National Instruments GPIB-SCSI-A User manual

© Copyright 1991, 1994 National Instruments Corporation.
All Rights Reserved.
GPIB-SCSI-A
User Manual
SCSI-to-IEEE 488 Controller
July 1994 Edition
Part Number 320427-01

National Instruments Corporate Headquarters
6504 Bridge Point Parkway
Austin, TX 78730-5039
[phone]
Technical support fax: [phone]
[phone]
Branch Offices:
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Germany 089/741 31 30, Italy 02/48301892, Japan [phone],
Netherlands 03480-33466, Norway 32-848400, Spain (91) 640 0085,
Sweden 08-730 49 70, Switzerland 056/20 51 51, U.K. 0635 523545

Limited Warranty
The GPIB-SCSI-A is warranted against defects in materials and
workmanship for a period of two years from the date of shipment, as
evidenced by receipts or other documentation. National Instruments will, at
its option, repair or replace equipment that proves to be defective during the
warranty period. This warranty includes parts and labor.
A Return Material Authorization (RMA) number must be obtained from the
factory and clearly marked on the outside of the package before any
equipment will be accepted for warranty work. National Instruments will
pay the shipping costs of returning to the owner parts which are covered by
warranty.
National Instruments believes that the information in this manual is
accurate. The document has been carefully reviewed for technical accuracy.
In the event that technical or typographical errors exist, National
Instruments reserves the right to make changes to subsequent editions of
this document without prior notice to holders of this edition. The reader
should consult National Instruments if errors are suspected. In no event
shall National Instruments be liable for any damages arising out of or
related to this document or the information contained in it.
EXCEPT AS SPECIFIED HEREIN, NATIONAL INSTRUMENTS MAKES NO
WARRANTIES, EXPRESS OR IMPLIED, AND SPECIFICALLY DISCLAIMS
ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE. CUSTOMER'S RIGHT TO RECOVER DAMAGES
CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL
INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE
PAID BY THE CUSTOMER. NATIONAL INSTRUMENTS WILL NOT BE
LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA, PROFITS,
USE OF PRODUCTS, OR INCIDENTAL OR CONSEQUENTIAL DAMAGES,
EVEN IF ADVISED OF THE POSSIBILITY THEREOF. This limitation of the
liability of National Instruments will apply regardless of the form of action,
whether in contract or tort, including negligence. Any action against
National Instruments must be brought within one year after the cause of
action accrues. National Instruments shall not be liable for any delay in
performance due to causes beyond its reasonable control. The warranty
provided herein does not cover damages, defects, malfunctions, or service
failures caused by owner's failure to follow the National Instruments
installation, operation, or maintenance instructions; owner's modification of
the product; owner's abuse, misuse, or negligent acts; and power failure or
surges, fire, flood, accident, actions of third parties, or other events outside
reasonable control.

Copyright
Under the copyright laws, this publication may not be reproduced or
transmitted in any form, electronic or mechanical, including photocopying,
recording, storing in an information retrieval system, or translating, in
whole or in part, without the prior written consent of National Instruments
Corporation.
Trademarks
NI-488® is a trademark of National Instruments Corporation.
Product and company names listed are trademarks or trade names of their
respective companies.
Warning Regarding Medical and Clinical Use
of National Instruments Products
National Instruments products are not designed with components and testing
intended to ensure a level of reliability suitable for use in treatment and
diagnosis of humans. Applications of National Instruments products
involving medical or clinical treatment can create a potential for accidental
injury caused by product failure, or by errors on the part of the user or
application designer. Any use or application of National Instruments
products for or involving medical or clinical treatment must be performed by
properly trained and qualified medical personnel, and all traditional medical
safeguards, equipment, and procedures that are appropriate in the particular
situation to prevent serious injury or death should always continue to be
used when National Instruments products are being used. National
Instruments products are NOT intended to be a substitute for any form of
established process, procedure, or equipment used to monitor or safeguard
human health and safety in medical or clinical treatment.

FCC/DOC Radio Frequency
Interference Compliance
This equipment generates and uses radio frequency energy and, if not
installed and used in strict accordance with the instructions in this manual,
may cause interference to radio and television reception. This equipment
has been tested and found to comply with the following two regulatory
agencies:
Federal Communications Commission
This device complies with Part 15 of the Federal Communications
Commission (FCC) Rules for a Class A digital device. Operation is subject
to the following two conditions:
1. This device may not cause harmful interference in commercial
environments.
2. This device must accept any interference received, including
interference that may cause undesired operation.
Canadian Department of Communications
This device complies with the limits for radio noise emissions from digital
apparatus set out in the Radio Interference Regulations of the Canadian
Department of Communications (DOC).
Le présent appareil numérique n’émet pas de bruits radioélectriques
dépassant les limites applicables aux appareils numériques de classe A
prescrites dans le règlement sur le brouillage radioélectrique édicté par le
ministère des communications du Canada.
Instructions to Users
These regulations are designed to provide reasonable protection against
harmful interference from the equipment to radio reception in commercial
areas. Operation of this equipment in a residential area is likely to cause
harmful interference, in which case the user will be required to correct the
interference at his own expense.

There is no guarantee that interference will not occur in a particular
installation. However, the chances of interference are much less if the
equipment is installed and used according to this instruction manual.
If the equipment does cause interference to radio or television reception,
which can be determined by turning the equipment on and off, one or more
of the following suggestions may reduce or eliminate the problem.
• Operate the equipment and the receiver on different branches of your
AC electrical system.
• Move the equipment away from the receiver with which it is interfering.
• Reorient or relocate the receiver’s antenna.
• Be sure that the equipment is plugged into a grounded outlet and that
the grounding has not been defeated with a cheater plug.
Notice to user: Changes or modifications not expressly approved by
National Instruments could void the user’s authority to
operate the equipment under the FCC Rules.
If necessary, consult National Instruments or an experienced radio/television
technician for additional suggestions. The following booklet prepared by
the FCC may also be helpful: How to Identify and Resolve Radio-TV
Interference Problems. This booklet is available from the U.S. Government
Printing Office, Washington, DC 20402, Stock Number 004-000-00345-4.

© National Instruments Corp. vii GPIB-SCSI-A User Manual
Contents
About This Manual ..........................................................................xvii
Organization of This Manual......................................................xvii
Conventions Used in This Manual.............................................xix
Related Documentation ..............................................................xix
Customer Communication..........................................................xix
Chapter 1
Description of the GPIB-SCSI-A................................................1-1
What You Need to Get Started...................................................1-2
Optional Equipment....................................................................1-3
Inspection ...................................................................................1-4
GPIB-SCSI-A Specifications .....................................................1-4
The GPIB-SCSI-A Front Panel ..................................................1-7
The GPIB-SCSI-A Rear Panel ...................................................1-8
The SCSI Port.............................................................................1-9
The GPIB Port ............................................................................1-10
Choosing Between S Mode and G Mode...................................1-10
Chapter 2
Installation and Configuration of the GPIB-SCSI-A.........2-1
Installation ..................................................................................2-1
Step 1. Verify the Voltage Requirement....................2-1
Step 2. Configure the Operating Characteristics .......2-2
Configuration Switch Settings for SW1 ........2-2
Configuration Switch Settings for SW2
in S Mode.......................................................2-5
Configuration Switch Settings for SW2
in G Mode......................................................2-7
SCSI Terminating Resistors...........................2-8
Step 3. Connect the Cables ........................................2-10
Step 4. Switch On Your GPIB-SCSI-A and
Power on Your System ..................................2-11
Chapter 3
Technical Information ....................................................................3-1
Assumption of Previous Knowledge..........................................3-1
Buffering Methods......................................................................3-1

Contents
GPIB-SCSI-A User Manual viii © National Instruments Corp.
S Mode Operation.......................................................................3-2
Configuration Switches at SW2...................................3-3
Switch 7.........................................................3-3
Switch 6.........................................................3-4
Switch 5.........................................................3-4
Switch 4.........................................................3-5
Switches 1 Through 3 ....................................3-5
G Mode Operation......................................................................3-6
Configuration Switches at SW2...................................3-6
Switch 7.........................................................3-6
Switch 6.........................................................3-7
Switch 5.........................................................3-8
Switch 4.........................................................3-9
Switches 1 Through 3 ....................................3-9
Chapter 4
Programming in S Mode................................................................4-1
Programming Messages..............................................................4-1
Programming Message Format ....................................4-1
Function Names and Opcodes....................................................4-2
GPIB Address...............................................................4-2
Status Information ......................................................................4-3
GPIB Read and Write Termination Method (END and EOS) ...4-3
The SCSI Message System and the GPIB-SCSI-A in S Mode ..4-4
S Mode Error Indication.............................................................4-4
Disconnection/Reconnection......................................................4-5
Disconnection/Reconnection during Data Transfers ...4-5
Disconnection/Reconnection while Waiting for
GPIB Events.................................................................4-8
S Mode Default Settings.............................................................4-10
S Mode Functions.......................................................................4-11
GPIB Function Group ..................................................4-11
SCSI Function Group...................................................4-14
General Use Function Group .......................................4-14
Alphabetical List of S Mode Functions......................................4-15
Chapter 5
S Mode Functions .............................................................................5-1
Points to Remember ...................................................................5-1
Understanding the Examples......................................................5-2
S Mode Function Descriptions...................................................5-4
brd - Board Level Read Data ................................................5-5
bwrt - Board Level Write Data...............................................5-10

Contents
© National Instruments Corp. ix GPIB-SCSI-A User Manual
cac - Become Active Controller ...........................................5-15
caddr - Change the GPIB Address of the GPIB-SCSI-A.........5-17
clr - Clear Specified Device*...............................................5-20
cmd - Send GPIB Commands.................................................5-23
config - Read/Change GPIB-SCSI-A Configuration.................5-26
eos - Change/Disable GPIB EOS Termination Mode ..........5-30
eot - Enable/Disable END Message on GPIB Writes ..........5-34
gts - Go from Active Controller to Standby.........................5-36
id - Identify System ............................................................5-39
inq - Inquiry..........................................................................5-41
ist - Set or Clear Individual Status Bit.................................5-45
lines - Return the State of the Eight GPIB Control Lines.......5-47
ln - Check for the Presence of a Listening Device
on the Bus.....................................................................5-49
loc - Go to Local *................................................................5-51
onl - Place the GPIB-SCSI-A Online/Offline.......................5-54
pct - Pass Control .................................................................5-56
ppc - Parallel Poll Configure.................................................5-58
ppu - Parallel Poll Unconfigure.............................................5-62
rd - Read Data *..................................................................5-64
rpp - Request (Conduct) a Parallel Poll ................................5-70
rqsns - Request Sense...............................................................5-72
rsc - Request/Release System Control .................................5-76
rsp - Request (Conduct) a Serial Poll...................................5-79
rsv - Request Service/Set or Change Serial Poll
Status Byte ...................................................................5-82
sic - Send Interface Clear.....................................................5-84
sre - Set/Clear Remote Enable .............................................5-86
stat - Return GPIB-SCSI-A Status........................................5-89
tmo - Change or Disable Time Limit.....................................5-98
trg - Trigger Specified Device * ..........................................5-102
wait - Wait for Selected Event ...............................................5-105
wrt - Write Data *.................................................................5-110
Chapter 6
Programming in G Mode...............................................................6-1
Programming Messages..............................................................6-1
Programming Message Format ....................................6-1
Example of a Programming Message............6-1
How Messages are Processed.......................................6-3
Function Names..........................................................................6-3
Function Argument Delimiters...................................................6-3
Numerical Input and Output.........................................6-4

Contents
GPIB-SCSI-A User Manual x © National Instruments Corp.
Status and Error Information......................................................6-4
Communicating with the GPIB-SCSI-A and SCSI
Peripherals ..................................................................................6-5
Addressing Terminology..............................................6-5
The GPIB-SCSI-A and SCSI System as Listener.......................6-5
The GPIB-SCSI-A and SCSI System as Talker.........................6-7
GPIB Read and Write Termination (END and EOS).................6-8
SCSI Data Transmission.............................................................6-9
The SCSI Message System and the GPIB-SCSI-A....................6-9
Handling of SCSI Phases in G Mode.........................................6-9
Commands That Do Not Require a Data Phase...........6-10
Commands That Require a Data In Phase....................6-10
Commands That Require a Data Out Phase.................6-11
Disconnection/Reconnection .......................................6-11
G Mode Default Settings............................................................6-12
G Mode Functions ......................................................................6-12
SCSI Function Group...................................................6-13
SCSI Configuration Function Group ...........................6-17
GPIB Configuration Function Group...........................6-18
General Use Function Group .......................................6-18
List of G Mode Functions in Alphabetical Order.......................6-19
Operation of the GPIB-SCSI-A as a GPIB Device ....................6-23
Serial Poll.....................................................................6-24
SCSI Bits .......................................................6-24
DCR Bit.........................................................6-24
RDY Bit.........................................................6-25
ERR Bit..........................................................6-25
SRQ* Bit........................................................6-25
Parallel Poll ..................................................................6-26
Group Execute Trigger (GET).....................................6-26
Go To Local (GTL)......................................................6-26
Take Control (TCT) .....................................................6-26
Device Clear.................................................................6-26
Chapter 7
G Mode Functions.............................................................................7-1
Points to Remember ...................................................................7-1
Points to Remember in the Function Examples .........................7-2
G Mode Function Descriptions...................................................7-3
autotst - Enable/Disable Automatic Testing of SCSI Targets..7-4
blksz - Set Blocksize ..............................................................7-7
cmd - Build SCSI Command Descriptor Block and
Execute SCSI Command Phase..................................7-9

Contents
© National Instruments Corp. xi GPIB-SCSI-A User Manual
cmp - Complete the SCSI Command Sequence By
Processing the Status and Message In Phases ............7-11
config - Read/Change GPIB-SCSI-A Configuration...............7-13
dtin - Transfer Data In Information from Selected
SCSI Target ................................................................7-16
dtout - Transfer Data Out Information to Selected
SCSI Target ................................................................7-21
format - Format Unit.................................................................7-26
getscsi - Arbitrate for the SCSI Bus .........................................7-28
hcmd - Execute a High-Level SCSI Command......................7-29
id - Identify System...........................................................7-32
inquiry - Inquiry.........................................................................7-33
lun - Set Logical Unit Number............................................7-35
mdsct - Mode Select................................................................7-37
mdsns - Mode Sense.................................................................7-39
msgin - Transfer Message Bytes from the Target to the
GPIB-SCSI-A.............................................................7-41
msgout - Transfer Message Bytes from the GPIB-SCSI-A
to the SCSI Target ......................................................7-43
pad - Set Pad Byte ...............................................................7-45
rblks - Reassign Blocks..........................................................7-47
rcdia - Receive Diagnostic Results ........................................7-49
rcnct - Reconnect the GPIB-SCSI-A to the SCSI..................7-52
rdbuf - Read Buffer.................................................................7-58
rdcap - Read Capacity.............................................................7-61
rdext - Read Extended............................................................7-63
rdfct - Read Defect Data........................................................7-67
read - Read............................................................................7-70
rewind - Rewind........................................................................7-74
rlseu - Release Logical Unit...................................................7-76
rqsns - Request Sense.............................................................7-78
rsrvu - Reserve Logical Unit..................................................7-80
rst - Reset SCSI Bus...........................................................7-82
selwa - Select a SCSI Target With SCSI ATN* Asserted ......7-83
selwo - Select a SCSI Target Without SCSI ATN*
Asserted ......................................................................7-85
sndia - Send Diagnostic..........................................................7-86
space - Space...........................................................................7-89
srqen - Enable/Disable Setting of SRQ ..................................7-91
stat - Return GPIB-SCSI-A Status.......................................7-94
tid - Set SCSI Id of Target Device.....................................7-101
tstur - Test Unit Ready..........................................................7-103
vcb - Set Vendor Unique Control Byte Bits ........................7-105
wfmks - Write Filemarks..........................................................7-107

Contents
GPIB-SCSI-A User Manual xii © National Instruments Corp.
wrext - Write Extended...........................................................7-109
write - Write...........................................................................7-113
wrtbuf - Write Buffer................................................................7-117
Appendix A
Multiline Interface Messages.......................................................A-1
Appendix B
Status and Message Information................................................B-1
Status Bits...................................................................................B-1
S Mode.........................................................................B-1
G Mode.........................................................................B-5
GPIB Error Codes.......................................................................B-7
SCSI Error Codes.......................................................................B-10
Status Bytes ................................................................................B-12
Message Bytes............................................................................B-13
Sense Keys..................................................................................B-16
Appendix C
Operation of the GPIB....................................................................C-1
Types of Messages .....................................................................C-1
Talkers, Listeners, and Controllers.............................................C-1
The Controller-In-Charge and System Controller......................C-2
GPIB Signals and Lines..............................................................C-3
Data Lines ....................................................................C-3
Handshake Lines ..........................................................C-3
NRFD* (not ready for data)...........................C-3
NDAC* (not data accepted)...........................C-4
DAV* (data valid) .........................................C-4
Interface Management Lines........................................C-4
ATN* (attention) ...........................................C-4
IFC* (interface clear).....................................C-4
REN* (remote enable)...................................C-4
SRQ* (service request)..................................C-4
EOI* (end or identify) ...................................C-5
Physical and Electrical Characteristics.......................................C-5
Configuration Requirements.......................................................C-9
Related Documentation ..............................................................C-9

Contents
© National Instruments Corp. xiii GPIB-SCSI-A User Manual
Appendix D
Operation of the SCSI.....................................................................D-1
History of the SCSI.....................................................................D-1
Operation of the SCSI.................................................................D-1
Communication on the SCSI......................................................D-5
SCSI Signals...............................................................................D-6
Data Bus Signals ..........................................................D-8
Control Signals.............................................................D-9
Handshake Lines............................................D-9
Phase Control Lines.......................................D-9
Miscellaneous Control Lines.........................D-9
The TERMPWR Pin.....................................................D-10
Physical and Electrical Characteristics.......................................D-11
Configuration Restrictions..........................................................D-11
Appendix E
Parallel Polling...................................................................................E-1
Operation ....................................................................................E-1
Configuration..............................................................................E-1
Issuing Remote Configurations in S Mode.................................E-3
Issuing Local Configurations in S Mode....................................E-4
The Parallel Poll.........................................................................E-5
S Mode Example.........................................................................E-5
Appendix F
Customer Communication............................................................F-1
Glossary.................................................................................................G-1
Index................................................................................................. Index-1

Contents
GPIB-SCSI-A User Manual xiv © National Instruments Corp.
Figures
Figure 1-1. GPIB-SCSI-A........................................................................1-1
Figure 1-2. The GPIB-SCSI-A Rear Panel..............................................1-8
Figure 1-3. The SCSI Connector and Signal Designations......................1-9
Figure 1-4. The GPIB Connector and Signal Assignments.....................1-10
Figure 1-5. SCSI Computer Controlling GPIB Devices..........................1-11
Figure 1-6. A SCSI Bus Connected to a GPIB Controller.......................1-12
Figure 2-1. SW1 Default Mode Switch Settings .....................................2-2
Figure 2-2. SW2 Default Switch Settings................................................2-5
Figure 2-3. SW2 Sample Setting for G Mode..........................................2-7
Figure 2-4. GPIB-SCSI-A Physically Located at End of SCSI Bus........2-9
Figure 2-5. GPIB-SCSI-A Not Physically Located at End of
SCSI Bus...............................................................................2-10
Figure 4-1. Command Descriptor Block Example...................................4-2
Figure 6-1. Serial Poll Status Byte...........................................................6-24
Figure 7-1. Valid Bits of mask.................................................................7-13
Figure C-1. The GPIB Connector and Signal Assignments.....................C-6
Figure C-2. Linear Configuration ............................................................C-7
Figure C-3. Star Configuration ................................................................C-8
Figure D-1. Standard 50-Pin SCSI Connector.........................................D-7
Figure D-2. Daisy-Chain Configuration of the SCSI Bus .......................D-11
Tables
Table 1-1. Electrical Characteristics........................................................1-4
Table 1-2. Environmental Characteristics................................................1-5
Table 1-3. Physical Characteristics..........................................................1-5
Table 1-4. Maximum Transfer Rates.......................................................1-6
Table 1-5. LED Descriptions...................................................................1-7
Table 2-1. Configuration Parameters for Switches 1 through 3...............2-3
Table 2-2. Configuration Parameters for Switches 4 through 8...............2-4
Table 2-3. Possible Configurations for SW2 in S Mode .........................2-6
Table 2-4. Possible Configurations for SW2 in G Mode.........................2-8

Contents
© National Instruments Corp. xv GPIB-SCSI-A User Manual
Table 4-1. GPIB Characteristics ..............................................................4-10
Table 4-2. GPIB Function Group.............................................................4-11
Table 4-3. SCSI Functions.......................................................................4-14
Table 4-4. General Use Functions ...........................................................4-14
Table 4-5. GPIB-SCSI-A S Mode Functions...........................................4-15
Table 5-1. Buffering Methods for Data Transfer Commands..................5-27
Table 5-2. Data Transfer Termination Methods ......................................5-31
Table 5-3. Inquiry Data Format for the GPIB-SCSI-A............................5-42
Table 5-4. Sense Data Format for the GPIB-SCSI-A..............................5-73
Table 5-5. GPIB-SCSI-A Sense Keys .....................................................5-74
Table 5-6. GPIB-SCSI-A Status Conditions............................................5-92
Table 5-7. GPIB Error Conditions...........................................................5-93
Table 5-8. SCSI Error Conditions............................................................5-94
Table 5-9. Timeout Limit Values.............................................................5-98
Table 5-10. Wait Mask Values ................................................................5-106
Table 6-1. SCSI Functions.......................................................................6-13
Table 6-2. SCSI Configuration Functions ...............................................6-17
Table 6-3. GPIB Configuration Function ................................................6-18
Table 6-4. General Use Functions ...........................................................6-18
Table 6-5. GPIB-SCSI-A G Mode Functions..........................................6-19
Table 7-1. Buffering Methods for High-Level Commands. ....................7-14
Table 7-2. SRQ Mask Bits.......................................................................7-91
Table 7-3. GPIB-SCSI-A Status Conditions............................................7-95
Table 7-4. GPIB Error Conditions...........................................................7-97
Table 7-5. SCSI Error Conditions............................................................7-98
Table D-1. Data Bus Signals....................................................................D-8
Table E-1. Parallel Poll Message Bits......................................................E-3

© National Instruments Corp. xvii GPIB-SCSI-A User Manual
About This Manual
This manual describes the function of the GPIB-SCSI-A and contains
information concerning its operation and programming.
The GPIB-SCSI-A is one of the National Instruments family of IEEE 488
support products. These products are small, high-performance, converters,
and controllers packaged in all-metal cases.
Organization of This Manual
This manual is organized as follows:
• Chapter 1, Description of the GPIB-SCSI-A, contains general
information about the National Instruments GPIB-SCSI-A, the
IEEE 488 port, and the SCSI port. This chapter also lists all the
components and accessories as well as electrical, environmental, and
physical specifications of the GPIB-SCSI-A, and explains the two
modes of operation for the GPIB-SCSI-A.
• Chapter 2, Installation and Configuration of the GPIB-SCSI-A,
contains the steps for installing and configuring the GPIB-SCSI-A in S
mode and G mode.
• Chapter 3, Technical Information, contains detailed information for
advanced users who want to increase the power of the GPIB-SCSI-A.
• Chapter 4, Programming in S Mode, explains how to program the
GPIB-SCSI-A when operating in S mode. In this mode, the
GPIB-SCSI-A can be programmed from any operating system and
language that has access to a SCSI port. This chapter describes
programming messages, their format, and how they are processed,
along with the functions and function arguments that make up the
programming messages.
• Chapter 5, S Mode Functions, contains a detailed description of each
S mode function. These functions are in alphabetical order for easy
reference.

About This Manual
GPIB-SCSI-A User Manual xviii © National Instruments Corp.
• Chapter 6, Programming in G Mode, explains how to program the
GPIB-SCSI-A when operating in G mode. It describes programming
messages, their format, and how they are processed, along with the
functions and function arguments that make up the programming
messages. This chapter also explains how to communicate with your
SCSI device(s) through the GPIB-SCSI-A.
• Chapter 7, G Mode Functions, contains a detailed description of each G
mode function. The functions are in alphabetical order for easy
reference and each function contains its syntax and purpose, as well as
some examples.
• Appendix A, Multiline Interface Messages, contains an interface
message reference list, which describes the mnemonics and messages
that correspond to the interface functions.
• Appendix B, Status and Message Information, describes the status and
error information that the GPIB-SCSI-A records as it executes each
programming message. Also described are the SCSI message bytes
that the GPIB-SCSI-A responds to or generates while operating, as well
as the Extended Sense keys that the GPIB-SCSI-A uses.
• Appendix C, Operation of the GPIB, describes the operation of the
GPIB.
• Appendix D, Operation of the SCSI, describes the operation of the
SCSI.
• Appendix E, Parallel Polling, explains the use and operation of parallel
polls.
• Appendix F, Customer Communication, contains forms you can use to
request help from National Instruments or to comment on our products
and manuals.
• The Glossary contains an alphabetical list and description of terms used
in this manual including abbreviations, acronyms, metric prefixes,
mnemonics, and symbols.
• The Index contains an alphabetical list of key terms and topics used in
this manual, including the page where each can be found.

About This Manual
© National Instruments Corp. xix GPIB-SCSI-A User Manual
Conventions Used in This Manual
The following conventions are used in this manual:
italic Italic text denotes emphasis, a cross reference, or
an introduction to a key concept.
monospace Lowercase text in this font denotes text or
characters that are to be literally input from the
keyboard, sections of code, programming
examples, and syntax examples. This font is also
used for the proper names of disk drives, paths,
directories, programs, subprograms, subroutines,
device names, functions, variables, filenames,
and extensions, and for statements and comments
taken from program code.
IEEE 488 and IEEE 488 and IEEE 488.2 are used throughout
IEEE 488.2 this manual to refer to the ANSI/IEEE Standard
488.1-1987 and the ANSI/IEEE Standard 488.2-1987,
respectively, which define the GPIB.
Related Documentation
The following documents contain information that you may find helpful as
you read this manual:
• ANSI X3.131-1986, small computer system interface (SCSI).
• ANSI/IEEE Standard 488.1-1987, IEEE Standard Digital Interface for
Programmable Instrumentation.
• ANSI/IEEE Standard 488.2-1987, IEEE Standard Codes, Formats, Protocols,
and Common Commands

About This Manual
GPIB-SCSI-A User Manual xx © National Instruments Corp.
Customer Communication
National Instruments wants to receive your comments on our products and
manuals. We are interested in the applications you develop with our
products, and we want to help if you have problems with them. To make it
easy for you to contact us, this manual contains comment and configuration
forms for you to complete. These forms are in Appendix F, Customer
Communication, at the end of this manual.