Looking for an IDE to EDSI adapter

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Allen Crist

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Mar 10, 2020, 6:14:40 PM3/10/20
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I have a very old drive IBM WD-2120 / 120 MB drive it's 26 pin.

From what I can tell it uses a EDSI connector. I'm having problems finding an adapter for this. Photos attached.

Any help is appreciated.
IMG_20200310_104304977.jpg
IMG_20200310_104310927.jpg
IMG_20200310_104321595.jpg

compos mentis

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Mar 10, 2020, 7:44:04 PM3/10/20
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I don't recall seeing any ESDI drives, but all the documentation I can find suggests that these interfaces were usually implemented with a 34-pin control cable and a 20-pin data cable. ISTM that, even if you were able to locate a system with an ESDI controller, you would still be stuck with adapting your 52-pin ESDI interface to the more common 34 + 20 configuration.

Here is the product manual for a more typical ESDI drive from that era:

CDC Imprimis 94246-383 Wren 6 / ST-2383E Product Specification:

Allen Crist

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Mar 10, 2020, 7:46:01 PM3/10/20
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ACE is who ID'ed it as being ESDI but it is definitely a 26 pin which I found odd given the specs I have seen for ESDI out there.

Networks

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Mar 10, 2020, 8:13:47 PM3/10/20
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That is a Micro Channel Drive MCA. It sure looks like SCSI but this website shows different. made by IBM and it shows this is the WD-2120. I can't tell but the site shows its a 2.5" drive but I can't tell from the picture.  I counted 50 pins minus the one missing.

Jim

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Networks

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Mar 10, 2020, 8:14:27 PM3/10/20
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compos mentis

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Mar 10, 2020, 9:22:48 PM3/10/20
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FWIW, here a WD-2120D which is described, perhaps incorrectly, as an "IBM WD-2120D 06G6455 120MB 2.5" ESDI Disk Drive 5.0V".

It has a 60-pin connector which looks like a mini-Centronics style SCSI:


Allen Crist

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Mar 10, 2020, 9:33:28 PM3/10/20
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The drive tray in the laptop looked SCSI to me, but then it goes to the 26 pin as shown in the photo.

compos mentis

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Mar 10, 2020, 9:34:40 PM3/10/20
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compos mentis

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Mar 11, 2020, 2:30:12 AM3/11/20
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AFAICT, IBM's SCSI and IDE model numbers of that era had WDS and WDA prefixes, respectively, so this would exclude these two interface types:


Here is the spec for IBM's MCA direct-access storage devices:

DASD Storage Interface Specification Micro Channel (REV 2.2):

What is the laptop model? Is it a CL57SX? If so, then the following site confirms that "on IBM laptops of the time, MCA architecture was also coupled with the use of ESDI Hard Disks".

compos mentis

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Mar 11, 2020, 2:40:33 AM3/11/20
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I wonder if the WDA-2120 is the 44-pin 2.5" IDE version of the same drive:


If so, could swapping the PCBs be a possible solution? Here is a complete IDE drive for US$30:

Allen Crist

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Mar 11, 2020, 7:53:55 AM3/11/20
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The Laptop is an IBM ThinkPad 700c.

Honestly I don't even know if the drive is bad or not since I can't access it. I tried searching for a Thinkpad 700c but no luck there. When turning on the laptop it seems to be doing something, but no display. I may check to see if a ribbon cable is loose... I'm thinking that this one will be more trouble than it's worth. Would IDE even work on this drive? I hate to do a board swap without knowing for sure it's compatible (or at least with some certainty).

Fraser Corrance

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Mar 11, 2020, 2:02:22 PM3/11/20
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I recently had a run in with an ESDI drive that burnt up more of my time than I would like to admit. From what I was able to ascertain from my research, the key appears to be having the original controller which is an important piece to the puzzle. It seems that the controller has a lot to do with how the drive is formatted (physically, not logically) unlike modern drives where the firmware handles that task. Since my client no longer had the original computer that the drive came out of, I had to purchase multiple controllers but still could not get any access to drive. 

If the laptop powers and has a floppy drive, perhaps try booting to a DOS disk with the ESDI driver on it. Or, if you can find out which controller the laptop was using, maybe try sourcing another with the same controller.

I ended up referring my client over to Drive Savers. They managed to figure out how to get access to the drive but they have been working on imaging the drive for over two months now. 

If you end up figuring out how to get access to the drive, please do share. ;-)

Fraser



compos mentis

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Mar 11, 2020, 2:46:22 PM3/11/20
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From the previous link ...

"Note that the original ThinkPad 700(C) and 720(C) were also MCA!"

I would ask the eBay seller to show you a photo of the PCB. If the only difference is in the interface IC(s), then ISTM that a PCB swap would be safe to try.

compos mentis

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Mar 11, 2020, 2:58:11 PM3/11/20
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compos mentis

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Mar 11, 2020, 4:14:13 PM3/11/20
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Here is a WDS-2120 (SCSI version):


Once again the PCB is almost identical.

compos mentis

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Mar 12, 2020, 12:15:28 AM3/12/20
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The more I look at this drive, the more confused I become.

Wikipedia shows an example of an "ESDI" drive which connects to an MCA riser card in an IBM PS/2 Model 55 SX.


This site shows both sides of the riser:


Here is the pinout of a 16-bit MCA connector:


It almost matches Slot2 and Slot3 on the riser (apart from the last 4 reserved pins). The card is passive, ie no controller.

So it would appear that the "ESDI" drive which is pictured with a Direct Bus Attachment edge connector is in fact a plug-in MCA HDD, as were used in PS/2 models.

Here is a similar example:


Wikipedia states that "many high-end SCSI drives of the era were actually high-end ESDI drives with SCSI bridges integrated on the drive".  Therefore, I'm wondering whether the WD-2120, WDA-2120 and WDS-2120 are actually all ESDI drives with MCA, ATA and SCSI bridges, respectively. If so, then this would support the feasibility of a board swap.


Allen Crist

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Mar 12, 2020, 9:56:40 AM3/12/20
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Yeah me too. I may just 'punt' to DriveSavers. Seems like I could put a lot of work into this one, and the drive owner doesn't know for sure what's even on the drive.

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---- On Wed, 11 Mar 2020 22:15:28 -0600 compos mentis <pbzcbf...@gmail.com> wrote ----

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compos mentis

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Mar 12, 2020, 2:12:56 PM3/12/20
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I have no faith in DriveSavers. 

I still say you should convert the drive to IDE with a board swap. All the spindle motor control, VCM control, preamp and read channel ICs are identical on all 3 versions of the drive. The S80C196KW chip is a ROMless 16-bit MCU. It would be the bridge IC, and the parallel flash IC under the sticker would contain its firmware.

Here is an excerpt from IBM's DASD spec (page 10):

"When 52 pin connector is used, the higher address(4-15) shall be decoded at the system side. (See 2.5" Drive Function Specification)"

This confirms that the drive has an MCA interface, not ESDI. Unfortunately I can't find the second document.





t...@desertdatarecovery.com

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Mar 12, 2020, 2:23:50 PM3/12/20
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I think Allen is in the situation we are dislike. He has a client that has an old drive and doesn’t even know what’s on it. You can put 100’s of dollars into a case like this and a huge amount of time for no return. In cases like this we would charge an ‘attempt’ fee to make sure the client has skin in the game and is serious, I am not sure if Allen did that.

 

Tim Homer - Lead Engineer

Desert Data Recovery

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www.desertdatarecovery.com

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Allen Crist

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Mar 12, 2020, 2:28:49 PM3/12/20
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We do charge just a $65 diagnostic fee. Keeps non-serious people from dropping off some of these "fishing expeditions".

If were were going to do this (vs. send them elsewhere, in this case we would charge attempt fees).



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compos mentis

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Mar 12, 2020, 2:35:12 PM3/12/20
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The outlay would be US$30. I would say that if you are not prepared to risk this amount, then it is you who are not serious. 

I would give the customer the option of a cheap recovery with a punt on an IDE conversion. Tell him that the alternative is to be screwed by DriveSavers. ISTM that 2 months is a very long time to fart about with Fraser's ESDI drive, so who knows what they will end up doing with Allen's.

t...@desertdatarecovery.com

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Mar 12, 2020, 2:46:16 PM3/12/20
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@Compos – this was a general comment as previous posts have referred to buying a donor laptop etc. You are omitting the fact that time is money, and these types of ‘time suck’ jobs prevent you from giving real clients the service they need. By ‘real clients’ I mean ones who actually do want the data.

 

Tim Homer - Lead Engineer

Desert Data Recovery

t...@desertdatarecovery.com

www.desertdatarecovery.com

 

From: datarecovery...@googlegroups.com <datarecovery...@googlegroups.com> On Behalf Of compos mentis
Sent: Thursday, March 12, 2020 11:35 AM
To: DataRecoveryCertification <datarecovery...@googlegroups.com>
Subject: Re: Looking for an IDE to EDSI adapter

 

The outlay would be US$30. I would say that if you are not prepared to risk this amount, then it is you who are not serious. 

 

I would give the customer the option of a cheap recovery with a punt on an IDE conversion. Tell him that the alternative is to be screwed by DriveSavers. ISTM that 2 months is a very long time to fart about with Fraser's ESDI drive, so who knows what they will end up doing with Allen's.

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Allen Crist

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Mar 12, 2020, 2:51:50 PM3/12/20
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So to answer the question, we always consider the time, cost of parts, likelyhood of something solving the issue. We are evaluating all options right now and just waiting on the client.

In this case we are waiting for more information from our client since it's a custom case.


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t...@desertdatarecovery.com

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Mar 12, 2020, 2:55:24 PM3/12/20
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😊

 

Tim Homer - Lead Engineer

Desert Data Recovery

t...@desertdatarecovery.com

www.desertdatarecovery.com

 

compos mentis

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Mar 12, 2020, 3:28:42 PM3/12/20
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AISI, the biggest problem is in determining what the drive actually is. Now that this question has been answered (via IBM's DASD MCA spec), the solution is straightforward and cheap.

The reason for my initial confusion was that every online resource incorrectly identified this drive as ESDI. Even Ace got it wrong. Wikipedia shows a photo of an "ESDI" drive which plugs into a passive MCA riser card, which is in fact an absurd scenario.

In short, the drive's interface is a cut down, 52-pin version of IBM's MCA bus, as implemented in IBM's 2.5" MCA drives. The reason that there are so few pins is that many are superfluous. For example, a 5V drive doesn't require -12V or +12V supplies. Also, the drive utilises only 4 of 16 address bits, the remaining 12 bits being decoded by the motherboard.

t...@desertdatarecovery.com

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Mar 12, 2020, 3:31:20 PM3/12/20
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Compos I am sure I speak for us all, we are very grateful for the work you put in researching this stuff on everyones behalf.

 

So THANK YOU!

 

Tim Homer - Lead Engineer

Desert Data Recovery

t...@desertdatarecovery.com

www.desertdatarecovery.com

 

From: datarecovery...@googlegroups.com <datarecovery...@googlegroups.com> On Behalf Of compos mentis
Sent: Thursday, March 12, 2020 12:29 PM
To: DataRecoveryCertification <datarecovery...@googlegroups.com>
Subject: Re: Looking for an IDE to EDSI adapter

 

AISI, the biggest problem is in determining what the drive actually is. Now that this question has been answered (via IBM's DASD MCA spec), the solution is straightforward and cheap.

 

The reason for my initial confusion was that every online resource incorrectly identified this drive as ESDI. Even Ace got it wrong. Wikipedia shows a photo of an "ESDI" drive which plugs into a passive MCA riser card, which is in fact an absurd scenario.

 

In short, the drive's interface is a cut down, 52-pin version of IBM's MCA bus, as implemented in IBM's 2.5" MCA drives. The reason that there are so few pins is that many are superfluous. For example, a 5V drive doesn't require -12V or +12V supplies. Also, the drive utilises only 4 of 16 address bits, the remaining 12 bits being decoded by the motherboard.

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Allen Crist

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Mar 12, 2020, 3:45:18 PM3/12/20
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I sure appreciate it... I am still new in the business so this one has thrown me for a loop.


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compos mentis

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Mar 12, 2020, 3:47:53 PM3/12/20
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The DASD MCA spec describes the function and content of the reserved cylinders.

A CE cylinder is reserved for controller diagnostics.

A second cylinder contains a secondary defect list (grown defects).

A third cylinder contains the primary defect map.

The last cylinder contains a factory-format defect list.

Therefore ISTM that these reserved cylinders contain no information which is unique to any interface type.

Allen Crist

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Mar 12, 2020, 3:54:14 PM3/12/20
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This thread is fairly large, can you re-send the link to the $30 option?

Fraser Corrance

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Mar 12, 2020, 8:13:10 PM3/12/20
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Compos, 

Once again you have truly outdone yourself here. Thanks for taking the time lend us your amazing research skills. ;-) It always turns out to be a great learning experience for us all. 

Fraser



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compos mentis

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Mar 12, 2020, 10:09:55 PM3/12/20
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Here it is:


Hopefully the client's drive is in working condition.

BTW, this will be a CHS drive, so you will need to select PIO mode in PC3K, IIRC.

Allen Crist

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Mar 12, 2020, 10:16:09 PM3/12/20
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Snagged it! I'll let you know.


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---- On Thu, 12 Mar 2020 18:12:57 -0600 Fraser Corrance <fraser....@gmail.com> wrote ----

compos mentis

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Mar 12, 2020, 10:31:06 PM3/12/20
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While I was comparing the 3 PCBs, I searched for datasheets.

Here are my very rough notes:


CXA1606AN, Sony, marking A1606AN, TSSOP-24 - read/write amplifier ?

HD153014SF, Hitachi, QFP-80:

HD153014RF = Data Separator with Built-in Read Pulse Detector and (1,7) Encoder/Decoder
https://www.datasheetarchive.com/hd153014-datasheet.html

HM65256BLFP-10T, Hitachi, 32768-word X 8-bit HIGH SPEED PSEUDO STATIC RAM, 5V, SOP-28:
https://www.bg-electronics.de/datenblaetter/Schaltkreise/HM65256.pdf

79F0845 + TC110G11AF, Toshiba, CMOS GATE ARRAY, QFP-20+30+20+30:
https://www.datasheetarchive.com/?q=TC110G11

M52841AFP (+ 95F3951), Mitsubishi, QFP-56

64F9479, QFP-44 - spindle motor controller

34G3348, IBM, QFP-160 - DSP ?

S80C196KW, Intel, MCU, 16-bit, 16MHz, 5V, ROM-less, QFP-64:
https://www.datasheetarchive.com/?q=S80C196

M52895FP (+ 95F3931), Mitsubishi, QFP-56

95F3948 + M91H057E (= M5M91H057E or MSM91H057E ?), OKI, QFP-20+30+20+30 - gate array?

HA13490MP, Hitachi, voice coil motor driver, 15V, marking 13490, MP-18T:
http://datasheetcafe.databank.netdna-cdn.com/wp-content/uploads/2019/01/HA13490FP-datasheet.pdf

TLC272CPSR, Texas Instruments, Dual Single Supply Operational Amplifier, 3V - 16V, marking P272, DIP-8:
http://www.ti.com/lit/gpn/tlc272
http://www.ti.com/lit/pdf/sloz008

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