IBM ESDI Controller

@DDFF.ADF IBM ESDI Fixed Disk Controller
   (ADP CDDFF.ADF not required / rename to @DDFF.ADF)
@DDFF.ADF IBM ESDI Fixed Disk Controller
CDDFF.ADF Init file for @DDFF.ADF

A modified IBM SCSI w/Cache ADF (8EFF) may be needed when installed together with IBM ESDI in the same system.

ESDI Fixed Disk Drive Adapter/A - Technical Reference

Setup and Benchmarks of Several ESDI Hard Disks and Controller Cards

Early ESDI Controller
Later ESDI Controller
BIOS and Microcode
   BIOS Extensions ROMs
   Microcode ROM
   Updating Microcode
Install Second ESDI Drive
Using Non-IBM ESDI Drives
60/80 HD Cabling Schematic
MFM/RLL Cable Source


Early ESDI Controller P/N 90X8063?, PCB P/N 90X6858 [P] [P]

Single-side load (components on one side only). All major parts are the same as on the later version (including the IDs).

Later ESDI Controller P/N 15F6586 or 15F6805, PCB P/N 72X8588 [P] [P] | [P] [P]

J1 Control Cable Connector
J2,3 Data Cable Connectors
U4 Hitachi HM6264ALFP-15T 8Kx8 SRAM
U6 Adaptec AIC-010FL
U12 72X7408
U14 Intel D27128A 128K ROM BIOS Low
U16 Intel D27128A 128K ROM Microcode
U18 Adaptec AIC-300FL
U22 72X8305
U25 Intel D27128A 128K ROM BIOS High
U33 Intel N8031AH
U37,38 Hitachi HM6264ALFP-10T 8Kx8 SRAM
Y1 10.00 MHz xtal 68X6852

Y1 is a unique flat, square clear plastic cased crystal.

The later version has a double-side load PCB with a slightly modified layout. All resistors and bypass caps were moved to the solder side of the PCB.


BIOS and Microcode (ROM images from David Beem)

BIOS Extensions ROMs

U14,25 2x 27128 EPROM (128KB, 16x8)

FRU P/N (low & high)Internal P/NDate
90X8064 & 90X806590X8066 & 90X806711 Feb 1987
90X8969 & 90X897090X8971 & 90X897205 Jun 1987

Microcode ROM

U16 1x 27128 EPROM (128KB, 16x8)

FRU P/NInternal P/NDateVersion
90X739990X685303 Feb 19870002
90X8635UnknownUnknownlikely 0001 or 0003
15F658715F658807 Oct 19870004
15F680715F680913 Jan 19880005
91F7430UnknownUnknownlikely 0006
04G375904G376105 Apr 19910007

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).

91F7430 experienced a highly intermittent system "HANG" only on 115MB ESDI fixed disks.

David Beem says:
   Version 0001 may have not been released since it would have been prior to the initial PS/2 models that used the ESDI controller coming out in April 1987.
   One of my 04G3759 EPROMs (I should look below the other two I have) had a confusing label on the underside: "COMPATIBILITY SOFTWARE (C) 1985 PHOENIX SOFTWARE ASSOCIATES LTD ALL RIGHTS RESERVED".

Updating Microcode

If U16 is 04G3759, then this ECA has already been applied. Modules with any other P/N should be replaced by using this ECA.

Downlevel ROMs: P/N 90X7399, 90X8635, 15F6587, 15F6807, and 91F7430.

Note: 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 updates.

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 operation.


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.

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.

Using 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-leveled 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.


60/80 HD Cabling Schematic (from Peter)

                    to Power Supply
                      |        |
  +----------------+  |        |    +----------------+
  |                |H-+        |   H|                |
  |                |        +------H|                |
  |                |H       |  |    |                |
  |     HD #1      |H-------------\H|      HD #2     |
  |    (Rear)      |H       |  |  /H|     (Front)    |
  |                |      +------/ H|                |
  |                |H     | |  |    |                |
  |                |H---+ | |  +---H|                |
  +----------------+    | | |       +----------------+
                        | | |
                        | | |
                        | | +---------+
                        +-|------+    |
                          |      |    |
         Rear             |      |    |        Front
         L_U-----------HHHHHHH--HHH--HHH-------+---+
          |            J1       J2   J3        |   |
          |                                    |   |
          |                                    |   |
          |    IBM HD-Adapter (MFM or ESDI)    |   |
          |                                    |   |
          +-+HHHHHHHHHHHHHHH+------------------+---+
            +HHHHHHHHHHHHHHH+

Cable from J1 to HDs #2 and #1 is twisted for 5 lines 6 to 10 between HD#2 and #1
The segment between J1 and HD#2 is wired 1:1
Cables from J2 to HD#1 and J3 to HD#2 are both wired 1:1 with no twists


ESDI Terminator (from Peter)

How to build your own ESDI terminator:

 +----o----o-- ... --o----o----+
 |    |    |         |    |    |
 |    |    |         |    |    |
+++  +++  +++       +++  +++   |
| |  | |  | |       | |  | |   |
|R|  |R|  |R|       |R|  |R|   |
|0|  |0|  |0|       |1|  |1|   |
|1|  |2|  |3|       |0|  |1|   |
| |  | |  | |       | |  | |   |
+++  +++  +++       +++  +++   |
 |    |    |         |    |    |
 |    |    |         |    |    |

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

MFM/RLL Cables from RadioShack (Dated, for reference only)

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 34-pin cables. What do I need to do to either get IBM's cable for this card (number please?).

From Peter:
   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 well.


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 installed 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 firmware?

From Peter:

  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 flavour.
  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 information.
   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 drive first)

(Ed. Peter points out the 16 bit compatibility mode the SCSI and ESDI controllers create. So you can run W95 with this setup, but...)

>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 Model 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 for completeness.

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