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Reliably writing a 360KB floppy in a 1.2MB drive

G

Great Hierophant

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I wish to know if there is a reliable software program that you can use to write 360KB floppies in a 1.2MB drive.

My main PC has a 1.2MB drive. I wish to copy disk images onto 360KB floppy disks to use in an IBM PC/XT with 360KB drives and standard IBM drive controller. Obviously, as the disk images will likely be written to in the XT, I would not want the writing to destroy the data stored on the disk, at least as far as the XT goes. I do not care as much if the disks cannot be read again on the main PC.
 
Try this, using 2 disks:
Format disk 1 in the XT first.
Write the data onto disk 1 using the HD drive.
Using the XT, copy disk 1 onto disk 2.
Re-format disk 1 in the XT to use again.

Takes time, but I have good luck doing it this way.

Or wait for a reasonably priced 360K drive on eBay (if your BIOS supports it). I generally get them for $10 plus S+H.
 
The track width is definately a problem. I have always had lots of 360 drives so never had occasion to try it, but it occured to me that if you wipe the disk with a regular tape demagnetizer first, that ought to give you a clean disk. Those cheap handheld ones are still available, if I'm not mistaken.
 
I found it depends on the disk. You should ALWAYS format the disk in the 360kB drive. Most of the time writing data in a 1.2MB drive leaves it unreadable in the 360kB one... but I have a couple of disks that always work! No idea why. :)
 
dongfeng said:
I found it depends on the disk. You should ALWAYS format the disk in the 360kB drive. Most of the time writing data in a 1.2MB drive leaves it unreadable in the 360kB one... but I have a couple of disks that always work! No idea why. :)
Click to expand...

All of the disks I have formated and used as 360Kb in my Teac FD-55GFR 149-U5 (1.2MB drive) tuns out to work just fine on my XT's FH 360Kb FDD's, however, I haven't tried too many yet, I have actually just tried a coupple (about five).
 
I'm a little rusty, and don't have the documentation handy - but aren't the furmulations different on the two kinds of disks? IIRC the drive does not recognize the need for a different field strength... unlike the 720/144 situation.
 
I think the common conclusion is that you can write a 360K floppy on a 1.2 MB drive, but that you should not write to it again from the vintage, 360K drive. If that happens, you may suffer bad data corruption due to this and that: both different coercivity and width of the write head.

kb2syd: Where are those 360K drives for $10 + shipping? The sellers I see on eBay tend to charge a lot - at least twice or thrice as much - for both 360K and 1.2MB drives. Of course international shipping would be even worse. I do have a 360K drive that works natively in MS-DOS but I never managed to get working reliably with those custom drives, neither with CatWeasel nor OmniFlop despite trying three modern PCs with supposedly compatible FDCs. On the other hand I've read that you may need to find about 5-10 floppy drives before you encounter one that will work reliably with foreign formats.
 
Northgate had a program named 'drives' (original, eh?) on a utility disk that would allow both copy and format function of 1.4 Mb, 720 Kb, 1.2 Mb, and 360 Kb disks. It would simply add seperate drive letters, D & E, for the floppy drives. You would simply place the disk to be formatted in the respective drive and type FORMAT D: or FORMAT E: for the 360 Kb and 720 Kb disks.
 
i've never been able to pull that off well. on the rare occasion i need to write to a 360 KB disk for one of my 8088's, (such as making a boot disk) i just pull a drive out of the 8088 and install it into a modern PC.

unfortunately since XP doesn't even know wtf a 360 KB formatted disk is it seems, i have to create an image with WinImage and write it directly from there. it works like a charm every time. big pain though. after i have a boot disk, i just transfer files between them via FTP! it's so much nicer.
 
I use the program Winimage. This lets me write to a blank DS/DD 5.25 180k or 360k disk from a 1.2MB drive under Windows XP and have that disk reads fine in an IBM 5150!!

This may be a rare thing and (by luck) I simply seem to have the right hardware. Mind you, from memory I haven't tried to WRITE to such a disk on the IBM 5150. Carlssons comment suggests this might not work.

Anyway, perhaps download the shareware version of Winimage and have a go?

Tez
 
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I'm afraid there is a lot of YMMV on this topic. Perhaps there are different 360K mechanisms more or less tolerant to floppies written on HD drives? It could also be a matter if you use a previously unformatted floppy or one that used to hold other data.

On a related matter, I remember that every floppy disk - both 5.25" and 3.5" - that I used on a IBM PC compatible computer, would become unreliable if I tried to reformat it on a C64 or Amiga. I had several floppy disks from the same batch and they would read, write and format perfectly fine on the Commodores. Then if I reformatted one for the PC, that disk was doomed to be only used with FAT12. Reformatting it again lead to lots of read-write errors. I simply think most PC drives are stronger in some respect than other systems. It can't be the coercivity, but perhaps the MFM encoding is harder to wipe out than GCR encoding. Again, YMMV but this is my experience.
 
I've got a high-end 1.2MB drive in my Packard Bell, and it writes to 360K disks just fine as well as formats them and are perfectly readable in my IBM 5150 and AT&T PC 6300. I can even write to them on a 360K drive and swap back and forth and it works great. I am using Windows 95 on that system. I've never had a read/write problem with that drive or any of it's disks.

--Jack
 
carlsson said:
kb2syd: Where are those 360K drives for $10 + shipping? The sellers I see on eBay tend to charge a lot - at least twice or thrice as much - for both 360K and 1.2MB drives. Of course international shipping would be even worse. I do have a 360K drive that works natively in MS-DOS but I never managed to get working reliably with those custom drives, neither with CatWeasel nor OmniFlop despite trying three modern PCs with supposedly compatible FDCs. On the other hand I've read that you may need to find about 5-10 floppy drives before you encounter one that will work reliably with foreign formats.
Click to expand...

I just find all that I can and watch them. Some go for $20 and up, but at least once a month I see them going for less than $10. Many of these sellers will not ship internationally though. If you want, I can watch a bunch and nab one for less than this and cross mail it to you. Just let me know via PM.

Kelly
 
Nah, there is no guarantee a random drive will be among the 10-20% which will work reliably with custom formats. I'll try to score some locally, I have only tested one drive.
 
I've had good results following the same procedure that Trixter posted. I use a bulk tape eraser I bought at Radio Shack years ago, bulk erase the 360k diskette then format it in the 1.2M drive. As long as you only write to it from the 1.2M and only read it from the 360k drive you are usually OK.

BTW, I purchased on E-bay this morning a 360k disk drive for $9.95 + $12 S&H. Here is the listing: http://cgi.ebay.com/5-25-Diskette-Drive-floppy_W0QQitemZ200243747055QQihZ010QQcategoryZ4193QQrdZ1QQssPageNameZWD1VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247 The seller has both 360k and 1.2M drives available. They are pulls, not new or reconditioned so I can't say anything about how well the one I bought will work until after I get it.
 
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I've had some success by first formatting the disks at 720K (which is 80-track), then at 360K and writing the files to them. These then seem to read OK in the 360K drive on my XT machine.



BG
 
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