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AA-M185B-TC

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Document:	UDA50 Maintenance Guide Nov82
Order Number:	AA-M185B-TC
Revision:	0
Pages:	53
Original Filename:	AA-M185B-TC_UDA50_Maintenance_Guide_Nov82.pdf

OCR Text

AA-M185B-TC

UDA50
Maintenance
Guide

Digital Equipment Corporation
Colorado Springs, Colorado

1st EDITION, FEBRUARY, 1982
2nd EDITION, NOVEMBER, 1982

The information in this manual is for informational purposes and is subject to change without notice.
Digital Equipment Corporation assumes no responsibility
for any errors which may appear in this manual.

Printed in U.S.A.

This document was set on DIGITAL's computerized typesetting system.

The following are trademarks of Digital Equipment
Corporation, Maynard, Massachusetts:
DEC
DECsystem-l0
DIBOL
lAS
OMNIBUS
Q-BUS
UNIBUS

DECUS
DECSYSTEM-20
Digital Logo
LSI-ll
PDP
RSTS
VAX
VT
ii

DECnet
DECwriter
EduSystem
MASSBUS
PDT
RSX
VMX

CONTENTS
INTRODUCTION
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
1.10
1.11
1..12

SCOPE OF MANUAL .,. '........... .
UDA50 MAINTENANCE
PHILOSOPHY .................... .
UDA50 FIELD REPLACEABLE
PARTS ...........................
UDA50 UPGRADE .................
UDA50 DIFFERENCES .............
UDA50 MAINTENANCE
FEATURES ........ ,...............
UDA50 ADDRESS SWITCHES
AND JUMPERS ....................
UNIBUS OVERLOADING ....... :...
UNIBUS OVERLOADING
EXCEPTIONS .....................
UDA50 PRIORITY PLUG ............
RELATED DOCUMENTATION ......
INSTALLATION OF
BOOTSTRAP ROM .................

UDA50 FAULT ISOLATION

2. 1
2. 1. 1
2. 1.2
2.2
2.2.1
2.2.2
2.3

UDA50- RESIDENT DIAGNOSTICS
UDA50 LED Error Codes ........
Status! Address Register Codes .....
UDA50 SUBSYSTEM DIAGNOSTICS.
PDP-II Subsystem Diagnostics ....
VAX Subsystem Diagnostics ......
UDA50 SUBSYSTEM
TROUBLESHOOTING ..............
UDA50-Resident Diagnostics .....
UDA50 Host-Resident Diagnostic ..
Subsystem Error Message
Information ....................

2.3.1
2.3.2
2.3.3

111

Page

1
1
2
3
5
8
11

11
12
13

15
15
18
22
23
24
25
25
25
27

FIGURES
1-1
1-2A
1-2B
1-3A
1-3B
1-4
2-1
2-2
2-3
2-4
2-5

Page

UDA50 Illustrated Parts
Diagnostic LED Locations
on the UDA50 Modules
Diagnostic LED Locations
on the UDA50 Modules ............. .
M7161 Address Switch and
Jumper Locations .................. .
M7485 Address Switch and
Jumper Locations .................. .
UDA50 Switch Setting for
Address 772150 ................... .
UDA50 Subsystem
Troubleshooting Flowchart ........... .
Real-Time Drive State
Interpretation ...................... .
Drive Status Bytes ................. .
Sub-unit Mask Bit Layout
Examples ......................... .
Status Message
Interpretation ...................... .

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

2
4

6
7
8
26

29
31
45
46

Page
UDA50 Modules ................... .
UNIBUS Delay .................... .
LED Error Codes .................. .
SA Register Error Codes ............ .
Real-Time Drive State Code
Interpretation ...................... .
Bit Description of Status
Message Bytes .................... .

3
9
15
18
33
37

INTRODUCTION

1.1

SCOPE OF MANUAL
The UDA50 Maintenance Guide describes the maintenance and troubleshooting procedures needed to support the
UDA50 Disk Controller. This guide covers both UDA50resident diagnostic and UDA50 host-resident diagnostic
operating procedures. When troubleshooting disk subsystem
problems, refer to the service manuals of the disk products in
the subsystem for device-specific service information.
1.2 UDA50 MAINTENANCE PHILOSOPHY
The maintenance philosophy planned for the UDA50 Disk
Controller is module replacement. Field Service personnel
should not attempt to replace or repair component parts
within these modules.
1.3 UDA50 FIELD REPLACEABLE PARTS
The UDA50 Disk Controller consists oftwo hex modules,
two flat ribbon intermodule cables, an unshielded Standard
Interface (SDI) cable assembly, an I/O bulkhead assembly,
and some assorted hardware. Figure 1-1 illustrates the major
Field replaceable Units (FRUs) in a UDA50 assembly.
1.4

UDA50 UPGRADE
The UDA50 has been upgraded to increase its performance. The differences between the old UDA50 and the
upgraded UDA50 will be called out in this manual where
applicable.

INTRODUCTION

50-PIN FLAT CABLE

M7162 OR
M7486

REAR SHIELD
HOUSING
174-26094-01 )
UDA BULKHEAD
SUB ASSEMBLY
170-18454-01 )

WITH MASSBUS
CUTOUT
OUTSIDE CABLE
RETAINER BRAcKET
(74-26095-01 )

CZ-0601

Figure 1-1

UDA50 Illustrated Parts

1.5 UDA50 DIFFERENCES
The upgraded UDA50consists of two new modules. Refer
to Table 1-1. Some of the features which increase the performance of the new UDA50 are:
•

Increased RAM size on the M7486 module from
4K to 16K.

INTRODUCTION

•

Minor hardware modification to make buffering
easier.

•

Etched-in capability to use larger PROMS.

•

Selectable jumpers for UNIBUS delays for various
systems.

Table 1-1 UDA50 Modules
OLD UDA50 NEW UDA50
MODULES MODULES
M7161
M7162

M7485
M7486

CAUTION
The new UDA50 M7485 and M7486 modules
are not upward or downward compatible
with the old UDA50 M7161 and M7162
modules. Under no circumstances should a
new UDA50 module be used to replace a
failing old UDA50 module unless both modules are replaced as a set.
1.6 UDA50 MAINTENANCE FEATURES
The UDA50 Disk Controller has the following maintenance features.
•
•
•

UDA50-resident diagnostics
UD A50 LED maintenance displays
UDA50 host-resident diagnostics

The UDA50-resident diagnostic is a PROM-based microcode program that performs UDA50 self-diagnosis upon
power-up or hard initialization.

INTRODUCTION

A UDA50 maintenance display is located on each UDA50
module. Each display consists of four LEDs. These LEDs
display current resident diagnostic activity and error codes
caused by malfunctions. Figures 1-2A and 1-2B show the
location of the maintenance LEDs on each module.

M7162 OR M7486

CZ-OB07

Figure 1-2A

Diagnostic LED Locations on the
UDA50 Modules

]::Q "'~~'" l?m ~
~

~ nmiii? 8421
MSD

LSD

M7181 OR M7485

CZ-OBOB

Figure 1-2B

Diagnostic LED Locations on the
UDA50 Modules

INTRODUCTION

The UDA50 host-resident diagnostics contain four tests
that isolate subsystem faults to the UNIBUS or disk drives. A
system exerciser program is also provided to test the performance of the entire disk subsystem.

1.7 UDA50 ADDRESS SWITCHES AND JUMPERS
The UDA50 Disk Controller contains two registers that
are visible to the UNIBUS I/O page. They are the initializing
and polling OP) register and the status and address (SA)
register. The IP and SA registers are assigned an octal UNIBUS address of 772150 and 772152, respectively.
The UNIBUS address selector switches and jumper plugs
W4 and W5 are used to set the UNIBUS address for the IP
register. The location of these switches and jumpers on
UDA50 module (M7161) is shown in Figure 1-3A. The
location of these switches and jumpers on UDA50 module
(M7485) is shown in Figure 1-3B. Set the UNIBUS address
switches and jumpers for both modules to the positions
shown in Figure 1-4 to select UNIBUS address 772150.
In past disk products, a vector address was also physically
selectable. This is not true with the UDA50 Disk Controller.
A vector address typically 154 (octal) will be supplied by the
software.

INTRODUCTION

&tid
DATA BUS

~~~~~~o~D~~~i~H

UNI:So/LAY JUMPER

W14

T4 T5 T6

ON 1
1D
OFF 00000
W5 W4

M7161

ADDRESS
JUMPER PLUG

~w~"
W6 -..............

r'~

V'"
M7161

~
~"'"
~

W14

M7181

CZ-0528

Figure 1-3A

M7161 Address Switch and Jumper Locations

INTRODUCTION

UNIBUS ADDRESS
SELECTOR SWITCH
UNIBUS
DELAY
Jumpers

~
1

g~F 0000

ADDRESS JUMPER PLUG

W~ W4

M7486

r.6

W14

M7486

CZ-0795

Figure 1-3B

M7485 Address Switch and Jumper Locations

INTRODUCTION

UNIBUS
ADDRESS
BITS

17 16 15

141312

11 10 9

8 7 6

543

-OCTAL
CODE

BINARY
CODE

1 1 1

o 1 0

o 0 1

1 1 1

1 1 S10

S9 S8 S7

S6 S5 S4

S3 S2 S1

I ON

OFFONQFF

OFF OFF ON

ON OFF ON

UDA50
SWITCH
SETTING

I
ALWAYS ONES

2 1 0

o 1

o 0 0

~4U
ALWAYS
ZEROS

CZ-0529

Figure 1-4

UDA50 Switch Setting for Address 772150

NOTE
UNIBUS address bit 2 is selected by jumper plugs
W4 and W5. Only one jumper plug can be in place
at a time. When jumper W4 is IN, bit 2 equals O.
When jumper W5 is IN, bit 2 equals 1.
NOTE
The UNIBUS address switches and jumpers should
be set for a floating address when a second UDA50
is installed on a system. Check the system configuration and UNIBUS addresses of all devices

1.8 UNIBUS OVERLOADING
A set of jumpers has been inserted on both the M7161 and
M7485 modules to prevent UNIBUS overloading. The location ofthese jumpers on UDA50 module (M7161) is shown
in Figure 1-3A. The location of these jumpers on UDA50
module (M7485) is shown in Figure 1-3B.
Table 1-2 shows the amount of delay, jumper configuration, and system configuration.

INTRODUCTION

Table 1-2

UNIBUS Delay

Amount
of Delay

Jumper
Config.

o usec

T4-T5

UDA installed and the only
disk drive is a RL02
or a RK07 (11/70
system with an RK07
and 1mb DMR will not work *)

6.2 usec

T5-T6

UDA installed with multiple
DMR11s or DMC11s
or DZ11s

Type of System

11/44 system (or any other
PDP-II with ECC
memory) using RM02 or
RP04/05/06 disk drives
11/44 with RL02 or RK07
disk drives
11/24 system (or any other
PDP-ll with non-ECC
memory) with one or two
UDAs installed with
other disk controllers and aDZ 11

* The UDA/RK07/DMRll configuration gives data late
errors from the RK07 regardless of the UDAs jumper
setting. Because of this, either an RK07 or a UDA, but
not both can be configured on the 11/70 when a 1mb
DMR11 is present.

INTRODUCTION

Table 1-2 UNIBUS Delay (Cont)
Amount
of Delay

Jumper
Config.

Type of System

VAX systems should be
treated as an 11/24 for
UNIBUS configuration
UDA installed on the
UNIB US with one or more
real time data acquistion
devices, and real
time data overrun or
underflow is observed t
10 usec

T5-T7

11/44 system with RL02
and RK07 disk drives
11/70 system with a
UDA/RL02/DMR11 (lmb) mix

t If underflow or overrun conditions are observed after
setting the UDAs jumper to the 6.2 usec. position, the
UDAs jumper must be set to the 10 usec. position (T5-T7).

·lNTRODUCTION

1.9 UNIBUS OVERLOAD EXCEPTIONS
There are exceptions to using the UNIBUS delay in
preventing overload and to the number of UDAs that can be
installed on a system. They are:
1.

The UDA should not be installed on a UNIBUS
system which has a bus repeater because the repeater slows the UNIBUS. Other devices such as
RK07, RM02, and RP04/05/06 may also experience data late conditions.

The UDA must be installed after all non-buffered
devices on the UNIBUS.

On PDP-II systems, there may be no more than
two UDAs installed on a UNIBUS. However on
VAX systems, no more than one UDA should be
installed on a UNIBUS with non-buffered UNIBUS peripheral devices.

NOTE
The old UDASO M7161 module has the UNIBUS
delay jumpers installed starting with M7161 module revision E. Check this module and its delay
jumpers if you are having UNIBUS overload
problems.
1.10 UDAS() PRIORITY PLUG
All UDA50 M7161 and M7485 modules are shipped with
a level 5 priority plug. This is the recommended priority level
for UDA50 disk subsystems and thus, the priority plug need
not be changed for the majority of installations. If another
priority level is required in some special circumstance, then
the current priority plug must be removed and the new one
inserted. The location of the priority plug is shown in Figure
1-3. It should be inserted so that the notch on the priority plug
aligns with the hole on the module socket.

INTRODUCTION

1.11 RELATED DOCUMENTATION
The UDA50 Disk ControlIer related documentation is
listed below.
Documentation is available from the Printing and Circulation Services, 444 Whitney St., Northboro, Massachusetts
01532.
•

UDA50 Disk Controller User Guide (EKUDA50-UG)

•

UDA50 Disk Controller Service Manual (EKUDA50-SV)

Documentation is available from the Software Distribution Center Order Administration/Processing, 20 Forbes
Rd., Northboro, Massachusetts 01532.

•

UDA50 Field Maintenance Print Set (MP-01331)

•

UDA50 Programmer's Documentation Kit
(QP905-GZ) - This kit consists of the folIowing
three software manuals.

• MSCP Basic Disk Functions Manual (AAL619A-TK)

• Storage System Diagnostic and Utilities
Protocol (AA-L620A-TK)

• Storage System UNIBUS Port Description
(AA-L621A-TK)

INTRODUCTION

•

UDA50 Maintenance Documentation Kit
(QP904-GZ) - This kit consists of a small looseleaf
binder, the UDA50 Maintenance Guide, and the
current drive maintenance guides that operate on
the UDA50.
•

UDA50 Maintenance Guide (AAM 185 B-TC) - The above maintenance
guide is an 8 x 5-1/2 inch looseleaf.

•

RA80 Maintenance
Guide
(AAM186A-TC) - The above maintenance
guide is an 8 x 5-1/2 inch looseleaf.

•

RA81
Maintenance
Guide
(AAM879A-TC) - The above maintenance
guide is an 8 x 5-1/2 inch -looseleaf.

•

Maintenance Guide Looseleaf Binder
(AV-L980A-TK)

1.12 INSTALLATION OF BOOTSTRAP ROM
The proper bootstrap ROMs will be shipped with the
UDA50. Bootstrap ROM # 23-767 A9-00 must be installed
on the PDP-II bootstrap ROM module M93l2.
Bootstrap ROM # 23-990A9-00 must be installed on the
VAX 11/750.

UDA50 FAULT ISOLATION

2.1

UDA50-RESIDENT DIAGNOSTICS
There are two ways of obtaining resident diagnostic information from the UDA50 Disk Controller. The first is
through the UDA50 LED error codes. The second is by
examining the contents of the UDA50 status/address (SA)
register. The SA register contents are also supplied to the host
CPU for error logs and diagnostic error reports.
2.1.1 UDA50 LED Error Codes
Table 2-1 lists the LED error codes and indicates which
FRU is most likely at fault.
Table 2-1

LED Error Codes

M71610r
M7485
LEDs
8421

M7162 or
M7485
LEDs
8421

Most
Likely
Failure

000.

xxxx

Undefined

00.0

000 0

M7161 or M7485
or software

00 • •

000 0

M7161 or M7485
or software

Note:

o = LED OFF
• = LED ON
x = Does not care condition

When two codes are given for the same error, both indicate
the same failure.

UDA50 FAULT ISOLATION

Table 2-1

LED Error Codes (Cont)

M71610r
M7485
LEDs
8421

M7162 or
M7485
LEDs
8421

0.00

0000

M7161 or M7485
or host
inactive

B
L
o.oJ
N
K

00(j0

No problem

0 •• 0

xxxx

Undefined

xxxx

0 •• 0

Most
Likely
Failure

0 •••

xxxx

0 •• 0

.000

o 000

M7161 or M7485
or software

.00.

0000

M7161 or M7485

0000

.00.

.0.0

o 000

.0.0

Note:

Undefined

M7162 or M7486

• = LED ON
o = LED OFF
x = Does not care condition

When two codes are given for the same error, both indicate
the same failure.

UDA50 FAULT ISOLATION

Table 2-1
M71610r
M7485
LEDs
8421

LED Error Codes (Cont)
M7162 or
M7485
LEDs
8421

Most
Likely
Failure

.0.0

xxxx

Undefined

xxxx
xxxx

.0 ••

• • 00

xxxx

• • 00

•• 0.

xxxx

•• 0.

M7161 or M7485
M7162 or M7486

••• 0

xxxx

••• 0

M7161 or M7485
M7162 or M7486

••••

M7161 or M7485

Cycling
pattern

No problem if
gone in less
than 2 seconds
after UDA50
initiation
otherwise
change M7161
or M7485.

Note:

• = LED ON
o = LED OFF
x = Does not care condition

When two codes are given for the same error, both indicate
the same failure.

UDA50 FAULT ISOLATION

2.1.2 Status/Address Register Error Codes
More detailed information on UDA50 functional and
diagnostic error codes is reported through the SA register.
The contents of this register may be examined manually
through the CPU console at the UDA50 UNIBUS address
plug 2. This address is normally 772152. Table 2-2 lists the
SA error codes and indicates the most likely FRU at fault.
Table 2-2

SA Register Error Codes

(Octal)

Error Description

Most
Likely
FRU
Failed

100001

UNIBUS packet read
error

M7161 or
M7485*

100002

UNIBUS packet write
error

M7161 or
M7485*

100003

UDA ROM and RAM
parity error

M7161 or
M7485 or
M7162 or
M7486

100004

UDA RAM parity
error

M7162 or
M7486

100005

UDA ROM parity
error

M7161 or
M7485

100006

UNIBUS ring read
error

M7161 or
M7485*

Error
Code

* Possibly the host CPU is at fault.

UDA50 FAULT ISOLATION

Table 2-2

SA Register Error Codes (Cont)

Error Description

Most
Likely
FRU
Failed

100007

UNIBUS ring write
error

M7161 or
M7485*

100010

UNIBUS interrupt
master failure

M7161 or
M7485

100011

Host access timeout
error

M7161 or
M7485*

100012

Host exceeded
command limit

M7161 or
M7485*

100013

UNIBUS bus master
failure

M7162 or
M7486

100014

DM XFC fatal error

M7162 or
M7486

100015

Hardware timeout
of ins.truction loop

M7161 or
M7485*

100016

Invalid virtual
circuit identifier

M7161 or
M7485*

100017

Interrupt write
error on UNIBUS

M7161 or
M7485*

104000

Fatal sequence error

M7161 or
M7485

Error
Code
(Octal)

Possibly the host CPU is at fault.

UDA50 FAULT ISOLATION

Table 2-2

SA Register Error Codes (Cont)
Most
Likely
FRU
Failed

Error
Code
(Octal)

Error Description

104040

D processor ALU

M71610r
M7485

104041

D processor control
ROM parity error

M71610r
M7485

105102

D processor with no
BD #2 or RAM
parity error

M7162 or
M7486

105105

D processor RAM
buffer error

M7162 or
M7486

105152

D processor SDI
error

M7162 or
M7486

105153

D processor write
mode wrap
serdes error

M7162 or
M7486

105154

D processor read
mode serdes,
RSGEN & ECC error

M7162 or
M7486

106040

U processor ALU
error

M71610r
M7485

106041

U processor control
register error

M71610r
M7485

UDA50 FAULT ISOLATION

Table 2-2
Error
Code
(Octal)
106042

106047

SA Register Error Codes (Cont)

Error Description
U processor
DFAIL/control ROM
parity/BD # 1
test CNT
U processor constant
PROM error with
D processor running
SI test

Most
Likely
FRU
Failed
M7161 or
M7485

M7161 or
M7485

106055

Unexpected trap found,
abort diagnostic

M71610r
M7485

106071

U processor constant
PROM error

M7161 or
M7485

106072

U processor control
ROM parity error

M7161 or
M7485

106200

Step 1 data error
(MSB not set)

M7161 or
M7485 or
RE-INIT

107103

U processor RAM
parity error

M7162 or
M7486

107107

U processor RAM
buffer error

M7162 or
M7486

UDA50 FAULT ISOLATION

Table 2-2
Error
Code
(Octal)

SA Register Error Codes (Cont)
Most
Likely

FRO
Error Description

Failed

107115

Test count was
wrong (BD 12)

M7162 or
M7486

112300

Step 2 error

M7161 or

122240

NPR error

M7161 or
M7485

122300

Step 3 error

M7161 or
M7485

142300

Step 4 error

M71610r
M7485

M7485

2.2 UDA50 SUBSYSTEM DIAGNOSTICS
The UDA50 host-resident diagnostics for both the PDP-II
CPU family and the VAX CPU family are described briefly
in the following paragraphs. A more detailed description of
these diagnostic programs is found in the diagnostic listings
that are available from the Software Distribution Center.
If the diagnostic programs report errors, refer to the
troubleshooting procedure in Paragraph 2.3.

tJDASO FAULT ISOLATION

2.2.1

PDP-ll Subsystem Diagnostics

2.2.1.1 CZUDECO - UDA Disk Formatter Program
Most disk drives will be shipped with formatted disks. On
formatted disk drives, it will not be necessary to run the
formatter program. Refer to the disk drive user guide to
determine if you must run the formatter program before the
diagnostic program.
2.2.1.2 CZUDCCO - UDASO and Disk Drive Diagnostic. This diagnostic consists of the following four tests:
•
•
•
•

Test 1 - UNIBUS addressing test
Test 2 - Disk-resident diagnostic test
Test 3 - Disk functional test
Test 4 - Di~k exerciser test

This program will ask some hardware and software questions of the user. ;\ sample printout of these questions, when
the default conditions are elected, is shown below.
CHANGE HW (L) ? N'

# UNITS (D) ? 1
UNIT 0
UNIBUS ADDRESS OF UDA (0) 172150 ?
VECTOR (0) 154 ?
BR LEVEL (D) 5 ?
UNIBUS BURST RATE (D) 0 ?
DRIVE NUMBER (D) 0 ?
EXERCISE ON CUSTOMER DATA AREA IN TEST 4 (L) N ?
CHANGE SW (L) ? N *
ENTER MANUAL INTER VENTI ON MODE FOR SPECIAL DIAGNOSIS (L) N ?
REMAINING SOFTWARE QUESTIONS APPLY TO TEST 4 ONLY

UDA50 FAULT ISOLATION

ERROR LIMIT (D) 32 ?
READ TRANSFER LIMIT IN MEGABYTES - 0 FOR NO LIMIT (D) 0 ?
SUPPRESS PRINTING SOFT ERRORS (L) Y?
DO INITIAL WRITE ON START (L) Y ?
ENABLE ERROR LOG (L) N ?

*The following questions will not be asked when you answer
this question with a "N". They are listed here to show you
what will be asked if you answer' 'Y", and what the defaults
are.

2.2.1.3 CXDUBCO -- DECXll Module - The DECX 11
module operates in two modes:
•

It performs data transfer over the UNIB US to the

UDA50 internal buffer.
•

It performs reads and writes to the customer data

area of the disks.

2.2.2

VAX Subsystem Diagnostics

2.2.2.1 ZZ-EVRLB -- UDA Disk Formatter- Most disk
drives will be shipped with formatted disks. On these disk
drives, it will not be necessary to run the formatter program.
Refer to the disk drive user guide to determine if you must run
the formatter before the diagnostic program.
2.2.2.2 ZZ-EVRLA -- UDA50 Disk Subsystem Diagnostics- The VAX UDA50 host-resident diagnostic contains
the same four tests as the PDP-II version.
•
•
•
•

Test I - UNIBUS addressing test
Test 2 - Disk-resident diagnostic test
Test 3 - Disk functional test
Test 4 - Disk exerciser test

UDA50 FAULT ISOLATION

Use the verify section ofthis diagnostic for system installation.

2.2.2.3 ZZ-EVRLC -- Generic Disk Drive Exerciser This program tests the read and write ability of any SDI type
disk drive, and will display differences in the read and write
data to the operator.
2.3 UDASO SUBSYSTEM TROUBLESHOOTING
A brief UDA50 subsystem troubleshooting flowchart is
illustrated in Figure 2-1. The troubleshooting procedure recommends examining the error log first.
2.3.1 UDASO-Resident Diagnostics
The UDA50-resident diagnostics are initiated when power
is applied to the UDA50 Disk Controller. The CPU should be
halted during this test. The four LED indicators on each
UDA50 module will display a cycling pattern in the LEDs.
The cycling pattern in the LEDs signifies the completion
of a successful UDA50 diagnostic test. Figure 1-2 shows the
location of the four LEDs on each UDA50 module.
If the UDA50 LEDs do not display the cycling pattern
after power is applied, look up the LED error code in Table
2-1 to locate the problem.
2.3.2 UDASO Host-Resident Diagnostic
A brief description of the UDA50 host-resident diagnostics is presented in Paragraph 2.2. Use the UDA50 hostresident diagnostic to isolate problems to the UNIBUS or the
disk drives.
These diagnostics will send back error messages concerning drive status or real-time drive state. Since the drive
status error messages are unique to each disk drive, they will
be described in the drive maintenance guide and service
manual. The real-time drive state error messages describe
what is happening in the drive. Paragraph 2.3.3 describes the
error message information.

UDA50 FAULT ISOLATION

SA register contents (Table 2-2)
Check drive error codes

Check UOA50 LEO code (Table 2-1)
Check SA register (Table 2-2)
Possible UNIBUS problem

Refer to Paragraph 2 2 and
to the diagnostic lisllngs

Probable UOA50 failure
(Tables 2-1 and 2-2)
Possible UNIBUS problem

Test 2 through 4 failure
Probable drrve problem
1) Take drive off-line
2) Run drive-resident diagnostics

Possible defective SOl cable

CZ-0555

Figure 2-1

UDA50 Subsystem Troubleshooting
Flowchart

UDA50 FAULT ISOLATION

2.3.3

Subsystem Error Message Information
Error messages will be typed out during the UDA50
host-resident diagnostic if a problem is detected. Three sample printouts are shown below. Sample 1 shows typical drive
error printout when running the PDP-II XXDP -+ program.
Sample lA shows typical drive error printout when running
the VAX diagnostics.
Note that the real-time drive state (RTDS) and the drive
status are given in the last examples of samples 1 and lA.
Sample 2 shows a typical UDA50 error printout. The last line
of sample 2 gives the contents of the SA register.
Sample 1:
Printout of a Drive Error using XXDP +
CZUDC HRD ERR 04041 ON UNIT 00 TST 004 SUB 000 PC: 21044
DISK EXERCISER DM PC: 5110 UDA AT 172150 DRIVE 032 RUNTIME 00: 00: 23
COULD NOT FIND REPLACEMENT FOR
LBN WITH HEA
NOT FOUND
LBN TO REPLACE 900
CZUDC SFT ERR 04006 ON UNIT 00 TST 004 SUB 000 PC: 21044
DISK EXERCISER DM PC:5324 UDA AT 172150 DRIVE 032 RUNTIME 00:00:37
SELECT TRACK AND WRITE LEVEL 1 CMD NOT EXECUTED
ATTEMPT 0
LBN 5252
SECTORS FROM INDEX 13 TRK 1 GRP 0 CYL 6
ORIGIN OF SEEK: GRP 1 CYL 5
REAL TIME STATE 8001
STATUS (R TO L) : 0001 1100 0000 OAOO 0000 0613 1020

UDA50 FAULT ISOLATION

Sample lA:
Printout of a Drive Error using VAX DS
EVRLA -- UDA50 Disk Subsystem Diagnostic -- 2.0
Pass 1. test 4. subtest O. error 4041 19-AUG-1982 12: 16:03.71
Hard error while testing DUA32: OM PROGRAM REPORTING AN ERROR

DISK EXERCISER CM PC; 5110 UDA a t address 772150 DRIVE _DUA32
COULD NOT FIND REPLACEMENT FOR
LBN WITH HEADER NOT FOUND
LBN TO REPLACE 900
END OF HARD ERROR NUMBER 4041
EVRLA -- UDA50 Disk Subsystem Diagnostic -- 2.0
Pass 1. test 4. subtest O. error 4006 19-AUG-1982 12:16:03.71
Soft error while testing DUA32: OM PROGRAM REPORTING AN ERROR
DISK EXERCISER DM PC; 5324 UDA at addre ss 772150 (0) DRIVE _DUA32
SELECT TRACK AND WRITE LEVEL 1 CMD NOT EXECUTED

ATTEMPT 0
LBN 5252
SECTORS FROM INDEX 13 TRK 1 GRP 0 CYL6
ORIGIN OF SEEK: GRP 1 CYL 5
REAL TIME STATE 8001
STATUS (R TO L): 0001 11000000 OAOO 0000 0613 1020

End of soft error number 4006

Sample 2:
Printout of a UDA50 Error using XXDP +
CZUDC DVC FTL ERR 00005 ON UNIT 00 TST 001 SUB 002 PC: 023710
UDA INITIALIZE ERROR
UDA RESIDENT DIAGNOSTICS DETECTED FAILURE
UDASA REGISTER = 106040

UDA50 FAULT ISOLATION

2.3.3.1 Real-Time Drive State Message Interpretation
The real-time drive state message consists of 4 hexadecimal
digits. Only four state bits within these hexadecimal digits
are of diagnostic value to the field service engineer. The rest
of the bits are too transitory and are masked out before the
RTDS message is printed. The following are the four important RTDS state bits.
•
•
•
•

Read/write ready (R/W RDY)
Drive available (AVAIL)
Attention (ATTN)
Receiver ready (RCVR RDY)

The location of these four state bits within the hexadecimal code is shown in Figure 2-2. The interpretation of the
RTDS message requires an understanding of the causes and
effects of each bit in the RTDS message. It also requires an
understanding of what is meant by drive on-line, drive offline, drive available and drive unavailable. Definitions of
each ofthe of the four RTDS message bits and the on-line and
available states are given.

HEX DIGIT 2

HEX DIGIT 3

HEX DIGIT 1

x = 00 not care condition

Figure 2-2

HEX DIGIT 0

CZ-D556

Real-Time Drive State Interpretation

The following four terms define the state of the drive as
seen from the controller.

UDA50 FAULT ISOLATION

•

Drive Off-line - The drive is not operational and
may not communicate with the controller via the
dri ve control protocol.

•

Drive Unavailable - The drive is operating, is visible to, and may at times communicate with the
controller. However, the controller may not fully
utilize the drive because the drive is drive on-line to
another controller.

• Drive Available - The drive is visible to, capable of
communicating with, and capable of executing an
on-line command. However, the drive is not currently drive on-line to any specific controller.

• Drive On-line - The drive is dedicated to the exclu-

sive use of a particular controller, and is not available to any alternate controller.

The following paragraphs explain the causes, effects, and
interrelationships of the four state bits within the RTDS
message.
•

RECEIVER READY - When RCVR RDY is asserted, it indicates that the drive is ready to receive
a command on the SDI interface WRITE/COMMAND line. RCVR RDY is negated while the
drive is processing a command.

•

ATTENTION - This notifies the controller that a
potentially significant status change has occurred
in the drive.
When in the drive on-line state, the drive asserts
this signal whenever any of its generic status bits
(see Figure 2-3) change, except for the following
three cases.

UDA50 FAULT ISOLATION

LSB

MSB
BYTE 1

RESPONSE CODE

BYTE 2
BYTE 3

UNIT
HI UNIT

SUBUNIT MASK

BYTE 4

BYTE 5

BYTE 6

BYTE 7

BYTE 8

REQUEST BYTE

MODE BYTE

ERROR BYTE

'--

DRIVE TYPE-SPECIFIC
EXTENDED STATUS
FOR LOGGING PURPOSES

BYTE 10

rBYTE 11

BYTE 13
BYTE 14

GENERIC
ST ATUS
BI TS

CONTROLLER BYTE

RETRY COUNT IFAILURE CODE

BYTE 9

BYTE 12

I--

r(7 BYTES)

BYTE 15

cZ-D557

Figure 2-3

Drive Status Bytes
1.

A generic status bit changes as a direct consequence of the correct operation of a command.

A generic status bit changes as the result of
an error in the reception, validation, or
execution of a command.

The RE status bit changes due to a transmission error outside of a command. The RE bit
is described in byte 6 of the drive status
message.

UDA50 FAULT ISOLATION

•

An on-line drive may assert ATTN regardless of
whether a command is in progress or not. The drive
will continue to assert this signal until it receives a
valid get status command from the controller. At
this point, the drive will negate the ATTN signal.
A drive in the available state, that is spinning,
always asserts the ATTN signal. The ATTN signal
is negated if any condition arises that would prevent the available drive from spinning up under
controller command.

•

READ/WRITE READY - When R/W RDY is
asserted, it indicates that the drive is capable of
handling a data transfer to or from the disk surface.
Upon receipt of a start frame of a command, the
drive will negate this signal prior to reasserting
RCVR RDY. Once negated, this signal will remain
negated until the drive has processed the command
and has transmitted the end frame of the response.
Any head motion will lower this signal until the
operation is completed, and the drive is again ready
to perform I/O operations.
The drive asserts R/W RDY after the successful
completion of a seek operation. If the operation is
unsuccessful, the drive will keep the R/W RDY
signal negated and use ATTN to signal the problem.

lJDASO FA lJL T ISOLA nON

•

AVAILABLE - When A VAIL is asserted, it indicates that the drive is in the drive available state
relative to the controller. It is asserted whenever
the drive enters the drive available state. The signal
is negated when the drive leaves the drive available
state.

Use the definitions given above to interpret the RTOS
message in Table 2-3.

Table 2-3

RTDS
HEX
CODE

Real-Time Drive State Code
Interpretation

DESCRIPTION

0000

The drive is either in
initial ization or in an off-l ine
state.

0001

The drive is on-line. Possihly an
error state was recently cleared,
or the drive spun down with the
RUN/STOP switch out.

0002

This code indicates an invalid
drive state. ATTN is asserted and
the drive cannot receive
controller commands with RCVR ROY
negated.

UDA50 FAULT ISOLATION

Table 2-3
RTDS
HEX
CODE
0003

Real-Time Drive State Code
Interpretation (Cont)

DESCRIPTION
The drive is on-line and one of
two conditions exist.
1. The disks are spinning, and
there is an error state.
2.

The disks are not spinning
and there is a switch change
active.

0040

This code indicates an invalid
drive state. RCVR RDY should be
asserted if the drive is in the
available state.

0041

The drive is available, but not
spinable. The RUN/STOP switch is
not pushed in, or there could be
an open interlock that prevents
spin up.

0042

This code indicates an invalid
drive state. ATTN is asserted and
the drive cannot receive
controller commands with RCVR RDY
negated.

0043

The drive is available and
spinable.

UDA50 FAULT ISOLATION

Table 2-3
RTDS
HEX
CODE

Real-Time Drive State Code
Interpretation (Cont)

DESCRIPTION

8000

This code indicates an invalid
drive state. R/W RDY should not
be asserted with RCVR RDY negated.

8001

This is the normal drive on-line
state.

8002

This code indicates an invalid
drive state. ATTN is asserted and
RCVR RDY is negated, preventing
the drive from receiving
controller commands.

8003

The drive is on-line and one of
two conditions exist:
1. There is a change of switch
state.
2.

8040

The drive is reporting a
successful retry of a seek
with recalibration.

This code indicates an invalid
drive state. R/W RDY and AVAIL
should never be asserted together.
-Also, ATTN should be asserted when
the drive is available and
spinable.

UDA50 FAULT ISOLATION

Table 2-3
RTDS
HEX
CODE

Real-Time Drive State Code
Interpretation (Cont)

DESCRIPTION

8041

This code indicates an invalid
drive state. R/W RDY and AVAIL
should never be asserted together.
Also, ATTN should be asserted when
the drive is available and
spinable.

8042

This code indicates an invalid
drive state. R/W RDY an9 AVAIl
should never be asserted together.
Also, ATTN is asserted and the
drive cannot receive controller
commands with RCVR RDY negated.

8043

This code indicates an invalid
drive state. R/W RDY and A VAIL
should never be asserted together.

FFFF

The controller is unable to get a
valid drive state.

UDA50 FAULT ISOLATION

2.3.3.2 Status Message Bytes - The status line found in
error message sample 1 is the result of the diagnostic performing a get status command. Fourteen of fifteen status
bytes are printed out by the error message.
Figure 2-3
shows the breakdown of the fifteen status bytes. The first
byte is not printed out since it is a response code to the get
status command. Bytes 9 through 15 contain drive-specific
status bits and the drive service manual or maintenance guide
should be consulted for interpretation. [ Table 2-4 gives a bit
description of status message bytes.]
Table 2-4
Status
Byte

Bit Description of Status
Message Bytes
Bit Description

Byte 1

Response Code Field - Byte 1 is
the response code to a controller
command.

Byte 2

Unit Number - The unit number
consists of two hexadecimal
digits representing the unit
number of the selected disk drive
returning the status (0-254).

UDA50 FAULT ISOLATION

Table 2-4
Status
Byte

Bit Description of Status
Message Bytes (Cont)

Bit Description

Byte 3

Subunit Mask - The subunit mask
is a four-bit representation of
the sub-unit that is returning
the status message. The
right-most bit position
represents sub-unit o. The
left-most bit position represents
sub-unit 3. Only one bit can be
set at a time. UDA50 subsystems
can handle only drives that can
contain up to two sub-units.
Therefore, the valid numbers in
this status byte can only be a
hexadecimal 1 or 2. Figure 2-4 *
shows the bit layout. For drives
that contain no sub-units (e.g.
the RA80), the right-most bit
position is always set indicating
sub-unit O.

Byte 3

High Unit Number - Byte 3
contains the upper four bits to a
12-bit (3 hexadecimal digits)
unit number.

Byte 4

OA - A logical one in this
position indicates the drive is
unavailable to the UDA50. A
logical zero indicates the drive
is available to the UDA50.

*See Figure 2-4 at the end of this table.

UDA50 FAULT ISOLATION

Table 2-4
Status
Byte

Bit Description of Status
Message Bytes (Cont)
Bit Description

Byte 4

RR - A logical one in this
position indicates that the drive
requires an internal
readjustment. Some drives do not
use this bit.

Byte 4

DR - A logical one in this
position indicates that there is
a request for a diagnostic to be
loaded in the dri ve
microprocessor memory. A logical
zero indicates that no diagnostic
is being requested of the host
system.

Byte 4

SR - A logical one in this
position indicates that the drive
spindle is up to speed. A
logical zero indicates the drive
spindle is not up to speed.

Byte 4

EL - A logical one in this bit
position indicates that there is
loggable information in the
extended status area (bytes
9-15). A logical zero indicates
that no information is available
in the extended status area.

UDA50 FAULT ISOLATION

Table 2-4
Status
Byte

Bit Description of Status
Message Bytes (Cont)

Bit Description

Byte 4

PS - A logical one in this bit
position indicates that the drive
port select switch for this
controller is pushed in
(selected). A logical zero
indicates that the switch is out.

Byte 4

RU - A logical one in this
position indicates that the
RUN/STOP switch is pushed in
(RUN). A logical zero indicates
the switch is out (STOP).

Byte 5

W4-Wl - Logical ones in any of
these four bit positions represent
the write-protect status for the
sub-unit represented. (e.g., a
0001 indicates that sub-unit 0
within the selected drive is
write-protected. )

Byte 5

DD - A logical one in this bit
position indicates that the drive
has been disabled by a controller
error routine or diagnostic. The
FA ULT light is on when this bit is
set. A logical 0 indicate~ that
the drive was enabled by a
controller error routine or
diagnostic.

UDA50 FAULT ISOLATION

Table 2-4
Status
Byte

Bit Description of Status
Message Bytes (Cont)
Bit Description

Byte 5

FO - A logical one in this
position indicates that the drive
can be formatted.

Byte 5

DB - A logical one in this
position indicates that the
diagnostic cylinders on the drive
can be accessed.

Byte 5

S7 - A logical one in this bit
position indicates that the 576
byte sector format is selected. A
logical zero indicates that the
512 byte sector format is
selected.

Byte 6

DE - A logical one in this
position indicates that a drive
error has occurred and the drive
FAULT lamp may be on.

Byte 6

RE - A logical one in this
position indicates that an error
occurred in the transmission of a
command between the drive and the
UDA50. The error could be a
checksum error or an incorrectly
formatted command string.

UDA50 FAULT ISOLATION

Table 2-4

Status
Byte

Bit Description of Status
Message Bytes (Cont)

Bit Description

Byte 6

PE - A logical one in this
position indicates that improper
command codes or parameters were
issued to the drive.

Byte 6

DF - A logical one in this
position indicates a failure in the
initialization routine of the
drive.

Byte 6

WE - A logical one in this
position indicates a write lock
error has occurred.

Byte 7

S4-S1 - This is a four-bit
representation of the sub-units
that have their attention
available messages suppressed in
the UDA50. The right-most bit
position represents sub-unit O.
The left-most bit position
represents sub-unit 3.

UDA50 FAULT ISOLATION

Table 2-4
Status
Byte

Bit Description of Status
Message Bytes (Cont)
Bit Description
If one of the bits is set, it

indicates that the controller is
not to interrupt the host CPU with
an attention available message
when the specified sub-unit raises
its available real-time drive
status line to the UDA50. The
S4-S 1 bits reflect the results of
a change controller flags command
in which attention-available
messages are not desired for
certain sub-units.
Byte 7

CI-C4 - This is a four-bit drive
status code i,ndicating various
states of drive operation. At the
present time only three codes are
valid. A code of 0000 = drive
normal operation. A code of 1000
= the drive is off-line due to
being under control of a
diagnostic. A code of 1001 = the
drive is off-line due to another
drive having the same unit
identifier (e.g. serial number,
drive type, class etc.).

UDA50 FAULT ISOLATION

Table 2-4
Status
Byte
Byte 8

Bit Description of Status
Message Bytes (Cont)
Bit Description
RETRY COUNT/FAILURE CODE
This 8-bit byte contains one of two
types of information depending
upon the status of the DF bit
(byte 6). The DF bit monitors the
drive initialization process. The
DF bit remains a zero if
initialization. is successful. In
this case, byte 8 contains the
retry count from the previous
operation, i.e., a seek operation
required fourteen retries to be
successful. If a get status
command is initiated, byte 8
cont~ins the number 14.
The DF bit being set indicates
that the drive initialization
failed, and therefore byte 8 now
contains a specific drive error
code. This error code can be
looked up in the appropriate drive
service manual.

UDA50 FAULT ISOLATION

Drive Sub-unit 0 Status

Hexadecimal 1

Drive Sub-unit 1 Status

Hexadecimal 2

DZ--05S8

Figure 2-4

Sub-unit Mask Bit Layout Examples

2.3.3.3 Status Message Interpretation - A printout of a
drive error was given in paragraph 2.3.3 sample 1. The last
line of this error printout gave a status message asfollows.
STATUS: 00101 11100 00100 OAIOO
BYTE:
15114 13112 11110 9 I 8

00100 06113 10120
71 6 51 4 31 2

Use Figure 2-5 to break down the status message byte
code. Then use the following byte descriptions to interpret
the above status message.
• Byte 1 is the get status response code and. is not
printed out.
• Byte 2 and the lower half of byte 3 comprise a 3
hexadecimal digit unit number. In the example, the
unit number is 020 .(hexadecimal)or 32 (decimal).
• Byte 3 (upper half) reflects the sub-unit mask and
informs us that the drive sending the status is subunit 0 (0001).
'. Byte 4 is the request byte and breaks down as follows.

UDA50 FAULT ISOLATION

Byte

Status: 00

0000

6
OA 00

00 00

06 13

Bytes 9 through 16 contain
specific status bits.
Consult appropriate drive diagnostic
maintenance guide for interpretation

RETRY COUNTIFAILURE CODE _ _ _ _ _---J

ERROR BYTE
(MSB OE-RE-PE-OF-WE-O-O-O LSB)
MODE BYTE
(MSB W4-W3-W2-Wl-0D-FO-OB-S7 LSB)
REQUEST BYTE
(MSS OA-RR-OR-SR-EL-O-PS-RU LSB)

8-BIT UNIT NUMBER - - - - - - - - - - -_ _ _ _ _ _ _ _ _---1

CZ-0559

Figure 2-5

Status Message Interpretation

HEX
BINARY

0001

0011

• The RU bit is set which informs us that the drive
has the RUN switch depressed.
• The PS bit is set which informs us that the port
select switch for the UDA requesting the status
is depressed. (The drive is available to the
UDA50).
• The SR bit is set indicating that the drive has
the spindle up to speed.

UDA50 FAULT ISOLATION

• The OA bit is not set indicating the drive is at a
drive available state.
• The RR bit is not set indicating the selected
drive needs no internal adjustment.
• The DR bit is not set, indicating the selected
drive has no request for an external diagnostic to
be loaded into it.
• Byte 5 is the mode byte and breaks down as follows.
HEX
BINARY

o
0000

6
0110

• The DB bit is set, indicating that a diagnostic
cylinder is being accessed on the drive.
• The FO bit is set, indicating that the drive can
be formatted.
• No bits set in the W4-WI field indicate that no
sub-unit is write-protected.
• The DD bit is not set, indicating the drive has
not been disabled by the UDA50 due to some error or diagnostic routine.
• The S7 bit is not set, indicating that 512
byte/sector format is selected for the drive.
• Byte 6 is the error byte, and for this example none
of the errors described earlier in this text are active
(DE-RE-PE-DF-WE).
• Byte 7 is the controller byte, and for this example a
normal drive status is observed (CI-C4 = zeros).
The S4-S1 bits being cleared indicate that the
UDA50 is to interrupt the host CPU whenever any
drive on the subsystem raises its available line to
the UDA50.

UDA50 FAULT ISOLATION

• Byte 8 is the retry count/failure code and for this
example, no retries by the diagnostic were attempted.