VOGONS


First post, by Planet-Dune

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Hello

I am running into floppy drive issues... I have 3 systems with the following configurations:

SysA:
1.44MB 3.5" drive, 1.2MB 5.25" drive

SysB:
720 3.5" drive, 360KB 5.25" drive

SysC:
2x 360KB 5.25" drives

Now I acquired a box of a few hundred floppy disks. I believe they are all DD 360b floppies. Beyond the expected some work, some don't, some half I am running into another issue. It seems if I use the 1.2MB drive in SysA to put data on the floppies I get very bad results once reading that data in the 360kb drives. Errors left and right, somefiles copy fine, then 5 don't, then a few do, then some don't etc.... I thought having the 1.44mb/1.2mb combo would allow me to get data on my 360 system the fastest (the SysC) as I could just put the data from my pc downstairs on a 1.44 diskette and then put that in SysA and copy it to the 360kb floppies... instead of having to use a 1.44mb diskette to copy the data to a 720kb diskette to copy the data to a 360kb floppy.

A few questions (to make this question more clear):

- Can I freely use a 1.2MB floppy to write data to 360KB floppies to be used on a 360KB drive?
- Can I format a 360KB floppy in a 1.2MB drive? I tried and it weirdly enough said it was "formatting 1.2mb" and then said there were 200kb of bad sectors and 900kb usable (on a 360kb floppy as far as I can tell) but the floppy really didn't work well anymore at that point, especially in the 360kb drive.

Bonus question:

- Is there a good DOS based utility that works with 360kb floppys that checks them and marks all bad sectors to not use them etc? So I can format all my floppies..

I think I wasted about 15 or so 360kb floppies testing out different scenarios and figuring out what is happening but the results are so erratic (sometimes the floppy is just dead, other times it works half etc)... I figured Id ask you guys 😀

EDIT: added a screenshot of the format I did, as you can see it said something about a "different file format" and that I wouldn't be able to "unformat" but then proceeded to format it labeling it a 1.2MB floppy.

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Reply 1 of 4, by derSammler

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Planet-Dune wrote on 2020-03-26, 21:11:

- Can I freely use a 1.2MB floppy to write data to 360KB floppies to be used on a 360KB drive?

No. You can write data to a 360KB disk and keep using that with the 1.2MB drive. A 360KB drive however won't be able to reliably read the disk. That is by design, as the head of a 1.2MB drive is much smaller, leaving junk of data left and right of the track that a 360KB drive will pick up, causing it not to understand what it reads.

Planet-Dune wrote on 2020-03-26, 21:11:

- Can I format a 360KB floppy in a 1.2MB drive? I tried and it weirdly enough said it was "formatting 1.2mb" and then said there were 200kb of bad sectors and 900kb usable (on a 360kb floppy as far as I can tell) but the floppy really didn't work well anymore at that point, especially in the 360kb drive.

You need to tell format that it's a 360KB disk. You can not format it to 1.2MB, for obvious reasons.

http://retro-net.de/blog.html

Reply 2 of 4, by Planet-Dune

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derSammler wrote on 2020-03-26, 21:31:
No. You can write data to a 360KB disk and keep using that with the 1.2MB drive. A 360KB drive however won't be able to reliably […]
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Planet-Dune wrote on 2020-03-26, 21:11:

- Can I freely use a 1.2MB floppy to write data to 360KB floppies to be used on a 360KB drive?

No. You can write data to a 360KB disk and keep using that with the 1.2MB drive. A 360KB drive however won't be able to reliably read the disk. That is by design, as the head of a 1.2MB drive is much smaller, leaving junk of data left and right of the track that a 360KB drive will pick up, causing it not to understand what it reads.

Planet-Dune wrote on 2020-03-26, 21:11:

- Can I format a 360KB floppy in a 1.2MB drive? I tried and it weirdly enough said it was "formatting 1.2mb" and then said there were 200kb of bad sectors and 900kb usable (on a 360kb floppy as far as I can tell) but the floppy really didn't work well anymore at that point, especially in the 360kb drive.

You need to tell format that it's a 360KB disk. You can not format it to 1.2MB, for obvious reasons.

Okay, that explains all my frustration... I figured it would work like a 720kb diskette where it can be used in a 1.44mb drive just fine without issues (and then still be readable on a 720 one)...

Well would still be nice to know if there are any good check and format utilities out there or should I just use default format.com ?

Reply 3 of 4, by derSammler

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FORMAT.COM should be fine. It has various options to check for bad tracks and such; just use the "/?" parameter to get all options listed.

http://retro-net.de/blog.html

Reply 4 of 4, by pentiumspeed

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1.2MB and 360K are completely different only in writing heads width track. 360K is wider than 1.2MB also is narrower.

Can read 360K on 1.2MB and can write a blank 360k disk on 1.2MB pretty good but comes up a problem when 360K drive formatted on 360K disk then write on 1.2MB in 360K mode then you have more problems on reading messy 36oK disk in 360K drive due to mixed width on each tracks.

Better find a real 360K drive.

And another issue is 1.2MB write amplification is stronger than 360K meant 1.2MB disk formatted as 360K in 1.2MB drive have hard time writing data hard enough impressions on 36oK drive.

Cheers,