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Strange problem with ST-125A and ST-157A

Xacalite

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Feb 13, 2015
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So I've got two early IDE drives, stepper-based: ST-125A and ST-157A.
Trying to run them in a 386DX/40 with a pretty generic Acer IDE/FDC/LPT/2xCOM/GAME card.
I'm confident the testing gear is OK - no problems with newer IDE drives.
The problematic drives are probably also OK - I can access them without any problems when I boot from a diskette, Checkit 3.0 tests do pass as well.

But I can't boot off these early drives!
Boot PC DOS 2000 from a diskette, fdisk, format, sys, and sometimes even fdisk/mbr to be sure, then trying to boot from the HDD - it waits for some time, and then displays "Non-system disk or disk error..."

I thought the problem might be geometry-related, at this moment I'm working on the ST-125A - it's auto-detected as 404/4/26 (C/H/S), Seagate docs suggest using IBM AT DRIVE TYPE 6, ie. 615/4/17, I tried both settings, but the problem persists.

I even tried The Forbidden Thing, ie. low-level format, using HDINIT from Checkit 3.0 - with 404/4/26 mapping it immediately fails with BIOS ERROR, with 615/4/17 it formats OK, but after fdisk/format/sys I still can't boot off the HDD.

Must be some weird incompatibility, I probably should try it with another machine, preferably older than that, but don't have anything else up and ready.
Any other ideas?
 
I have an ST-157A.

Native (physical) geometry is 560/6/26, although that it not available for use.

According to the documentation, many logical geometries can be used, as long as certain restrictions are not exceeded. However, my particular ST-157A only works when set at one of the two documentation-suggested geometries: 733/7/17 and 1024/5/17

A low-level format action is what switches the drive from one geometry to another.

PROBLEM: Always auto-detects as 560/6/26 (the native geometry). Thus, a C: drive setting in CMOS/SETUP of "Auto" will not work.

To get my ST-157A working as the 733/7/17 geometry, I execute:
1. Set geometry of 733/7/17 into CMOS/SETUP.
2. LLF/FDISK/FORMAT as 733/7/17
 
I have a st157a drive in my 286 machine, and the parameters are 560 6 and 26. I tried to use the published parameters on the internet and the drive would never boot correctly. it turns out the parameters crudely written in sharpie on the psu were more reliable than whatever I found on the internet. I dont really know about the st125a though. good luck!
 
Back to playing with ST-157A.
I tried the native geometry before, now I tried both 733/7/17 and 1024/5/17.
This HDD has a sticker with big red "CAUTION: DO NOT LOW-LEVEL FORMAT".
So I LLF'ed it several times, but nothing interesting happened, I still can fdisk/format/sys and so on without problems, but can't boot off it.

Giving up for now, some time gonna try them again in a 286.
 
This HDD has a sticker with big red "CAUTION: DO NOT LOW-LEVEL FORMAT".
Mine does not have that sticker.

The ST157A-1 document at [here] includes, "After the drive has been properly configured for the system, and the correct drive type has been specified to the system CMOS, the drive should be low-level formatted."

The low-level formatting action is what gets my drive to change geometries. I doubt very much that at the low level, re-writing of sectors is happening. I expect that the code in the drive is simply taking note of the maximum cylinder/head/sector used during the low-level formatting commands, and switching the drive's logical geometry to that.

Assuming that the "CAUTION: DO NOT LOW-LEVEL FORMAT" sticker was added to your drive by Seagate, I wonder what mechanism they expected owners to use to get the drive to switch to an alternate logical geometry. Perhaps there was a dedicated program for that on the Seagate BBS ?
 
BTW, today I connected yet another early IDE HDD to my test machine, this time WD95044-A
And it worked without any problems!
This WD thing seems more backward - it requires parking its heads manually, while the Seagates already have auto-park, but in terms of compatibility the WD definitely wins.
 
"After the drive has been properly configured for the system, and the correct drive type has been specified to the system CMOS, the drive should be low-level formatted."

Gave me yet another idea: perhaps the LLF should be performed by some Seagate's special tool?
I only tried it with HDINIT from Checkit 3.0
So, what was the LLF utility recommended by Seagate back then?
 
Gave me yet another idea: perhaps the LLF should be performed by some Seagate's special tool?
I only tried it with HDINIT from Checkit 3.0
So, what was the LLF utility recommended by Seagate back then?

SGATFMT4.ZIP or something like that. Although I haven't confirmed that tool supports the ST-157A etc
Eventually got replaced by DiscWizard, so an old version of DiscWizard may support that model too.
 
Assuming that the "CAUTION: DO NOT LOW-LEVEL FORMAT" sticker was added to your drive by Seagate, I wonder what mechanism they expected owners to use to get the drive to switch to an alternate logical geometry. Perhaps there was a dedicated program for that on the Seagate BBS ?

Mine has that same sticker too, and I had to LLF it to get it running in my Tandy TL/2 properly (otherwise the computer thinks it's 20MB).
 
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