Disassembling an older IBM USB Floppy?

[lparsons]

I am trying to build an external USB 5.25" floppy drive to read some old disks I have around*. I already have a floppy drive and an enclosure that will fit it and provide the needed power. I even have the edge->34pin connector so I can use a regular floppy (MFM) cable. What I need now is a floppy -> USB converter. I'm trying to find a USB floppy drive that might have one that could be extracted for this purpose.

I know a lot of newer USB floppy drives have proprietary chipsets and even not-quite-standard (in terms of interface) floppy drives. I have a source on a circa-2003 IBM USB floppy that I might be able to cannibalize for parts, but I can't find any diagrams or howtos on it that might clue me in to whether or not it will be a useful drive to do this with.

Drive in question looks to be 08K9835. Has anyone here taken one apart before and knows what is in it? Or can someone find a schematic for it that might give me some idea? Nothing came up at ibm.com or lenovo.com when I searched for that FRU.

thank you




*yes, I know others have tried with varying degrees of success, but I want to try for it and see if I can make it work

[RealBlackStuff]

http://www.techpowerup.com/forums/showt ... p?t=151939
http://ascii.textfiles.com/archives/2503
http://www.deviceside.com/fc5025.html

[lparsons]

http://www.techpowerup.com/forums/showt ... p?t=151939
http://ascii.textfiles.com/archives/2503
http://www.deviceside.com/fc5025.html

Thank you for digging that up, it may be helpful down the road. I might even try replying to the author in the techpowerup.com discussion with something I think may be helpful to him.

FWIW, I found a TEAC combo 5.25/3.5 drive (which of course may make things more complicated) which uses only a single ribbon connector (no edge connector required) for its workings. This would get me around one fo the problems the author noted.

I have noticed that some USB drives specifically say that they access the floppy drives via MFM, which gives me some (perhaps misplaced) hope that some drives might be better parts donors than others.

Of course, that deviceside.com solution is the best of all; but if I can pull off the same functionality without spending $55 on an adapter, that would be preferable.

EDIT: I just looked at the cable mentioned in the forum you linked to; the cable was $28. At that point it might not be advantageous to buy the cable rather than just buying the $55 adapter and being done with it.

[automobus]

lparsons: Those 3.5-inch USB floppy chips are intended for 3.5-inch 1440 / 720 format, I assume. By contrast, when the controllers in PC mobos could address different formats, it was configurable in BIOS. Maybe one can reprogram them?

edited to seem less authoritative; honestly, I do not know what I am saying.

[lparsons]

lparsons: one cannot simply re-wire those adapters to work with 5.25-inch diskette drives. Full stop.

Those 3.5-inch USB floppy chips are programmed exclusively for 3.5-inch 1440 / 720 format. By contrast, when the controllers in PC mobos could address different formats, it was configurable in BIOS.

Some people - particularly in the thread linked earlier - provide an argument to suggest that is not necessarily the case. One technical argument is that the hardware commands for the 3.5 floppy is an extension of the command set for 5.25 floppy, hence the former brings with it the ability to address the latter.

Of course, theory is great in theory. We have very little to go on in terms of how well it applies in the real world.

[cadillacmike68]

Interesting. I'm looking for a way to get a bunch of files from a huge stack of 5.25 diskettes onto my Thinkpads. I have an old Pentium MMX tower with a combo FDD, that should allow me to easily copy 5.25s to 3.5s. But it's cumbersome. The DeviceSide doohickey looks like it'll work, If i can find a 5.25 drive because I'm not sure it will like that combo drive. I'd also need power, but i have an old Plextor USB CDRW that i could use for that purpose. I hadn't bothered with it, figuring that i could get an external 5.25 FDD, but apart from some very old IBM PS/2 parallel units, that probably won't work, there aren't any.

[RealBlackStuff]

How about a USB ZIP-drive?
There's a program around to copy floppies onto a zipdrive, each floppy in its own sub-directory.

[cadillacmike68]

But I didn't think a ZIP drive could read a 5.25 diskette?

I can fire up the old tower. I've been wanting to upgrade it to W98SE (it still has w95 on it!!!) and reconfigure the 5 SCSI drives in it. and configure the NIC i bought for it, but even my old T22s are more powerful than it is, and it's mainly a novelty for me now.

Except for the fact that it's the only thing I have that can read & write 5.25 diskettes. I hadn't realized that there was no such thing as an external 5.25 (other than a few PS/2 models).

BTW, will any of those IBM PS/2 external 5.25 FDDs work with a Thinkpad with ANY windows (say W98). If they do, I can get one and use it with my T22s for file transfer.

Otherwise, it's hook the tower back up, reconnect the KVM setup and manually copy to 3.5s or get that Device Side item, find a separate 5.25 drive and an enclosure for power. I'm sure i could find an old Teac FDD and an enclosure. I might even have an old 5.25 FDD in my stack of ancient drives.

[RealBlackStuff]

The Zip-drive cannot read floppies, but I thought to use it as an intermediate storage medium, due to that easy program (which I just found again in my archives).
That's how I got rid of tons of floppies in the past.
I still have a boatload of 3.5" disks with old(er) programs on it, some dating back to W95, W3, OS/2, DOS and CP/M

[cadillacmike68]

Oh, OK,

I have a huge stack of blank 3.5s that i can copy to instead. If i put some effort into it i can write a batch script that will copy each 5.25 to a named directory on the HD then label and copy to a 3.5. I would only have to sit there and babysit the computer, which if i remember will take quite a while. Then when it's all done, I can copy that HDD directory to a CDR or a USB stick.