@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
@8EFF.ADF - IBM PS/2 SCSI Adapter w/Cache 
                    (modified, needs no ADP, ROM area selectable / German comments) Use this if you 
     want to use IBM ESDI and SCSI Controllers in the same system.
ESDI Hard Disk Attatchment
Mystery Card

U30 is covered with a grey-black resiliant 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.

Card Identity
From Peter
   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 It is a early downlevel card, which has been withdrawn with ECA 002, service  code 33 available from 87-06-17 / IBM Boca Raton.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 (untypically) unchanged.
   [Source: IBM Engineering Changes Group 819 - PC-Family / PS2 Family Service Information Manual, IBM Doc.No. SR28-0280-2 / 3rd Edition Nov. 1987]

MFM Controller 90X8643

J1 Data-cable J2 Data-cable J3 Control cable U1 6127893 U2 T5627 U3 Motorola MC3486P U4 AMD AM26LS3IPC U5 SSM 8736 24D resistor- 220/330 ohm

U6 5960904 U7 6127784 U15 Hitatchi? HM6116LFP-3 U18 Intel P8051AH U27 83X3202 Y1 20.0T7J Y2 12.0MC TDK

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 adressing 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 adressed with the motor-on and drive select lines - and a twisted cable for the first drive, which "corrects" the false adressing logic. The IBM PS/2 BIOS also and consequently supports only two MFM drives (and two ESDI as well ... they repeated the mistake there again).
   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.

U25 appears to be the Even BIOS, U13 the Odd BIOS
Y1 is a unique flat, square clear plastic cased crystal.

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). 

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

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
   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. 

Using Non-IBM PS/2 ESDI Drives
>- Will the HD run in my 8580 even if it is nothe 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 recipie, look HERE

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.

 IBM PS/2 Mod. 60/80 Harddisk Wiring Schematic
Thanks, 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+
 

The cable from J1 to HD#2 and HD#1 is  twisted for 5 lines 6 to 10 between HD#2 and HD#1
The part between J1 and HD#2 is wired 1:1
The cables from J2 to HD#1 and J3 to HD#2  are both wired 1:1 with no twists

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.

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 truely doubt that the startup will "know" the ESDI-drive *because* the adapter is notsupported in that machine. However worth trying and looking atanyway. 
   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 lifely 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 ressource" 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 compatability 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 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 for completeness.