494408 80056970 FFCOAOOO •••• pi ••• DISPLAY
00000000 00000000 00000000 3130305F 001 ••••••••••••

GSD

80057000

00010004 00150028 80057320 80056FDO .o •• s •• ( •••••••
59414C50 53494408 80056970 FFB8AOOO •••• pi ••• DISPLAY
00000000 00000000 00000000 3230305F 002 ••••••••••••
KFH

KFI

80057030

80057120

80057160

800571AO

800571EO

80057220

80057260

240
0028007C
00000101
02000000
00000000
00000002
00000000
00000000
00003032
00000001
00000005
00800007
00000000
OOOOOOOA
FDOOOOOC
00000000

80056970
00000000
00000000
0000373E
00000010
59414C50
00000000
00864404
00000000
00000002
00000006
oooooooc OOOAOOlO
00000016 OOOBOOlO
003FFFEC 0014000C
00000000 00000000

80057114 .q •• pi •••• &. I. (.
00440038 8.D ••••• 0201 ••••
00000000
00000000 •••• >7 ••• "
00000000
53494407 • DISPLAY ••••••••
00313002 • 01 •••••••••••••
064AOE20
.J •• D ••• 01.20 ••
00000000
00000000
OOOOOOOA

00340000
800630CO
00000001
00000000

04180040
00000233
00000000
00000057

80057160
00020387
00108001
4F485304

800569FO • i •• q •• @••••• 4.
00000001 •••••••• 3 •••• 0 ••
800574FC .t . . . . . . . . . . . . . .
80057120 q ••• SHOW •••••••

00340000
800630FO
00000000
00000000

04180040
00000400
00000000
00000000

800571AO
00008001
00000000
50495003

80057120 q ••• q • • @•••• • 4.
00000001 ••••••••••••• o ••
00000000
00000000 ••••• PIP ••••••••

00340000
80063120
00000001
00000000

04180040
OOOOOOAO
00000000
00000000

800571EO
00018205
00000000
534F5303

80057160 q ••• q •• @••••• 4.
00000001
1 ••
00000000
800571AO • q ••• sos ••••••••

00340000
80062F50
00000001
00000000

04180040
000002F5
00000000
00000000

80057220
00010307
00000000
58535203

800571AO
00000001
800578DC
800571EO

00340000
80062F80
00000001
0000534E

04180040 80057260
000004El 00010307
00000000 00000000
41525448 43414209

002600E4
31303230
00000000
00002285
00000000
00000000
00000000
2E313005
00040010
00020010
0005000C

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

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

................
00000008 ................

oooooooc ................
00000012 • • • • • • • • • • ? •••••
FFFFOOOO

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

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

64
.q •• r •• @••••• 4.
• • • • • • • • •• • .P/ • •
.x ••••••••••••••
.q ••• RSX ••••••••

64
800571EO .q •• r •• @••••• 4.
00000001
/
80057AOC • z •••••••••••.•••
80057220 r ••• BACKTRANS ••

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

64
00340000 04180040 800572AO 80057220

Figure 5-8

r ••• r •• ra ••••• 4.

Paged Dynamic Storage Pool

5-38

SDA COMMANDS

SHOW PROCESS
The SHOW PROCESS command displays the software and hardware context of
any process in the balance set.
Format

[name]
SHOW PROCESS [/INDEX=nn]
[/SYSTEM]

Qualifiers

Defaults

/PCB
/PHD
/REGISTERS
/WORK ING SET
/PROCESS-SECTION TABLE
/PAGE TABLES
/ALL -

/PCB

Parameters
name
A 1- to 15-character alphanumeric string assigned to the process.
The name can include the symbols underline (_) and dollar sign
( $) •

/INDEX=nn
The index to the software PCB;
nn consists of the last
hexadecimal digits of the Process Identification (PID).

four

/SYSTEM
The system process control block.
The system PCB and process
header
(PHD)
are dummy structures that are located in system
space and contain the system working set, global section table,
global page table, and other system-wide data. When you specify
this parameter, SDA displays the system PCB rather than a given
process.
If no parameter is specified,
the command displays the current
process.
See the description of the SET PROCESS command for the
definition of the current process.
Qualifiers
/PCB
Produces a formatted list of the data contained in the software
process control block
(PCB).
The software PCB is the central
control mechanism for process swapping and scheduling.

5-39

SDA COMMANDS
The display produced by the /PCB qualifier lists:
•

Software context for the process

•

Condition handling information

•

Interprocess communication data

•

Counts and quotas

/PCB is the default display for the command.
/PHD
Lists information included in the process header.
The process
header contains a process's vital statistics and is swapped into
memory when a process becomes part of the balance set.
Each item
listed by the /PHD qualifier gives a quantity, count, or limit
for the process concerning:

• Process memory
• Pager
•

Scheduler

• Asynchronous system traps
• I/O activity
• CPU activity
/REGISTERS
Lists the process's hardware context. When a process executes,
its hardware context is saved in the processor registers (see the
description of the SHOW CRASH command).
If the process
is not
executing,
its hardware context is stored in the hardware PCB,
which is part of the process header.
The /REGISTERS qualifier
organizes the saved process registers into:
•

General-purpose registers

•

Stack pointers

•

Special-purpose registers

•

Base and length registers

/WORKING_SET
Displays the working set list for the process.
The working set
list is a table for all virtual pages residing in physical memory
that the process can access without a page fault.
The values
exhibited by this command are:
•

INDEX -- index used in PFN data base to access the entry

•

ADDRESS -- address of
address space

•

STATUS -- a 3-part section that lists the location of the
page in physical memory,
the type of page (see the
description of the SHOW PAGE TABLE command), and whether
the page is locked into the working set

5-40

virtual

page

the

process

SDA COMMANDS
When SDA locates an unused
message:

working

set

entry,

issues

the

The value of n is the number (in decimal) of unused entries
SDA has found.

that

---- n empty entries

/PROCESS_SECTION TABLE
Lists data within the process section table. The process section
table contains information needed to locate a page in a process
section. SDA notes the boundary of the Process Section Table in
the "Process Section Table Information" section of the listing
and then displays the actual process section table in readable
format. The parts of the process section table are:
•

INDEX -- the word that locates the corresponding
section table entry

•

ADDRESS -- the virtual address in the program region that
marks the location of a process section table page

•

PAGES -- the length of a process section in pages

•

WINDOW -- the mapping window that translates
block numbers to logical block numbers

•

VBN -- virtual block number; the number of a block on a
mass storage device (the block number is relative to a
file rather than to a device)

•

CLUSTER -- the cluster factor used when faulting pages in
the corresponding process section

•

CHANNEL
the channel
section to a device unit

•

REFCNT -- a number that indicates
part of a working set

FLINK

the forward link word in the PST list

BLINK

the backward link word in the PST list

•

FLAGS
the flags that
during process execution

number

describe

connecting
whether

the

process

virtual

process
page

section

/PAGE_TABLES
Displays the
program
control
and
/PAGE TABLES produces a list in the
PAGE TABLE command.

region
page
tables.
same format as the SHOW

/ALL
Displays the information produced by the /PCB, /PHD, /REGISTERS,
/WORKING SET,
/PROCESS SECTION TABLE,
and
/PAGE_TABLES
qualifiers.
-

5-41

SDA COMMANDS

Examples
1.

SDA> SHOW PROCESS/PCB

The top portion of Figure 5-9 shows the display produced by
command.
2.

SDA> SHOW p1:mcESS/PH[I

The middle portion of Figure 5-9 shows the
this command.
3.

display

produced

display

produced

SDA> SHOW PFWCESS/REG:CBH'.RS

The bottom portion of Figure 5-9 shows the
this command.
VAX/VMS 2.0 -- System Dump Analysis
Process 2B dump: ELDRIDGE
Process status:

00040001

PCB address
Master PIO

3-JAN-1980 16:54:45.57

RES,PHDRES
8008BD20
0004002B
0004002B
80180AOO
LEF

PIO

PHO address
State
Current priority
9
Base priority
4
UIC
[011,0131
Mutex count
0
Waiting EF cluster
0
Starting wait time
00000000
Event flag wait mask
F7FFFFFF
Local EF cluster 0
4000031B
Local EF cluster 1
80000041
Global cluster 2 pointer 00000000
Global cluster 3 pointer 00000000

JIB address
8009DB80
Creator PIO
00000000
Subprocess count
0
Swapfile disk address
00000000
Termination mailbox
0000
AST's enabled
KESU
NONE
AST's active
AST's remaining
14
5/6
Buffered I/O count/limit
fi/6
Direct I/O count/limit
1205'1/12336
BUFIO byte count/limit
# open files allowed left
10
10
Timer entries allowed left
Active page table count
0
Process WS page count
235
14
Global WS page count

Process header
First free PO address
Free PTEs between PO/Pl
First free Pl address
Free page file pages
Page fault cluster size
Page table cluster size
Flags
Direct I/O count
Buffered I/0 count
Limit on CPU time
Maximum page file count
Total page faults
File limit
Timer queue limit
Paging file index

0002C800
7478
7FFD3200
25252
127
2
0002
727
4958
00000000
25600
7154
lfi
10
03000000

Accumulated CPU time
CPU since last quantum
Subprocess quota
AST limit
Process header index
Backup address vector
WSL index save area
PTs having locked WSLs
PTs having valid WSLs
Active page tables
Maximum active PTs
Guaranteed fluid WS pages
Extra dynamic WS entries
Locked WSLE counts array
Valid WSLE counts array

00000000
00000000
7FFDC120
7FFD5914
7FFEFOOO
00000164

R2
R6
RlO
PC
SSP
Pl BR

0000144fi
0031
8
lfi
0018
03A5
0380
2
fl
7

20
3f.i0
OFB8
OFFS

Saved process registers
RO
R4
RB
AP
KSP
POBR

this

08000000
8008BD20
7FFDSA58
7FFD590C
7FFEE400
80181COO

Rl
RS
R9
FP
ESP
POLR

Figure 5-9

80001ADO
000008DC
7FFDC008
80000328
7FFEF878
7F989COO

R3
R7
Rll
PSL
USP
PlLR

8008BD70
00000003
7FFDBA8C
03COOOOO
7FFD590C
001FFE9A

Process Information

5-42

SDA COMMANDS

SDA> SHOW PROCESS/WORKING_SET
Figure 5-10 shows the display produced by this command. The size
of the working set and its boundaries are listed at the head of
the display.
The actual working set
list
follows
this
information.
21-MAY-1979 15:19:08.57

VAX/VMS 2.0 -- System Dump Analysis
Process 34 dump: GROVE
Working set information
First WSL entry
First locked entry
First dynamic entry
Last entry replaced
Last entry in list

Current authorized working set size
Default (initial) working set size
Maximum working set allowed (quota)

0046
0051
0052
015A
01A3

Working set list

---------------INDEX

ADDRESS

STATUS

0046
0047
0048
0049
004A
0048
004C
004D
004E
004F
0050
0051
0052
0053
0054
0055
0056
0057
0058
0059
005A
0058
005C
005D
005E
005F
0060
0061
0062
0063
0064
0065
0066
0067
0068
0069
006A
0068
006C
006D

7FFEEAOO
7FFEE800
7FFEE600
7FFEFEOO
8010ACOO
8010AEOO
80108000
8010COOO
8010C200
80113EOO
80114000
80108200
00054400
00054AOO
00055400
00054EOO
00054COO
00055000
00055200
00063EOO
00056600
00055600
00068 EOO
00055COO
00058EOO
00069000
00056200
00056400
00069200
00056AOO
00069400
00056COO
00056EOO
00064000
00069600
0005C400
00057200
00057400
00059200
00059000

VALID PROCESS WSLOCK
VALID PROCESS WSLOCK
VALID PROCESS WSLOCK
VALID PROCESS WSLOCK
VALID PPGT8L WSLOCK
VALID PPGT8L WSLOCK
VALID PPGT8L WSLOCK
VALID PPGT8L WSLOCK
VALID PPGT8L WSLOCK
VALID PPGT8L WSLOCK
VALID PPGT8L WSLOCK
VALID PPGT8L WSLOCK
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS
VALID PROCESS

Figure 5-10

Working Set List

5-43

1000
350
1000

SDA COMMANDS

SDA> SHOW PROCESS/PROCESS_SECTION_TABLE
Figure 5-11 shows the display produced by this command.

VAX/VMS 2.0 -- System Dump Analysis
~rocess 34 dump: GROVE

21-MAY-1979

15:29:24.5~

Process section table information
Last entry allocated
First free PST entry

FFEO
0000

Process section table
INDEX

ADDRESS

PAGES

WINDOW

VBN

FFF8
FFFO
FFE8
FFEO

00000200
00076600
00003COO
00077600

OOOOOOOF
00000008
00000188
00000033

80068980
80078050
80068980
80079220

00000002
00000002
00000013
0000019C

Figure 5-11

CLUSTER

CHANNEL

REFCNT

7FFE1DEO
7FFE1D90
7FFE1DEO
7FFE1D60

0
7

0
0

355
51

FLINK BLINK
FFE8
FFFO
FFF8
FFEO

FFE8
FFFO
FFF8
FFEO

this

Process Section Table

SDA> SHOW PROCESS/PAGE-TABLES
Figure 5-12 shows a portion
command.

5-44

the

display

produced

FLAG~

VAX/VMS 2.0 -- System Dump Analysis
Process 01 dump: SWAPPER

22-MAY-1979 10:40:52.99

PO page table

------------ADDRESS
00000000
00000200
00000400
00000600
00000800
OOOOOAOO

I
~

U'1

PTE

OOOOOEOO
00001000
00001200
00001400
00001600
00001800

--------

NULL PAGES

OOOOlCOO
OOOOlEOO
00002000
00002200
00002400
00002600
00002800
00002AOO
00002COO
00002EOO
00003000
00003200
00003400
00003600
00003800
00003AOO
00003COO
00003EOO
00004000
00004200
00004400
00004600
00004800
00004AOO
00004COO
00004EOO
00005000
00005200
00005400
00005600
00005800

8005EE68 DOOOOAA6
8005EE6C D0000960
8005EE70 DOOOOlCB
8005EE74 DOOOOD04
8005EE78 D00005AO
8005EE7C D0000271
8005EE80 DOOOOBC7
8005EE84 D0000066
8005EE88 D0000076
8005EE8C DOOOOC32
8005EE90 D000080C
8005EE94 D0000539
8005EE98 DOOOOBCl
8005EE9C D00006AA
8005EEAO DOOOODE9
8005EEA4 DOOOOA9B
8005EEA8 D0000012
8005EEAC D000094D
8005EEBO D0000448
8005EEB4 D00007E5
8005EEB8 D0000456
8005EEBC D000006F
8005EECO DOOOODCC
8005EEC4 DOOOODB9
8005EEC8 D0000234
8005EECC DOOOOA59
8005EEDO D000074B
8005EED4 D000083B
8005EED8 D0000900
8005EEDC D000070F
8005EEEO D00002CB

ooooocoo

U'1

SVAPTE

8005EE30 DOOOOB6D
8005EE34 D000066E
8005EE38 D40009DD
8005EE3C D0000075
8005EE40 DOOOOB77
8005EE44 DOOOOB73
8005EE48 D00005FB
8005EE4C D4000C4C
8005EE50 D00009DD
8005EE54 D0000075
8005EE58 DOOOOB77
8005EE5C D4000290
8005EE60 D4000397

TYPE

PROT

BITS PAGTYP

LOC STATF.: TYPE

REFCNT

BAK

SVAPTE

FLINK

BLINK

87
87
07
87
87
07
07
07
07
87
87
87
87

04
04
00
00
00
00
00
00
00
00
00
04
04

1
1
1
1
1
1
1
1
1
1
1
1
1

03000000
03000000
03000000
03000000
03000000
03000000
03000000
03000000
03000000
03000000
03000000
03000000
03000000

801FA7D8
801FA900
800C81FC
800C803C
800C80C8
800C81D4
800C81DO
800C81CC
800C81FC
800C803C
800C80C8
801FA7EO
801FA7DC

0000
OOOF
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000

004A
0050
0049
0051
0052
0046
0047
0048
0049
0051
0052
004C
004B

FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00
FREELST 00

00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
00
02
00
00
00
00
00
02
00
00

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
0040FF08
00000000
00000000
00000000
00000000
00000000
004CFFDO
00000000
00000000

00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
00000000
801FE2E4
00000000
00000000
00000000
00000000
00000000
801FD34C
00000000
00000000

05E4
01C9
0271
OBCl
0596
0331
049E
06DF
OOCB
OD04
OC32
080C
0456
ODDS
ODDl
09A7
0779
04E7
0763
0557
OlCB
0952
054C
070F
OA8B
009A
0407
0050
074D
086A
0511

0288
OOAE
0456
OC32
0523
OlCB
OBCA
0384
09FO
080C
0539
0038
OD04
OB24

VALID SRKW
VALID SRKW
VALID SRKW M
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW M
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW M
VALID SRKW M

K PPGTBL ACTIVE
K PPGTBL ACTIVE
K PROCESS ACTIVE
K PROCESS ACTIVE
K PROCESS ACTIVE
K PROCESS ACTIVE
K PROCESS ACTIVE
K PROCESS ACTIVE
K PROCESS ACTIVE
K PROCESS ACTIVE
K PROCESS ACTIVE
K PPGTBL ACTIVE
K PPGTBL ACTIVE

VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW
VALID SRKW

K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K GLOBAL
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K PROCESS
K GLOBAL
K PROCESS
K PROCESS

(/)

Figure 5-12

Program Region Memory

ocac

0044
08BA
03FC
0839
OAC3
OBCl
ODES
075E
OOCE
067B
0557
040A
0522
08EO
ODB9
0889

>
n

0
3
3'

>
z
0

(/)

SDA COMMANDS

SHOW STACK
The SHOW STACK command displays the location and contents of the four
stacks used by a given process as well as the system-wide interrupt
stack.
Each qualifier displays one of four stacks that correspond to the four
VAX/VMS processor access modes for a specific process. The /INTERRUPT
qualifier displays the system-wide interrupt stack. The default for
SHOW STACK is the stack that is currently being used or that was in
use when the system failed.
Figure 5-13 shows the display produced by the SHOW STACK command. The
display is the same for each stack, and is composed of four sections:
•

Stack Pointer -- the stack pointer identifies the top of the
stack. The display indicates tte stack pointer by the symbol:

SF' => 7FFEF868

00000001

•

Stack address -- SDA lists all the virtual addresses allocated
to the stack by the operating system. The stack addresses are
listed in a column which increases by 4 (one longword).

•

Stack contents -- SDA lists the contents of
column next to the stack addresses.

•

Global symbols -- SDA attempts to display the
location symbolically using a symbol and
example:

7FFEF868
7FFEF86C

7FFEE200
7FFEE208

the

stack

contents of a
an offset. For

MMG$HDRBUF
MMG$HDRBUF+08

If the value is not within range of any existing
field will be left blank.

symbols,

the

If a stack is empty, the stack pointer will point to the message:
SP

:::>

SDA will display only five pages of any stack.
Format

SHOW STACK
Qualifiers

Defaults

/INTERRUPT

Stack currently in use (running system)
or in use when system failed

/KERN SL
/EXECUTIVE
/SUPERVISOR
/USER
/ALL
Parameters

None

5-46

SDA COMMANDS
Qualifiers
/INTERRUPT

Displays the interrupt stack. This stack is always resident
memory and is used during hardware interrupt processing.

/KERNEL

Displays the kernel stack for the current process.
/EXECUTIVE

Displays the executive stack for the current process.
/SUPERVISOR

Displays the supervisor stack for the current process.
/USER

Displays the user stack for the current process.
/ALL

Displays all the stacks described above.

Examples
1.

SDA> SHOW STACK/KERNEL
Figure 5-13 shows a portion
command.

5-47

the

display

produced

this

SDA COMMANDS
VAX/VMS 2.0 -- System Dump Analysis
Current operating stack

21-MAY-1979 15:34:40.49

Current operating stack (KERNEL):

7FFEEB18
7FFEEB1C
7FFEEB20
7FFEEB24
7FFEEB28
7FFEEB2C
7FFEEB30
7FFEEB34

00001000
7FFEEB20
7FFEFOOO
7FFEF8 28
7FFDB65C
8007C200
8000fi074
00070000

7FFEEB38
7FFEEB3C
7FFEEB40
7FFEEB44
7FFEEB48
7FFEEB4C
7FFEEB50
7FFEEB54
7FFEEB58
7FFEEB5C
7FFEEB60
7FFEEBfi4
7FFEEBfi8
7FFEEB6C
7FFEEB70
7FFEEB74
7FFEEB78
7FFEEB7C
7FFEEB80
7FFEEB84
7FFEEB88
7FFEEB8C
7FFEEB90
7FFEEB94
7FFEEB98
7FFEEB9C
7FFEEBAO
7FFEEBA4
7FFEEBA8
7FFEEBAC
7FFEEBBO
7FFEEBB4
7FFEEBB8
7FFEEBBC
7FFEEBCO
7FFEEBC4
7FFEEBC8
7FFEEBCC
7FFEEBDO
7FFEEBD4
7FFEEBD8
7FFEEBDC
7FFEEBEO
7FFEEBE4

8006BACO
7FFDFEOO
00000000
801F18fi8
80007814
00070000
00000000
00000002
00020004
8000C4DF
8000C487
3FFFFFFF
00000000
800077 lF
00000000
00000000
00000000
00000000
00000000
7FFEEBC4
7FFEEB98
8000B4E3
80000116
00800000
00000000
20FCOOOO
7FFEF854
7FFEEBE4
8000BBF7
7FFEEBD4
7FFE1DFO
8006BACO
7FFDFEOO
FFFFFFFF
00000003
00000003
7FFEEBD4
00000000
00000000
3FFFFFFF
00000000
00000000
80008E38
00000000

Figure 5-13

CTL$GL KSTKBAS+520
CTLSGL-KSPINI+400
CTLSGL-KSPINI+C28
EXESSWAPINIT+9F8

MMGSEXTRADYNWS+lfi4

EXESDELTVA+OAA
EXE$DELTVA+052
MMGSEXTRADYNWS+06F

CTL$GL KSTKBAS+5C4
CTL$GL-KSTKBAS+598
EXESCMODEXEC+OD3
SYS$DELTVA+006

CTLSGL KSPINI+C54
CTL$GL-KSTKBAS+5E4
MMGSIMGRESET+030
CTLSGL KSTKBAS+5D4
CTLSGL-CCB

CTL$GL_KSTKBAS+5D4

EXE$RUNDWN+04E

Current Operating Stack (Kernel)

5-48

SDA COMMANDS

SHOW SUMMARY
The SHOW SUMMARY command displays a formatted list of all active
processes.
The display shows the values used in swapping and
~cheduling for these processes.
Figure 5-14 is an example of the
display produced by the SHOW SUMMARY command. The information listed
in the display includes:
•

PID -- the
process

bit

quantity

that

uniquely

•

PROCESS NAME -- the name assigned to the process

•

IMAGE NAME -- the VAX/VMS file specification
currently executing in the process's context

the

image

•

STATE -- the condition of the process (see the VAX/VMS
Manager's Guide for a description of possible states)

System

PR!

the current scheduling priority of the process

•

UIC

User Identification Code

•

WKSET -- the total number (in decimal) of pages
the working set

If the process has been swapped out of the balance set,
appears in the "Image Name" column:

identifies

currently
this

--- SWAPPED OUT ---

Format

Qualifiers

Defaults

None

Parameters
None

Examples
1.

SDA> SHOW SUMMARY
Figure 5-14 shows the display produced by this command.

5-49

the

message

SDA COMMANDS
VAX/VMS 2.0 -- System Dump Analysis
Current process summary
PID

PROCESS NAME

00010000 NULL
00010001 SWAPPER
00010019 TTA3:
0003001A -TTF7:
0005001B MANDERLEY
OOOBOOlC TTAl:
00140010 KAREN
OOOCOOlE CRAIG
0001001F DERF
OOOB0020 USER
00100021 NOAH
00050022 LYNN
001E0023 LAMONT
00170024 OZZIE
00060025 CLEO
00020026 MAJA
00170027 BOUSQUET
00020028 BACH
00040029 WIZARD
OOOF002A BOUFFON
OOOB002B HARLEY
0018002C DAVIDSON
OOOF002D RMS
0007002E TTG4:
0013002F KURT
OOOF0030 MEYERS
OOOF0031 EDWIN
00040032 TTG3:
00090033 WOODROW
00200034 FRED
00190035 REID
00160036 LOWELL
00210037 OPPENHEIM
00010038 NETACP
00010039 PRTSYMB4
0001003A PRTSYMB3
0001003B PRTSYMB2
0001003C PRTSYMBl
0001003D DBA2ACP
0031003E GUITAR
0001003F ERRFMT
00010040 OPCOM
00010041 JOB CONTROL
00010042 DBAOACP
00020043 DBAlACP

21-MAY-1979 15:36:2fi.03

IMAGE NAME

STATE PRI

DBAO: [SYSEXE]VMOUNT.EXE;
DBAO: [SYSEXE]MAIL.EXE;
DBAO: [SYSEXE]RSX.EXE;
DBAO: [SYSEXE]LOGINOUT.EXE;
DBAO: [SYSEXE]BACKTRANS.EXE;
DBAO:[SYSEXE]LOGINOUT.EXE;
DBAO:[SYSEXE]SUBMIT.EXE;8
DBAO: [SYSEXE]SHOW.EXE;
DBAO:[SYSEXE]TYPE.EXE;31
DBAO: [SYSEXE]DELETE.EXE;4
DBAO:[SYSEXE]COPY.EXE;
DBAO: [SYSEXE]TALK.EXE;
DBAO: [SYSEXE]BACKTRANS.EXE;
DBAO: [SYSEXE]SHOW.EXE;
DBAO:[SYSEXE]BACKTRANS.EXE;
DBAO:[SYSEXE]COPY.EXE;
DBAO: [SYSEXE]DISPLAY.EXE;
SWAPPED OUT
--- SWAPPED OUT --DBAO: [SYSEXE]USERS.EXE;
DB2:[F4V2.TOOL]BLISS32.EXE;43
SWAPPED OUT
--- SWAPPED OUT --DBAO: [SYSEXE]PRTSMB.EXE;
DBAO: [SYSEXE]PRTSMB.EXE;
DBAO: [SYSEXE]PRTSMB.EXE;
DBAO: [SYSEXE]PRTSMB.EXE;
DBAO: [SYSEXE]FllBACP.EXE;

COM
HIB
LEF
COM
LEF
LEF
LEF
LEF
LEF
LEF
LEF
LEF
LEF
LEF
LEF
LEF
LEF
LEF
LEF
COM
LEF
LEF
LEF
LEF
LEFO
LEF
LEF
LEFO
LEF
CUR
LEFO
LEF
LEFO
HIB
HIB
HIB
HIB
HIS

HIB
HIS

DBAO: [SYSEXE]FllBACP.EXE;

Figure 5-14

HIB
LEF
HIB
HIB
HIB

UIC

0 [000 ,000)
(000,000]
4 [017,022)
4 [320,100]
7 [3fi0,007]
4 [010,0401
4 [3fil,006]
4 [320,111]
8 [320,114]
7 [304,003]
7 [3fil,002]
4 [320,110]
4 [360,003)
4 [3fi0,002]
4 [361,004]
4 [304,002)
4 [011,0lfi]
7 [3fi0,016]
5 [017 ,022]
4 [300,041)
4 [017 ,022)
8 [3fil,013]
4 [011,0lfi]
7 [311,001)
4 [3fil,003]
4 [360,005)
8 [3150,001)
4 [311,001)
4 [201,201)
5 [320,100)
7 [361,010)
5 [301,021)
4 [3fi0,023]
9 [001,001)
8 [001, 004]
8 [001,004)
8 [001,004)
8 [001,004)
11 [001,003)
7 [3fil,010]
9 [001,006]
8 [001,004]
13 [001,004]
11 [001,003]
10 [001,003]
Hi

Summary of Acti~e Processes

5-50

WK SET
0
0

59
74
148
39
41
70
41
150
67
68
fil
70
68
55
53
45
149
300
58
43
70
39
fil
65
150
45
50
338
106
45
43
54
41
41
41
41
104
32
30
38
100
100
105

SDA COMMANDS

SHOW SYMBOL
The SHOW SYMBOL command displays a local or global symbol and the
value associated with it. If the value is a valid memory location,
SDA examines that address and displays its contents.
Format
SHOW SYMBOL symbol-name
Qualifiers

Defaults

/ALL

None

Parameters
symbol-name
Specifies an SDA symbol that corresponds to an SDA expression.
See Section 4.2.5 for more information on SDA symbols.
Qualifiers
/ALL
Displays two lists of the entire SDA symbol table.
The first
list organizes the local and global symbols in alphabetical
order. The second list organizes these symbols by their values,
starting at the lowest value.
If the value represents an
address, the contents of the memory location will be displayed:
TTYSA_CTRl...Z 80002A12

=> OOOD5A5E

If you specify a symbol name and the /ALL qualifier, SHOW SYMBOL
displays a list of all the symbols that begin with the specified
symbol name. For example, SHOW SYMBOL IOC$GL displays all the
symbols with starting characters IOC$GL.
Examples
1.

!:>DA> SHOW SYMBOL Bl.JG~~FATAI...
BUGSFATAI...
80008256
08309F9E

In this example, the global symbol, its system
and the value stored at the address are shown.
2.

virtual

address,

BDA> DEFINE ~3TART :::: 00000000
SDA> SHOW SYMBOi... BTAl:~T
START
00000000
009A029A

In this example, a local symbol is defined. See the description
of
the
DEFINE command for more information about symbol
definition.
3.

SDA> SHOW SYMBOL/ALI...

Figure 5-15 shows a page of the listing produced by this command.

5-51

VAX/VMS 2.0 -- System Dump Analysis
System global symbols by name

I
U1
('..)

IO$M FCOOE
0000003F
IO$ LOGICAL
0000002F
IO$-PHYSICAL
OOOOOOlF
IO$-REAOLBLK
00000021
IO$-REAOPBLK
oooooooc
IO$-REAOVBLK
00000031
IO$-WRITEL8LK
00000020
IO$-WRITEP8LK
00000008
IO$-WRITEV8LK
00000030
IOCSALOUBAMAP
8000A807 => A53C3888
IOC$ALOU8AMAPN 8000A803 => 15113888
IOC$ALTUBAMAP
8000A7E5 => 5326Al9A
IOC$APPLYECC
8000A8AC => C53Cl888
IOC$CANCELIO
8000A551 => 58A508El
IOC$CREATE UCB 800087F6 => 5108A53C
IOC$CVTLOGPHY
8000A920 => 34A35000
IOC$CVT OEVNAM 8000887A => 007E5070
IOC$0ELM8X
8000A568 => 5024A500
IOC$0IAG8UFILL 8000A5EE => 534CA500
IOC$0IRPOST1
80005544 => 5024A500
IOC$0ISMOUNT
80008665 => A60028B8
IOC$FFCHAN
800088AF => 463BEFC1
IOC$FILSPT
8000A3CO => 04C55300
IOC$GL AOPLIST 8000083C => 8005E800
IOC$GL-AQ8LIST 80003Al0 => 80063310
IOC$GL-DEVLIST 80000838 => 80000848
IOC$GL-OIALUP
80003AlC => 800688AO
IOC$GL-OPTLIST 80000840 => 80069090
IOC$GL-IRPBL
80003AOC => 80078390
IOC$GL-IRPFL
80003A08 => 80076F70
IOC$GL-MUTEX
80003828 => OOOOFFFF
IOC$GL-PSBL
80003A04 => 80003A00
IOC$GL-PSFL
80003AOO => 80003A00
IOC$GQ-BRDCST
80003A20 => 80003A20
IOC$GQ-MOUNTLST 80003Al4 => 80056A60
IOC$GW-MAXBUF
80004466 => 04000400
IOC$GW-MBXBFQUO 80004468 => 01000400
IOC$GW-MBXMXMSG 8000446A => 00100100
IOC$GW-MBXNMMSG 8000446C => 00100010
IOC$ INlTORV
800126FF
IOC$ INITIATE
8000A6F4 => 4CA55300
IOC$IOPOST
80005078 => 707E5470
IOC$LOADMBAMAP 8000AA04 => A53C5300
IOC$LOADU8AMAP 8000AA4E => 3C7E5370
IOC$MAPV8LK
8000A947 => 120AA291
IOC$MOVFRUSER
8000A388 => A5A83610
IOC$MOVTOUSER
8000A3A4 => A5A81Al0
IOC$PTETOPFN
8000AAB7 => 00008FCA
IOC$QNXTSEG
800053CO => 5218A3DO
IOC$QNXTSEG1
800053CC => 3044A4B7
IOC$REINITORV
80012705
IOC$RELCHAN
8000A628 => 5020A500
IOC$RELOATAP
8000A729 => 5020A500
IOC$RELMAPREG
8000A799 => 5120A500
IOC$RELSCHAN
8000A61E => 5020A500

21-MAY-1979 16: 04 s 51."71

IOC$REQCOM
8000A6B3 •> 534CA500
IOC$REQOATAP
8000A762 => A5000100
IOC$REQOATAPNW 8000A75E => 02110000
IOC$REQMAPREG
8000A703 => 50E83210
IOC$REQPCHANH
8000A67F => 5020A500
IOC$REQPCHANL
8000A688 => 5020A500
IOC$REQSCHANH
8000A668 => 5020A500
IOC$REQSCHANL
8000A675 => 5020A500
IOC$RETURN
8000A869 => 6E02C005
IOC$SEARCHOEV
80008806 => 11520200
IOC$SEARCHGEN
80008808 => 88520100
IOC$UNLOCK
8000B9F9 => EFOOSOOO
IOC$UPOATRANSP 8000A9C8 => 6EA550A2
IOC$VERIFYCHAN 8000BA08 => 13500FAA
IOC$WAKACP
800053F4 => OA7El208
IOC$WFIKPCH
8000A86A => 706E02CO
IOC$WFIRLCH
8000A88A => 706E02CO
IPL$ ASTOEL
00000002
IPL$-HWCLK
00000018
IPL$-IOPOST
00000004
IPL$-MAILBOX
00000008
IPL$-POWER
OOOOOOlF
IPL$-QUEUEAST
00000006
IPL$-SCHED
00000003
IPL$-SYNCH
00000007
IPL$-TIMER
00000007
KFI$GL FllAACP 80003840 => 80056830
LIB$CVT OT8
8000F03E => OA00003C
LI8$CVT-HTB
8000F04C => l000003C
LIB$CVT-OTB
8000F045 => 0800003C
LOG$AL DISKLOG 80011A08
LOG$AL-LOGTBL
800039C8 => 800039E8
LOG$AL-MUTEX
80003904 => OOOOFFFF
LOG$0ELETE
8000BA3E => 0050610F
LOG$GL SLTFL
800039E8 => 80056A30
LOG$INSLOGN
8000BA60 => 530BA59A
LOG$LOCKR
80008AA7 => OF64CF9F
LOG$LOCKW
8000BAAO => OF44CF9F
LOG$SEARCHLOG
8000BAC8 => 00608FBB
LOG$TRNSLOGNAME 80008814 => 1350613C
LOG$UNLOCK
80008AB3 => OFB7CF9F
MB$OOT
8000127C => 00000318
MB$0PT
80000F34 => 80001046
MB$GL 008
80000BE4 => 80000078
MB$GL-UC81
80000C90 => 80000C90
M8$GL-UCB2
80000004 => 80000004
M8$UCBO
80000ClC => 80000ClC
MBA$ INITIAL
80001271 => 04A40100
MBA$INT
80001200 => 5300BEOO
MMG$ALCPAGFIL
80006FFO => 160F4100
MMG$ALCPHD
8000B05E => 5024A53i
MMG$ALCSTX
80008035 => 5126A532
MMG$ALLOCPFN
80006882 => 92305204
MMG$AL BEGORIVE 80001200 => 5300BEOO
MMG$AL=ENOORIVE 80002EOO => 01AD0983

Figure 5-15

Global Symbols

MMG$AL PGOCOO
80008400 •> 0500CF31
MMG$AL-PGOCOOEN 80011000
MMG$AL-SBICONF 80003264 ~> 00000000
MMG$AL-SYSPCB
80003808 => 80003808
MMG$A ENOVEC
80000600 •> 0000007A
MMG$A-PAGFIL
80003108 => 80060B7C
MMG$A-SYSPARAM 80004400 => EOBECC20
MMG$CRECOM1
8000C39F => 54705510
MMG$CRECOM2
8000C3A7 => OAOOEE30
MMG$CREPAG
8000C510 => lEElSOOD
MMG$CRETVA
8000C380 => AC9A01FC
MMG$0ALCPAGFIL 800070C4 => 4FOF4100
MMG$0ALCSTX
8000B01E => 5520A5Cl
MMG$0ALCSTXSCN 8000BCA5 => 3AA501E7
MMG$0ALLOCPFN
80006023 => 40855204
MMG$0ECPHOREF
8000682C => 5146A53C
MMG$0ECPHOREF1 80006830 => 280F41B7
MMG$0ECPTREF
80006AC5 => 531509EF
MMG$0ECSECREF
8000712E => 5520A5Cl
MMG$0ELCONPFN
80006897 => F80F4000
MMG$0ELGBLSEC
80007963 => 501CA300
MMG$0ELGBLWC8
80000639 => 6409FFOF
MMG $OELPFNLST
80006C8C => 10889610
MMG$0ELWSLEPPG 80006989 => A4870710
MMG$0ELWSLEX
80006995 => 52654100
MMG$DGBLSC1
80000518 => 071100FC
MMG$EXTRAOYNWS 80007680 => A56CA5A3
8000682F => EF327E7C
MMGSFREWSLE
MMG$FREWSLX
800067E7 => 7E7COlOO
MMG$FRSTRONLY
80004800 => El56220B
MMG$GETPTIPAG
80007Al2 => 007El20B
MMG$GL CROCNT
80003F90 => 00000001
MMG$GL-CTL8ASVA 80004540 => 7FFOFEOO
MMG$GL-FRESVA
80004558 => 80200000
MMG$GL-GPTBASE 8000454C => 801F9000
MMG$GL-GPTE
80004550 => 801FOOOO
MMG$GL-IACLOCK 80002E84 => 00000000
MMG$GL-MAXGPTE 80004554 => 80200000
MMG$GL-MAXPFN
80004584 => OOOOOE17
MMG$GL-MAXSYSVA 80004558 => 80200000
MMG$GL-NPAGEOYN 8000457C => 8005E800
MMG$GL-PAGEOYN 80004580 => 80056800
MMG$GL-PAGSWPVC 80003218 => 8000322C
MMG$GL-PFNLOCK 80002E88 => 40000000
MMG$GL-PHYPGCNT 8000445E => 00004000
MMG$GL-RMS8ASE 800032A4 => 80019COO
MMG$GL-SBR
80004578 => OOlFCOOO
MMG$GL-SPTBASE 8000455C => 801F9000
MMG$GL-SPTLEN
80004560 => 00001000
MMG$GL-SYSPHO
80004564 => 801F8400
MMG$GL-SYSPHOLN 80004568 => OOOOOCOO
MMG$GSDMTXULK
80000503 => 5ClBEFOO
MMG$GSOSCN
80000599 => 5105527C
MMG$IMGACTBUF
7FFEDA00 => 00000000
MMG$IMGHOR8UF
7FFEE200 => 7FFEE208

Cll
tj

>
n

3
3

>
2:

tj
Cll

CHAPTER 6
ANALYZING SYSTEM FAILURES -- GUIDELINES AND EXAMPLES

This chapter discusses how VAX/VMS handles internal errors and
suggests procedures that can aid in determining the cause of these
errors.
The final sections of the chapter illustrate, through
detailed analysis of a sample system failure, how SDA helps you find
operating system problems.

6.1

GENERAL PROCEDURE FOR SOLVING SYSTEM FAILURES

When the VAX/VMS operating system detects an internal error so severe
that normal operation cannot continue, it signals a condition known as
a fatal bugcheck and shuts itself down.
A bugcheck describes the
error discovered by the system;
each error is associated with a
particular bugcheck code.
To resolve the condition, you must find the reason for the bugcheck.
You generally need the VAX/VMS source code to locate the error, unless
the error exists in a driver that is not supplied by DIGITAL. If this
is the case, you may simply need the driver listings.
The best way to start the search for the error is to locate the line
of code that signaled the bugcheck. The address of this instruction
is usually contained in the Program Counter register (PC). Invoke SDA
and give the SHOW CRASH command. The display SDA produces gives the
contents of the PC.
Next, examine the system map file SYS$SYSTEM:SYS.MAP. This file lists
the addresses of each VAX/VMS module that resides in system space (the
part of the operating system that performs basic system services and
scheduling).
Compare the address in the PC with the addresses in the
system map file to locate the module that uses the instruction pointed
to by the PC.
If you do not have the system map file, you can use SDA's symbol
table.
All the system global symbols that appear in SYS.MAP also
exist in the SYS.STB file that SDA reads during the initialization
process.
To determine the offset from the closest global symbol,
issue the command:

SDA> EXAMINE @PC
Once you have narrowed the search to a particular module, subtract the
module's starting address from the address in the PC to get the offset
into the code.
Now, to determine the general cause of the system failure, examine the
code that signaled the bugcheck.

6-1

ANALYZING SYSTEM FAILURES -- GUIDELINES AND EXAMPLES
6.2

FATAL BUGCHECK CONDITIONS

If a bugcheck is
conditions:

signaled,

•

A fatal exception

•

An illegal page fault

6.2.1

usually

caused

one

two

Fatal Exceptions

A fatal exception is an event that causes VAX/VMS to signal a fatal
bugcheck. An exception is fatal when it occurs while a process is:
•

Using the interrupt stack

•

Executing above IPL 2 (IPL$_ASTDEL)

•

Executing in a
access mode

privileged

(kernel

executive)

processor

When the system fails, it lists the immediate cause of the failure on
the LSI-11 console.
For fatal exceptions, the messages appear as
follows:

FATALEXCPT' Fatal executive or kernel mode exception
INVEXCEPTN' Exception while above ASTDEL or on interrupt stack
Although there are several possible exception conditions, the type
that most commonly occurs is the access violation. The rest of this
section discusses the access violation in
detail.
For
more
information on other kinds of exceptions, see the VAX-11 Run-Time
L i bra r y f3._~-~-~-~ ~!!~-~---r.1anua1 •
When an access violation is detected by the VAX-11
hardware,
information useful in finding the cause of the violation is pushed
onto the current operating stack, that is, the stack that the process
was using when the access violation occurred. This information is
described by three structures, referred to as vectors.
A vector is
structured as follows:
31

r-------·-···--····-·~····~·"'---

-------- ------------longword

series of
longwords

_____________

.,..__

------··-··.,···---··--·-··-··- ----------~- --~~---·------------------·-

6-2

ANALYZING SYSTEM FAILURES -- GUIDELINES AND EXAMPLES
The first longword in the vector shows the number of longwords that
follow.
Each longword in the series contains information describing
conditions at the time of the exception.
The first vector that appears on the stack gives the addresses of
next two vectors:

the

------------···------·-·--·-···00000002
signal vector
address
mechanism vector
address

The mechanism vector follows the first vector.
This structure
describes the process that was executing when the exception occurred.
The diagram below illustrates the sequence of longwords in a mechanism
vector:
31
--------------~-~-~-~

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

00000004

-------------··-·-·" ........ .
frame

depth

The values contained in this vector are:
00000004 -- the number of longwords that
• mechanism
vector, this value is always four.

follow.

• Frame the address of the stack frame.
• Depth the stack depth.
• RO the contents of RO at the time of the exception.
the contents of Rl at the time of the exception.
• Rl

n-3

ANALYZING SYSTEM FAILURES -- GUIDELINES AND EXAMPLES
The next vector created on the stack is the signal vector.
violations, the signal vector is set up as follows:

For access

0
00000005

oooooooc
reason mask

'---------·----·--·--·---1
virtual

address

···-"•"• -·---- ..---·-··---,··-·---. . .,--.------------1
PC

!----------·------·----.-- ---------· - - - - - - - - - - - -. . .
PSL

The parameters shown in the above diagram are:
For

access

•

00000005 -- the number of longwords that follow.
violations, this value is always five.

•

OOOOOOOC -- the exception code. This value is C (hexaaecimal)
to represent an access violation.

•

Reason mask -- the longword whose lowest three bits, if set,
indicate that the instruction caused a length violation (bit
0), referenced the process page table (bit 1), and attempted a
read/modify operation (bit 2).

•

Virtual address -- the virtual address that the
to reference.

•

PC -- the Program Counter. The PC contains the address of the
instruction that signaled the exception.

•

PSL -- the processor
exception.

status

longword

the

system

time

tried

the

Signal vectors differ in length, depending on the kind of exception
the system detects. See the VAX-11 Run-Time Library 13_efe~~ence_Manual
for details.
If VAX/VMS encounters a fatal exception, you can find the code that
signaled it by examining the PC placed in the signal vector. Issue
the SHOW STACK command to display the current operating stack, then
locate the vectors.
Once you obtain the PC, which points to the
instruction that signaled the exception, you can identify the module
by the procedure outlined in Section 6.1.

6-4

ANALYZING SYSTEM FAILURES -- GUIDELINES AND EXAMPLES
6.2.2

Illegal Page Faults

VAX/VMS also signals a bugcheck when a page fault occurs while the
Interrupt Priority Level
(IPL)
is greater than two (IRP$ ASTDEL).
When VAX/VMS fails because of an illegal page fault,
it issues the
following message on the console:

PGFIPLHI, Pase fault with IPL too hish
In this case, information is pushed on the stack as longwords
following sequence:
31

the

0
R4

reason mask

virtual address

----------------·-··- -··---··--------·-·-·-·· ---~
PSL

The longwords pushed on the stack are:
the contents of R4 at the time of the bugcheck.
• R4
• RS the contents of RS at the time of the bugcheck.
• Reason mask -- see Section 6.2.1.
address -- the virtual address that caused the
• Virtual
fault.

page

•

PC -- the Program Counter. The PC contains the address of the
instruction that was executing when the page fault was issued.

•

PSL -- the processor
bugcheck.

status

longword

the

time

the

If the operating system detects a page fault while the IPL is higher
than two, you can obtain the faulting instruction by examining the PC
pushed on the current operating stack. Follow the steps outlined in
Section 6.1 to determine which module issued the instruction.

6-S

ANALYZING SYSTEM FAILURES -- GUIDELINES AND EXAMPLES
6.3

DEBUGGING A SYSTEM FAILURE -- AN EXAMPLE

This section steps through the analysis of
events that lead up to this failure are:

6.3.1

system

failure.

The

•

The line printer goes offline for three hours.

•

The line printer comes back online.

•

The operating system signals a bugcheck, writes information to
the system dump file, and shuts itself down.

Identifying the Bugcheck

Invoke SDA to analyze the system dump file.
message indicates the type of bugcheck signaled:

The

initialization

VAX/VMS S~stem dump analwzer
Dump taken on 31-JUL-1979
20:43:13.32
INVEXCEPTN, ExcePtion while above ASTDEL or on interrupt stack
SDA>
VAX/VMS encountered an exception that caused it to signal a bugcheck.
Signal and mechanism vectors are created on the current operating
stack.

6.3.2

Identifying the Exception

Issue the SHOW STACK command to display the current operating stack,
which, in this case, is the interrupt stack. Figure 6-1 shows the
interrupt stack and highlights the three vectors.
Current oPeratin~ stack <INTERRUPT>

BP ::::)

mechanism
vector

8006A378

8000844B

8006A:'598

'7FFDC340

BOObA3<.»C

8006A~5AO

!3006A:3AO
8006A:3A4

80004E7D
04080009

~1006A:3A8

000000.04

'1:t006A~lAC
J~OC>6A3~0

1r1::·1:1c3.6e
1::-1:='(:~ FF Ft: r1·

BOOl.>A:3B4

8001774E
00000f4F
0000000!5

B006A3B8
8006A3I{C
Boo6A~~co

signal
vector

:~~006A3C4
i90()6A3C~:~

ACPtWRITEBLK+OAO

EXE$liEl... ECT +OD4

()OOOOOOC
00000000·
tW()69EOO

BC>06A:3CC

. 800~)t100:·5 .

800·6A:m<>

04()~100()()

BOObA:3D4

nooo9c'>04

EXESFORKDSPTH+OlC

Figure 6-1 Interrupt Stack and Vectors

6-6

ANALYZING SYSTEM FAILURES --· GUIDELINES AND EXAMPLES
Examination of the signal vector shows that:
•

The exception code is C
(hexadecimal)
access violation occurred.

which

means

that

instruction
reason mask is zero,
which means that the
• The
(instead of a
length
generated
a
protection violation
violation) when it tried to read
write to it).

the

location

(rather

than

•

The virtual address is 80069EOO and is the
instruction tried to reference.

that

the

•

The PC is 80050003 and is the address of the instruction
signaled the exception.

that

•

The IPL was eight at the time of the exception (shown by
16 through 20 of the PSL) •

bits

•

The current operating stack was the interrupt stack
the PSL is set to 1).

•

The process was executing in kernel mode at the
exception (shown by bits 24 and 25 of the PSL).

address

(bit 26 of

time

the

Use the SHOW PAGE TABLE command to display the system page table,
as
shown in Figure- 6-2.
The page containing location 80069EOO is not
available to any access mode (a null page);
thus, the virtual address
is not valid.

6-7

10•DEC•1979 t91211ee,32

VAX/VMS 1,0 •• Syatem Oymp Ane1Yl11
Syetem page teble

ADDRESS

SVAPTE

PTE

TYPE

PROT

BITS PAGTVP

L.OC STATE TVPE

REFCNT

BAK

Page 17

SVAPTE

l'L.INK

BL.INK

;,.:,,..;,,.,..;.iit. 1 NUl.L PAGE
800bA000

800CD340 B0000~ED
R00CD344 81.10005EE

8~0&A20Cll

-------·

800&Ab'1llil
80!0bA800
8Qli11bA400

VAL.ID ERKW
VAL.IO ERl<W M

>
z
>
c-i

I(
I(

t-<
N

NUL.L PAGE

1-1

8~CllC034C

D400038q

8~~C0350
80~CD354

040~~144
0400~Ql28

VALID SRKl>I M
VAL.ID SRK..i M
VALID SRKW M

K PPGTBL.
K ?F'GTBL
K PPGT~L

ACTIVE
ACTIVE
ACTIVE

87
87
87

01.1
Cll4
;!14

1
1

0300111000
0300.,,00QI
030'1!0000

800C034C
800CD.35111
800CD351.1

0000
0000
00e0

Pl04A
00/.IB
1'10/.IC

ai:;,0Bc1rn

8~0C0370
8~0C0374
8~0CD378

Ofi'l00~2FS
500000~~
5000000~

800bBf.0~

8~0CD37C

5000000fi'I

81"1'.lbC':!lbi1'
8!il00C200
ae0bCa0~

8~fi'ICD3e0
8~~C0384
BM~CD388

5000~00P
50000~~0
5000~0fi'l0

8:i'fi'lbCbi"~l

80fi'IC038C

5000~0~0

BJ..,bC8~~

e~0co39~

s0a0~00~

8?-0bCA00

R~0CD391.1

500~00~~

8~0bCC00

IH110bCE'l0

8~~CD39A
q~0CD39C

50~0~111J0
5000~~~1"

l'<'tJbD~0111

8~0COJA0

50B~~~J~

8-'0bD200

R~0CD3A4

S00~00V?

R0~bl"'400

8~0CD3A8

500~0~~0

~i.;,,COJAC

5(10?,~c..i.'!•

80@b080~

a~rCD3BVl

Blll!ObDAli'l(ll

81i'llllC03Bl.I

50~~00Ar
50~~~~'~
S0Vl0~~0P

8~''11bAA0~

I
00

A0t>,bD&~0

811i~bDC0CI!

8~~CD3B8

81/!l-lt>!"lE00
8e:0oEl1'0Vl

8d0CDJ9C
8~VlC03C0
8~0CD3C4

801i'lt>E2QI~'
i:i~0eE1.10~

8~~C03C8
8~~CD3CC

81/!0&Eo0v,
8l'li'lbE80~

8~0CD300
e~~CD3Dl.I

8Vl~bEA00

800bFC00
801<'bF200
80it!bF400
800bFo0i'.I
8o:l0bF80'11
••••••••

500~~•0~
50~01i'lli'l0P
50~1i'l~~~~
50~0~~0~
5001i'lli'l~?CI!
5000~~~0
SC11000~0~

800C0308 5000..,000
800CD3DC D4001i'l2E9
A~li'ICD3E0 04000353

8~~oEE00
8~1i'lbFill00

8~?CD3E4

5001i'l~li'l~~

e00CD3E8 oa00a1q1.1
800C03EC 04000050
800C03F0 04000122
j

~UL.L

VAL.ID SRKW
VAL.ID SRKW
VALif> SRKill
vALID SRKW
OZERO SRK"4
DZERn SRKW
OZE~O SRKW
DZEF<'O SRKW
l..)ZfRO SRKW
D'lERO SRKw
11ZERO SRK"I
()ZfRn SRKW
!)ZERO SRKW
iJZERQ SRKW
DZERO SRl<tl
OZE.RO SRKw
l)ZEPO SRKW
DZERO SR1<.i
DZERD SRI011
DZERO SRIOI
f'lZE"RO SRKW
DZERiJ SRI<'"
DZEl<>l) SRK>'I
J)ZE.Rt) $Rl(;1
<:>ZE.R!') SRKW
DZERO SRK'>I
vZE.RO SRKW
~ZERO SRKW
OZERO SRKW
OZERO SRl(W
VALID SRKl!i
¥AL.ID SRKiol
OZERO SRKW
VALlO SRKW
VALID SRKl'I
oJALIO SRKW

M
M
M

K PPGTBL
K .,PGT6L
K PPGTRL
K PPGT8L

ACTIVE
ACTIVE
ACTIVE
ACTIVE

87
87
87
87

0!4

1
1
1

04
[,llJ

0301?-0000
030Ql242A
033FFF'FF
03"1!02&4B

800CD3&1.1
800CD3&8
800CD3bC
80"'CD370

0000
0035
011121
"1001ll

00E3
0082

>
1-1
c

::0

tZl
(/)

I
I

K
I<

1-1

tZl
c-i

K
I<.

1-1

tZl

(/)

>
z

K
K

tZl

:><

K
K

>
3:

"'O

K i:>PGT~L
I( P"i,T8L

ACT IVE
ACTIVE

87
87

ACTIVE
ACTIVE
ACTIVE

87
87
87

I'll.I
04

1
1

;,,J3FFFFF
a3000000

800CD3DC
800CD3E0

0003
0040

1
1
1

030001i'l00

0300"'"'00

800CD3E8
800CD3EC
800CD3F0

0000
111000

01485

004E

M
M

l'Z]

c-i

K
I(

tZl

0Ql4D
00E0

K. J:)?G TBL
P?GTBL.
I< PPGTBL

I<:

i214

01.1
04

03~00000

PAGES

Figure 6-2

t-<

""'3

800C03&4 D40000A7
8~~CD3&8 0400041.16
B~~C03bC D40004A8

8~"1&9200

(/)
(/)

•••••••• 3 MILL PAGES
61110&8404.'\
1100&6Mh1
Afi110&A80VI

G"l

Page Table Display Sh9wing Invalid Location 800n9EOO

01d00

1111'1!4A
004B
0~'1C

c-i
t2l

(/)

ANALYZING SYSTEM FAILURES -- GUIDELINES AND EXAMPLES
6.3.3

Locating the Source of the Exception

Because the line printer went offline and then online, the problem may
exist in the driver code. To determine which driver might contain the
faulty code, take the address contained in the PC on the stack and
compare it with the bounds of each driver.

6.3.3.1 Finding the Driver Using the DPT List - The Driver Prologue
Table
(DPT)
is a data structure that describes each driver. All the
driver prologue tables form a linked list;
each DPT is followed
directly by driver code.
The location IOC$GL DPTLIST contains the
address of the first DPT. Figure 6-3 illustrates-the linked structure
of the driver prologue tables •

....

IOC$GL_DPTLIST
DPT

DPT

DRIVER
CODE

DPT

... ...

DRIVER
CODE

---·-·-

Figure 6-3

Linked List of Driver Prologue Tables

Use the FORMAT command and specify the contents of IOC$GL DPTLIST as a
parameter:

SDA> FORMAT@IOCSGL_DPTLIST
00060~.)()()

DF'T!l>L. .... FI... INK

80060!:.:;oA
f:l0060!:50B
noo6o!:_:;oc

DPT$B .... TYPE
DPT~>B .... l:~EFC
DPT!l>B .... ADPTYPE
DPTSB .... Fl... AGB

f:!()()6()~.)()[I

BOO!'.)F 400

:l.E
():I.

():I.

o::?.

B006 O!'.)OE
B0060~5 l 0

DPT$W .... l.JCBS I ZE

80060~.:; :I.::?.

DPT$W .... F~EINITTAB
DPTSW .... UNLOAD
DPT$T .... NAME

B0060!7i :l 4
80060~5 :I. 6

OOFO

DPT!~W .... IN I TTAB

00:1.F

SDA>

6-9

0062

0000
• DF'Dl=i::t:VEF~"

ANALYZING SYSTEM FAILURES -- GUIDELINES AND EXAMPLES
The formatted display identifies the size of the driver by the
DPT$W SIZE.

symbol

Calculate the end of the driver by adding the value of DPT$W SIZE to
the starting address of the DPT for the driver. The driver code
begins just after the DPT.
Next, determine whether the address in the PC falls within the range
of addresses that contain the driver code. If the address is not part
of the driver you are examining, continue on to the next driver by
stepping through the linked list with the FORMAT command (see the
description of the FORMAT command in Chapter 5 for an example of the
commands used to step through a linked list of data structures).
In this example, the instruction that caused the exception falls
within the range of addresses that contain the line printer driver
code.

6.3.3.2 Calculating the Offset into the Driver - Once you have
identified the driver, you can locate the instruction in the source
code by subtracting the starting address of the driver prologue table
from the address contained in the PC. Match the resulting offset with
the offsets in the driver code listing.
After you have located the routine that caused the exception, you
should examine memory to make sure that the instruction in the routine
matches the instruction that signaled the exception.

6.3.4

Finding the Problem within the Routine

Examine the line printer driver code. The instruction that caused the
exception is MOVB (R3)+,(RO), as shown in Figure 6-4. To check the
contents of R3, use the SHOW CRASH command.
The invalid virtual
address 80069EOO is indeed stored in R3.

6-10

°'I

I-'
I-'

029F
480
START NEXT OUTPUT SEQUENCE
029F
481
029F
482
so
S4
02
Cl
029F
483 10$:
ADDL3
#LP DBR,R4,RO
;CALCULATE ADDRESS OF DATA BUFFER REGISTER
Sl
6C AS
3C
02A3
484
MOVZWL
UCBSW BOFF(RS) ,Rl
;GET NUMBER OF CHARACTERS REMAINING
8080 8F
BO
02A7
48S
MOVW
#AX80SO,R2
;GET CONTROL REGISTER TEST MASK
S2
08
11
02AC
486
BRB
2S$
;
64
S2
B3
02AE
487 20$:
BITW
R2,(R4)
;PRINTER READY OR HAVE PAPER PROBLEM?
.
08
lS.
02Bl
488
BLEQ
30$
;IF LEQ NOT READY OR PAPER PROBLEM
';~~~11~J{;.~:1;,:~;~\k.%'.1,'.:\~J~i~1'tJ;:1[;;;XJrJ(t~Jil:,l:10;;:r:\;~L:t~~;\;.,\:;i;.~~;~~;. \·;~'t~;~:i;;:~v~;;;~\;'.j{'.:h:\:;!,~'.;,'].'(g~)::.+::·i:::~~() .):r.t;,,·.;.:~.,:~:c~;X'rj~'~l:~'.\'.%:l~{~;Zt~h;;J~t1;~~\:l;'+'·)~'t'J E '5.'.r CitA;gZ\.crT ER
FS Sl
F4
02B6
490 2S$:
SOBGEQ
Rl,20$
;ANY MORE CHARACTERS TO OUTPUT?
70
11
02B9
491
BRB
70$
02BB
492
02BB
493
02BB
494
PRINTER IS NOT READY OR HAS PAPER PROBLEM
02BB
49S
02BB
496
21
12
02BB
497 30$:
40$
;IF NEQ PAPER PROBLEM
BNEQ
Sl
01
Al
02BD
498
;SAVE NUMBER OF CHARACTERS REMAINING
ADDW3
#1,Rl,UCBSW_BOFF(RS)
6C AS
02CO
02C2
499
DSBINT
DISABLE INTERRUPTS
64 40 8F
88
02C8
BISB
#AX40,LP CSR(R4)
soo
SF.T INTERRUPTS
02CC
WFIKPCH 40$,#12 SOl
WAIT FOR INTERRUPT
0206
S02
IOFORK
CREATE A FORK PROCESS
Cl
11
02DC
S03
10$
BRB
02DE
S05
02DE
S06
PRINTER HAS PAPER PROBLEM
02DE
S08
7A AS
94
02DE
S09 40$:
CLRB
;CLEAR OFFLINE COUNTER
UCB$B LP OFLCNT(RS)
Sl 01
Al
02El
;SAVE NUMBER OF CHARACTERS REMAINING
SlO
ADDW3
#l,Rl~UCB$W_BOFF(RS)
6C AS
02E4
64 B4
02E6
Sll SO$:
CLRW
LP CSR(R4)
;DISABLE PRINTER INTERRUPT
02E8
Sl2
SET IPL UCB$B FIPL(RS)
;LOWER TO FORK LEVEL
64
BS
02EC
LP CSR(R4)
;PRINTER STILL HAVE PAPER PROBLEM?
Sl3
TSTW
AF
14
02EE
BGTR
.1
lOS
; IF GTR NO
3E S8 AS
03
EO
02FO
SlS
BBS
#UCB$V CANCEL,UCB$W STS(RS) ,80$ ;IF SET, CANCEL I/O OPERATION
01
OF
9D
02FS
Sl6
ACBB
#1S,#l~UCB$B_LP_OFLCNT(RS) ,80$
;SKIP UNTIL TIMEOUT
0017 7A AS
02F8
7A AS
94
02FC
517
CLRB
UCBSB LP OFLCNT(RS)
;RESET COUNTER
BB
18
02FF
518
PUS HR
rM<RJ ,R4>
;SAVE REGISTERS
S4
OS
9A
0301
Sl9
MOVZBL #MSGS DEVOFFLIN,R4
;SET UP MESSAGE TYPE
OOOOOOOO'GF
9E
0304
520
GASYSSGL_OPRMBX,R3
MOVAB
;ADDRESS TARGET MAILBOX
53
030A

Figure 6-4

Location of Instruction in Driver Routine

~
>

t1
i<
N
H

en
en

i-3

Cz:I

"z:1

::0
Cz:I

Cf)

I
I
Cl

c:
H

Cz:I

~
0

Cz:I

>
3:

l"O
t1
ts:1

ANALYZING SYSTEM FAILURES -- GUIDELINES AND EXAMPLES
6.3.4.l Stepping through the Routine - The MOVB instruction is part
of a routine that reads characters from a buffer and writes them out
to the line printer. The routine executes the following steps for
each character in the buffer:
•

The driver gets a character from the buffer, moves it to the
device data register (pointed to by RO in this example), and
auto increments.

•

The preceding step is repeated until the byte count
exhausted or the printer signals that it is NOT READY.

•

If the printer gives the NOT READY signal,
for an interrupt from the printer.

•

When the printer becomes READY, it interrupts the
the loop is resumed.

the

driver
driver

waits
and

Examine the code to determine which variables control the loop.
In
this case, the byte count (BCNT) is the number of characters in the
buffer. This value controls the number of times the loop is executed.
(BCNT is set by a Function Decision Table (FDT) routine to the number
of characters in the buffer.) The number of characters left to be
printed is represented by the byte offset (BOFF).
Because the exception is an access violation, you can infer that R3 is
outside the range of the buffer.
It seems likely that the MOVB
instruction has executed too many times, that is, a number of times
greater than BCNT.
To prove this theory, you must examine BOFF and
BCNT.

6.3.4.2 Checking the Values of Key Variables - If you examine the
code, you can see that RS contains the address of the Unit Control
Block (UCB) of the device that was active when the system failed.
If
you use the FORMAT command to display the contents of RS, SDA will
display the values of BCNT and BOFF:
SDA> FORMAT @R5

8005D160
8005[1164
8005[1:1.68
8005Dl.6A
8005D16B

800~3D1C8

EtO()$~•fcc·•····•·

.......

ao.<>,~snJ¢F{ ,.
800~5D :I. DO
800~iD1D:L
800~5[11

[12

800039A8

UCB$L_RQFL
UCB$L_FQFL
LJCB$L._RQBL
UCB$L._FQBL
UCB$W_SIZE
UCB$B .... TYF'E
UCB$R.SIF'L

800039A8
0080
10
()8

UCB$l.. .... SVAPTE

.,:; ;:Q~£!,~~n~~~~FJ:::..
~ .~lf.;I1~l4Jr. ~C~f'{L,.
UCB!t>B .... El~TCNT
UCB$B .... El:~TMAX
UCB$W .... E1:~1~CNT

()()

()()
() ()()()

SDA>

6-12

ANALYZING SYSTEM FAILURES -- GUIDELINES AND EXAMPLES
If you have only one line printer in your system configuration, you
need not use the FORMAT command. Issue the SHOW DEVICE command with
device code LP as the parameter; since there is only one line printer
device connected to the VAX-11 processor there is only one line
printer UCB to display.
The output produced by the FORMAT @R5 command shows that BOFF contains
a value greater than BCNT, when it should be the reverse. This means
that an illegal value is being stored in BOFF.
Thus, the value of
BOFF is not the number of remaining characters in the buffer but some
meaningless number that eventually causes the system to fail when it
tries to access a null page (unreadable to all access modes).

6.3.4.3 Identifying and Fixing the Defective Code - Examine the line
printer driver code again to locate all instructions that modify BOFF.
The value changes in two important places.
1.

Immediately after the driver detects that the printer is
ready.

not

When the wait for interrupt (WFIKPCH) routine timeout count
of 12 seconds is exhausted. At this time, Rl+l is stored in
BOFF.

The second modification to BOFF should not be made because R4 and RS
are the only registers that retain their values after the WFIKPCH
routine is executed. To correct the problem, change the WFIKPCH line
to transfer control to 50$ rather than 40$ (see Figure 6-5) if the
timeout count expires.

6-13

S4
Sl

6C
8080
64
60
FS

02
AS
8F
08
S2
08
83
Sl
70

Cl
3C
BO
11
B3
lS
90
F4
11

21
Sl
01
6C AS
64

°"I

.......

12
Al

40 8F

7A AS
Sl 01
6C AS
64

94
Al

.ti.

64
AF
3E S8 AS
03
01
OF
0017 7A AS
7A AS
18
S4
OS
OOOOOOOO'GF
S3

B4
BS
14
EO
90
94
BB
9A
9E

029F
029F
029F
029F
02A3
02A7
02AC
02AE
02Bl
0283
02B6
02B9
02BB
02BB
02BB
02BB
02BB
02BB
02BD
02CO
02C2
02C8
02CC
02Dl1
02DC
02DE
02DE
02DE
02DE
02El
02E4
02E6
02E8
02EC
02EE
02FO
02FS
02F8
02FC
02FF
0301
0304
030A

480 ;
START NEXT OUTPUT SEQUENCE
481 ;
482
483 10$:
ADDL3
#LP DBR,R4,RO
;CALCULATE ADDRESS OF DATA BUFFER REGISTER
484
MOVZWL
;GET NUMBER OF CHARACTERS REMAINING
UCBSW BOFF(RS) ,Rl
48S
;GET CONTROL REGISTER TEST MASK
MOVW
#"X80SO ,R2
2S$
486
BRB
'
;PRINTER
READY OR HAVE PAPER PROBLEM?
487 20$:
BITW
R2,(R4)
30$
;IF LEQ NOT READY OR PAPER PROBLEM
BLEQ
488
(R3)+, (RO)
;OUTPUT NEXT CHARACTER
489
MOVB
490 2S$:
Rl,20$
SOBGEQ
;ANY MORE CHARACTERS TO OUTPUT?
BRB
70$
491
;
492
49 3 ;
49 4 ;
PRINTER IS NOT READY OR HAS PAPER PROBLEM
49S ;
49fl
40$
497 30$:
BNEQ
;IF NEQ PAPER PROBLEM
498
ADDW3
#1,Rl,UCBSW_BOFF(RS)
;SAVE NUMBER OF CHARACTERS REMAINING
499

DSBINT

BISB
#AX40,LP CSR(R4)
soo
SOl
WFIKPCH l4,$l,#12 S02
IO FORK
BRB
S03
SOS ; r-------SOfi ; I
PRINTER HAS PAPER PROBLEM
S08
S09 40$:
CLRB
UCB$B LP OFLCNT(R5)
SlO
ADDW3
#l,Rl~UCB$W_BOFF(RS)

;DISABLE INTERRUPTS
; SET INTERRUPTS
;WAIT FOR INTERRUPT
;CREATE A FORK PROCESS

>
z
>
I:""'

N
H

Cl
00

""'3
trJ

l'Zj

1-1

I:""'

::0
trJ
00

;CLEAR OFFLINE COUNTER
;SAVE NUMBER OF CHARACTERS REMAINING

c:
H

trJ

I:""'

Sll SO$: ..
Sl2
Sl3
.1
SlS
Sl5

ICLRW
SET IPL
TSTW
BGTR
BBS
ACBB

LP CSR(R4)
;DISABLE PRINTER INTERRUPT
UCB$B FIPL(RS)
;LOWER TO FORK LEVEL
LP CSR (R4)
;PRINTER STILL HAVE PAPER PROBLEM?
lOS
; IF GTR NO
#UCB$V CANCEL,UCB$W STS(RS) ,80$ ;IF SET, CANCEL I/O OPERATION
#lS,#l~UCBSB_LP_OFLCNT(RS) ,80$
;SKIP UNTIL TIMEOUT

Sl7
Sl8
Sl9
S20

CLRB
PUS HR
MOVZBL
MOVAB

UCB$B LP OFLCNT(RS)
rM<R} ,R4>
#MSG$ DEVOFFLIN,R4
GASYSSGL_OPRMBX,R3

1-1

trJ
00

>
z

trJ

Figure 6-5

;RESET COUNTER
;SAVE REGISTERS
;SET UP MESSAGE TYPE
;ADDRESS TARGET MAILBOX

Location of Defective Code in Driver Routine

.,,r>3:
trJ
00

ANALYZING SYSTEM FAILURES -- GUIDELINES AND EXAMPLES
6.4

INDUCING A SYSTEM FAILURE

If the operating system is not performing well and you want to create
a system dump file so that you can examine it later, you can induce a
system failure by typing the following commands at the console:

.> .> .> EXAM I NE P ~;;I...

>>> DEPOSIT PC = -1

>>> DEPOSIT PSI... = 1FOOOO
>>>

CONTINUE

The system responds to the HALT command by displaying the PC;
it
responds
to
the
EXAMINE PSL command by displaying the PSL.
Immediately after you type this commans sequence, the system signals a
fatal bugcheck, writes information to SYSDUMP.DMP, shuts itself down,
and automatically reboots.
Make a note of the PC and PSL displayed on the console before you
perform the procedure outlined above.
When you induce a system
failure, the values you deposit into these registers destroy their
previous contents, and you will need the pre-failure values contained
in the PC and PSL when you begin to examine the system dump file, as
described in Section 6.1.

6-15

CHAPTER 7
SDA ERROR MESSAGES

SDA error messages can be divided into messages that occur during SDA
initialization and messages that occur during SDA operation. Messages
that appear before SDA is initialized indicate problems encountered by
SDA as it tries to run. SDA prints the message but does not execute.
Messages that appear when SDA is
operating
concern
problems
encountered during command execution.

7.1

INITIALIZATION ERROR MESSAGES

The dump file contains no valid dumP

This message appears if SDA cannot read the contents of the
system dump file. The file may be unreadable because the data is
bad or because the file is empty.
The dump onlhl contains n Pases of Phhlsical memorhl

This message occurs if the system dump file is not large enough
to accommodate all of physical memory. The number of physical
pages SDA can analyze is represented by n. To change the size of
the system dump file, see Section 2.1.
Shlmbol swmbol-name not found in SDA shlmbol table

This message appears if SDA cannot find a symbol in
file which is vital to its initialization.

7.2

the

SYS.STB

OPERATIONAL ERROR MESSAGES

Invalid block thlPe in specified block

This message appears if SDA is unable to identify the block type
of a particular block.
The invalid block type message most
usually occurs when the FORMAT command tries to identify a block
type using a byte offset.
See the description of the FORMAT
command in Chapter 5 for further information about byte offsets.
No "block-twpe• swmbols found to format this block

This message appears if SDA cannot locate the symbols
format a block as a particular block type.
You may need to use the READ command to include
block type symbols in the SDA symbol table.

7-1

the

needed

specific

SDA ERROR MESSAGES

No such Process
This message occurs if the process name specified in a SHOW
PROCESS or SET PROCESS command refers to a process that does not
exist.
Process swapped out

This message occurs if the process name specified in a SHOW
PROCESS or SET PROCESS command represents a process that was
swapped out of the balance set when the system failed.
Unable to access location location

This message indicates that SDA is unable to read a certain
location.
The inaccessible location may be an implied reference
to memory made during the execution of an SDA command.
Unknown symbol

s~mbol-name

This message occurs if SDA cannot identify a specified symbol.
Unknown twPe of GSD entry:

GSD

This message occurs when SDA encounters a type of global symbol
that it does not recognize, either in the SYS.STB file or in a
file specified in the READ command. The type of global symbol
definition GSD is represented by a byte. This message can occur
during either initialization or operation of SDA, and usually
means that the file being read has been corrupted.

7-2

INDEX

A
Abbreviated commands, 4-1
Access violation, 6-2
ACP queue, 5-26
Active processes, displayed, 5-49
Add symbols to table, 5-3
Analyzing system failures, 6-1
Ancillary control process queue
block (AQB), 5-26
Arithmetic operations, 4-3
ASCII text, and quotation marks,
5-3
Assigning values to symbols, 5-3
Asterisk (*), to examine running
system, 3-2

Commands, (Cont.)
SHOW PFN DATA, 5-33
SHOW POOL, 5-36
SHOW PROCESS, 5-39
SHOW STACK, 5-46
SHOW SUMMARY, 5-49
SHOW SYMBOL, 5-51
Compute, value of expression, 5-5
Conditions, and fatal bugcheck,
6-2
Contents, location displayed, 5-6
Controller data structures, 5-24
Copy command, 5-2
Creating,
symbols, 4-3
Current process, 5-19

Bad page list, 5-33
Base, specification of numeric,
4-2
Binary operators, 4-3
Block type, 5-11
byte, 5-11
symbols, 5-12
Blocks, formatted, 5-12
Byte ranges, displayed as, 5-8
Bugcheck, fatal, 6-1
identifying, 6-6

Decimal, values displayed, 4-2
Debugging system failure, 6-6
Default file specification, for
system dump file, 3-1
Default radix, 4-2
Defective code, identifying and
fixing, 6-13
DEFINE command, 5-3
Device Data Block (DDB), 5-24
Device data structures displayed,
5-24
Device status information, 5-25
Device unit data structures, 5-24
Discontinue display, 5-10
Displayed,
active processes, 5-49
contents of location, 5-6
formatted block, 5-11
global page table, 5-31
hardware process context, 5-39
IRP pool, 5-36
nonpaged dynamic storage pool,
5-36
paged dynamic storage pool,
5-36
PFN data base, 5-33
physical page, 5-33
process regions, 5-6
process working set list, 5-40
software process control block,
5-39
stacks, 5-46
system regions, 5-6
system-wide interrupt stack,
5-46
Dollar sign ($), to indicate
foreign command, 3-2
Driver dispatch table (DDT), 5-24

c
Channel Request Block (CRB), 5-24
Characters, in arithmetic operations, 4-3
Colon (:), in EXAMINE command, 5-6
Command format, 4-1. See also
HELP command
Commands,
COPY, 5-2
DEFINE, 5-3
EVALUATE, 5-5
EXAMINE, 5-6
EXIT, 5-10
FORMAT, 5-11
HELP, 5-14
optional, to produce SDA
listing, 3-4
READ, 5-15
REPEAT, 5-17
SET OUTPUT, 5-18
SET PROCESS, 5-19
·SHOW CRASH, 5-21
SHOW DEVICE, 5-24
SHOW PAGE_TABLE, 5-29

Index-1

INDEX

Driver, finding, using DPT list, 6-9
calculating end of, 6-10
calculating offset into, ~-10
Driver Prologue Table (DPT) , 6-9
DUMPBUG parameter, 2-1
Dump file,
copy of, 5-2
flag, 3-4

Global page table, 5-31
Global symbols, 3-4
and DEFINE command, 5-3
and READ command, 5-15
copying to symbol table, 5-15
displayed, 5-51
symbol table, 5-51
value displayed, 5-51

E
Equal sign (=) , in expression, 5-3
Error messages,
initialization, 7-1
operational, 7-1
Escape key (<ESC>), and REPEAT
command, 5-17
EVALUATE command, 5-5
Evaluating expressions, 5-5
EXAMINE command, 5-6
Examine,
data structures, 5-19
location contents, 5-6
memory regions, 5-6
running system, 3-2
sequence of memory locations, 5-17
Exceptions, fatal, 6-2
EXIT command, 5-10
Expressions,
as command parameters, 4-2
as parameter to the DEFINE
command, 5-3

F
Fatal bugcheck, 6-1
conditions, 6-2
Finding problem in routine, 6-10
Fixing, and identifying defective
code, 6-13
Flag, dump file and SDA command
execution, 3-4
Foreign command, invoking SDA
with, 3-2
Fork block, 5-25
FORMAT command, 5-11
Formatting blocks, 5-12
lists of blocks, 5-12
linked lists, 5-12
Free page list, 5-33

G
General purpose registers,
contents, 5-21

Hardware maintenance register
contents, 5-21
Hardware process context, 5-39
HELP command, 5-14
He.xadecimal expression, how SDA
evaluates, 5-5
Hexadecimal values displayed, 4-2

Identifying,
and fixing defective code, 6-13
bugcheck, 6-6
exception, 6-6
Illegal page faults, 6-5
Index number, 5-19
Inducing system failure, 6-15
Initialization error message, 7-1
Interrupt Dispatch Block (IDB),
5-24
I/O request packet, 5-25
I/O request packet pool, 5-36
Invoking SDA, 3-1
as a foreign command, 3-2

K
Key variables, checking values of,
6-12

L
Line of code, and bugcheck, ~-1
Linked lists, formatting, 5-12
Linked structure of DPT, 6-9
List,
data structures, 5-24
process's hardware context, 5-40
Local symbol, displayed, 5-51
Local symbol value, displayed,
5-51
Location,
contents displayed, 5-6
examine by symbol, 3-4
parameters, 5-6

Index-2

INDEX

Printing,

Mechanism vector, 6-3
Modified page list, 5-33
~oving process context to specific
process, 5-19
Multiple qualifiers, 4-1

(Cont.)

nonpaged dynamic storage pool,
5-36

paged dynamic storage pool, 5-37
program region, 5-7
summary of the pools, 5-37
writeable system region, 5-7
Problem, finding, in routine, 6-10
Process,
context, 5-19
N
control block (PCB), 5-19
Nested parenthetical expressions,
header (PHD), 5-19
4-3
identification (PID), 5-19
Nonpaged dynamic storage pool,
information, in SHOW CRASH
5-36
command, 5-21
Nonprinting characters, represented
regions, displayed, 5-6
by period, 5-3
register contents, 5-21
Processor registers, loss of
contents during SYS$DMP.DMP,

3-2' 3-3

Object module file, 5-15
extracting global symbols from,

5-15

Offset, into code, 6-1
Omitted location parameter, 5-6
Operational error messages, 7-1
Operating system information, in
SHOW CRASH command, 5-21

Qualifier, 4-1
abbreviated, 4-1
multiple, 4-1
Quotation marks (" "),around
ASCII text, 5-3

Paged dynamic storage pool, 5-36
Page faults, illegal, 6-5
Page file quota, 3-1
/PAGE TABLE, in SHOW PROCESS
command, 5-41
Page table entries, displayed,

Radix operators, 4-2
Radix, specifying SDA use, 4-2
READ command, 5-15
to create symbols, 4-3
Reading dump file, prerequisites
for, 3-1
Register contents, 5-21
REPEAT command, 5-17
Return to interactive display,
in SET OUTPUT command, 5-18
Routine, finding problem in, 6-10
stepping through, 6-12
RUN command, invoking SDA with,

5-29

Parameter,
as file specification, 4-1
expressions as, 4-2
Parentheses, as special operators,
4-3
Period (.),as nonprinting characters, 5-3
PFN data base, displayed, 5-33
Physical page,
displayed, 5-33
information, 5-30
/PO, as EXAMINE qualifier, 5-7
/Pl, as EXAMINE qualifier, 5-7
Preserving a system dump file,
5-2

Printing,
both program and control
regions, 5-7
control region, 5-7
I/O request packet pool, 5-36

3-1

Running system, examination of,
3-2

s
Sample crash analysis, 6-9
Screen overflow prompt, and exit
command, 5-10
SDA, definition, 1-1
command format, 4-1
in site-specific start-up
procedure, 3-4

Index-3

INDEX

SDA, definition, (Cont.)
operation. See HELP command
utility. See HELP command
SET PROCESS command, 5-19
SHOW CRASH command, 5-46
SHOW CRASH display~ 3-3
SHOW DEVICE command, 5-24
SHOW PAGE TABLE command, 5-29
SHOW PFN DATA command, 5-33
SHOW POOL command, 5-36
SHOW PROCESS command, 5-39
SHOW STACK command, 5-46
SHOW SUMMARY command, 5-49
SHOW SYMBOL command, 5-51
Signal vector, 6-4
Signal vector, examination, 6-7
Slash (/), used with qualifier,
4-1
Software process context, 5-39
Space, in expression, 5-3
Special characters, 4-3
Special operators, 4-3
Special register contents, 5-21
Special symbols, 4-3. See also
DEFINE and READ commands
Stack configuration for illegal
page faults, 6-5
Stacks, displayed, 5-46
Stepping through routine, 6-12
Step through linked list, 5-17
Stopping SDA, 5-10
SWAPFILES command procedure, 2-1
SYS$DISK default, 3-1
Symbol evaluation, 5-5
Symbols,
add to table, 5-3
assign value to, 5-3
defined, 4-3
global, 5-3
Symbol table, displayed, 5-51
System dump file, 2-1
calculating size of, 2-1
creating new, 2-1
default file specification, 3-1
reading, 3-1
saving, 2-1

System failure, 1-1
debugging, 6-6
causes while examining running
system, 3-2
inducing, 6-15
solving, 6-1
System map file,
SYS$SYSTEM:SYS.MAP, 6-1
System parameter. See parameter
System process control block, 5-39
System region, displayed, 5-6
System-wide interrupt stack,
displayed, 5-46

T
Table of contents, SDA creates,
5-18

u
Unary operators, 4-2
Underline ( ), 4-3
Unit controY-block, 5-25

v
Values, checking, of key variables,
6-12
Vectors, 6-2
mechanism, 6-3
signal, 6-4
Violation, access, 6-2
Virtual memory, and SET PROCESS
command, 5-19
Virtual page information, 5-29
Volume control block, 5-26

w
Writing output to a file, 5-18

Index-4

VAX/VMS
System Dump Analyzer
Reference Manual
AA-J526A-TE
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