The Final Frontier?
@DDFF.ADF - IBM ESDI Fixed
Latest Firmware and ESDI BIOS
all were intel D27128A
(ADP CDDFF.ADF not required /
rename to @DDFF.ADF)
@DDFF.ADF - IBM ESDI Fixed Disk
CDDFF.ADF - Init file for
- IBM PS/2 SCSI Adapter w/Cache Working on it 08
(modified, needs no ADP, ROM selectable / German
comments) Use this for IBM ESDI and SCSI Controllers in
the same system.
@DFFD.ADF - IBM ST506 Fixed Disk
90X8969 Marked 90X8971
90X8970 Marked 90X8972
04G3759 Update ESDI firmware
Early MFM Adapter
Later MFM Adapter
ESDI Hard Disk
Second ESDI Drive
Non-IBM ESDI Drives
HD Cabling Schematic (Signal and Data)
Is the IBM
Integrated HD Adapter ESDI?
U5 1700874 (TI
U30 is covered with a grey-black resilient compound
that has a heatsink? pushed into it?? The edgecards at
the top are not labelled. U4 and U7 have the metal
can/ceramic construction you love so much.
Intel P8051AH (MCS 51
This "Mystery Card" is also a MFM
controller, IBM P/N 72X8540. It is a early downlevel
card, which has been withdrawn with ECA 002,
service code 33 available from 87-06-17 / IBM Boca
Raton. This adapter has been used in early PS/2 Mod.
8560-041 with serial No. range from 8001342 -
8009651 (US production only).
The ceramic shield has been obsolete on the
new redesigned MFM adapter for Mod. 60 & 80. These
adapters were already a "factory reworked" card -
first series cards had the U30 module without the
shield and experienced "sudden death" due to some
sensibility against electrostatic discharge. Therefore
the shield. The P/N for the various cards stayed
[Source: IBM Engineering Changes Group 819
- PC-Family / PS2 Family Service Information Manual, IBM
Doc.No. SR28-0280-2 / 3rd Edition Nov. 1987]
J3 Control cable
U5 SSM 8736
24D resistor- 220/330 ohm
Intel P8051AH (MCS 51
Charles Lasitter impudently asks
I've had an inquiry about how the 72X8540
ST-506 / MFM adapter works in Model 8560 computers, and
specifically I'm wondering about the usual stuff:
Is this some Unique IBM flavor of ST-506, such that
"Don't Bother!" is the word of the day when it comes to
considering non-IBM MFM drives?
Any hope of substituting larger drives for
this machine, and if so, what's the point at which it
will freak out over translation issues and require
exquisitely unique device drivers to step in front of
the operating system and hide the messiness?
From Anarcho-Hacker Peter
From the principle the stuff IBM used there
is the usual Western Digital stuff ... with the major
difference of a "BIOS type look-ahead" table with fixed
values and no "User Type". Back in the glorious old days
we used to solve this problem with a software called
"SpeedStore". You enter the BIOS type of a drive which
comes closest to the one you want to install and then
override the CMOS settings with the software and a
boot-sector resident driver.
Another significant difference: IBM has
castrated the 4-device ST-506 interface down to 2
devices with altering the device addressing a bit. All
drives have to be set to "second drive" (DS1 when
counting "0"-based from DS0 to DS3). The two possible
drives are addressed with the motor-on and drive select
lines - and a twisted cable for the first drive, which
"corrects" the false addressing logic. The IBM PS/2 BIOS
also and consequently supports only two MFM drives (and
two ESDI as well ... they repeated the mistake there
This part is still missing in the PS/2
Reference PDF section. I *think* I have the MFM
controller HITRM or TRM anywhere ... but I might be
wrong. I PDFed the ESDI and SCSI controllers - which
seemed the more important to me.
ESDI Hard Disk Attatchment
J3 Control cable
U25 appears to be the Even BIOS,
U13 the Odd BIOS
Y1 is a unique flat, square clear plastic cased crystal.
Intel N8031AH (MCS 51
Programmable Storage Controller Datasheet (One
Adaptec AIC-300FL Dual
Port Buffer Controller Datasheet
How Many Drives are Supported?
Two are supported.
ESDI natively supported 7 to 8 drives - but IBM (and
others) cut that down to 2 or 4 ... the original IBM /
WD controller has two ports for drives.
for ESDI Adapter/A
If U16 is 04G3759, then this ECA has
already been applied. Modules with any other P/N should be
replaced by using this ECA.
DOWN - level U16
P/N 90X7399, P/N 90X8635, P/N 15F6587, P/N
15F6807 and P/N 91F7430.
15F6587 :caused a
diagnostic formatting problem and an intermittent
hardfile delay during system operation (the hardfile
light would remains "on" for approx. 13 seconds). also,
in rare instances, a write fault could result in a data
shift problem during error recovery, which would be
detected during read operations and during diagnostics
as a "10473" error (ECC error; read error).
15F6807 : caused a
highly intermittent problem of undetected write faults
on the last 1/3 of the last sector written (detected
during system read operations and by diagnostics as
error code 10473, ECC read errors).
experienced a highly intermittent system "HANG" only on
115MB ESDI fixed disks.
Some older versions of direct driver
software, which bypass BIOS (basic input/output system)
may experience failures accessing the Fixed Disk after
the installation of this ECA. This may occur because
changing this module may alter how the Fixed Disk
subsystem "appears" to the software. Software which uses
BIOS is not affected and will function normally. DOS and
OS/2 use BIOS.
If the user software fails after this
module is changed, the original module should be re -
installed, and the appropriate software support function
should be contacted for any possible software patches or
After replacement of the module, FRU P/N
92F0062 (P/N 04G3759) advanced diagnostics ESDI fixed
disk(s) routine should be run to insure proper hardfile
Installing a Second ESDI Drive
From Joe Kovacs
You will need another data-cable for the new drive.
The wide control cable has a second plug already. To
make it a D: drive, you take out the resistor (Or some
models use a DIP switch).
Run automatic configuration, low level format
it (CTRL-A on the main menu), fdisk it, DOS high level
format it, and you're away.
Non-IBM PS/2 ESDI Drives
>- Will the HD run in my 8580 even if it is not the
original IBM-HD ?
As I understand it, the ESDI drives for the
80-class machines had identity data stored on the drive
itself. If it's not an original equipment ESDI
drive, or if it *IS* an IBM drive but has since been
low-levelled in another (non-IBM) machine, it can't be
put back in an 80 unless the Reference Diskette is
"cooked". For Peter Wendt's recipe, look HERE
8560/8580 Harddisk Wiring
to Power Supply
|H | |
|H---+ | |
+----------------+ | |
| | |
| | |
| | +---------+
| IBM HD-Adapter (MFM or
ESDI) | |
Cable from J1 to HDs #2 and #1
is twisted for 5 lines 6 to 10 between HD#2 and
The segment between J1 and HD#2 is
Cables from J2 to HD#1 and J3 to
HD#2 are both wired 1:1 with no twists
"How to build your own ESDI terminator"
| | |
| | | +++
+++ +++ |
| | | | |
| | | |
| | | | |
| | | |
| | +++ +++
| | |
| | |
12 11 10
... 3 2
1 = Pin No.
Pins 12 - 2 are 150 Ohms against Pin 1
Pin 1 is the common contact
All resistors are 150 Ohms / 0.25 Watts
(C) 1999 by Peter H. Wendt
MCA Mafia of Germany
Cables from RadioSchlock
Dual MFM/RLL Drive Kit 950-0325
28" dual data cable and a 28" dual
control cable (?)
MFM/RLL Replacement Cable 950-0326
18" 20-pin IDC to edgecard socket
MFM/RLL Replacement Cable 950-0327
28" 34-pin IDC to edgecard socket
Maxtor 8760E ESDI drive problems
on IBM ESDI controller
What could be causing so many 10480s (seek
errors)- The drive light flickers on the disk, but is
constant on the top hd light, and only gives 10480, even
though it looks like it works. The drive was pulled from a
486, what could be wrong with the drive/controller in the
model 80? I've read a post about setting a 380MB and other
nearly alike ESDI drives similar to mine, but none of the
tips work/apply so far. I've even tried custom cables, and
different types of 34pin cables. What do I need to do to
either get ibm's cable for this card(number please?)
The IBM ESDI controller is a 10MHz
controller that has a limit on the speed (10Mb/s
disk-to-interface) and the sectors (36). So most likely
the XT-8760E will not work with that controller. It is a
52-sectors drive and seems to be an ESDI 15Mhz device as
ESDI in a 9577 Bermuda?
From Werner Förtsch
I have a 9577 with an onboard SCSI with one
hd drive which was up to now my boot disk. I found from an
old PS/2-80 an ESDI controller and two ESDI drives which I
istalled in the 9577. After long I got the system up
running. My problem now is that my 9577 now boots from the
first ESDI drive. Is there any possibility to boot
from the SCSI harddrive in changing something in the
1. The ESDI controller has *not* been
announced for use in the later models after Mod.
80 - so it is no good idea to use it in a 77 of any
2. If any ESDI drive is recognized during
setup the machine BIOS handles it directly on the
BIOS-Int Level as system hardware extension (INT 80h
device) just like an MFM-drive. The SCSI-Bios is in this
case "one step behind" and the MFM (if any), IDE (on
"Lacunas") and ESDI-drives like in your case will called
first and attached to the Int80h device-call.
3. It *might* be possible to use the
"Selectable Startup Sequence" in the machine setup
("Features" in the main menu) - but I truly doubt that
the startup will "know" the ESDI-drive *because* the
adapter is not supported in that machine. However worth
trying and looking at anyway.
4. The 16-bit MCA Stage 1 ESDI-Adapter will
most likely have some influence on the systems
performance. I would recommend to remove it - in case
you really plan to do something with the machine and not
only do that for curiosity only. The investment in a new
faster and larger SCSI hardisk (like the IBM DCAS-32160,
2.16GB Ultra-SCSI) is not wasted money. The system acts
a lot more lively with that.
>Thank you anyway for your helpful
Nothing to thank for. I even forgot to
mention another nasty effect of this combination: you
cannot run Win95 or WinNT with it. Both adapters, the
IBM SCSI and the IBM ESDI are hardwired to use IRQ 0Eh
(14) and are tied up at the same time. This
interrupt-sharing is a technical feature of the MCA -
and causes no problem under DOS / Win 3.x or OS/2 ...
but Win95 / 98 or NT cannot handle that, because it runs
against their "one device / one resource" strategy. So
much for the "guys in Redmont" and their understanding
of modern technologies.
So if you just tried it for curiosity
- you better leave it. I tried something similar back in
1989 with the Mod. 80-311 to add an SCSI adapter for
larger drives and wanted to boot from the SCSI ... did
not work. The ESDI always started first. This
misbehaviour is (as far as I know) buried in the
different handling of ESDI and SCSI from the BIOS.
If anyone else finds a way - okay - I am
interested. But as far as I know - and from my own
experimenting - it does not work. (Also: Mod. 70 with
IBM SCSI and SCSI-HD: also starts from the DBA-2 ESDI
(Ed. Peter points
out the 16 bit compatibility mode the SCSI and ESDI
controllers create. So you can run W95 with this setup,
>You are right it will be much better to invest some
money for a new SCSI drive.
Please keep in mind that the 9577
with the onboard-SCSI is limited to a drive size of 3.94
GB (corresponding to IBM) for the "first drive to boot
from and which holds the system partition". This point
was topic on an older (or: several older) threads in
this group. Therefore I recommended the 2.16GB IBM and
not the 4.2GB ... ! But any modern 2GB - 3.5GB drive
will do fine. Quantum makes (made ?) a Fireball with
3.5GB capacity. This would mark the maximum installable
in the Mod. 77. The "over 4GB" appear to be installable,
are even recognized with the exact capacity - but the
IML-partition will not be installable. Now: will install
- but will not work. And then you ran in a nasty
IML-error of the I999 00nn category. That
the IBM Integrated HD Adapter an ESDI Controller?
First off: The "IBM integrated harddisk
adapter" (Card-ID DF9F) as it can be found in 50Z, 55SX,
70 and P70 is not a real ESDI drive. It is more or less
technically an MFM RLL 2.7 drive - but combined with a MCA
harddisk adapter in one physical unit. The "ESDI or not
misunderstandment" is caused by the PS/2 BIOS.
They (IBM) treated the drive as ESDI, because
back in those days the MFM harddisk standard was limited
to 17 sectors per track (and still is for pure Non-RLL MFM
drives) and while the "modern drives" used to be smaller
and use lesser platters and -therefore- lesser heads it
was easier to translate the physical geometry with e.g.
929 cylinders, 56 sectors and 4 heads into a scheme with
64 heads, 32 sectors and "downscale" the number of
The above example (929 x 56 x 4) would result
in 208.096 data blocks á 512 bytes = 106.545.152 bytes.
The translation into the 64/32 ESDI scheme would result in
the more handy 101 cylinders ... by cutting down the total
capacity to 105.906.176 bytes total. However the values
101 cylinders, 64 heads and 32 sectors give a better match
into the old XT/AT controller scheme - particularly the
cylinder register was -according to the basic WD1007
controller- the problem. It could not hold values over
1.024 ... the ESDI translation in the BIOS opened a more
handy way to handle bigger drives up to 1GB IIRC.
So after all the "ESDI" in the desktops using
the integrated harddisk thingy is only imaginary. The
towers (60 and 80) used "Real" ESDI controllers and
Secondly the DF9F HD / controller combo was primarily
designed as "single device". The later @DF9F.ADF allowed
to set one as "primary" and one as "secondary". But as
far as I know this has been included to match an early
draft of the PS/2 Mod. 90 hardware .... which *had* two
integrated harddisk controller ports at the front end of
the sysboard. These however had been made non-functional
in the later platform BIOSes and don't work. I have
played around with them in the early 90s but found no
clue to get them working with any Type 1 - 3 platform.
As well as Alfred Arnold tried recently - don't know if
he gave up yet.
I hadn't been that desperate to try installing the
386DX-20 (Type-0) platform in my 8590 and see if I get
the front drivebays going with that.
Due to the lack of appropriate connectors none of the
PS/2 machines support two integrated harddisk adapters.
These *are* MCA connectors. The 72-pin layout of these
drives is basically a slightly stripped-down 16-bit MCA
connector. And the planar ADF for e.g. a Mod. 55SX says
"4 slots" where the Slots 1 - 3 are for expansion cards
and Slot 4 is at the end of the riser card - extended
with a flat-ribbon cable over and down to the
And - No - you cannot just crimp another 72-pin
connector in that cable. There are signals that select
the slot number - and that for this "cable port" is
fixed set to Slot 4 ... so any other connector on that
cable would signal "Slot 4" to the sysboard. It is
-as said- "stripped down" ... means: apart from some DC-
and GND-wires also "other unimportant signals" are not
passed over to the HD-connector.