Frequently Asked Questions for: IBM RT system hardware

This is a reworked and HTMLized version of Mark Whetzel's (MW) RT pages, as of Mon Jul 4 22:53:45 CDT 1994. The original can be found here. -MK

H.01 What is an IBM RT?

(and some of its history)

The IBM RT is a RISC based processor designed by IBM, and unique to that platform. The RT was first announced by IBM in January 1986. The processor is generally referred to as 032 processor. In some documentation it is also refered to as the 'ROMP' processor.

[ I have had some excellent feedback on the ROMP name and a little on RT history. See the submissions in this section below my notes for some interesting information. More information on RT history is always welcomed. - MW ]

The RT PC Advanced System Processor has a 32-bit Reduced Instruction Set Computer (RISC) architecture developed by IBM and implemented in a 1-micron CMOS technology. It has sixteen 32-bit general purpose registers and uses 32-bit addresses and data paths. The microprocessor is controlled by 118 simple 2- and 4-byte instructions. An IBM-developed advanced memory management chip provides virtual memory address translation functions and memory control. It provides a 40-bit virtual address structure capable of addressing one terabyte of virtual memory. Internal processor organization enables the CPU to execute most register-to-register instructions in a single cycle.
The model 115/125 RT PC with their FAST ECC memory, is capable of providing the processor with a 32-bit word of data plus ECC each 100 nsec cycle. This memory consists of 40 1-megabit IBM RAM chips. These chips are the same megabit technology used in the IBM 3090.
The model 130/135 version of the processor uses an 80 nsec cycle time with the maximum of 16 Megabytes of real memory installed on the processor card.

The IBM RT has had a varied life even from its initial announcement. Most industry watchers considered the RT as "not enough power, too high a price, and too late". Many thought that the RT was part of IBMs Personal Computer line of computers. This confusion started with its initial name, "IBM RT PC". Initially, it seemed that even IBM thought that it was a high end Personal Computer given the initiallly stunning lack of support that it received from IBM. This confusion even was reflected in the design of the manuals for the RT, they are the same odd size three ring binder (except longer), with slip cases like the original IBM PC manuals. Condidering the RT systems modest processing power (when first announced) coupled with announcements later that year by some other workstation vendors made most industry analysists question IBMs directions. To be fair, AIX for the RT was IBMs first *PUBLIC* foray into UNIX. IBM had a very tough task ahead of them, completely changing how traditional UNIX design had been done. The VRM (Virtual Resource Manager) is the real operating system of the RT, and controls all the hardware. AIX is running as a guest OS, in a similar fashion to the VM product of IBMs mainframe processors. The lack of software packages and IBMs sometimes lackluster support of AIX, plus the sometimes unusual changes from traditional UNIX operating system defacto standards caused most software suppliers to be slow to embrace the RT and AIX. The RT found its home mostly in the CAD/CAM and CATIA areas, with some inroads into the Scientific and educational areas, especially after the announcement of AOS and substantial discounts for the Educational community. The RT also found use as shopping store control systems, and interface system between IBMs larger mainframes and some of its point of sale terminals, store control systems and also machine shop control systems.

One of the RT systems claim to fame was its use as packet switch hubs for part of the internet backbone, utilizing specially designed hardware communication sub-processors and specially written operating system control software.

[More information on this would be welcomed! Start/stop dates, number of machines used per node and netwide, ect.. - MW]

Submitter: David Snearline <>

NSFnet used the 6151 desktop model RT systems for the NSS's (Nodal Switching Stations). Each RT in the group had two interface cards: one IBM token ring, and one other interface (ethernet, T1, etc). A typical NSS would look like:

                          +---- local ethernet
                        |   | IBM RT
                        |   |
                         | |
                         | |  +---+ IBM RT
                         | +--|   |
        Token Ring ----> +----|   |---- T-1 to another NSS
        (more RTs here)
Except for backup links in some places, most of the RT NSS's have been replaced by RS/6000's, which have all of the cards in one workstation. Most of the RTs are sitting around, waiting to be used for parts or dismantled. ANS/Merit could probably give you more details on when this switchover occurred, but I believe that November 1992 was one of the official changeover dates.

Submitter: <gerald@vnet.IBM.COM> (Gerald Oskoboiny)

Last night I was reading "Computer Wars" by Charles H. Ferguson and Charles R. Morris (ISBN 0812921569, Random House, 1993), and it has the code names of the RT and other projects. I forget most of the details, but it is very interesting reading. It explains how IBM had RISC technology in 1968 but mismanaged it until the disappointing RT was released in 1986. As far as "history of the RT" goes, this book explains it all.

Submitter: (Mike Johnson)
Newsgroup: comp.arch
Subject: Re: First Commercial RISC Computer

That's Research OPD Mini Processor. OPD = Office Products Division.

ROMP was originally designed to be used in office products, primarily text editing systems such as the IBM Office System/6 and DisplayWriter. The architectural work started in late spring of 1977, as a spin-off of the T.J. Watson Research 801 work (hence the "Research" in the acronym). Most of the architectural changes were for "cost reductions," such as adding 16-bit instructions for "byte-efficiency"--a main concern at IBM at the time.

The first chips were working in early 1981. The delay from architecture to working chips was caused mainly by building two models of the chip in TTL: an emulator that just executed the instruction set and a nodal-equivalent model that was more-or-less an exact duplicate of the chip (about 6000 7400-series DIPs plus a number of IBM bipolar gate arrays and static RAMs). The delay was also caused by two major revs to the architecture: one change to a 32-bit architecture from a 24-bit architecture (I'm serious), and another to support demand paged virtual memory (the implementation supported out-of-order loads, so precise interrupts were hard to come by).

ROMP was arguably the first working commercial RISC. The arguments would be over whether or not it was a "true" RISC and whether or not one could count it as a commerial product in 1981, since it didn't actually ship until 1986. *This* delay, in my opinion, was caused by overly ambitious software plans, in the form of porting an IBM version of UNIX to a virtual software layer called VRM (Virtual Resource Manager), rather than porting Berkeley UNIX directly to the hardware. The path from having hardware to developing VRM to porting UNIX and then getting VARs to write applications was just too long--a problem that IBMs resources couldn't overcome.

I was the first member of the ROMP design team--something I credit to random chance rather than any personal expertise (my graduate work at the time had been in digital control systems). ROMP was a good way to learn microprocessor design by learning what *not* to do.

I understand that ROMP was also used in an IBM laser printer, but I don't have any first-hand knowledge that this is true.

H.02 What types of processors were made?

There are 2 basic types of machines called an RT: There exists a special version machine that used the same processor, available only to educational sites that is a hybrid IBM PS/2 model 60 with a special micro-channel board version of the 032 processor, dubbed as a 'crossbow' board. [project name? -MW] That machine was IBM machine number 6152. The 6152 ran only the AOS operating system downloaded from another IBM 6150 or 6151 also running AOS, via a lan TCP/IP interface (either Token-ring or Ethernet). Later versions of AOS could be loaded directly on the 6152 once larger hard disk drives for PS/2 became available. The availablity of support for VGA adapters in the X11 releases was because of the existance of this machine.

I am not sure the 6152 machine can rightly be called an RT, as the only interface boards used were the same as used in PS/2 machines. This version may be somewhat rare, and I have never seen one. The rest of this list does not generally cover the 6152 machine, mostly because of a lack of information on the beast. More information on the 6152 processor is covered in the AOS FAQ posting in this newsgroup. The 6152 model was discontinued by IBM as of August 31, 1990.

[ More details about the mysterious 6152 model RT would be interesting. How widespread is it? History? Are any still running? - MW ]

There are three versions of the 6150/6151 processor card, and several unique RT models using each version of the card. IBM used the different model numbers to designate different base configurations of processor speed, installed main memory and installed hard disks. Model numbers can be deciving, as some machines may have been field upgraded to different models and/or processor types.

The standard 032 processor card was in models: 10, 15, 20, 25 and A25.

The Advanced processor card was in 2 different types: The 115 which had 4MB memory ON the processor card, available only on the desktop 6151. The 125 and B25 models which had all their memory on external FAST ECC 4MB memory cards, used in the 6150 tower models.

The Enhanced Advanced processor card: Available only with the model 135 and B35 (6150 tower), and with the model 130 (6151 desktop).

Enhanced Advanced processors are easily recognized. Soldered directly to the processor board are 20 'SIMM like' memory boards sticking up on about 1/2 of the processor card providing 16 Megabytes of ECC parity checked memory.

All processor cards are installed in the special board slot labeled 'A' on both the tower and desktop machines.
The A## and B## model machines shipped without the native keyboard, and instead used a preinstalled 5080 attachment interface card allowing the RT processor to share the keyboard that was attached to the 5080 graphics system hardware. Via a special interface card, the 5080 lighted program function keypad (LPFK) and dials unit (three variable position X,Y and Z controls) could be attached either to the RT or the 5080 graphics system. Primarly used in a CADAM and CATIA setup running AIX.
System processor board timings:

Board Bus Cycle time
Memory Bandwith
Original 032 170 23.5
Advanced 100 40
Enhanced Advanced 80 50

H.03 How fast are the different models of RT?

[ I would like to see some results from users with later benchmark tests on both the native C and Fortran compilers. Tests with a 135 processor using the last available compiler patches from IBM, and side-by-side tests with the now available GCC compiler for AIX RT would be an interesting addition to this section. I would like to see how those compilers stack up to each other in performance tests. I would also like to see how the RT still stands using some of the newer industry standard benchmark programs. Comparisons against other popular processors now in use would be interesting. This information may be dated, considering that IBM continued to improve the performance of the native C compiler available with the AIX V2 operating system. Comparison running AOS or MACH would also be interesting to see how much difference compiler and OS technology has on overall performance. Challenge anyone? - MW ]

These performance numbers are dependent on various factors, including complier update levels, language, Fortran or C, compiler options, and installed floating point accelerators. Times given are using the AIX operating system. These numbers were obtained from an IBM announcement letter number 188-120 dated July 19, 1988, announcing the release of the 135 Enhanced Processor. Refer to that IBM announcement for more complete information.

Test Jan 86 Feb 87 July 88
Dhrystones 1780
8300 (1)
10400 (2)
FP KWhetstones (double precision)
LINPACK KFlops (double precision)
780K (3)
Disk Maximum
Data Rate
210 MB
0.26 MB/s
5810 MB
1.08 MB/s
7460 MB
1.08 MB/s (4)


The date in the columns above refer to IBM announcement letters for the RT, released on the the date indicated. The IBM announcment letter partially quoted above indicates that the benchmarks were achieved by running the Dhrystone benchmark V1.1 on AIX/RT Operating system V2.2 after installing the June 1988 updates to the C compiler.

H.04 Can you upgrade from one processor type to another?

The general answer is yes. However, this is dependent on two things:
  1. If you can find the necessary parts.
  2. If the planar is of a particular hardware level.
The memory cards in the models earlier than the 115/125 are too slow for the later Advanced Processor (125). That processor will only allow use of the 'Fast ECC' memory cards available in either 4MB or 8MB sizes, for a total of 16 Meg. If you have a two different sizes of memory cards, the larger must be in slot 'C'.
The 135 model has all 16 Meg available SOLDERED to the processor card and require no external slot C or D installed memory.

The Floating Point Accelerators only work when matched with the correct type of processor.

The standard FPA board is easily recognized as it is a single board, and the slot fingers are uniquely placed so as to fit only in slot B on the 6150 and 6151. The later model AFPA is a double layer board, constructed so as to still fit in one slot. Descriptions of level1 and 2 FPA boards are described in the adapters section (H.07) below.
To perform an upgrade from the slower version of the 032 processor to the APC (115/125) needs different Fast ECC memory cards, and a optionally a faster FPA. To upgrade from a APC to an EAPC (130/135), you must remove any installed memory boards because the EAPC has onboard memory. The Enhanced processor also requires Enhanced FPA (level 2 version ONLY). The faster processors also require later versions of AIX upgrades that were minimum for each model, and the appropiate minimum memory for the type of processor. AOS has a compile flag for the kernel use on the faster processsors. See the appropiate OS faq for more specific information.

The EARLY model APC card had 4 Meg bytes of memory ON the procssor card. It looks like a small array of metal can chips about 1/2 inch square covering the right half of the processor board. It is the ONLY APC card that will work with ALL boards removed. Later model APC cards RELIED on memory on the processor bus (Slots C and D) and *WILL NOT* work with no memory installed. With NO memory installed in slots C and D you will ALWAYS stop with a '5c' LED code, as the processor has no memory! If you have an early processor board, then you must NOT have two 8Mb boards installed, otherwise there will be a memory address conflict with the last board! You will need a 8Mb board and a 4Mb board for that setup.

A Maximum of 16 Mbytes of main memory is supported by the RT hardware.

When using 'Enhanced ECC memory' boards, make sure that the jumper on the memory cards is in the 'fast' position. The undocumented jumper allows the newer cards to work with the older processors by moving it to the 'slow' position. If the memory boards are of different sizes, make sure the LARGER one is in slot C, and the smaller in slot D. To run an APC card requires att least 4 Mb of memory and AIX 2.1 or later for the OS version.

As shipped from IBM the APC 125 model upgrade kit was IBM part Number 61X6833 and included the following:

Users without ESDI cards had to buy an E70 drive, minimum to upgrade. The R40 drive and MFM controller had a maximum of one drive supported when moved to the secondary slot and jumpering.

I do know that the upgrade kit, when ordered, needed the base serial number of the machine as part of the order, and that serial numbers BELOW a selected value were a different upgrade. However, the upgrade announcement letter (187-022) does NOT mention a planar upgrade in its text.
The only planar problem I know of was with REAL old model RT's not working with ethernet adapters... - MW

Here is a cut of the 6150 model hardware information..dated Feb 26, 1991:
   Hardware Requirements:  The Baseband Adapter will plug into any model of the
   6150 and 6151 system units.
   Software Requirements:  This product requires that the RT AIX Operating
   System Version 1.1 (59X8994) be installed.
   Limitations:  The Baseband Adapter must NOT be plugged into slot 8 on the
   6150 Models 020, 025, and A25, or slot 5 on the 6151 Model 010.
   Planar must be at, or higher than, EC A31282M on the 6150 Models 020, 025,
   and A25, or EC A31283M on the 6151 Model 010.  If the customer serial number
   is 3500 or lower on Models 020, 025, and A25, or lower than 2250 on Model
   010, have them contact IBM for an upgraded planar board.  There will be an
   "Attention" card placed in each Baseband Adapter box.  The upgraded planar
   board will be installed at no charge to the customer.

[ I am still searching for more complete upgrade information. IBM had some specific minimum planar serial numbers that were required for the faster processors, but I do not have any of that information. Anybody? - MW ]

H.05 How can I tell what kind of processor type is installed?

For a quick determination of the processor type, observe the LED digits during a power on IPL. The general sequence for initial 'Power On Self Tests' (POST) codes is:

88, xx, zz, yy, 09, 10, 14 (long), 15, 16, 21, 22.
The XX, YY and ZZ LED values will have a value of:

   XX  YY  ZZ
   01  03  05  = Standard 032 processor. (010,020,025,A25)
   1c  3c  5c  = Advanced 032 processor. (115,125 and B25)
   1u  3u  5u  = Enhanced Advanced 032 processor. (130,135,B35)
The XX and YY codes stay around the longest, and are easiest to see. A few other codes fly by as well, but try as I could, I could not tell what they were. Other codes can show up, depending on what other I/O boards are found in the system during power up. If any code remains in the LED display for over 5 minutes, a failure had been found with the system during self tests. All LED codes after the code 22 (boot record processing), are dependent on the operating system being loaded into the RT. LED codes prior to the 22 are placed in the LED display by the Power On Self Tests (POST) of the RT planar. Almost all the other LED codes are displayed by Loadable POST (LPOST) routines invoked during VRM initialization and IPL. Obviously systems NOT running AIX with VRM will have different LED codes.

H.06 Where can I get parts for RT systems?

[ This section needs more entries, addresses and/or phone numbers. Third party suppliers or used equipment dealers known to deal in RT hardware would be great. - MW ]

Parts at this time are still available from IBM. At this time, IBM does not have any announced discontinuance of individual parts.

As of September 15, 1993, IBM has announced (letter 193-161 dated June 15, 1993) discontinuance of selling all the different monitors (6153, 6154, 6155, 5081) and some of the external peripherals (6156, 6192). The 6157 tape drive was discontinued earlier in the year.
IBM still offers maintence contracts for RT computers and equipment.
IBM parts may be ordered by calling IBM-Direct, 1-800-426-2468.
Other IBM numbers:

   1-800-426-7378  Service/Maintenance
   1-800-426-2468  Supplies/Dealer Referral
   1-800-426-3333  Information
However, IBMs prices may be a little steep.

Some used and surplus parts houses from time to time get RT systems, but not on any regular basis. Lots of times, they are broken up for some of the re-usable parts, and the rest junked. :-(

Dickens Data Systems used to make special 8, 16 and 64 port async adapters for RT systems. They also sold device drivers for various SCSI attached devices, including 9-track tape. I am not sure if they still make any of these.

Submitter: (Richard Rogers)

[ I have made a few editorial changes and corrections to Richards submission, mostly phone number corrections or address/contact corrections. - MW ]

In searching for a source of RT Megapel cards I put a call out over the net for RT parts sources and said that I would summarize back to the net. Two responses were received, so a personal thank you to Jon Brinkmann and Matt Rush. All leads were contacted with the following results:
   Dickens Data Systems      1-800-848-6177
           Don't inventory RT parts, but do have some RT
           add in hardware and software.

   Dickens Technologies      404-418-0630
           Carry all parts.

      From: (Mike (Woody) Woods)
      Subject: Re: RT Products
      Date: Thu, 30 Dec 93 15:14:20 EST

      > Inclosed Prices for I/O Boards for the RT 
      P/N     Desciption        Current Stock St      List Price
      10011   64 Port Controller    5 in stock        $1,000.USD,
              for RT
      10012   16 Port Cluster Box   10+ in stock      $1,295.USD

      10001   8 Port board Plus for  1 in stock       $1,395.USD 
              RT DB25
      10003   16 Port board RJ45 RT  16 in stock      $2,195.USD
      10003DB 16 Port board DB25 RT   7 in stock      $2,895.USD

      NOTE: On hard Drives RT 310 -- out of stock -- don't know if I
            can get any more.

   Next Generation Systems   313-435-5086
   Contact: Randy Hastings

   Alpine Computer Sales
   P.O. Box 1500
   1052 Hwy 395
   Gardnerville, NV  89410
   (800) 274-5876
           Carry all parts.

   International Data Products
   4445 W. 77th St.
   Mpls, MN  55435
   (714) 851-0222
           Don't inventory RT parts any longer.

   RGdata Inc.
   975 Jefferson Road
   Rochester, NY  14623
   (716) 424-7500
           Carry all parts.
           Contact: Dave Gerritsen

   Dempsey Business Systems
   18377 Beach Blvd., Suite 323
   Huntington Beach, CA  92648
   (800) 637-2620
           Carry all parts, "large quantity".
           Contact: Steve
We purchased purchased 5 cards and cables from Dave Gerritsen at RGdata. Everything arrived OK. We've had good experiences with RGdata in the past, I just didn't realize that they carried RT parts.

H.07 What adapter cards are supported in an RT?

(Includes information on non-IBM adapters.)

The IBM RT has what is called in the industry a ISA bus. Based on the original IBM PC AT bus in design, the RT has 8 I/O slots in the tower (6150 model), and 6 slots in the desktop (6151 model). Slot 3 and 6 on the tower model and slot 1 on the desktop models are eight bit style slots. Slot 8 on the tower and slot 5 on the desktop model are wired slightly different than standard. These special slots were intended for use with the PC AT Coprocessor card, and do NOT have the memory refresh signal, and replace IRQ7 with IRQ8. However, most regular interface boards not requiring these signals will operate just fine in these slots.

Technically, any adapter that conforms to ISA standards would work provided there are appropiate device drivers AND no conflicts with existing adapter registers and bus addresses.

The RT diagnostics program disks are unfortunately rather particular about OEM cards that EMULATE IBM adapters, or respond to memory addresses assigned to standard RT adapters. This can sometimes lead to problems running diagnostics, where the system MAY otherwise run fine with the regular operation system. The diagnostics will usually ignore any board it does not recognize without a problem.

SEE THE OS DEPENDENT FAQ LIST FOR ADDITIONAL HARDWARE, OR ADAPTER DIFFERENCES THAT MAY BE SUPPORTED BY A PARTICULAR OPERATING SYSTEM. The information and part numbers shown below generally reflect AIX usage, and from IBM offical announcement of support letters.

Feature code numbers and part numbers, where known, are shown in parenthesis like this (#feature,partnum). Part numbers DO change with EC (Error Correction) changes and production run changes.

[ These numbers should be able to be cross-referenced if no longer correct. - MW ]

Memory cards

Peripheral adapters

Fixed Disk adapters

Tape Drive adapter

Display Adapters

Communication adapters


Special non-IBM made adapters

[ I KNOW there are more.. send me information!! - MW ]

H.08 What IBM peripherals were available?

There may be other devices supported by other operating systems. Refer to the one of the OS specific FAQ lists for more information. The following IBM peripheral devices were officially supported by IBM for use on the 6150 and 6151:

[ Feature code numbers and part numbers, where known, are shown in parenthies like this (#feature,partnum) - MW ]

Storage Devices

Tape Devices


Pointing devices

Special devices


ASCII Terminal devices

H.09 What cables are available?

Feature codes, where known are listed like this (#xxxx).

P/N Description
61X6937 Cable, fixed-disk and diskette drive positions A-D
79X3777 Cable, fixed-disk and diskette drive positions A-E
6298359 Cable, power distribution.
6450217 PC AT Communications Cable (#0217)
(3 Meters 9-pin to 25 pin)
6450242 IBM PC AT Serial Adapter Connector Cable (#0242)
(10-inch DB 9-pin to 25 pin)
79X3914 RS232 Terminal attach cable. (#????)
(3 meters 10-pin MODU to DB25 pin MALE use with 8-port, 4-port or native serial ports)
6298526 RS232 Terminal attach cable. (#3913)
(3 meters 10-pin MODU to DB25 pin FEMALE use with 8-port, 4-port or native serial ports)
6298525 RS232 Serial Printer attach cable.
(3 meters 10-pin MODU to DB25 pin FEMALE use with 8-port, 4-port or native serial ports)
6294704 RS232 Modem attach cable.
(3 meters 10-pin MODU to DB25 pin MALE use with 8-port, 4-port or native serial ports)
1525612 IBM PC Printer Cable (#5612)
79X3468 SCSI interface card to device cable (#3468)
(8 Meters) Includes Terminator plug 79X3795.
79X3470 SCSI device to device cable (#3470)
(1 Meter)
6294812 Modem Cable RS232C for Multi-Protocol adapter
( 3 meters 16 Pin MODU to DB25 male )
6294814 Autocall Cable RS366 for Multi-Protocol adapter
( 3 meters 16 Pin MODU to DB25 male )
6294816 Modem Cable X.21 for Multi-Protocol adapter
( 3 meters 16 Pin MODU to 15 pin male )
08F3157 8-Port RS232C Fan-out cable assembly (#3157)
( 6 foot cable to fanout box with 8 10-pin MODU connectors)
(also used with MIL-188 adapter)
08F3158 8-Port RS422A Fan-out cable assembly (#3158)
( 6 foot cable to fanout box with 8 6-pin MODU connectors]
6487586 RT PC 5083 Tablet cable kit. (#7586)
used only to attach a model 1 or 2 tablet to an RT. not needed for 11A or 12A tablets.
6487563 RT PC 5080 Peripheral Adapter cable kit
6247861 RT PC 5080 Attachment cable kit. (#7861)
Includes two cables, terminator, diskettes and documentation.
22F9207 RT PC Expansion unit cable, 2m.

H.10 What is the pinout of the 6150 serial ports?
(How do I make my own RS232 cables compatible for use with AIX?)

The funny connector on the back of the 6150 labeled 'S1' and 'S2' are the native serial ports built into the system planar board of the 6150 tower models of the RT. This connector is referred to in the IBM hardware manuals as a MODU connector.

The 10-pin connector used on the native serial ports, is also used by the fan-out box for the RT RS232 8-port card. These part numbers for the connector were given to me by the IBM support center in Austin, TX for the RiscSystem/6000. The 6000 has the same 10 pin MODU connectors for the 6000 systems native serial ports, and is the same connnector used by the RT systems native serial ports.

AMP Product Corp.

Housing       AMP P/N         102394-3
Cover         AMP P/N         102541-3
Back Cover    AMP P/N         102536-3
Ferrule       AMP P/N         102903-3
Receptacle    AMP P/N         2-87195-0
Receptacle    AMP P/N         86491-4
Shield Kit    AMP P/N         103125-2
You can also get a 10-pin MODU connector pre-wired to a DB 25 pin male connector, used for the Risc/System 6000 and is a short stub about 4 inches long. It is IBM P/N 00G0943. This stubby cable will work just fine for connecting modems, and with a properly wired extension able, for printers and terminals as well.

Looking INTO the connector pins in the back of the RT tower, here is the pin-out assignments and functions. The connector on the back of the RT tower model is a male MODU connector. This pinout is the same for the IBM 4-port card, and the fan out box of the IBM 8-port card.

                               @   pin  abb   function
    +-----------------+        T    1   TX  = Transmited data from RT
    |                 |        T    2   DTR = Data Terminal Ready   
    |  1  2  3  4  5  |        T    3   RTS = Ready to send
     |               |         R    4   RI  = Ring Indicate
     | 6  7  8  9 10 |         -    5   -     No connection
     |               |         R    6   RX  = Received data to RT
     +---------------+         R    7   DSR = Data Set Ready
                               R    8   CTS = Clear to send
                               R    9   CD  = Carrier Detect
                               -   10   GND = Signal Ground
       @ means   T = RT transmits  R = RT receives (listens)
RS232 Modem attach cable. Feature #4704, Part# 6298240 Option #6294704
IBM supplied cable is 3 meters long, with a 25 pin male connector.

This has worked for my modem attach.. I have not actually used a meter on a STOCK IBM RT modem cable, but this works for me. - MW

Metering the IBM RS6000 stubby cable P/N 00G0943 matches this pinout.

   Pin#   1   2  3   4  5  6  7  8  9  10      10-PIN MODU  female
          |   |  |   |  |  |  |  |  |  |
          |   |  |   |     |  |  |  |  +--+
          |   |  |   |     |  |  |  |  |  |
          2  20  4  22     3  6  5  8  7  1    DB25 male connector

   NOTE: pin 5 of the MODU connector is unused.
The following cable wirings were discovered by using a meter probe on IBM RT RS232 cables and by opening the hoods on the DB25 connector ends. IBM part numbers and option numbers listed where known.
They are still orderable from IBM the last time I checked. -MW

RS232 Terminal attach cable. Feature #3913 Part# 6298526 Option# 6298186

     Pin#  10     6   1     9   2  8   3   7   10-PIN MODU female
            |     |   |     |   |  |   |   | 
            |     |   |     |   |  +---+   |
            +--+  |   |  +--+   |  |       |
            |  |  |   |  |  |   |  |       | 
     Pin#   1  7  2   3  4  5   6  8       20   DB25 Female connector
RS232 Serial Printer attach cable. Feature #4803 Part# 6298525 Option# 6294803
     Pin#  10      6   1   7  9  3  2      8     10-PIN MODU female
            |      |   |   |  |  |  |      | 
            |      |   |   |  +--+  |      |
            +--+   |   |   |  |     +--+   |
            |  |   |   |   |  |     |  |   | 
     Pin#   1  7   2   3   4  5     6  8   20    DB25 female connector

H.11 What is the pinout of the 6150/6151 Mouse/Tablet port?

Has anybody gotten a NON-IBM RT mouse running on an RT? Or have a 3 button mouse that works on an RT? - MW

Here is pin-out and information on the RT locator port. More information is available from "IBM RT PC Hardware Technical Reference" Volume 1 P/N 75X2032, Chapter 9 pages 9-24 thru 9-29, and from Chapter 5, pages 5-131 thru 5-135 and page 5-145.

The connector is a AMP type, I don't have the P/N of how to get the parts to construct one - MW

Connector Specifications: (view is looking into the connector (male receptacle) socket on the back of the RT system unit.

         +--------------+            1 = ground.
         |    1  3  5   |            2 = Transmit to device.
         |              |            3 = +12 Volts
          -   2  4  6  -             4 = -12 Volts
           |          |              5 =  +5 Volts
           +----------+              6 = Receive from device.
The RT standard locator device is a two button mouse. The middle button on a three button mouse can be simulated by pressing both buttons simultaneously, mostly used for X-windows. IBM part numbers for the RT mouse are: 00F2384 Mouse. Also called a 6100 pointing device.

A IBM 5083 tablet may also be used as a locator device.

IBM part numbers for the 5083 tablet are:

H.12 What is the pinout of the 6150/6151 Keyboard port?

Here is pin-out and information on an RT keyboard. More information is available from IBM RT PC Hardware Technical Reference Volume 1 P/N 75X2032, Chapter 9 pages 9-3 thru 9-23, and from Chapter 5, pages 5-85 thru 5-114.

The connector is a AMP type, I don't yet have the P/N of how to get the parts to construct one. Anybody? - MW

Connector Specifications (view is looking INTO the female connector socket on the cable attached to the keyboard):

   +--------------+            1 = +5 Volts
   |    5  3  1   |            2 = Keyboard Data
   |              |            3 = Speaker Signal
    -   6  4  2  -             4 = Speaker Return (+5V)
     |          |              5 = Ground
     +----------+              6 = Clock  (diagrams in the book seem
                                   to indicate that clock is generated
                                   BY the keyboard)
Microprocessor in keyboard performs following functions: IBM part numbers for the RT keyboard are: Ten other part numbers are listed for other language layout keyboards.

H.13 Can I use an AT keyboard on an RT?

NO. While most of the signals are the same, there are four major differences:
  1. There is a speaker in the keyboard.
  2. The physical connector is not the same.
  3. Some of the scan codes are different.
  4. Some of the programing commands are not implemented in the AT keyboard.
Difference 1 and 2 are manageable, but 3 and 4 imply some way is needed to alter the keyboard ROM chips, or basic hardware.

ANY input on how to hack a keyboard for RT compatibility is gladly welcomed! - MW

H.14 How do I get a parallel printer attached to an RT?

This information has been taken from the AIX manuals, if there is a difference for AOS, let me know. - MW

There are three different ways to attach a centronics parallel printer to the RT. A maximum of two parallel printer interfaces are supported, but only by using a AT serial/Parallel card, jumpered at the secondary printer port address.

Recent discussions in this newsgroup indicate that clone printer port cards will work with AIX. Personally, I have used both the AT Serial/Parallel card and the XT monochrome adapter just fine to run parallel printers. The megapel parallel port also works under AIX fine. -MW

H.15 What are the switches on the Megapel adapter for?
(Technical information on Megapel adapter and display.)

DIP Switch 1 is located on the display processor card (the one with the 25-pin parallel printer connector on it).
   S1 pos   feature/usage
   ------   -----------------------------------------
     1      Not used. Must be set to OFF.
     2      On = Enable printer port.   Off = Disable printer port.
     3      Enable CGA emulation mode.  Off = Normal Megapel mode.
     4      Not used. Must be set to ON.

Anybody know what the 'not used' switches do? - MW

Megapel and display Technical information:
   Slot position           Must be installed in slots 4 and 5 ONLY.
   I/O Addresses           0930-094F
   Memory ddresses:        0B8000-0BBFFF   CGA emulation mode.
                           C00000-C3FFFF   Adapter data space.
                           D60000-D7FFFF   Adapter program space.
   DMA channel             7
   Interrupt level         11  (shared)
   Horizontal Frequency    63.36 Khz
   Vertical Frequency      60 Hz,  Non-Interlaced.
   Display connector       3-pin Video (D-shell)

Submitter: (Pim Zandbergen)
Date: 24 Oct 93 21:20:48 GMT

The original Megapel RAMDAC is the Brooktree BT 451 KG 110. It does 4 bits per color, yielding a color palette of 4096 colors.

You can replace it with a BT 458 KG 110 (or the BT 458 KG 135). There's a #define in the Megapel X server sources [ for AOS ] which defines the number of bits per color. With the BT 458 you will have a color palette of 16M colors.

I tried to order one, unsuccessfully. The Dutch Brooktree dealer wouldn't sell me RAMDACS in quantity one, and Brooktree did not want to deal with me directly.

This DAC replacement was a IBM RPQ (Request for Price Quotation) feature for the Megapel card, and did upgrate the color palette to 16 Million colors.
If ordered at ship time: RPQ 8A0158
for field upgrade: RPQ 8A0159

The megapel with a replaced DAC will only use the 16 Million colors with the special X server compiled and running on AOS, *AND* with patches applied to the IBM supplied microcode that is loaded in the megapel adapter. See the AOS RT FAQ for more details on patches and X support.

To the best of my knowledge, this was never made available to AIX/RT users. - MW.

H.16 - AT Co-Processor information.

The IBM PC AT Math Coprocessor, Feature code #4756, contains an Intel 80286 processor chip and the necessary support circuitry to provide basiclly a PC AT on a board.
Technical Information:

Identifiable by the square 80286 processor chip located in the lower left corner, along with a socket for a 80287 chip. In the silkscreen printing along the left edge (with the electronics up and the gold fingers towards your body) are the numbers 6453987. Ink stamped along the bottom edge are 60X5745 A6328262340.

Must be installed in I/O option slot #8 for the 6150 tower models, and in slot #5 for the 6151 desktop.

Optional feature #0211, the IBM PC AT Math Coprocessor, adds a matched 80287 floating point chip to the empty socket on the board.

The Coprocessor board can also be used with the IBM PC AT 512Kb Memory Expansion Option (Feature #0203), containing 512Kb of dedicated memory for coprocessor use. This improves performance of the coprocessor as it no longer has to share main RT processor memory. Use of a second AT 512Kb board is also supported. A dedicated PC display (IBM 5151 monochrome) or IBM 5154 EGA color) is also recommended for improved performance of the coprocessor.

To the best of my knowledge, the AT Coprocessor is ONLY supported in an RT running AIX V2.x. - MW

The megapel display adapter is not usable as a console for the Coprocessor services, or for application output for the PC AT coprocessor.

Does anyone know what the long row of DIP pins are for that are located along the bottom edge of the coprocessor board? - MW

H.17 - How can I get the maximum data on a 6157 tape drive?

While the 6157 hardware is the same, and the type of tape used is the same, the default values for the tar command for AOS may be different than AIX. Other OS and drive types may vary these numbers. - MW

   Submitter: (David L. Crow)
              IBM Advanced Workstations Division
   Date: 30 Apr 92 14:12:59 GMT

  >We have the 6157-002 model (150Meg, I think) and for some
  >reason, it needs three tapes to backup only 240Meg of data.
DC 600A tapes should hold 118 MB of data. Of course this is somewhat dependent on the RT systems ability to keep the data moving to the tape as it is streaming. If there is a break in data because the backup command can't get it there quick enough, then you'll lose some of your capacity. Here is an item from ASKQ two or three years ago that describes what flags to use to make sure that you get the maximum capacity out of your 6157. This probably could go into the FAQ (except the FAQ is pretty much just for AIX Version 3. [ Until the RT one! :-) MW ] ============================================ Subject: 6157 TAPE INFORMATION FOR AIX BACKUP COMMAND The correct descriptions for the -s and -d flags of the AIX backup command are: -slength Specifies the length of the usable space on a tape medium. This is a combination of the physical length and the number of tracks on the tape. The default "length" is 2700. To get the value for "length", you should multiply the physical length of the tape by the number of tracks (see table below). -ddensity Specifies the amount of data a system can write to a tape medium in bytes per inch. The default "density" is 700 bytes per inch. The density written to the tape is hardware controlled and can not be changed. The 6157-001 writes at 10,000 ftpi (flux transactions per inch) which is approximately equivalent to a density rating of 8,000 bits per inch. The 6157-002 writes at 12,500 ftpi which is equivalent to a density rating of 10,000 bits per inch. The -d (density) parameter is used with 0.5 inch tape drives to specify the density, such as 800, 1600, or 6250 bpi, but doesn't affect the density, that is, bits per inch, of the 6157. The -d parameter is used for the 6157 in the calculation of what quantity of data will be put on the tape. To increase the amount of data on the tape, the value for -d should be 1000 for 6157-001 or 1200 for 6157-002. Reference: AIX/RT Commands Reference Volume 1, SC23-2011-1, page 91. AIX PS/2 Commands Reference, SC23-2025, page 35. CALCULATION OF TAPE CAPACITY: The following formula yields the approximate capacity of a tape: # tracks * length * 11 inches * density = capacity (in bytes). 9 * 300 * 11 * 1000 = 29,700,000 bytes or about 29 MB 18 * 600 * 11 * 1200 = 142,560,000 bytes or about 142 MB The "11 inches" is the length of the recording foot, the actual amount of data stored on the tape per foot, and the interblock gaps take up approximately 1 inch per foot. TABLE: For the following AIX command(s), the values for -s and -d are in the table below: find ./ -print | backup -iv -C2000 -f/dev/rmt0 -sXXXX -dYYYY Recommendations for 6157-001: TAPE CARTRIDGE LENGTH TRACKS -s -d CAPACITY 3M DC 300A 300 feet 9 2700 1000 29 MB 3M DC 300XLP 450 feet 9 4050 1000 44 MB 3M DC 600A 600 feet 9 5400 1000 59 MB Recommendations for 6157-002: TAPE CARTRIDGE LENGTH TRACKS -s -d CAPACITY 3M DC 600A 600 feet 15 9000 1200 118 MB 3M DC 600XTD 600 feet 18 10800 1200 142 MB ==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**== Submitter: "Andrew J V Yeomans" Subject: More on 6157 tape recording, and backup. Date: Mon, 25 Apr 94 15:23:44 BST Density in flux transitions per inch is ten times density in bytes per inch. (5 tape bits/4 data bits) RT backup rounds the block length up to next integral inch, adds 1 inch inter-block gap, then calculates how many blocks fit. (AIX 2.2.1 - I've determined this by reverse-engineering the values returned by backup. This is not the same as the IBM note you printed). Blocks = blocksize * floor(length*12 / ceil(blocksize*512/density + 1)) 6157-001 drive (RT 6150) -------------- Write at 10000 ftpi = 8000 bits/in = 1000 bytes/in. Format: QIC-24 Speed 90 inches/second Only DC300XLP recommended due to tape head wear. By experiment, writes: DC300XLP: 46*2000 blocks = 92000 blocks; 923*100 blocks = 92300 blocks DC600A: 63*2000 blocks = 126000 blocks; 1275*100 blocks = 127500 blocks DC6150: 63*2000 blocks = 126000 blocks; 1275*100 blocks = 127500 blocks Backup flags: DC300XLP: -s4000 -d1000 -C2000 gives 92000 blocks. tar -s4000@1000 DC600A: -s5400 -d1000 -C2000 gives 126000 blocks. tar -s5400@1000 DC6150: -s5400 -d1000 -C2000 gives 126000 blocks. tar -s5400@1000 6157-002 drive (RT 6150) -------------- Write at 12500 ftpi = 10000 bits/in = 1250 bytes/in. By experiment, writes: DC300XLP: Read only DC600A: 131*2000 blocks = 262000 blocks; 2638*100 blocks = 263800 blocks DC6150: 157*2000 blocks = 314000 blocks; 3155*100 blocks = 315500 blocks Backup flags: DC600A: -s9000 -d1250 -C2000 gives 262000 blocks. tar -s9000@1250 DC6150: -s10750 -d1250 -C2000 gives 314000 blocks. tar -s10750@1250 Depending on your particular tape drive (i.e. exact speed of the tape) you might get one block more or less than above. I got these values pretty consistently. You might get slightly more data if you use shorter blocks; 2000 * 512 bytes is about 70 feet of tape, so you might lose up to this capacity on the last block on the tape. ==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**==

H.18 - What non-IBM hard disks can be used in an RT?

This section may need to be refined, as AOS hackers may have introduced other disk interface cards to its support. Anybody with other non-IBM drives running in your RT, using AIX or AOS let me know how you achived this, and what steps are necessary to make this work. - MW

The RT uses two different type of drives in the internal drive bays, ST-506 MFM and ESDI interface.

There were FOUR different disk controller cards used by IBM in 6150 and 6151 systems.

Both, the AT as well as the ESDI controller can be run in any combination for a maximum of two controllers and three drives.

On all of the above controllers when jumpered for secondary operations, the floppy drive function of that controller is inaccessible by AIX, not sure about AOS.

The MFM and ESDI adapters in the RT were made for IBM by Western Digital. The EESDI adapter and ported EESDI adapter appears to have been made by IBM, they have IBM PROMs and PAL devices on the boards.

The EESDI adapters are very SENSITIVE to timing problems with *SOME* OEM drives. * The IBM H310 drive was a relabeled MAXTOR XT-4380E drive. I personally have had success only when a specific TLA number controller board is installed on the drive, with what MAXTOR calls 'a short index pulse'. * Drives known to work with the EESDI controller have the following ientification numbers: MAXTOR XT-4380E Series: 2 TLA: 1094508-2 HDA: 1014294 PCBA: 1018528_A MINISCRIBE: Model 9380E 9380EF HDA: 01P4 PCBA: 04P1 BDMT: 05P1 Unique: 02P2 TDA: 3077A 3041A PIRAM: Model # ID337-RT-H2 Barcode says: model #638 AWE 00015432 PCB: 201384 EC: 11665 CCL A [ Watch this space for more JUMPER details. Also.. anybody with experiences with OTHER vendor drives running on an RT with AIX or AOS would be welcome. - MW ] * The E70 and E114 hard drives use a 150 Ohm inline resistor. It has pin one as the common pin, and has 12 total leads. This is NOT documented ANYWHERE that I could find! * Switch settings for E70 and E114 hard drives. For RT installation, the switches must be as follows: 1 2 3 4 5 6 +------------------+ On | X X X | Off | X X X | +------------------+ - Eliot reports that the switch meanings are: switch 1: on = pwr up via software (factory default) off = pwr up with system 2: on = diags (factory default) off = ? [ My guess.. since on is the RT normal position, then off must activate diagnostic mode. - MW] 3: on = 512 byte sectors (factory default) off = 256 byte sectors 4,5,6: drive select in binary i.e. 4 off 5 on 6 off = drive select 2 * Switch settings for E310 hard drive ONLY. For RT installation, the switches must be as follows: 1 2 3 4 5 6 7 +---------------------+ On | X X X X X | Off | X X | +---------------------+ [ Anybody know the meanings of the switches for the E310 drive? - MW ] ==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**== Submitter: Robert Fickling Subject: Fujitsu as H310 Date: Mon, 7 Feb 1994 09:58:31 -0800 (PST) I found a good replacement for the IBM RT H310 drive. Fujitsu M2249E - a jumper (34 sectors/track) + VRM format utility = H310 Just tell the VRM format program that the drive is an H310. The program writes the IBM info on the drive and formats it as the H310. Worked great for me! FUJITSU DISK DRIVE SPECIFICATIONS MODEL: M2249E PART NUMBER: B03B-4945-B003A INTERFACE: ESDI RECORDING CODE: RLL (1,7) CAPACITY----Unformatted: 389.0 Mbytes Formatted: 305.5 Mbytes Per Track: 20.864 Kbytes Sectors/track: 64 NUMBER OF---Heads: 15 Servo Tracks: Dedicated Cylinders: 1243 POSITIONING TIME: Track to track: 4 msec. Average: 18 msec. Maximum: 35 msec. POSITIONING METHOD: Rotary Voice Coil Motor SPINDLE SPEED: 3,600 R.P.M. AVERAGE LATENCY: 8.3 msec. DENSITY---Recording: 19,295 B.P.I. Track: 1,267 T.P.I. DATA TRANSFER RATE: Burst: N/A Sustained: 1,250 Kbytes/sec. BUFFER SIZE / TYPE: N/A START TIME: 20 sec. STOP TIME: 15 sec. ERROR RATES: Recoverable: 10 errors per 10E11 bits read Non-recoverable: 10 errors per 10E13 bits read Seek: 10 errors per 10E7 seeks PHYSICAL SPECIFICATIONS DIMENSIONS: 146mm X 83mm X 203mm WEIGHT: 3.5 Kg POWER REQUIREMENTS: +12V +/- 5% , +5V +/- 5% CONSUMPTION: 38 Watts OPERATING NON-OPERATING Temperature - - - - | 5 C to 45 C | -40 C to 60 C | Humidity - - - - - -| 20% to 80% RH | 5% to 95% RH | Altitude - - - - - -| 0m to 3,000m | 0m to 12,000m | Vibration - - - - - | less than 0.2G | less than 0.4G | Shock - - - - - - - | less than 2G | less than 20G | Temperature Gradient| 15 C/h or less | 15 C/h or less | RELIABILITY DATA Mean Time Before Failure (MTBF) : 30,000 Hrs. Mean Time To Repair (MTTR): 0.5 Hrs. Component life: 5 Years. STANDARDS UL APPROVED CSA APPROVED TUV APPROVED ==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**== I see you have listed the Fujitsu M2249E in the FAQ Missing is complete jumper information. Jumper diagrams and settings 1-408-428-0456 Fujitsu FAX-BACK (call from FAX machine) Request Doc# 2450 ==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**==**==

H.19 What is the difference between an R70 and an E70 drive?

Both drives are physically identical 'IBM type 0667' hard drives. The difference is in the formatting, and coupled with the Extended ESDI Magnetic Media Adapter. This adapter also employs the RT PCs burst DMA I/O capability and incorporates a more efficient alternate-sector scheme than the previous ESDI adapter.

The R70 drive has a 4:1 interleave.
The E70 drive has a 1:1 interleave.

There is however, a discrecpency between the reported number of cylinders between the different versions, and the VRM utility.

Anybody know which is correct? - MW

H.20 What are the characteristics of the various IBM RT disk drives?

This table is collected from the various hardware manuals for the IBM RT, and from other sources.

All drives have a 512 byte sector size.

        Drive   part#           type    Cyl     head    Sects intrl (2)
        R40     6299235         MFM     733     7       17      2
   (1)  R70     61X6942         ESDI    566     7       36      4
        E70     73X3989         ESDI    582     7       36      1
        E114    00F2273         ESDI    914     7       36      1
        E310    08F3358         ESDI    1225    15      34      1
   (3)  H310    08F3358         ESDI    1225    15      34      1

Note 1:
I am not sure why the tech manuals give such radically different number of available cylinders for the identical disk drive. I have seen an R70 and E70 side by side, and they are identical, and are 'IBM type 0667' drives! [ Are there some other 'R70' drives out there?? -MW ]

Note 2:
intrl = Sector interleave value, sects = Sectors per track.

Note 3:
The MAXTOR documentation indicates that the drive normally has 36 sectors per track, yet all the IBM drive tables and documentation indicate differently. See also the VRM table below.

An interesting recent addition is this table I built by examining the VRM utility format program. When you need to reformat a new or non-IBM drive, this utility will place the minidisk partition table and other IBM required identification information on the drive. While you can enter non-standard parameters, built into the program are the parameters for all the IBM drives. Anybody know the reason for the discrepancy? Which is correct? The R30 is interesting, I have never seen it described in any IBM literature for the RT. -MW

        Drive   type    cyls    heads   sects   intrl   skew    precomp
        R30     MFM?     733     5      17      2       0       300
        R44     MFM      733     7      17      2       0       300
        R70     ESDI     566     7      36      4       0       none
        E70     ESDI     683     7      35      1       0       none
        E114    ESDI     915     7      35      1       7       none
        E310    ESDI    1225    15      33      1       8       none
   (3)  H310    ESDI    1189    15      34      1       0       none

H.21 What SCSI devices can be attached?

The amount and type of support for SCSI devices varies by the operating system used. Please refer to the different RT operating system specific FAQ list for more information about SCSI support.

The IBM suported SCSI adapter is a 'Differential Driver/Receiver option' with the 'Alternative 2 connector'. The SCSI interface conforms to (then) proposed ANSI standard X3T9.2/82-2 Rev. 17B.

Two wires are used for each signal lead in a push-pull signaling method also called 'differential-ended'. Most drives for other vendor workstations and PCs use a 'single-ended' SCSI implementation. What this boils down to is that the IBM SCSI card is electriclly incompatible with a lot of the off-the-shelf SCSI drives.

IBM officially supported only one device attached to the SCSI interface card, the 9332 'Athens' disk drive.

However, all is not lost. :-)
Some vendors do offer their SCSI drives with an optional differential interface. There also exist a couple of manufacturers of 'Differential-to-single-ended' converter boxes. These boxes allow a bi-directional conversion of the SCSI bus and will allow attachment of these single ended disk drives.

See the AIX FAQ for more information about using OEM SCSI disks on an RT using the IBM SCSI board.

Under the AOS operating system, several people have modified the system to use an Adaptec SCSI controller. That controller uses single-ended devices.

More information about this Adaptec controller can be found in the AOS specific FAQ list. - MW

H.22 What do the LED codes mean during power on?

When power is first applied, initial self tests are performed by built it ROM routines and special processor on the system planar board. These self tests should complete with in 1-2 minutes. The tests labeled 'fatal' indicate that if this code remains for more than five minutes, indicates that component has failed.

I have seen tests 14,15,16 and 17 last for up to three to four minutes, depending on the number of hard disks and/or floppy drives connected to the installed adapters. -MW

        ROS LED Values during IPL
        00      Initialization of Mono/Printer adapter failed
        01      ROS CRC did not compare - Fatal
        02      Soft IPL check failed - Fatal
        03      Memory error or no memory - Fatal
        04      Processor card logic error - Fatal
        05      Processor or memory error condition - Fatal
        07      IOCC test resident POST - Fatal
        08      Bad processor card in IOCC test - Fatal
        09      Keyboard adapter resident POST - Fatal
        0c      initialization failed - Mono/Printer adapter and APC
        10      System timer resident POST - Fatal
        11      Interrupt controller POST - Fatal
        12      DMA arbiter resident POST - Fatal
        13      Serial port resident POST
        14      Fixed disk resident POST adapter 1 test
        15      Fixed disk resident POST adapter 2 test
        16      Diskette resident POST adapter 1 test
        17      Diskette resident POST adapter 2 test
        18      Extension ROS
        19      Attemting Manufacturing IPL
        1c      Advanced Processor card - Fatal
        1u      Enhanced Advanced Processor and memory Mgmt card - Fatal
        20      NVRAM CRC check
        21      No boot record found (NVRAM selected devices)
        22      No boot record found (ROS selected devices)
        23      Disk or diskette adapter slot or address - Fatal
        25      User error - invalid RamSpecReg - Fatal
        26      Attempting soft IPL
        27      Bootable code exceeds available storage - Fatal
        28      Unexpected return from loaded code - Fatal
        29      IPL process passed control to loaded code.
        3c      Advanced Processor card and first 128K of memory.
        3u      Enhanced Advanced Processor and memory Mgmt card.
        4c      APC logic (Advanced Processor Card).
        4u      Enhanced Advanced Processor and memory Mgmt card Logic.
        5c      APC logic and system memory.
        5u      Memory expansion option or Enhanced Advanecd Processor and 
                memory managment card.
        88      reserved - POR or processor check
        89      Unexpected machine or program check - Fatal.
        8c      IOCC test for APC.
        8u      Enhanced Advacned processor and memory managment card.
        96      Memory card 1 resident POST error condition.
        97      Memory card 2 resident POST error condition.
        98      Memory card 1 and 2 resident POST error condition.
        99      KEY locked, locked response.

H.23 What does LED code xx mean (during runtime)?

LED codes displayed while running vary greatly depending on the operating system used. Please refer to the different RT operating system specific FAQ list for more information about these LED codes used.

H.24 What is different about the RT I/O slots? What cards will run in slot 8?

The IBM RT 6150 and 6151 system units use ISA (AT) style I/O slots, however slot 5 on the 6151 and slot 8 on the 6150 are unique to the RT. Most cards that do not use memory refresh, or DMA channel 7 will have no problem with that slot. Bus timings for all the RT bus slots may be slightly different from an AT, as I/O accesses are not driven by the processor directly, but are routed via a special bus processor in the planar, called the IOCC.

The 8th slot in the 6150 RT (and the 5th slot for the 6150 only) have three signals different from the normal PC/AT assignments.

     Pin    Standard     CO-proc slot usage    My notes.. 
     B19    REFRESH      + SPK DRV             (Wire or'd to speaker control)
     D14    DACK 7       - DACK 8              DMA channel is reassigned..
     D15    DRQ 7        + DRQ 8                 .. ditto
The following cards cannot go in slot 8: These cards require special slot placements:

I have had reports that clone monochrome cards also may have problems running in an RT. I have not tried them myself. -MW

In general, any 8-bit card is better off in slots 3 or 6 (6150) or in slot 1 (6151), as those slots are 8-bit only anyway. Save the 16-bit slots for a card that needs it.

H.25 How do I run diagnostics.

IBM supplied with most RT systems several books, one set of three books are maroon in color, and contain setup, install and one book labeled IBM RT PC Problem Determination Guide (RT PD). The Problem Determination guide is usually composed of two manuals in one binder. IBM manual number SA23-2604, and for those users who ordered AIX with their systems, it also contains SA23-2603 titled: IBM RT AIX Operating System Problem Determination Guide. This binder also contains three diskettes with maroon labels. Volume one of the three diskettes is bootable, and when booted, causes it to examine the system hardware, and place a menu of diagnostic options on the screen. Most of the diagnostics are menu driven and are self-explanatory. The RT PD guide will take you thru any special procedures if necessary.

Further problem diagnosis is available in the dark blue book with the title IBM RT PC 6150 System Unit Hardware Maintenance and Service Manual# SA23-2605 or Part Number 22F9803. This book contains problem isolation charts, part numbers, installation information and a SRN (Service Request Number) to FRU (Field Replaceable Unit) part index. This book also contains a LED fault code to SRN reference, as well as probable failure part analysis charts.

H.26 Serial port cards maximums and limitations.

The following information is gleaned from the IBM announcement letters and general information sheets. It is the only information I have access to and concentrates on the limitations imposed by AIX 2.2.1 on the RT hardware, the only announced OS IBM supported for the RT systems. AOS users report that the baud rate limits have been exceeded up to 56Kb by modifications to the standard AOS kernel. I am not sure at this time what the exact speed capabilities and limitations may exist with the modified AOS kernel. - MW

H.27 What are the switches on the 3278/79 adapter?

The 3278/79 emulation adapter short version has one set of dip switches in the top left corner.
   SW      Usage
   1        Address range 1  1-ON  2-ON
   2        Address range 2  1-OFF 2-ON
            Address range 3  1-ON  2-OFF
            Address range 4  1-OFF 2-OFF
   3        OFF=Disable interrupts, ON=Enable interrupts
   4        reserved 
   5        ON for address range 1, OFF for address range 2-4
   6        OFF for slots 1-7 on PCXT and all RT slots.
            ON  for PCXT slot 8.

H.28 Jumper location and information on AT Fixed disk adapter.

The IBM RT PC Fixed disk adapter is a MFM controller, and is stock original IBM PC AT controller. The only drive that IBM used for the RT using that controller was the R40. (standard PC-AT 40 MB drive).

The MFM controller documentation for the RT that I have indicates that it can support only TWO of EXACTLY the same type of drive. The RT books indicate that no matter how the drives are arranged, the MFM controller MUST have both drives the same. The RT docs where quite specific about that limitation. Most likely a limitation of the drvice driver, not the hardware.

Interesting note, if the only MFM drive was the R40, why the warning on mixing drive types? A clue to this mystery may be the VRM drive table that mentions a R30 drive.. Humm, unannounced old feature? Was there ever an *MFM* R70 drive?? Mystery! - MW

If running two controllers make sure that one controller is jumpered for PRIMARY controller and is in slot 1. The secondary controller is supposed to be in slot 2, and can run a maximum of one hard disk. The floppy interface is not usable on the second controller. Secondary addressing is set by placing the jumpers in the position AWAY from the metal plate on the card. This arrangement was intended to have 2 R40 drives on the primary MFM controller and 1 R40 attached to the secondary.

     ----------------------------------------------------- ---
     |                     ::  ::  ::  ::                 ||
     |           o-o .     ::  ::  ::  ::                 ||
     |           o-o .     D   C   ::  ::                 ||
     |           S   P             B   A                  ||
     |                                                    ||
     --------------------------+     +--+            +----+ 
                               |_____|  |____________|     |

   Position A is for floppy drive cable.
   B  = for dasiy chained data cable for both hard drives.
   C  = for first drive control cable, or third drive on second card.
   D  = for second drive control cable.
   Jupmers in "S" direction for secondary, "P" for Primary.

   I/O addresses used (jumpered primary, slot 1):
      Floppy drives A and B - 03F0 - 03F7
      Drives C and D        - 01F0 - 01F7

   I/O addresses used (jumpered secondary, slot 2):
      Drives E              - 0170 - 0177

   DMA channel 2 (diskette only)
   IRQ diskette - 6  Fixed disk - 14.

H.29 Jumper locations and information on ESDI adapter.

The ESDI controller has the same connector arrangement as the MFM controller and only a SINGLE jumper in about the same position as the MFM controller. Looking at the card, the jumpers would be with the "S" direction being for Primary (backwards from the jumpering for the MFM controller) and the "P" direction for secondary. This interface board was discontinued with the announcement of the EESDI controller card.

This controller has a part number of 00F2160.
I/O addresses used (jumpered primary, slot 1): Floppy drives A and B - 03F0 - 03F7 Drives C and D - 01F0 - 01F7
I/O addresses used (jumpered secondary, slot 2): Drives E - 0170 - 0177
DMA channel 2 (diskette drives only) IRQ diskette = 6 Fixed disk = 14.

H.30 Jumper locations and information on EESDI adapter.

The Extended ESDI controller had two versions: (see below)
    ----------------------------------------------------- ---
    |                 ::  ::  ::  ::  ::                 ||
    |                 ::  ::  ::  ::  ::                 ||
    |                 E   D   C   ::  ::                 ||
    |                             B   A  X Y Z           ||    early card
    |                                    . o-o           ||
    --------------------------+     +--+            +----+ 
                              |_____|  |____________|     |

    ----------------------------------------------------- ---
    |                 ::  ::  ::  ::  ::                 ||
    |                 ::  ::  ::  ::  ::                 ||
    |                 E   D   C   ::  ::                 ||
    |    Z Y X                    B   A                  ||    later card
    |    o-o .                                           ||
    --------------------------+     +--+            +----+ 
                              |_____|  |____________|     |

       Position A - is for floppy drive cable both floppies.
       Position B - dasiy chained data cable for all three hard drives.
       Position C - for first drive control cable.
       Position D - for second drive control cable.
       Position E - for third drive control cable.

       Primary address,  jumper  Z to Y.
       Secondary Address, jumper Y to X.

   Later version Part Number, 08F3766.

   I/O addresses used:
      Floppy drives A and B - 03F0 - 03F7
      Drives C, D and E     - 01F0 - 01F7  and  05F0 - 05F7

   DMA channels  Diskette = 2  FIxed disk = 0 or 1 (set by program).
   IRQ diskette = 6  Fixed disk = 12 or 14 (set by program).

H.31 Jumper locations and information on the 'PORTED' EESDI adapter.

The "Ported" or Portable Drive adapter was a special version of the standard Extended ESDI controller that had the same identical layout, jumper and pin configuration as the "later" version of the Extended ESDI controler. The one difference was an external connector on the end plate of the card that could hook up the IBM "Portable drive bay" enclosure.
The portable controller had the same connectors in the middle, and I suspect that the "portable" controller was not any different from the stock controller. -MW

In a non-standard configuration, I have run run 6 ESDI drives by having a standard Extended ESDI controller in slot one and a PORTED controller in slot 2. The portable controller even had to be jumpered to the "secondary" position for installation. I also have tested the card in the primary position (undocumented on the jumper setting in the manual, but it looked JUST like the standard EE-ESDI card!) running the internal E310 drives, and it worked just fine. -MW

Part Number, 08F3612.
I/O addresses used: [looks like secondary addresses to me! - MW] Drives F, G and H - 0170 - 0177 and 0570 - 0577
DMA channels FIxed disk = 1 or 3 (set by program). IRQ Fixed disk = 12 or 14 (set by program).

H.32 IBM 9332 Disk drive information.

No Longer Available, for ordering by IBM US as of May 17, 1993.

The IBM 9332 "Athens" fixed disk drive has models with both IPI-3 and SCSI interfaces. The only version attached to the RT was via the differential SCSI interface. During boot time the AIX operating system has the ability to download microcode to the drive.

The Models 240 and 440 drives are intended to be Rack-mounted in a 9309 Rack Enclosure. The Models 250 and 450 are mounted in a standalone enclosure providing cooling and power.

The pinout of the SCSI connectors on the back of the 9332 conforms to (then) proposed ANSI standard X3T9.2/82-2 Rev. 17B, In accordance with that standard, the 9332 uses the 'Alternative 2' style shielded connector, wired for differential SCSI devices.

These are the only model 9332 drives issued with SCSI interfaces. Other model 9332 drives use an IPI-3 interface.

   Model.................  240,250  440,450

   Capacity in Mb          200.3      400.6

    Number of Cylinders     1349       1349 
     User                   1346       1346
     Reserved                  3          3

   Access in Milliseconds
    Average                 19.5       19.5
    Track-to-Track           3.2        3.2

   Data Rate--Mb/sec
     Maximum burst           4.0        4.0  
     multisector         1.4-1.9    1.4-1.9 

   Rotation Speed RPM       3119       3119

   Latency in
    Milliseconds             9.6        9.6

   Number of Actuators         1          2

H.33 Pin connections and tech. info on 6153, 6154 and 6155 monitors.

IBM 6153 Advanced monochrome Graphics adapter. - P/N 00F2357

IBM 6154 Advanced Color Graphics adapter. - P/N 00F2350

IBM 6155 Extended Monochrome Graphics Display

Low voltage 90 - 137 VAC - P/N 6848215
Hi voltage 180 - 259 VAC - P/N 6848216
Power Frequency 48 - 62 Hz

H.34 5081 Display technical information.

The 1280x1024 resolution is not available from the standard megapel display adapter. A Matrox PG1281/R display adapter and corresponding device drivers supported this adapter/display combination.

The megapel adapter will NOT work with the 5081 model 2 monitor.

H.35 Jumpers and documentation on the Ungermann-Bass IBM ethernet board.

The IBM ethernet board was made by Ungermann-Bass, and is the exact same board as Ungermann-Bass model 2273A NIC Baseband adapter. Ungermann-Bass may be reached direct at 1-800-873-6381.

With the gold fingers towards your stomach, and the bracket on the right with the electronics up, the IRQ jumpers are just above the gold contacts. The Address jumpers W10 thru W13 are to the left of the prom about the middle of the board. The unlabeled jumpers (W14 on some boards) on the almost far left are the timer interrupt interval. The jumper connects only one pair of pins.

          1    2    3    4
  W14    . .  . .  . .  . .    position 1 = interrupt ever  9.1 ms
                               position 2 = interrupt ever 18.3 ms
                               position 3 = interrupt ever 36.6 ms
                               position 4 = interrupt ever 73.2 ms

  IRQ jumpers are labeled:
   IR3 IR4 IR5 IR6 IR7 IR2 <--- IR2 is really IRQ 9, all others are correct.
    .   .   .   .   .   X      connect only one vertical pair of pins.
    .   .   .   .   .   X      IRQ9 is the factory default.

  I/O Memory address jumpers  (Labled W10 thru W13)

   W10   W11   W12   W13               
   . .   . .   . .   . . 

   XXXX     =  jumper is connected two adjacent pins together.
   X        =  Jumper is actually only jumpering ONE pin, the other side
   X           of the jumper is hanging off of the row of pins and is
               just there for future use.

   W10   W11   W12   W13    ADDR        W10   W11   W12   W13    ADDR 

 ========================   ======  +   ======================   ======
   X     X     X     X              |   X     X     X      
   X  .  X  .  X  .  X  .   080000  |   X  .  X  .  X  .  XXXX   0C0000
 ========================   ======  +   ======================   ======
         X     X     X              |         X     X      
   XXXX  X  .  X  .  X  .   088000  |   XXXX  X  .  X  .  XXXX   0C8000
 ========================   ======  +   ======================   ======
   X           X     X              |   X           X      
   X  .  XXXX  X  .  X  .   090000  |   X  .  XXXX  X  .  XXXX   0D0000
 ========================   ======  +   ======================   ======
               X     X              |               X      
   XXXX  XXXX  X  .  X  .   098000  |   XXXX  XXXX  X  .  XXXX   0D8000
 ========================   ======  +   ======================   ======
   X     X           X              |   X     X            
   X  .  X  .  XXXX  X  .   0A0000  |   X  .  X  .  XXXX  XXXX   0E0000
 ========================   ======  +   ======================   ======
         X           X              |         X            
   XXXX  X  .  XXXX  X  .   0A8000  |   XXXX  X  .  XXXX  XXXX   0E8000
 ========================   ======  +   ======================   ======
   X                 X              |   X                  
   X  .  XXXX  XXXX  X  .   0B0000  |   X  .  XXXX  XXXX  XXXX   0F0000
 ========================   ======  +   ======================   ======
                     X              |                      
   XXXX  XXXX  XXXX  X  .   0B0000  |   XXXX  XXXX  XXXX  XXXX   0F8000
 ========================   ======  +   ======================   ======

H.36 RT Token Ring card jumpers and addressing.

The Token-Ring card has a 9-pin female connector, and usually a green dot sticker on the metal plate, but not always. The adapter card had two versions, early and late.

For both versions, with J1 and J2 to the left, indicates no proms are installed in the sockets shown by the XXX's.

      ----------------------------------------------------- ---
      |       ...  ...  +----------+           ...         ||
      |       J1   J2   |small card|           J5          ||=|  9-pin connector
      |                 +----------+                       ||=|
      |  XXX                                               ||    
      |  XXX                                               ||    early card
      |   XXX                 YYYZZZ J3                    ||
      --------------------------+     +--+            +----+|
                                |_____|  |____________|     |
      ----------------------------------------------------- ---
      |       ...  ...                      ...  ...       ||
      |       J1   J2                       J5   J6        ||=|  9-pin connector
      |                                                    ||=|
      |  XXX                                               ||    
      |  XXX                                               ||    late card
      |   XXX                 YYYZZZ J8                    ||
      --------------------------+     +--+            +----+|
                                |_____|  |____________|     |

During installation, make sure that the interrupt/DMA level does not conflict with any other card, and that the I/O and DMA address jumpers match, in accordance with the devices settings. Note how the address and DMA settings travel together.
        I/O range     DMA     J5     J6
        01c0-01cf      5      up     up
        0140-014f      6      up     down
        11c0-11cf      7      down   up     (see note below)
        11d0-11df      3      down   down   (can conflict with serial port 1)
The 11c0 address cannot go in slot 8 of the tower (6150) model 25 or slot 5 of the desktop (6151) model 10. DMA channel 7 conflicts with use of the megapel adapter. DMA channel 3 conflicts with serial port 1 (S1) on the planar. Only a problem if you have that port defined via devices, otherwise you can use DMA channel 3.

The early version of the RT Token ring card can only go at ONE of two possible addresses. It is recognized by having a daughter card plugged on it about in the middle of the card (sometimes). It also has a J1 and J2 jumpers in upper left and a J3 jumper in the middle of the card along by the gold fingers, and a J5 address jumper only. I personally have never seen the 'early' version of the RT Token card.

See page 1-21 of the User Setup Guide and Options Installation manual for more complete matrix of interrupt/DMA conflicts.

H.37 - What are the differences between the 032, APC and EAPC processor types.

H.38 Speed and capability of the Floating Point options for the RT computers.

(FPA, MC68881, AFPA.)

All models of the RT systems running AIX can run with no floating point hardware assist and provide for simulation routines for floating point operations. Most code requiring floating point operations will operate correctly, unless compiled on AIX with specific flags that force the use of the floating point hardware. (The -f compiler flags.)

The standard Floating Point Accelerator (FPA) contains instructions for general floating point operations, but does not include direct hardware support for trancendental functions (sin, cos, tan, ect..).

The model 115 and 125 computers, with the Advanced Processor card include a Motorola MC68881 chip running at 20 Mhz. This chip is faster than the FPA, but not as fast as the Advanced Floating Point Accelerator (AFPA).

In general the FPA is slower than the MC68881, which in turn is slower than the AFPA. The FPA advantange is it can run in parallel with the processor, providing some overlap of operations.

H.39 Where can I obtain a replacement battery?

The battery located under the front cover of the tower model RT next to the keylock, and inside the case on the desktop unit behind the keylock mounting bracket. It maintains the real-time clock for the system when the power is off. It also maintains the non-volatile ram (NVRAM) contents. The NVRAM contains several items, among which are: the last error record, and the current list of boot devices.

Submitter: Matt "C P." Rush <>
Subject: RT batteries through Radio Shack
Date: 26 Oct 93 21:10:43 GMT

Just in case anyone out there needs to replace the battery in their RT, they can be Special Ordered through your local Radio Shack. Amazingly, the IBM-RT is actually listed in their battery cross- reference, but in case YOUR Radio Shack is lame, the part no. is: CLB-5293/W
The painful thing is the PRICE: $15.99. I decided that it wasn't that bad to do a 'date' command every time I booted up. :-)

My notes here..
This is average price for a lithium computer battery. The batteries on some RT systems that I have used, have lasted as long as 6 years before needing replacement, others are still going strong, so it is a relatively small price comared to other replaceables.

Someone asked: > Are these batteries any different from garden-variety AT batteries?

There IS NO one common AT battery. Some are 3V some a 6V. Some are plug in, some snap in more traditional battery carriers.

The RT battery (IBM P/N 6299201) for the RT is 6.8 volts!

Last I heard, IBM wanted $25.00 US for a RT battery. The Radio Shack battery sounds like a good deal, if it is a proper replacement. I have seen FIRES start in an RT that had an improper battery!

At least one user has reported using AA batteries in a traditional carrier and rewiring the carrier with the old battery plug.

As always.. caveat emptor, user beware, your milage may vary, ect.. - MW.

H.40 - RT 6157 tape interface card pinout and drive information.

> I have a type 6157 RT tape drive here, and I'm trying to find out what
> sort of interface it uses. It's the 45 meg 1/4" cartridge drive, and
> popping it open revealed a Cipher modem 540 (or 640?) tape mechanism.

Depending on the model of the drive, it is

Both models can read QIC-24, but only the model 1 (no dash) can write QIC-24.

The drive is used with either the IBM RT interface card, or a compatible vendor QIC-02 interface. This is a industry standard interface, so you may be able to find another interface card that will support it. IBM used this drive on several pieces of equipment besides RT systems: 6152 (PS2/60), and AS/400 and maybe others.

I have never examined the internal works on one of these drives myself, so I was not sure of the pinout of the internal connector used between the IBM 37-pin cable and the internal transport. See Marc Papen's post attached below for the internal cabling of the transport. I have no information on the actual transport itself. TANDON or CIPHER made the drives for IBM. This transport was used by lots of other vendors. -MW

This is the pinout of the cable connector on the back of the IBM tape interface card. The original cable terminates in a 37 Pin Male D-Shell connector.
   Signal name         Signal pin      Matching ground pin

   Cable shield        19              1
   Parity Bit (odd)    20              2
   Bit 7               21              3
   Bit 6               22              4
   Bit 5               23              5
   Bit 4               24              6
   Bit 3               25              7
   Bit 2               26              8
   Bit 1               27              9
   Bit 0               28              10
   On-Line             29              11
   Request             30              12
   Reset               31              13
   Transfer            32              14
   Acknowledge         33              15
   Ready               34              16
   Exception           35              17
   Direction           36              18
   Reserved            37

Signal Interface:      QIC-02 Industry standard
Transfer Rate          86.7K bits per second (model-1)
Tape Speed             90 Inches per second
Internal data buffer   2K bytes

I have the IBM schematics on the RT interface card. -MW

My notes:
Take with a minor grain of salt, I have not gotten out a scope or meter on this.. - MW

Submitter: Marc Papen
Subject: More answers to connecting a non IBM Tape drive
Date: Sun, 6 Mar 94 17:23:16 MET

I have a cipher(sp?) QIC-02 tape drive working with the IBM tape-controller. I did have to build my own custom cable. For this purpose I include the pinout for the 50 pin dual inline connector on the drive:

These are listed in the QIC-02 specs (rev. F):

even pins:

   10: HBP- host bus odd parity
   12..26: HB7-..HB0- host bus bits 7..0
   28: ONL- (online)
   30: REQ- (request)
   32: RST- (reset)
   34: XFR- (transfer)
   36: ACK- (acknowledge)
   38: RDY- (ready)
   40: EXC- (exception)
   42: DIR- (direction)
   rest unconnected.
"All odd pins shall be connected to signal GND at the Host".

While build a cable one has to look out for not making the cable too long. I used an unshilded cable and had to shorten it to 1/2 meter because else I would get a Drive not Ready when trying to acces the drive.

[ The drive Marc got to work was a Cipher 540 rev H 60 Mb drive. - MW ]

One more thing about tape controllers. I think that most "normal" QIC-02 controllers won't work as they are 8 Bit cards and can't be jumpered to Int 12. Also IBM uses some special mode with this card that utilizes the drive as a blockdevice. (At least I saw this in the man-pages to AOS)

I hope this helps others to get a tape drive to work.

H.41 What non-IBM devices attached to an RT?

Support for these devices usually varies by OS. Some value added resellers added drivers or had compatible features.

More work on this section is needed. - MW

X.1 Acknowledgements and copyright information.

This file is provided AS IS with no warranties of any kind as to the usefullness/correctness of these procedures/questions. The author shall have no liability with respect to the infringement of copyrights, trade secrets or any patents by this file or any part thereof. In no event will the author be liable for any lost revenue or profits or other special, indirect and consequential damages.

IBM, AIX, AT, XT, RT, RT PC and RT Personal Computer are trademarks of International Business Machines Inc.
UNIX is a registered trademark of American Telephone & Telegraph in the United States of America and other countries.
Any other trademarks not specifically mentioned are owned by their respective companies.

X.2 RT software FTP site(s).

See the AIX master index FAQ file section X.2 for FTP site information.
See the AOS software FAQ file for various FTP site locations.

X.3 Credits for hardware FAQ

The following people have either submitted articles for inclusion, made suggestions, or had parts of old articles included within re-arranged information. If you want your name dropped please let me know.
Marc Brett              <>
Jon Brinkmann
John Carr               <>
David L. Crow           <>
Bjorn Engsig            <>
eliot                   <>
Robert Fickling         <>
Mike Johnson            <>
John R. Moore           <>
Francois Normant        <>
Gerald Oskoboiny        <gerald@vnet.IBM.COM> 
Marc Papen              <>
Richard Rogers          <>
Matt Rush               <>
Russell Schulz          <>
David Snearline         <>
Bennett Todd            <>
John Tracey             <>
Andrew Yeomans          <>
Pim Zandbergen          <>

Last updated: 20-Oct-2013, M.Kraemer