PS/2 FAQ, Section 1

S) 1.0 Introduction 

These pages are based on Chris Feeny's FAQ version 5.5.

  The previous guardians of the Holy Grail were Lewis Getschel (original creator), then revised by Carl Benker ( and Gerry Morgan (, with a further updating by David Smudski ( PC Helpcenter) and Jeff Holleman (PCCBBS). I'd like to thank Chris Feeny ( for the ressurection of the PS/2 FAQ. 

   If you think the PS/2 was odd or rare, think again. The PS/2 experience covered a mere ten or so years. In Tom Watson's IBM, they sold  17,000,000 machines, 13,000,000 of them Micro Channel.  The PS/2 division was IBM's biggest money maker for three years running in the early 90s, and  IBM said then that PS/2 was the most popular model of computer in the world. (Thanks, Joe!) 

   Many people do not understand the reason for a PS/2. IBM built them to run 24/7. They sold reliability. Those annoying extensive self tests and the cryptic error codes all support that goal. Why power up a server if the POST misses a (at the time) non-fatal error that a few hours later brings down a major corporation's network? 
   Eventually, I hope to restore more of these Ardent Tools of Captitalism to gainful employment through a better public understanding of the machine. 

Q) 1.1  What does this FAQ cover and how do I use this FAQ?

This FAQ is for the PS/2's and most other MCA machines.  There may be some information that is inaccurate for non-IBM machines and this information should be gathered from the appropriate manufacturer. If there are deficiencies, errors, and/or missing information you would like to see email me at: 

Q) 1.2  What are the different PS/2s and their features?

Note: A very good reference can be found HERE (ZIP) (#25,30,50,55,60,70,73,80).

ModelModelCPUWaitL2Bus Type# of Slots# of BaysItr. Date
57 Ult.9557-1BA/2BA486SLC2-50MCA
77 0Ux9577-0UF/UA486SX-330MCA325410/92
77 0Nx9577-0NA/0NF486DX2-660MCA325410/92
77 Ult.9577-1UA/1NA486DX2-660MCA325410/92
90 XP 4868590-0G5/H5/+486SX-20/250MCA324410/90
90 XP 4868590-OPTION486DX-330MCA324410/90
90 XP 4869590-DLA/LG/+486DX2-500MCA324403/93
95 XP 4868595-0G9/F486SX-200MCA328710/90
95 XP 4868595-0H9/F486SX-250MCA328710/90
95 XP 4868595-0J9/D/F486DX-250MCA328710/90
95 XP 4868595-0KD/F486DX-33256*MCA328710/90
95 XP 4868595-0LF486DX2-500MCA328710/90
95 XP 4868595-0MG/T486DX-50256MCA328710/90
95 XP 4869595-0LF/G486DX2-500MCA328710/92
95 XP 4869595-0MF/G/T486DX-50256MCA328706/91
95 Server9595-1NG/T/V486DX2-66128MCA328708/92
95 Server9595-0PT/V/0PTFP-60256MCA328708/93
95 Server9595-0QG/V/+P-66256MCA328709/93
95 Array9595-3NG/T486DX2-66128MCA328908/92
95 Array9595-3PG/TP-60256MCA328908/93
95 Array9595-3QG/TP-66256MCA328909/93

* Optional L2 Cache module

The -xxx suffix can usually be broken down to -ABC where:

A - number of hard drives usually
B - processor type
C - hard drive type

Fourth letter is county/language identifier (F=Canadian French)

More info about model numbers HERE.
More info about CPU type encoding HERE.

85xx models are XGA or VGA, 95xx models are XGA-2 or SVGA.
LS models are usually identical to the SX counterparts but are diskless.

Q) 1.2a  What are the Processor Complexes and their features?


Q) 1.3  What are the IBM brand MCA cards?

These are usually denoted with a /A suffix.  Here is a list of what is current. 

See Appendix A for full list. 

Q) 1.4  Where do I get a Reference Disk for my PS/2?
[Rewrite by Aron Eisenpress <>] 

Reference Disks used to be available from two IBM sources, via ftp to or by dialing the IBM PC Co. BBS at 1-919-517-0001.

Neither of the two is available anymore, use THIS page instead.

After the files are obtained: 

For .EXE files: 
o Put a blank, formatted 1.44MB floppy in A: (old systems like 8525 may need 
720K) then run the self creating disk image file (ex rf90954a.exe). 

Do NOT use "DIR" under W95 to look at the newly created reference disk. This overwrites the special bytes needed to access the system partition. I have created MANY refisks with NT and W95 using Win Exploiter, er, Explorer. They all worked. You can look at them with File Eplorer all day long. Just do NOT go to MS-DOS mode and do a "DIR". 

For .DSK files: 
o Run LDF.COM so that the files LOADDSKF.EXE and PRODAID.TXT are extracted.  LOADDSKF.EXE is what you need, PRODAID.TXT is the IBM agreement. 
o Insert a blank disk and type LOADDSKF filename.DSK A: (or B:) [/F to format 
  and /C to convert a 720KB image to a 1.44MB disk.]
o Ensure the proper disk is inserted and answer: "Y".
o Your reference disk is ready to go.

For .TG0 files: 
o Run TGSFX.COM so that the files TELEGET.EXE and TGCONFIG.EXE are extracted. 
o Run TGCONFIG and follow the prompts. 

Also check

Also QBMCA utility can tell you what ADF you need.

Q) 1.4a Where can I get a Reference Disk for my non-IBM MCA System?

Apricot (now Mitsubishi) is HERE
Tandy 5000 (250-6000/1/2) is HERE
Olivetti is HERE

Q) 1.5  Which file is my Reference Disk?  They are all cryptically written.

See Appendix B. 

Q) 1.6  What does the Reference Disk do?

The Reference Disk is your access to the internals of the PS/2, much like accessing CMOS on other computers.  From the Reference Disk you can add options, change the time and date, set up a configuration, check SCSI device, change the settings of the options you added and test your system for problems.  Once you have the Reference Disk running go to the Main Menu and 
Backup the Reference Disk and take one copy BEFORE you add options to it and put it in a safe place. 

Q) 1.7  How can I run the Advanced Diagnostics?

This little known command allows one to test the system one test at a time. This is useful if the system hangs or gets an error early in the full-test. To access the Advanced Diagnostics press <CTRL>-A from the Reference Disk Main Menu and it will allow you to select which test to perform after verifying the present configuration.  Also these are more through tests and also offer hard drive formatting options and some wrap plug port tests (see Q6.6 for details). 

Q) 1.8  Why can't I copy my Reference Disk, I want to make a backup?

You can by selecting the option to backup the Reference Disk from the Reference Disk Main Menu.  The files are written in a special way to the diskand only the Reference Disk and LOADDSKF can create new/backup Reference Disks unless a total disk copy program is used to copy the hidden files, DISKCOPY works. 

Q) 1.9  I need an Option Diskette.What are they and Where do I get them?

Option Diskettes are the .ADF files that allow the PS/2 to communicate properly with installed options and the 165 error code is also saying that the proper .ADF file was not used to configure the system.  The BBS and both have all the IBM option diskettes and some common third party ones.  A file index of all the files on the ftp site can be obtained by getting the FILES.TXT file which has 100k of disk name and descriptions of every disk IBM included with option, computers, and devices as well as some third party software.  When you get the right one go to Copy an Option Diskette in the Reference Disk Main Menu and it should do the work for you. Now just configure the system and you should be set. 

Q) 1.10  I got the Option Diskette, but the Reference Diskette is telling me no option files can be found, What am I doing wrong?

Nothing usually.  Sometimes the Reference Disk can not copy the proper files, so look in the manual for the device and see what file(s) must be copied manually over to the Reference Disk.  As always use a backup copy of the Ref  Disk. 

Q) 1.10a  I copied the option's ADF to the refdisk, but Setup cannot find it!

You must use "Copy an Option Diskette" under Setup to correctly copy a new or updated ADF to the Reference Disk or to the System Partition. 

Q) 1.11  I bought my PS/2 second hand who can I get technical support from?

IBM.  The 800-772-2227 (1-800-PS2-2227) is open 24 hours a day for warrantied systems; however; there is no PS/2 models still under warranty so you will have to use the 1-900-555-2582 number.  They bill at $1.99 per minute the last time I called (10/27/98).  Usually the staff is dead accurate and only rarely is misinformation handed out.  However, the chances of misinformation is greatly increased when calling during non-standard EST business hours as I 
have experienced at 3am calls from the East Coast. 

It seems lately I have been getting emails for people who have called the 900 number, but could not get there questions answered.  This is not to fault IBM, it simply is not practical to train your people on every machine released, but do I get to collect the 900 charges you the questions I answer? :). 

Q) 1.12  IBM tech. support says they do not know my answer now what?

Well if they didn't connect you to the premium support section ask to be connected there.  The Premium (I think that is what they call it) support techs are usually a lot more adept at in-depth tech help, but sometimes the normal tech does not connect you to them when you have a more advanced problem so ask for them if you feel the person helping you is lost (usually symbolized by a lot of being put on hold 'while I find out the answer' type responses).  Also it is a good idea to always call back later to double check on things that you are not totally comfortable with the given answer. Since these calls are no longer free it may not be practical to call back.   Also I am not sure the still have normal and Premium support since the phone  support has changed to the 900 number system, but of course, you can always  email me. 

Q) 1.13  Where can I find support on the internet?

All official support channels are long gone.
See the External Links page for a list of alternative online sources.

Q) 1.14 I got an IBM MCA card with no labeling, How do I tell what it is?

This is a big problem with IBM cards. Most card manufacturers get label crazy silk-screening their name and the card's name all over the card's PCB, yet IBM being the marketing giant doesn't need the extra production step and goes with bare PCBs.

The first thing to do is to ground yourself (by touching the power supply of a turned OFF computer is a good way) and try to set the card on an anti-static surface and try not to move around to much because one static charge to a key area and it won't matter what the card is for. Then try and find out what IBM part numbers (IBMPN) and FRU (Field Replacement Unit)(IBMFRU) are listed on the front and back of the card. Contrary to popular belief you cannot tell what the card does by these numbers as a class, i.e. not all 87Xxxxx cards are disk controllers and made in 1987. When you are done, place the card in a anti-static bag and store it carefully. With all the numbers written down, you are ready to post your problem to for answers. Try to render an ASCII image of the card to give people an idea of what it is and this might also help someone identify it on the spot.

Also the FCC# could be used as it almost never changes and is unique for each card. The FCC website is Lately these have proven excellent resorts though sometimes the descriptions given are vague you at least will know the manufacturer and purpose of the card.

Another method though I believe you need to have it installed and configured is a program on PC-DOS 6.3 which takes the 'electronic name' (POSID, a four digit number) of the MCA card and gives the description.

And of course, QBMCA.
Another utility that reports on the POSID from MS-DOS is Snooper (download HERE).

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Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

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