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Need help with IBM 5150 5.25 drive having trouble writing

Mochatea396

Experienced Member
Joined
Feb 9, 2021
Messages
106
Location
Hudson Valley, New York, USA
Hello group,
I need help with my 5.25” floppy drive in my 5150. The drive seems to only like formatting one disk I have. Trying to format over 15 disks from a box that all format fine on an Apple drive, the IBM only is able to format one. And it will format that one disk every time. AND transfer the system to the disk. All others it says something’s wrong with the disk. And when I try to copy files to the one disk it likes, it says the files copied fine, I can hear the head moving back and forth but when I look, the files aren’t on the disk. I try and make a directory on the disk, it says it made it but it’s not there. I would say the drive doesn’t appear to be writing but it just formatted it, and why only one disk? And it says the files copied fine. I understand disks go bad commonly but this drive is the only drive that doesn’t like them. I cleaned the drive heads with a qtip and alcohol also.
Any ideas why I’m experiencing this?
Thanks group.
 
Could you list the error you are seeing?

DOS 5 and later have an unconditional switch "FORMAT /u" which forces DOS to format a disk. That solves some of the more common problems with DOS trying to preserve existing tracks.

There is a specific DOS 5 or 6 bug with FORMAT that prevents FORMATs after reading an unformatted disk. Otherwise, I might suspect an alignment issue with the drive and the quick formats used by default in later DOS versions leave the tracks in the wrong place relative the drive. If it is a serious alignment issue, the disks created may be a challenge to read on other drives. If you have two drives, check if both drives have the same problems.
 
Thanks for the replies. I made sure I could hear the write protect tank drop down telling it the disk isn’t write protected. And yes I am using dos 5. I’ll try the format string with the u. I’ve posted 2 pics. One of the error I’m getting when I try to format the unformatted disks (pretty much all) and the other is the mirror error I’m getting when I try to reformat the one disk that will actually format. I’ve dealt with alignment issues many times before, some so out of wack nothing would read what it wrote but itself, but it formatted disks fine, just put the tracks where it liked it. This doesn’t even like formatting. I only have the one 5.25 drive, someone at one point replaced the other with a HD and a 3.5 floppy. (Which I’m able to format disks on with no problem)
 

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The obvious first question is what is the disk drive and what type of disks are you using with it? For example, HD, QD, DD etc.

Dave
 
That's interesting, a couple of websites specify they are double sided.

It won't matter if the disks are double sided if the floppy itself is only single sided.

EDIT: 360K drives on a few other websites I have looked at are quoting 40 Track double sided. What physical drive type have you got - just to double check.

What disk media are you using?

Dave
 
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What model drive is being used? Are you positive that the system recognizes the drive as single sided? It may be necessary to specify the single sided (180K) formats.

FORMAT A: /1 /F:180 /u
/1 tells the system to make the disk single sided
/F:180 defines 180K format Probably redundant with /1 and with early DOS version it is needed to define tracks and sectors directly
/u is the unconditional format which would lay down new tracks and might correct the Track 0 problem shown.
 
The media I’m using is mixed. Mostly verbatim but some are a no name brand. Formatted over 30 of these on an Apple never one bad. And my TRS80 likes them also. I’m going to be using this drive to write TRS80 disks so keeping the tracks in the two drives the same would be important. I’ll try the string you suggested and let you know my results.
Thanks again
 
Obviously, I made a mistake. Which version of DOS is being used? Different versions have different switches and I don't remember all the interactions.

The model of the drive would be helpful to know. Single sided drives were rare so I want to be sure that suggestions are not chasing after the wrong problem.
 
I seem to recall running in to similar symptoms when a drive was not really writing to the disk. The one disk that "formats" is likely already formatted without error and therefore passes all read verification. When writing files or directories, DOS does not verify what it has actually written unless you set the VERIFY command to ON.

Try reformatting that one disk on the Apple II and then see if the IBM will "format" it now. It probably won't.

If that is correct, then that means something is badly wrong with the drive, cable, or controller. Narrow things down by trying a different drive.
 
I've run into this. Part of the info placed on a disk when formatted is a media type byte. If you've formatted fresh disks in a DOS system they will read an write fine. Bit if you put one of them into a machine running a later issue of Windows, Windows will overwrite the media type to something the DOS will not recognize. Degauss the disk and reformat it using a DOS system and it will likely experience a miraculous cure. Put it back into the Windows system, then back into the DOS machine and surprise, surprise, it will again say "Invalid media or track 0 bad" even if all you let the Windows machine do is mount the floppy.

 
Media byte? No, what is happening is that DOS thinks it is writing to the disk when it really isn't. If the disk is already formatted, during formatting it will think it is blasting format bits to the disk and when it goes to verify, it finds "something". Later when it tries to write data, the drive seeks to the right tracks, reads the sector header, thinks it is blasting bits to the sector, but never looks back.

Since we are talking about a 5150, I'm guessing the drive in question is a Tandon TM 100-2A?

First sanity check with a different drive. Make sure the controller and cable are working OK.

If those check out, chances are there is a damaged component on the logic board involving the "write gate". Start by looking for any visible damage and make sure all the plugs to the various parts are plugged in the right place.
 
I ran into the exact same problem. Testing what I say about later versions corrupting the vital parts of a DOS floppy will take someone all of 10 minutes. Take a clean disk, or one that's already corrupted. Degauss or reformat /u in a later DOS version. Verify it can be formatted in an older version of DOS. Then allow a later version of Windows to mount it. Retry it in DOS and it will say "Invalid media or track 0 bad." Reformat /u in a later DOS version or degauss and format and everything is all good again. This one bit me hard and I spent hours figuring it out with a lot of web help.

Or you can start ripping your system apart looking for a hardware fix. Your time, your system, your money.

It is well known that a later Windows system rewrites critical data on any floppy it comes in contact with unless that floppy is write protected. Look at a floppy with a disk editor before and after letting Windows 98 & above touch it. Notice that the field that tells what system was used to format the floppy gets overwritten.

From here: https://thestarman.pcministry.com/asm/mbr/DOS50FDB.htm

"This is followed by the OEM System Name which happens to be "MSDOS5.0" in this case, but could be anything as far as the code is concerned (CAUTION: Any diskette that is not write-protected, will have these bytes overwritten by any Microsoft Win 9x or later OS; for more info see: Notes about the "IHC" string under DEBUG's Load Instruction here )."

And here: https://thestarman.pcministry.com/asm/debug/debug2.htm#IHC

"[ Many floppy disks have the letters IHC in their OEM ID field. What kind of OEM Name is that? None. Someone at Microsoft decided that this was where they'd place a new pseudo-random type of identification to make sure that any information cached by 'Windows 9x' from one disk wouldn't be mixed up with info from a different one if you swapped disks. The whole string begins with five pseudo-random hex bytes, and always ends with the characters IHC. All floppy diskettes that are not write-protected will have any original OEM ID overwritten. Once Windows has written this string, it will remain the same for any future disk reads or writes. However, performing even a quick format under Windows, will change the five hex bytes every time.
Some have concluded the characters 'IHC' are the first three letters of the word "Chicago" in reverse order, since Chicago was the 'code name' for Windows™ 95 before it was ever released (it would have appeared as ' OGACIHC' on the hypothetical disk). Although certainly a possibility, I have no proof of that. Due to our interest in some very old Greek Manuscripts, we still can't help but see the 3 characters 'IHC' as an Iota, Eta and old style Sigma since this combination of letters was often used as an abbreviation for the Greek word "IHSUS" (Jesus). Just another of many coincidences in our lives.
REMEMBER: If you really want to preserve all of the contents of an important diskette, you can't even perform a simple Directory read under a Windows OS, UNLESS it is 'write-protected' and you know the drive's write-protect system is functioning correctly! ]"

The result when such a disk is put into an older DOS system is exactly what the OP is seeing. Cost me about a week to figure it out. Try my recommended fix.
 
I didn't read anywhere that the OP used his 5.25" disks in a later Windows machine. He mentions using an Apple II and a TRS-80. This sounds like a drive problem, probably due to age. Trying another drive or two should at least help troubleshoot. I had a 360k drive in my 5162 that would not read or write disks. I replaced it with a 1.2M drive. I needed to use the Setup program and keep a fresh backup battery or the 1.2M won't boot.

Seaken
 
By all means, the OP should do whatever they need to do to get their machine running. BUT.....

It isn't necessarily a hardware problem. Checking for a case of a disk "corrupted" by Windows is one of the easiest things to rule out, and at the same time one that many folks are not even aware of. How many people today are in a position to put a floppy in a newer Windows machine then try to use it in an older DOS machine?

That the OP hasn't posted in a few days might inicate the trouble is fixed. If so it will be interesting to hear what they found.
 
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