VOGONS


First post, by kikendo

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Hello, yeah it's me again, the guy with the 386 😜

I just realized that my 5.25 drive reads disks just fine, but writing to them causes a error and disks immediately get thrashed. LIke, they don't read the content anymore after I tried formatting, or copying a file to them.
I never had a drive that reads fine but doesn't write, usually they either work or not at all.

Any idea what could be wrong here? The magnetic heads are both for reading and writing, right? This isn't a cassette deck...

Reply 1 of 26, by Deksor

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Which kind of drive do you have ? 1.2MB drive or 360KB drive ?
1.2MB drives often can read from 360KB disks but can't properly write to them.

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Reply 2 of 26, by darry

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Deksor wrote on 2020-06-15, 00:14:

Which kind of drive do you have ? 1.2MB drive or 360KB drive ?
1.2MB drives often can read from 360KB disks but can't properly write to them.

True, but drives should still be able to read the disks they have written themselves, even if it is 1.2MB drive writing a 360K floppy .

Reply 3 of 26, by Deksor

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It depends, if he tries to write on a 360KB disk, it may not work properly.

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Reply 4 of 26, by darry

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Deksor wrote on 2020-06-15, 01:46:

It depends, if he tries to write on a 360KB disk, it may not work properly.

My understanding of the issue related to using 360K floppies in a 1.2MB drive is that a 1.2MB will usually write too narrow a track for it to be usually read reliably in a 360K drive . I have never seen a 1.2MB be unable to read a 360KB disk that it had itself written .

In my high school days, I was so low on storage space, that I used to re-purpose old 360K floppies and write 800K to them using a 1.2MB drive, quite reliably I might add.

The software I used at the time was 2M . https://en.wikipedia.org/wiki/2M_(DOS) .

Reply 5 of 26, by Deksor

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Well not all 360KB disks are the same and so they won't all react the same.
But anyways I think we should wait for his answer ^^

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Reply 6 of 26, by darry

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Deksor wrote on 2020-06-15, 02:01:

Well not all 360KB disks are the same and so they won't all react the same.
But anyways I think we should wait for his answer ^^

True, through I will say that I was pretty universally successful with using a multitude of different brand 360KB floppies, even at 800K . I was using a Panasonic JU-475 variant floppy drive at the time and will add that the 2M program would likely not have been a thing if my experience with 1.2MB drives and 360KB floppies was an uncommon exception.

That said, let's indeed wait for the OP .

Reply 7 of 26, by Horun

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kikendo wrote on 2020-06-14, 23:59:
Hello, yeah it's me again, the guy with the 386 :P […]
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Hello, yeah it's me again, the guy with the 386 😜

I just realized that my 5.25 drive reads disks just fine, but writing to them causes a error and disks immediately get thrashed. LIke, they don't read the content anymore after I tried formatting, or copying a file to them.
I never had a drive that reads fine but doesn't write, usually they either work or not at all.

Any idea what could be wrong here? The magnetic heads are both for reading and writing, right? This isn't a cassette deck...

Is it a 360k floppy drive or 1.2Mb drive and what exact disks are you writing too ?
Yes the same heads both read and write in a floppy drive. When you say "reads" do you mean you can DIR and see the contents or can you actually copy the files to an HD and have them work ? There is a difference between a drive reading the FAT versus actually reading the data so need to know if you actually read the data proper. Another issue that is rare but can happen is the electronics may not be feeding the heads properly creating the proper electro-magnetics needed to properly write or format but are able to read data already written by another drive.

Hate posting a reply and have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. 🤣 Second computer a 286 12Mhz with real IDE drive ! After that came 386, 486, Pentium, P.Pro and everything after....

Reply 8 of 26, by kikendo

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Deksor wrote on 2020-06-15, 00:14:

Which kind of drive do you have ? 1.2MB drive or 360KB drive ?
1.2MB drives often can read from 360KB disks but can't properly write to them.

Seems like you guys probably hit the nail right in the head again.
This is a 1.2MB drive.
I am trying to write to a 360KB floppy.
It read them just fine (I successfully imaged them)
But any write operation to it, destroys the disk contents.
If format, stops at track 0, says " disk is unusabe", and ruins the disk.
If copy, stops with a "hardware error", and ruins the disk.
(I'm guessing it's ruining the FAT?)

Thank goodness I imaged all these disks beforehand.

Reply 9 of 26, by babtras

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I found this snippet from http://jope.fi/drives/40200A03.pdf

"The PC originally produced 360KB diskettes on a 48 TPI (tracks per inch) drive. The diskettes used were known as 2D (2 sides, double density). A dual density drive can operate in either double density or high density mode. Dual density drives are 96 TPI units and can record twice as many tracks in the same area. These higher capacity units use 2DD (2 sides, double density, double track) media. This is the same media used forthe standard AMS format. In order to emulate a double density 48 TPI drive, only the even tracks are recorded, with the odd tracks being skipped. Since a double track drive is being used, 2DD media must be used to record these 360KB diskettes"

So even though a 1.2MB drive is capable of reading these disks, writing at that density still requires a 96 TPI disk and only writes even tracks. If you try to write to 48 TPI media, it'll likely mangle it (probably correctable with a low-level format with a 48 TPI drive I'd guess).

This is very relevant to what I'm working on right now too. I'm happy to have seen this thread before I got too frustrated trying to make a boot disk for an old 8088.

Reply 10 of 26, by darry

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I still think there may be something wrong with the 1.2MB drive if it can't write to 360KB disks in a way that's readable by the 1.2MB drive itself . Even if it did work in the 1.2MB drive, the resulting disk would likely not work correctly in a 360KB drive .

What model is the drive and can it write 1.2MB disks correctly ?

EDIT: the 1.2MB should be able to read 360KB disks it has written itself, but it is not the case 100% of the time. It probably depends on the drive . Bulk erasing the floppies and re-writing from scratch may be something to try .
See http://www.retrotechnology.com/herbs_stuff/drive.html#thin

Reply 11 of 26, by Disruptor

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kikendo wrote on 2020-06-15, 04:37:
Seems like you guys probably hit the nail right in the head again. This is a 1.2MB drive. I am trying to write to a 360KB floppy […]
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Seems like you guys probably hit the nail right in the head again.
This is a 1.2MB drive.
I am trying to write to a 360KB floppy.
It read them just fine (I successfully imaged them)
But any write operation to it, destroys the disk contents.
If format, stops at track 0, says " disk is unusabe", and ruins the disk.
If copy, stops with a "hardware error", and ruins the disk.
(I'm guessing it's ruining the FAT?)

Thank goodness I imaged all these disks beforehand.

Did you format it using DOS?

Try
format b: /4
or
format b: /N:9 /T:40
or
format b: /F:360

Reply 12 of 26, by kikendo

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darry wrote on 2020-06-15, 05:11:

What model is the drive and can it write 1.2MB disks correctly ?

I cannot tell because I have no 1.2MB disks. Can't remember the model right now.

EDIT: the 1.2MB should be able to read 360KB disks it has written itself, but it is not the case 100% of the time. It probably depends on the drive . Bulk erasing the floppies and re-writing from scratch may be something to try .

It's what I am trying to do and failing.

But here's some more info, maybe this could shed some light on the subject: to do this process, I took the drive out of the 386 and stick it in my Pentium II system.
Could it be a BIOS limitation? This shitty BIOS doesn't even let me have two drives at the same time (Gateway 2000 440BX motherboard)

Disruptor wrote on 2020-06-15, 06:37:
Did you format it using DOS? Try format b: /4 or format b: /N:9 /T:40 or format b: /F:360 […]
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Did you format it using DOS?
Try
format b: /4
or
format b: /N:9 /T:40
or
format b: /F:360

I only tried the last option you gave. I will try the others. But as I said, this problem happens too when I try to do ANY write operation on the disks, not just format. Copying a file will also wipe the disk.

By the way, the disks are fine, I reformatted them all on my C64 and they run just great. So the disks are not ruined physically, just the information gets ruined as soon as I try to write to them on my PC, and as I said I think it's just blanking the FAT.

Reply 13 of 26, by darry

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kikendo wrote on 2020-06-15, 17:43:
I cannot tell because I have no 1.2MB disks. Can't remember the model right now. […]
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darry wrote on 2020-06-15, 05:11:

What model is the drive and can it write 1.2MB disks correctly ?

I cannot tell because I have no 1.2MB disks. Can't remember the model right now.

EDIT: the 1.2MB should be able to read 360KB disks it has written itself, but it is not the case 100% of the time. It probably depends on the drive . Bulk erasing the floppies and re-writing from scratch may be something to try .

It's what I am trying to do and failing.

But here's some more info, maybe this could shed some light on the subject: to do this process, I took the drive out of the 386 and stick it in my Pentium II system.
Could it be a BIOS limitation? This shitty BIOS doesn't even let me have two drives at the same time (Gateway 2000 440BX motherboard)

Disruptor wrote on 2020-06-15, 06:37:
Did you format it using DOS? Try format b: /4 or format b: /N:9 /T:40 or format b: /F:360 […]
Show full quote

Did you format it using DOS?
Try
format b: /4
or
format b: /N:9 /T:40
or
format b: /F:360

I only tried the last option you gave. I will try the others. But as I said, this problem happens too when I try to do ANY write operation on the disks, not just format. Copying a file will also wipe the disk.

By the way, the disks are fine, I reformatted them all on my C64 and they run just great. So the disks are not ruined physically, just the information gets ruined as soon as I try to write to them on my PC, and as I said I think it's just blanking the FAT.

If the Gateway BIOS lets you set the right drive type, it should just work, AFAIK . Then again, by the 440BX era, 5 1/4 drive support was an afterthought, so maybe it could be a strange bug .

Reply 14 of 26, by kikendo

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darry wrote on 2020-06-15, 18:01:

If the Gateway BIOS lets you set the right drive type, it should just work, AFAIK . Then again, by the 440BX era, 5 1/4 drive support was an afterthought, so maybe it could be a strange bug .

I'm gonna put it back in the 386 and see what happens.

Reply 15 of 26, by kikendo

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kikendo wrote on 2020-06-15, 20:21:

I'm gonna put it back in the 386 and see what happens.

OK I didnt even get to this point yet. I found a 1.2MB disk around, and I tested it. SAME error. "cannot format track 0, disk unusable".
So the drive refuses to write any disk.

If I try in Windows 98, it says "there's no disk in drive or the drive door is open".

Reply 16 of 26, by darry

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kikendo wrote on 2020-06-16, 04:33:
OK I didnt even get to this point yet. I found a 1.2MB disk around, and I tested it. SAME error. "cannot format track 0, disk un […]
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kikendo wrote on 2020-06-15, 20:21:

I'm gonna put it back in the 386 and see what happens.

OK I didnt even get to this point yet. I found a 1.2MB disk around, and I tested it. SAME error. "cannot format track 0, disk unusable".
So the drive refuses to write any disk.

If I try in Windows 98, it says "there's no disk in drive or the drive door is open".

Sorry to hear about the drive's apparent demise . Hopefully, it can be repaired or replaced at a reasonable cost .

There are service manuals floating around for at least some drive models, maybe you'll get lucky and find one to point you in the right direction. Maybe you'll open the drive, find obviously bad capacitors and fix the drive by replacing them .

Good luck, either way .

Reply 17 of 26, by BoraxMan

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I have been working with a few 1.2M drives in the last month or two, and found quite a few problems, especially when trying to use 360K disks. For what it is worth, I had two drives fail multiple times after using 360K disks. The most common mode of failure was that it would write, but not read. I could format a disk, but it wouldn't write the BOOT sector, or, it would say that "track 0 was unusable".

In both cases, I fixed it by opening the drive and gently cleaning the heads. I also moved the heads up and back on their track as well as lifting the top head while in operation. I don't know why this worked, but it did. Essentially, I had to 'play' with the drives until they worked again. I have also found that while 360K disks are pretty reliable, some cheaper brands can shed coating, which I think caused this problem.

Maybe someone can shed light on what happened, but this problem seemed similar.

Reply 18 of 26, by kikendo

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BoraxMan wrote on 2020-06-16, 10:37:

In both cases, I fixed it by opening the drive and gently cleaning the heads. I also moved the heads up and back on their track as well as lifting the top head while in operation. I don't know why this worked, but it did. Essentially, I had to 'play' with the drives until they worked again. I have also found that while 360K disks are pretty reliable, some cheaper brands can shed coating, which I think caused this problem.

VERY interesting point. I will clean the heads and move them a bit.

I did some more findings now... I put the drive back into the 386, and I had a lot of trouble getting it to work, wasn't booting disks it booted before, etc... got a bit angry at it, added a 3.5" drive to the chain, and booted from it.
Now while in DOS, I managed to read disks from t he 5.25" drive, and even though a lot failed, I even managed to write a file to one of them. So that's some progress.

I am now building a better 3.5" MS-DOS boot disk with FORMAT in it to test some more... but first I will give the heads a nice clean as suggested by BoraxMan.

By the way, the drive is an EPSON SD-600, and it has a shit-ton of jumpers on it that I have no idea what they do. I found a thread about this drive in the VCF forums, and it wasn't very conclusive regarding jumper info.

Reply 19 of 26, by kikendo

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OK I am more confused than before. I did a lot more tests, and I managed to format a bunch of 360KB disks, but not all. Also the only 1.2MB disk I have, I couldn't format (same error, track 0 unreadable). I made a MS-DOS 6.22 boot disk which seemed more successful at formatting disks than the Windows 98 DOS boot disk I had before. Could it be that Windows 98 had something to do with this, too?

The weird thing is that the disks that I can't write to on the PC I can write to on my C64.

I think the drive is fine, but maybe it's more sensitive to media on the verge of bit rotting, which might be read OK but losing density to be written on.
I would have to buy a box of new old stock 2HD disks to do more tests, but for now I feel like I spent way too much time with this unit.