IBM SCSI w/Cache
@8EFF.ADF IBM PS/2 SCSI Adapter w/Cache
C8EFF.ADF Init file for _8EFF.ADF
192-067 PS/2 Micro Channel SCSI Adapter with Cache
(32-bit busmaster, autoterminating)
Block Diagram for SCSI-C w/Cache (WIP)
10 pin Artifact on Newest SCSI w/cache
New BIOS Benefits
Swapping BIOS chips for >1GB Support
Description and Specifications for SCSI w/cache (possibly OLD)
Results from upgrading to 2MB cache
Non-Compatible SIMM Results
Converting Standard 30-Pin SIMMs
8MB Cache Hack?
Testing SIMMs for 2MB upgrade
Autotermination Capability- Yellow vs. Orange Termpacks
Terminator Resistance Values
Old "Spock" (FRU: 84F8014, FCCID: ANO6451018, Single oscillator)
F2 Bourns Transorb
U32 80C188 10 MHz (busmaster CPU)
U44 Hitatchi HM62256LFP-12T
U47 Adapter BIOS 64F5984
U48 OKI 15F7917
U68 SCSI BIOS, Even
U69 SCSI BIOS, Odd
U70 15F6903 Memory Controller
U73 Adaptec AIC-6250EL Line Interface
U79 33F6715 SCSI Controller
U87-U88 30 pin SIMM
Y1 20.0 MHz Oscillator
Pin 2 of the internal port is on the component side. Pin 1
is on the circuitboard side.
The C188 has 2x8-bit parallel-ports but only an 8-bit external
The "old" IBM SCSI Adapter with cache /A has no internal
termination resistor and needs the large external Terminator block. This
adapter needs the update SCSI BIOS P/N 92F2244 / 92F2245 in order to handle
Note: The Adaptec AIC-6250EL
Line interface chip is just "glue logic".
Newer "Spock" (FCCID: ANO6451018, Dual oscillator)
U32 80C188 10 MHz
U47 Adapter BIOS, 33F5546
U70 15F6903 Memory Controller
U73 AIC-6250EL Line Interface
U79 33F6715 SCSI Controller
U68 Even SCSI BIOS
U69 Odd SCSI BIOS
U87-U88 30 pin SIMMs
Y1 20.0 MHz Oscillator
Y2 25 MHz Oscillator
The "newer" version is mostly seen in Europe. This adapter needs the
SCSI BIOS P/N 92F2244 / 92F2245 in order to handle drives >1GB. The
"dual OSC"-adapter needs an external terminator.
Ed. Odd, I have a single osc
6451018, BUT it has the solder pads and the outline for Y2.
"Spock Prime" (FRU: 85F0063, FCCID: ANOSPRIME, Triple oscillator)
J300 C60 Port
T-Res SCSI terminator
U32 80C188 16 MHz
U33 84F8324 Line Interface
U47 BIOS 61G2976
U68 SCSI BIOS Even
U69 SCSI BIOS Odd
U70 15F6903 Memory Controller
U79 33F6715 SCSI Controller
U87, 88 30 Pin SIMMs
Y1 20.000 MHz
Y2 25.0000 MHz
Y3 32.0000 MHz
Functions of Late Adapter Oscillators
20 MHz oscillator is for the SCSI-Line interface processor.
25 MHz drives the cache controller.
32 MHz clock for 80C186-16 microcontroller,
which supplies the busmaster functions.
This card is significantly faster than the "old" adapter.
NOTE: This adapter
is also referred to as a "three can" Spock, because of
the three square silver oscillators, or "cans".
It has a burst transfer rate of 16.6MBps over the MCA
bus and can be used in either a 16- or 32-bit Micro
Channel slot. The IBM PS/2 Micro Channel SCSI Adapter
with Cache is a 32-bit busmaster SCSI adapter containing
a 512KB cache buffer that allows system memory to be
totally dedicated to running the application rather than
a portion being reserved for software caching.
This SCSI adapter is recommended where improved
data transfer rates and multiple SCSI devices are
required and system memory is constrained.
However, 512KB cache is too small for the LAN Server
The "latest" cached SCSI, FRU 85F0063
(FCC-ID is ANOSPRIME), has no Adaptec chip present and a
larger yellow 20-pin DIL terminator chip close to the
external port. This card has the strange
10-contact card edge connector close to the
internal 50-pin card-edge. It has a third oscillator as
well: a 32.0000 MHz (Y3).
Description and Specifications (possibly OLD)
||SCSI-1 w/SCSI-2 commands
|SCSI bus path / speed
||8 bit / 5 MB/sec
|I/O bus path / speed
||16 bit / 3 MB/sec
||None (use software)
|Tagged Command Queuing
|Old SCSI w/cache CPU
||80C188 at 10 MHz
|New SCSI w/cache CPU
||80C188 at 16 MHz
||Type 3 (long)
||One internal; one external
||7 devices per adapter
|Cache std / max
||512 KB / 2MB
||Two 30 pin SIMMs
||0, 512K, 2MB
|Cache write policy
ECA 032 Possible Replacement Required
The old adapter w/cache can be identified by PN 64F1333
on module U47 (just below the MMKs). If you have this adapter, replace
Ed. I saw something about potential
data loss concerning this ECA. Not sure- my U47 is the adapter BIOS.
New BIOS Benefits (From Tim Clarke)
The upgrade provides the following additional capabilities:
1. More efficient use of Adapter ROM memory - minimizes adapter
2. BIOS support for fixed disks up to 3.94 gigabytes per device.
3. 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
4. Allows redundant system partitions (IML).
5. 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.)
From Charles Lasitter
With the triple oscillator (newest) versions of the Enhanced
SCSI w/cache, I see some Microcode differences but don't see much in the
way of any particular pattern for when one Microcode will be in use versus
One adapter has 10G4890 dated 1991. Another has 61G2976
dated 1993. What is the difference between these two microcodes?
I invariably see the "1993" microcode with some unusual looking cache SIMMs,
but changing them doesn't seem to make a difference. I see "1993" on some
boards labeled as "CARD 1" and others" CARD 3". There is nothing
I can track there.
I can't figure out why they would change it if they didn't
make something better, but I don't know what that would be or how it would
manifest itself. I know that the microcode from triple oscillator adapters
can't be switched to the old unterminated adapters, but I'm uncertain about
from one two another for the same "3-oscillator" family.
From Tony Ingenoso
(guessing) There may have been a change to deal with
the low-power mode problems of certain microcode level Kazuza series drives...
Had to tweak the heads off the cylinder they were idled over to keep from
losing data when the next write (after power restoration) happened to be
on that cylinder... nasty problem...OS/2 had an ABIOS patch to
deal with it on the pseudo-ESDI versions of the drive.
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.
Remove the 50 pin dual row header (pry it open or cut it off)
and crimp on the 50 pin edgecard connector. Watch pin 1!
NOTE: On original
IBM ribbon cables, the cable exits the edgecard connector TO THE LEFT as
the connector is seated on the internal port. As installed, this means the
cable goes straight up towards the top of the 95 case and away from other
adapters. This makes it possible to route it away from them towards the
front of the case, then down the site of the DASD structure, then to the
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.
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
Autotermination Capable Adapters or Planars
If the card or planar has a red colored T-Res, it does not have
the circuitry to support autotermination (you have to pull the termpack
if you add an external device). If the termpack is yellow, then the
additional circuitry exists and you can add or remove external devices
without having to pull the T-Res off the adapter.
> Peter, for the $64,000 Question. If you use a yellow termpack
on a adapter or board that had a red one initially, will that enable
it to autoterminate?
Definitely: Not. 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.
Fact sheet is HERE
Bourns 4120R-003, -221/331
Model (41 = Molded DIP), 20 Pins, R = Thick Film Low Profile, 003 =
Dual Terminator. Resistance Code in the format R1 / R2, First 2 digits
are significant, Third digit represents the number of zeros to follow. 220
ohm, 330 ohm.
It looks like this..
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.
What about that Artifact?
From Ian Brown
Interesting bit of history this. And no,
you won't find it documented anywhere. IBM was one of
the members of the organization that originally set the
standards for SCSI, and as usual they had their own
One of these 'unique' ideas was the
ability to be able to set the SCSI ID# remotely from the
host adapter rather than having to set it on the device
itself. The result of this was the 'legacy' small
connector on some 'high end' SCSI hosts, and that
awkward RS6000 socket as the external port, which became
the IBM standard for a while.
The idea was good, but be grateful it
never took off, as I understand it required decoding
hardware on the devices, which could have left us
looking for special 'IBM SCSI' HDD's etc.
It was never fully implemented as far as I know, SCAM
How did I find out? I went to a 'Big Blue'
re-union recently, and met one of the original designers
of the IBM SCSI host adapters. I'd been wondering about
that extra connector for years, so I took the
opportunity to ask him.
Pinouts for the SCSI /A and the SCSI w/Cache
The MCA edgecard of the SCSI Adapter /A has less contacts than
the later SCSI w/Cache. Still wondering why. You can see a tableized version
of Peter's observations HERE.
Swapping BIOS chips for >1GB Support
From Peter Wendt:
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 SCSI-BIOS.
To my undescribeable 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 system halted.
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 systempartition 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 used.
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.
If replacing the earlier version adapter with the new version, the
following problems may be encountered on fixed disks larger than 1
a. Non-IML systems with Fixed Disk "C" greater than 1 Gigabyte, formatted
/S with the early version SCSI adapter with cache (old version of BIOS)
will experience "Unable To Boot Operating System" message. This is because
the IBMBIO.COM and IBMDOS.COM (hidden files) are placed in absolute
positions on the Fixed Disk, not relative. If a boot from a DOS diskette
is done, Drive "C" is still accessible. A backup of the Fixed Disk should
be done, then a low-level Format, followed by an operating system format.
This will reorganise the Fixed Disk with the new version BIOS on the new
b. Full capacity of greater than 1 Gigabyte will not be accessible on
Fixed Disks which were originally attached to the old version SCSI adapter
with Cache until the Fixed Disk is operating system formatted, (DOS, OS/2,
etc) by the new version adapter (new BIOS code).
2MB SCSI w/cache
Increasing the cache to 2MB
MY 1MB SIMMs are marked MSC2314-12YS9A 183004 68X5721.
One module that can be used to expand the IBM SCSI Adapter with cache
/A from 512K cache to 2MB cache is the IBM P/N 30F5360 / FRU 74X8637, which
is a 1MB x 9 bit (Parity) 100ns module *with* IBM-specific presence detection.
These IBM modules are in the Mod. 30-286 (8530-Hxx or -Bxx) with 80286 CPU
- if anywhere at all.
It has 9 OKI M511000A-1AJ chips, mnf. 89335521
Kingston modules labeled KTM-1000/M30 (From Peter)
From Jerry Dumer
I have 3 boards with Toshiba THM91010AS-10 SIMMs that do
the job fine. I found these on a memory card in a Model 60. They are gold
pins. I imagine Toshiba made them for the 30-286s. They do work.
Trying Non-Compatible SIMMs
If you try some likely looking 30 pin SIMMs and they don't
have the correct CAS/RAS wiring, the system will disable them it and you
will see SCSI Adapter w/Cache with 0KB. Don't freak out. Replace the original
SIMMs and run Advanced Diags and test the SCSI Adapter to restore your 512K
cache. Been there, done that.
Converting Industry Standard Memory
Yes. Alfred Arnold has finally figured it out. Dr. Jim
Shorney confirms this triumph. The biggest hurdle was the IBM modules have
a different RAS/CAS scheme in addition to the different pin-out. As time
goes on, exceptions MAY be found. News as it happens
Alfred's 30-pin SIMM Hack
Original article HERE.
For those that have the burden of college education, I
made some assumptions. First, the SIMM pins will always be performing
the same function (like parity Data Out, parity CAS). Second, those SIMM
pins can be used to positively identify the parity chip's DO and CAS pins.
This makes manufacturer's data sheets unnecessary. Assuming
they even have them.
- Break connection between SIMM pin 26 and parity chip's DataOut
pin; This inferrs that SIMM pin 26 goes to Data Out-
- Connect parity chip's DataOut pin to SIMM pin 29
- Tie parity chip's lead that USED to go to SIMM pin 26 to SIMM pin 29
- Break connection between SIMM pin 28 and the parity chip's CAS pin
- Parity chip CAS is attached to SIMM pin 28
- Connect parity chip's CAS pin to SIMM pin 2
- Attach lead that used to go to SIMM pin 28 to SIMM pin pin 2
- Connect both SIMM pins 26 and 24 to SIMM pin 22 (GND).
- Tie SIMM 26 and 24 off to SIMM 22
A picture of Dr. Jim's 2MB Hack
No. It is a little miracle that the 1MB modules work
for the 2MB total cache, but the 4 Meggers are -again- different to the
1MB ... apart from the presence detection and the RAS/CAS scheme. There are
1MB modules that behave the same way than the 256K modules - but no 4MBs.
The 4MB you find are either Industrial Parity (9 bit, but
w.o. presence detect) or non-Parity Industrial modules (8-bit). IBM itself
never introduced 4MB modules of that scheme for their own machines. The
PS/VP Series 1 used 1 and 4MB 30-pin modules, but these were "industrial
The PS/2 256K, 512K and 1MB modules are very unique. They
depend -technically- on a very old (1985) Hitachi patent to which IBM only
added the presence detection. From the principle the "Single RAS" scheme
of these modules is similar to the Hitachi HB61009BR-15, 150ns module -
a very antique construct, which were superseeded by the much more common
HB41256-style design, which uses separate RAS/CAS timing for interlaced access
to the cell-array, which then allowes much faster RAM access (typically 100
for use in SCSI Adapter w/cache
The secret is out...
Results of upgrading
From an article by Peter Wendt....
The IBM Adapters with and without cache /A are in fact SCSI-1 adapters
with 5MB/s interface speed (!) to the device. This however does not tell
how high the effective data-throughput might be.
This depends on more factors than just the interface-speed:
- speed of the drive mechanism (track-to-track / average seek)
- adapter-cache (size, speed and degree of optimizing)
- device-cache (size / usage)
- cable and degree of disturbances through line noise / spikes etc.
- termination (reflection of data packets)
- adapter and device cmd set (autonomy of device / command queing)
- the adapters chipset
Okay - for the curiousity: I have tested the 2MB-cache
in my 8595-AK9 (32MB RAM / Kingston TurboChip / modified BIOS) with 2
different IBM adapters and a Quantum Fireball TM2110S (2.1GB Ultra-SCSI).
This drive is known as quite fast and should not be the bottle-neck. I
used the IBM SCSI adapter with cache /A in the version *without* the internal
termination resistor and the Adaptec AIC Line interface chip (IBM old) and
I used the IBM SCSI Adapter with cache /A *with* the internal yellow termination
resistor and the IBM SCSI Interface (IBM new).
Here are some test-samples (results are temporary examples)
old SCSI w/cache
|Weighted Average (KB/s)
new SCSI w/cache
|Weighted Average (KB/s)
Results of reading and writing blocks from 512 bytes to 63.5KB in
linear and random methods.
Read Linear with large data-blocks
shows a 20% gain, due to 2MB cache.
Write Linear values are only 2 -
5% smaller in either case.
Write Random values show the influence
of the drive mechanism.
What does this mean in practice?
- Only way to get minimum values up is to use a harddisk with a faster
- Combination drive - adapter doesn't reach the data-throughput for
the SCSI-1 interface speed.
- Any GUI operating system that uses a temporary swap file operating
with large blocksizes will make use of the enlarged SCSI-Adapter cache during
the swapping process.
- Effects are noticeable in Win95 applications and -probably- much
more noticeable on OS/2 and NT, which use the harddisk-subsystem more intensely
than DOS/Windows or Win95. (That's a prediction from my experiences with
- If you cannot -by what reason- use a F/W-adapter / F/W-drive combination
(or don't want to) the enlarged cache to 2MB is one simple method to get
out around 10 - 20% better performance of an unmodified system running
under i.e. Win95 (I'd kept this careful - you cannot await wonders if you
have a slow harddrive)
The testing will continue as soon as possible. Like very often
my job came in the way and I needed the 95 (which is usually my network-server)
for the daily purposes again. But this first testing suite shows that
the enlarged cache *has* in fact a good impact on the over-all performance
of the system. I'll try to fix up the results and try bringing them here
- if you like "data cemetries"... the tables are *very* complex and have
hundreds of numbers, which must be set in proper relation to each others.
And must be interpreted the correct way.
U47 Firmware - 27C512 Original on ST M27C512 -12F1 Use any 27512 equivalent
SCSI BIOS 92F2244, 1991, for PS/2 Caching SCSI controller. 27C256
SCSI BIOS 92F2245, 1991, for PS/2 Caching SCSI controller 27C256
SCSI BIOS 64F4376 1990 (Old Spock)
SCSI BIOS 64F4377 1990 (Old Spock)
33F5546 reports itself internally as 33F5547
AdapterID 8EFF "IBM PS/2 SCSI Adapter w/Cache"
Each SCSI adapter must have a unique
I/O address range
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. Adapter releases
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
<"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.
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