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Scandisk encountered a data error while reading the FAT

uriahsky

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Joined
Jan 23, 2012
Messages
37
This is on my ST251-1 that I thought was OK, but it seems to be getting worse and worse. I know it is probably on the way out, but could it have anything to do with the way it is setup in the Bios? I am unsure of a few of the settings. Cylinders:820, SEC:17 HEADS:6 those I think are correct. The precomp I have seen 65xxxx which doesn't fit or -1, or 0. That one I am unsure of. The LZ: is it 820 or 910 or?? '

If those aren't at the root of the drive getting worse and worse. Is there a DOS utility that runs on a 286 that might try and fix the FAT error? and other errors.
Thanks
Russ
 

krebizfan

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May 23, 2009
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Seagate's documentation claims that drive automatically parks so the landing zone should not be an issue. Cylinder and head listed match their documentation so that too should be correct. ftp://ftp.seagate.com/techsuppt/mfm/st251.txt

What computer and controller do you have it attached to? Is there any type of overlay software or driver in use? Most of the times I had MFM hard disks with intermittent failures reading the FAT the problem was related to the controller or drive cables. That is one crazy robust drive. Look at the controller and drive and look for signs of failed capacitors and similar problems.

Fixes: Well, if you are lucky, a low level format could allow you to skip a bad or failing sector that is underlying one of the FATs. Sometimes. Maybe. Or if you want to try it, Spinrite and similar tools were intended to handle this type of issue. Note that whatever you try, there is a very good chance that the data on the disk will be lost in the process of getting the disk back to working again. Try to back up just in case.
 
Last edited:

Chuck(G)

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Jan 11, 2007
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Your geometry agrees with my sources. I'd make the LZ 820; i.e. one cylinder past the last data cylinder (819).

You probably see 65535, which is the same as -1 (for a 16 bit value). You could also make the precomp 820 to turn it off.

Do you have any idea what error is being reported?
 

uriahsky

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Joined
Jan 23, 2012
Messages
37
It is not giving me any error messages, but files that worked one day start to fail the next day. I ran CHKDSK on it and then I was able to run SCANDISK and it fixed about 100 errors. I ran it about a half hour later and it found another 3 errors. But, most of the software started to work. I did order another controller and once it shows up I will swap out the ST251-1 and use a newer IDE.

The controller it is using right now is a LONGSHINE MICROSYSTEM, INC. LCS-6622/W I don't think there is any overlay software but I am not sure. I will see if I have another cable and swap it out. I do have most of it backed up so I guess I am safe if the worst happens. I will try setting the precomp to 820 and see if it helps.

Thanks very much
Russ
 

uriahsky

Member
Joined
Jan 23, 2012
Messages
37
If you mean that resistor pack that plugs into the pins on the bottom. Yes, that is installed. I am pretty sure that is what you are referring too.
 

Chuck(G)

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Jan 11, 2007
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Pacific Northwest, USA
Yes, that's it--leaving it out can sometimes result in erratic operation. I'm trying to determine if your problem is with the drive itself (the recording surfaces and read/write circuitry) or the circuitry that links the drive with your controller.

If you use a disk editor, can you discover the bad sectors? If you re-read a sector, does the error go away?
 
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