@8EFE.ADF IBM PS/2 SCSI Adapter
C8EFE.ADF Init file for @8EFE.ADF
@8EFE.ADF IBM PS/2 SCSI Adapter - different version
@8EFEh.ADF "IBM PS/2 SCSI Adapter - PHW modified ADF 1.0.1"
(For Historical Purposes Only! Could not pass other IRQs)
Japanese SCSI/A Adapters
Long SCSI /A
Swapping BIOS chips for >1GB Support
Modified ADF for ESDI and SCSI Coexistence
Could Not Pass IRQs to System!
New BIOS Improvements
Multiple SCSI Device Order
Short SCSI /A (>1GB support!)
Long SCSI /A (FRU 15F6561, 85F0002)
F1 PTC Resistor
T-RES Term pack
Y1 25MHz (old) 20MHz (new)
Y2 20MHz (old) 12.5MHz (new)
ZM1 Adaptec AIC-6250EL
ZM5 Microcode 64F5801
ZM26 SCSI BIOS Even 64F4376
ZM27 SCSI BIOS Odd 64F4377
The SCSI Adapter/A lacks auto termination.
For proper termination of the SCSI chain, you will need
to either use the internal T-Res or the external
ECA 032 Explanation
The old non-cached adapter can be
identified by the FRU 15F6561on the lower left hand
corner of the component side of the card. Some adapters
may have been updated.
The old card, Y1 is 25MHz and Y2 is 20 MHz.
On the updated adapters, Y1 is 20MHz and Y2 is 12.5MHz.
Yellow wires may or may not exist on any level of the
card. If PN 85F0002 is present, it is the latest level
and does not need to be replaced. If you have either of
these versions of the 15F6561, replace them.
Joe Kovacs says:
The original IBM 32-bit SCSI (without cache)
worked OK with HDs, but lost bits with CD-ROMs. So
an engineering change was specified, and it was patched
with a couple of wires in the upper right hand corner,
becoming an 85F0002...
The reworked 15F6561 cards I have seen have
the rework wires just about dead center (FAIR). Not sure
if this is it...
The SCSI Adapter is a 16-bit Micro Channel
bus master adapter that features an 8.3MB per second burst
data transfer rate, 16-bit data path with 32-bit address
capabilities, and can be installed in either a 16- or 32-bit
system card slot.
The bus master capability of
this SCSI adapter optimizes data flow from each SCSI
device configured to the system. This capability can
provide performance benefits in applications where
multitasking or high-speed data flow is essential. It
allows the processor to be off-loaded from many of the
input/output activities common to DASD transfers. This
SCSI Adapter also conforms to the Subsystem Control
Block (SCB) architecture for Micro Channel bus master.
Is the SCSI /A SCSI-2?
The IBM SCSI adapter is 8-bit narrow,
single-ended SCSI with SCSI-2 style command set and
SCSI-1 speed of 5MB/s. It can handle 7 Fast- or
Ultra-SCSI devices and can handle even 7 Wide-devices if
there are converters used from Wide-to-narrow SCSI
(68-to-50 pin) but these devices must use device numbers
from 0 - 6. The SCSI-ID 7 is used for the controller
itself. First device on IBM SCSI controllers is the one
with the highest ID (6) opposed to Adaptec or Buslogic
controllers which boot from ID (0) or (1). It can handle
even Ultra-SCSI drives, because SCSI is compatible in
any directions - other than shit-IDE.
These SCSI adapters have a single bus that
provides both internal and external SCSI bus
connectors. For these adapters, devices are
logically ordered depending only on adapter slot
number and the SCSI IDs of the devices.
Note: IBM SCSI adapters
that use a SCSI BIOS earlier than the 92F2244 / 92F2245
pair will require the IML drive to be SCSI ID6.
The SCSI w/Cache is a "Single Ended" SCSI
controller, which means that every signal has GND as
return line. The other relevant SCSI standard of
"Differential" means, that every signal has a return
line with inversed polarity ... when -for example-
+DATA0 sends a logical "1" on the active line the return
line -DATA0 sends a logical "0". The transceiver circuit
in the device checks the *difference* between the two
signals (therefore "differential") - line disturbances
afflict both lines at once and are eliminated therefore.
Multiple SCSI Device Order
Now, I got four 1GB 0662s w/ CD-ROM in my 9595-OMT. The problem is
that Win 3.1 doesn't see all of these, only 2 -0662s and CD-ROM. Ref. disk
sees all 5 w/ CD-ROM. I just added 2 0662s and not sure what's on them.
I tried "fdisk" and "dos" but their not there. Any suggestions?
SCSI IDs are as follows:
- ID 1 0662
- ID 2 0662
- ID 3 CD-ROM
- ID 4 0662
- ID 5 0662
From Brad Parker:
Hi Bob, Using the ANSI/IBM standard, I would set the IDs as
- ID 6 boot drive (c)
- ID 5 2nd HD (d)
- ID 4 3rd HD (e)
- ID 3 4th HD (f)
- ID 2 CD-ROM (g)
Because the standard gives the greatest
SCSI bus priority to the highest numbered drive and the
lowest priority for the lowest numbered drive. If you
have more than one partition on each drive, then the
drive letters may change, but the device IDs will stay
the same. In fact, I might just set the CD to id 0 to
give yourself room for future expansion :-)
I have five HDs, three floppies, a 6 disc
changer and a Zip drive on one of my 95s, of course I
have two host adapters....
New BIOS Improvements (From Tim Clarke)
The upgrade provides the following additional capabilities:
- More efficient use of Adapter ROM memory - minimizes adapter configuration
- BIOS support for fixed disks up to 3.94 gigabytes per device.
- Supports "Search IML" from any PUN (Physical Unit Number) or SCSI ID.
The system partition is no longer restricted to only SCSI ID=6.
Each fixed disk ID will be searched for a valid system partition.
- Allows redundant system partitions (IML).
- Sharing of SCSI devices. An external SCSI device, such as the 3511, may be
shared between two system units. The menu item is "Target"
Multiple, redundant partitions are useful if
drive id. 6 fails. 'Recovery' can be automatic
without partially ripping the machine down to
change SCSI Id.s. You do, however, need to have
planned for this and set up the appropriate
'IML/Reference Partition'(s) and 'Active Partition'(s)
on the 'fallback' drives (Id. 5, 4, 3... etc.)
Mandatory Replacement of SCSI Adapter FRU P/N15F6561
This is the long uncached adapter. See
this ECA for more info.
Short SCSI /A (P/N 66G1080)
The short uncached SCSI adapter was likely designed by IBM Japan.
More information about this card (and its close relatives) can be
The short card (with microcode dated 1993 and later) can handle
The short card was built by IBM to fulfill
longer running service contracts on old machines after
production of the long uncached adapter ran out. The
BIOS ( 92F2244 and 92F2245) is the same as used on
the "later" cached SCSI Adapter so it can support IML
drives up to 3.94GB. The adapter card itself is an
interesting mix of components from the uncached (long)
and later cached (long) SCSI adapters. Works
Terminating the IBM SCSI-1 Adapters (archive)
> Peter, if you use a yellow termpack on a adapter or
board that had a red one initially, will that enable it to
Definitely no. The "Auto-Terminate" is a
function that require a little more hardware: a
switching transistor that disables the TermPwr wire from
the T-RES and another transistor / IC function that
senses the voltage on the TermPwr line and the voltage
on the data lines to figure out whether the line is
terminated or not.
From Tim Clarke:
AFAIK, there is only one FRU for the
"internal" termination resistor pack for the IBM SCSI
w/cache (adapter FRU 85F0063) that has the appropriate
20-pin socket and the IBM SCSI w/o cache (adapter
FRU 85F0002). The termination resistor pack
(20-pin) is FRU 57F2870 and, provided you insert it with
Pin 1 correctly oriented, should work O.K.
Enable Termpower or Not?
Back in the "good old times" there was a
fairly common problem with the TERMPWR: if you had an
external box and the device was set to supply TERMPWR as
well as the adapter it could happen that the external
device tries to feed back +5V via TERMPWR line into the
controller once the "computer" was turned off. Which
often fried the cable and / or blew the TERMPWR
The later standard defined the TERMPWR
circuit as a "fuse / diode" combo:- the fuse (pico fuse
or PTC / auto-reset fuse) to protect the adapter /
device against short-circuits on the TERMPWR line and
the diode to prevent backflow of +5V from external
devices to the controller.
So *normally* there should be no problem
to have TERMPWR enabled on all devices - which makes
sense on setups with very long cables and multiple
external devices. The importance of TERMPWR is often
underestimated in SCSI-1 environment. Here it is pretty
important to feed the TERMPWR line from *at least* one
device to have the proper pull-up on the signal lines at
all. On SCSI-2, where each device *should* have its own
active termination and *should* monitor the TERMPWR and
set the termination accordingly it is of lesser
importance. In the worst case one device supplies the
termination at least - if not the host adapter
The main problem occurs, when the TERMPWR
line on SCSI-1 setup is interrupted between two devices
and none of the devices supplies TERMPWR: in this case a
proper termination cannot be achieved, because the
(passive) terminator at the end of the chain has no
TERMPWR to act on.
Multiple installed IBM SCSI
MC/A (w/o Cache) Adapter
If more than one IBM MC/A SCSI Adapter (FRU
P/N 85F0002 or 15F6561) is installed in a MC-System, and
during setup two or more adapters are shown with same
PU/LU setup, or SCSI HD-drives connected to this card(s)
are not correct responding, check the EPROM's in
position X5 (ZM5). The EPROM-P/N in position X5 should
sure what this means. None of the SCSI Adapters I have
use the mentioned EPROM. Good or bad?
Swapping BIOS chips for >1GB Support
From Peter Wendt:
Some time ago Charles Lasitter sent me one of
the rare short IBM SCSI adapters without cache /A ... and
I found out, that this adapter uses the same two SCSI BIOS
chips 92F2244 and 92F2245 as the "later" SCSI adapter with
cache. This card however is a strange mix of this "later"
adapter and the uncached ... on half the length.
Today, while juggling around with parts & cards on
a Model 90, I decided by what reason to remove the
SCSI BIOS from an old uncached SCSI and stuff that from
the "later" cached on it. Earlier this year I'd tried to
swap the entire EPROM sets among the old and the later
cached - and it did not work. Today I left the busmaster
microcode EPROM on the card and only swapped the
To my indescribable surprise it worked.
To make sure that it is not a gimmick of that
machines' BIOS I tried it on a Mod. 70-A21, which has
definitely no enhanced SCSI BIOS support in the planar
microcode. I pulled the 2GB IBM 0664 harddisk from my
WinNT Server and installed it in the Mod. 70. I have a
heavily modified Mod. 70 - has a standard power-plug (as
described on my page, folks !) and a Kingston 486DX-33
upgrade. I also installed the uncached SCSI with the old
EPROMs. No surprise: "No operating system" and the
Then I used the 92F2244 and 92F2245 on that same
adapter... Voilà: "OS Loader V4.00 ..." and WinNT 4.0
Server started up... ! (Ever seen that on a Mod. 70 ?)
Tried the same procedure with the old IBM SCSI adapter
with cache (the one *with* the AIC-6250EL Line
Interface) - with the same results. Old BIOS chips:
No operating system - New chips: Win NT starts.
Conclusion: If you have one of the older SCSI-Adapter
*cards* you can use the SCSI BIOS from the later-level
SCSI Adapter with cache to make the system capable to
handle drives over 1GB.
I do *not* know if there is another limit after 4GB -
but assume it is (I don't have drives over 2.2GB
currently). This limitation will at least exist on the
IML-machines, since the principle that starts up the IML
cannot handle drives over 3.94GB (the mysterious
IML-border) due to the technical method of putting the
system partition MBR at *the end* of the physical
diskspace. The register width is obviously limited to
any number of total data-blocks below 4GB. So that does
not change at all.
Some Other Thoughts
From Charles Lasitter:
I've had some VERY entertaining results in
my installations, depending on what other drives were
present, and which version of the processor BIOS was
With the 52G9509 in place, ID6 in bottom
bay (Mod 95) at end of cable, ID5 in bay above on next
spot on cable, I couldn't get the IML to go to ID6 to
save my ass. It made a beeline for ID5 every time. Put
in the old BIOS, and it goes straight for ID6.
I think there are a LOT of quirks like
this (and yours) to be mapped out, and that seemingly
innocuous settings changes in the ABIOS make differences
you'd never guess sometimes.
I also suspect that the Mod 90 is it's very
own distinct bird with it's own eccentricities in this
and related matters.
Making Your Own IBM Cable
The actual cable itself is a standard SCSI-1
cable. The unusual part is the 50 pin edgecard connector.
Note that Pin 1 on the adapter is towards the mounting bracket
on the circuit board side of the adapter. (the pin on the component
side is marked "2").
(see also HERE)
(Thanks to Rick Ekblaw for these ZM5 - 27C256 images)
SCSI BIOS 92F2244, 1991, for PS/2 Caching SCSI controller. 27C256
SCSI BIOS 92F2245, 1991, for PS/2 Caching SCSI controller 27C256
Modified ADF for ESDI and SCSI Coexistence
For a mixed ESDI+SCSI installation, the "incorporated
BIOS" (if any) plus adapter ROM address determine the BIOS
"Drive Number" and the ESDI ROM has to be processed
first (i.e. Be BIOS Drives 80h & 81h) for correct
operation. Which is why there can be problems with onboard SCSI
and/or System Partition (but not Convenience Partition, IIRC)
As far as I recall the German version ADF is the
one I rewrote for manual selection of the ROM addresses. It
was written to gain compatibility with a) the IBM SCSI adapter
and b) the Adaptec AHA-1640. It allows to put the ESDI
address range after them - to make the SCSI adapter
come primary HD adapter.
The English (original IBM) version requires the ADP - the
German does not use it. It does not harm if it is still on
the refdisk, but it is necessary and you could delete the
CDDFF.ADF to get some few bytes of room. Then rename the
@DDFFA.ADF to @DDFF.ADF and copy it onto your refdisk.
After that you get the German comments and can select your
adapter address range manually - or autoconfig does it for
you - using C800 as a default value if no other adapter
in a lower-numbered slot already allocates that range.
(I rewrote this file for operation of Mod.80's along with
a hardware encryption card - Utimaco SafeBoard - which
required the ESDI adapter to reside on C800, and which was
barely gained with the ADP.)
From Unal Z:
Safe to use before 1990, I would say...
The German version is from 1988 and contained in the
refdisk of Mod. 70/80. At this time and on this refdisk,
there were no any SCSI adapters resp. SCSI ADFs. Hence,
standalone ESDI mode without SCSI, because Spock/Tribble
were not yet available. The "Adapter Memory Location" item
is functional on the 1988-DDFF.ADF, it is not commented
The English version you posted is from 1990 and contained
on Mod. 8580-Axx refdisk. This refdisk has a WORM
support for the MO drive and contains now SCSI ADFs, Spock
and Tribble (SCSI with/without cache). The "Adapter Memory
Location" item is partly disabled on the 1990-DDFF.ADF
where only the "ROM Enabled" choice is enabled.
The English version of the ADF I referred to is from 1993
and contained on the latest refdisk v1.12, about 1993,
along with support for SCSI adapters resp. SCSI ADFs,
Spock/Tribble/Corvette are there. The "Adapter Memory
Location" item is completely disabled on the
1993-DDFF.ADF, it is commented out.
Furthermore, the 1993-SysConfig SC.EXE has doubled in size
compared to 1988, you can see strings like "EXABYTE 21F TOSHIBA
XM 3232 MD3125A I8EFF.ADF I8EFC.ADF I8EFE.ADF" which you don't
see in 1988-SC.EXE but see some in 1990-SC.EXE "I8EFE.ADF I8EFF.ADF".
(Would that mean better Corvette support in Mod. 80 with
1993-SC.EXE?) Ed. use XGAOPT
to patch Model 80 refdisk...
The best ESDI case is to get and use always the latest
refdisk. The ADF and SC.EXE history above may help to
explain ESDI/ESDI+SCSI anomalies, especially in
combination with older SC.EXE and newer DDFF.ADF.
P.S. History and behavior of SysConfig Mod.70/80...?
Could Not Pass IRQs to System!
I had one Adapter with a modified MCA bus decoder, which
*should* be able to pick one of the five IRQs manually
with a jumper field - but unfortunately it did not work as
If you look on the hardware of the card you find only
IRQ14-line (0Eh) is tied up into the bus interface, the
others "just hang there". I wired them to a jumperfield
hotglued to the board and *thought* it would suffice to
set the IRQ manually and just tell the ADF about it.
The "Set Configuration" (SC.EXE) however failed to
properly include the infos and set the card to 0Eh
nonetheless regarding the infos used for other adapters
even if it were jumpered to (eg) 09h hardware-wise. That
consequentially led to confusion and the system crashed.
At one point I stopped further work on it. The original
goal was more flexibility on the adapter settings, but it
did never take off. You cannot trick out MCA that easy...
Pinouts for the SCSI /A and the SCSI w/Cache
You can see a tableized version of Peter's observations
AdapterID 8EFE IBM PS/2 SCSI Adapter
I/O address for adapter. Each adapter must have a unique address
3548-354F, 3550-3557, 3558-355F, 3560-3567, 3568-356F, 3570-3577, 3578-357F
DMA Arbitration Level
DMA channel used to transfer data.
< "Level C">,
D, E, 8, 9, B, 1, 3, 5, 6, 7
Bus Arbitration Fairness. Whether the adapter will release control
of the bus when it has been using it exclusively
ROM Wait State Disable
Whether a wait state is added to accesses of the ROM on the adapter.
<"Enable Wait State>,
No Wait State
SCSI Adapter Address (ID)
SCSI ID of the adapter
6, 5, 4, 3, 2, 1, 0"
ADPItem 1 ROM Address Range
This field shows the address of the 32K block of memory that is
assigned to the adapter. Only one SCSI Adapter will have the ROM assigned, and
any other SCSI Adapter installed will share that address range. If the ESDI
adapter is also installed, then the address of the SCSI adapter must be greater
than the ESDI adapter address.