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Seagate ST351A/X hard drive

oblivion

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I posted this in Commodore but noone responded after several days so maybe that wasn't the best place to post.

I have 3 Seagate ST351A/X hard drives that are supposedly 8/16 bit drives. I am trying to install one in my Commodore Colt which has an 8 bit XT interface built in for hdd's. does anyone know the correct jumper configuration? I've read other posts and jumper schematics but none of my drives seen to be detected even though they all spin up and power on.

 
The Commodore PC's onboard IDE-XT interface was designed to work with Western Digital drives, and I have not had good luck at getting a Western Digital IDE-XT interface to recognize Seagate IDE-XT drives. For example my Zenith eaZy PC came with a WD93028X IDE-XT drive and I wanted to replace it with a Seagate, but it wouldn't recognize either an ST-325X or an ST-351A/X (in XT mode). I ended up having to stick with the WD drive, which is unfortunate because the early WD 3.5" stepper motor drives are well known to be unreliable, as well as slow, noisy, and hot-running.
 
hmmm, I also keep reading about the wrong jumper configurations on this drive can actually damage it but I haven't seen any references to how this happens and what I should avoid doing to prevent it.
 
I can tell from personal experience that it works.
I used to have a PC10-III, which has the same motherboard as the Colt/PC20-III. I installed an ST351A/X 40 MB IDE drive in it and it worked like a charm.
I don't recall the exact jumper config, but I believe there was a single jumper to select between XT or AT style interface, so that is probably what I set.

IIRC the BIOS will not auto-detect the drive. I believe you have to run the BIOS routine to initialize the drive. You can find how to do that in the manual. It involves starting debug.exe and jumping to the proper address.
After you went through that init routine, you should reboot and then you should be able to fdisk and format the disk.

Note also that there is a jumper on the motherboard to enable or disable the IDE controller. Make sure you have the jumper set correctly.
 
I can tell from personal experience that it works.
I used to have a PC10-III, which has the same motherboard as the Colt/PC20-III. I installed an ST351A/X 40 MB IDE drive in it and it worked like a charm.
I don't recall the exact jumper config, but I believe there was a single jumper to select between XT or AT style interface, so that is probably what I set.

IIRC the BIOS will not auto-detect the drive. I believe you have to run the BIOS routine to initialize the drive. You can find how to do that in the manual. It involves starting debug.exe and jumping to the proper address.
After you went through that init routine, you should reboot and then you should be able to fdisk and format the disk.

Note also that there is a jumper on the motherboard to enable or disable the IDE controller. Make sure you have the jumper set correctly.

ah, I'll give it another shot then. I did indeed set the jumper. the guide to the PC-10/Colt I found on here stated that if the drive was properly detected you won't get a "hard disk not found" error and didn't mention anything about running a BIOS routine
 
thanks but I actually have the manual here. no luck so far. Ive tried how my drive is jumpered in the image above as well as having only a jumper on pins 1 & 2 but when I get to formatting I get a "Error---completion code 80"
 
Here are the jumper settings:

ftp://ftp.seagate.com/techsuppt/at/st351ax.txt

It's hard to read because the formatting was designed for the DOS extended character set, but for the 12-pin version in XT mode using the full 40 MB capacity, you should have jumpers on pins 1-2, 5-6, 7-8 and either 10-12 or 11-12 depending if the bus reset is low or high (probably you'll just need to experiment to see which one works).
 
Which begs the question, is the drive hosed?

possibly, I have 2 more I can test. do you have the link to the jumper chart you found? I cant seem to find the same one. The one I found lists pins 8 & 7 as being XT mode

whats Bus rest mode? theres a high and low but i have no idea what that means
 
okay, seems third disk is a charm. other two must be dead...anyways i did a format and i got an option to format bad tracks. I have virtually no experience with low level formatting or DOS 3.2 outside of games. do I want to format bad tracks? do I need to? how do I?
 
okay, seems third disk is a charm. other two must be dead...anyways i did a format and i got an option to format bad tracks. I have virtually no experience with low level formatting or DOS 3.2 outside of games. do I want to format bad tracks? do I need to? how do I?

Edit: I incorrectly remembered how it works. Apologies.

If you have a list of bad tracks and no bad tracks were already entered, Seagate recommends entering the list.
 
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thanks for all the info guys. got it working. and it now boots from the drive. unfortunately I have a older BIOS so it can only see up to 20mb but that's better then nothing.

not bad for a random find at a thrift store. at least one of the three worked wich I guess is kinda amazing considering how much this drive was possibly manhandled through its life and on a thrift store shelf.
 
On my Tandy 1000 TL/2 it was 20MB formatted - until I used their disk based prep tool (HDFORM I think?) and that wrote the proper configuration record.
I was under the understanding that Commodore had a similar tool in ROM that could be accessed via debug, for prepping it's XTA drives.

Don't have the link on me, can't confirm what models or anything - that's just what is ringing bells in my head.


Edit: Nevermind, did some searching and found the proper information here : http://www.vintage-computer.com/vcforum/showthread.php?26427-Commodore-PC10-III - I get it now, early BIOS is 20MB only, if drive is unlocked it'll drop to 10MB - bummer :/
 
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yhea, i checked. from the commodore pc-10 III guide on this site
"the first BIOS revision (4.35) appears to be limited to drives under 20MB. If you use a drive larger than 20MB on an early BIOS, the system will see it as a 10MB drive. With the ST-351A/X, it is possible to set a jumper on the drive to force it into 20MB mode. While this has the unfortunate effect of cutting the drive's capacity in half"
 
yhea, i checked. from the commodore pc-10 III guide on this site
"the first BIOS revision (4.35) appears to be limited to drives under 20MB. If you use a drive larger than 20MB on an early BIOS, the system will see it as a 10MB drive. With the ST-351A/X, it is possible to set a jumper on the drive to force it into 20MB mode. While this has the unfortunate effect of cutting the drive's capacity in half"

Ah, that's a shame. I must have had a later revision, since mine used the full 40 MB.
You mentioned DOS 3.2. Note that you can only create partitions of 32 MB max with those.
So if you were to go with a BIOS upgrade to use the full 40 MB (you can probably find the ROM image online, perhaps here: http://www.vintage-computer.com/vcforum/showthread.php?32440-Commodore-PC10-III-BIOS, and get it burned to some EPROM chips or such... if not, there's probably someone on this forum who could dump it from their machine. I have a PC20-III now, it may have the newer ROM, I'd have to check), you'd probably also want to upgrade to DOS 5.0 so you can make a single 40 MB partition.
I ran DOS 5.0 on my PC10-III anyway, at the time. Worked like a charm.
 
That's a good idea. I don't have the ability to burn an EPROM so I'll have to find some help with that but its certainly something to look into. would be nice to be able to use the whole drive.
 
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