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Are any of these ISA Floppy cards compatible with a PS/2 4869-001 External Drive?

Ozzuneoj

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PA, USA
I was recently given an IBM PS/2 4869-001 External 5.25" drive, in beautiful condition, in the original box.

I have never even set eyes on a PS/2 system in person, so my only hope of using this drive is to hook it up to something else. I've read that they are only partially compatible with non-PS/2 systems, but it would seem to come down to the drive controller being used.

I have a PC 5150 and a 5160 (which needs some work), and they both have the original IBM floppy cards. I also have these four other floppy controllers I've picked up over the years. It has proven to be quite difficult to find information about external drive compatibility with these.

Is there a chance that any of these could be put into an IBM PC and then attached to a 4869-001 external drive and just work?

Here's a gallery of the drive and the cards I have on hand (not pictured are the standard IBM floppy cards I have already in my PCs).

https://photos.app.goo.gl/Q8Gozk1Xhw3Fb2qn9

I know the Compaticard IV is a very versatile (and valuable) card but I'm not sure if it helps at all in this situation. The others I can't find much about. Is the "Stepping Stone Expander" a floppy card? It really looks like one, but I don't get a single result when I Google that.

Any help is much appreciated!
 
Well, the Compaticards, as well as the SMC card have their own BIOS, which means that high-density 1.2M 5.25" and 3.5" 1.44M support is built in--definitely a plus. The 4869 drive should work (don't jumper the Compaticards to supply power to the 4869!). but bear in mind that the external connector is used for the third and fourth floppy drives on the system. Depending on your version of MS-DOS, you may need the Compaticard drivers to provide BIOS support for those. Not a big deal, normally.
 
I see. Thanks for the info!

I forgot to mention that my 5150 currently has the original Tandon 5.25" full height drive, and a 3.5" floppy (works as 720K), so I guess having the external show up as something else would work in this situation. The computer also has a C: drive (original half height Miniscribe 3.5" MFM hard drive) and can be assigned a D: drive (Parallel port CF Card reader).

I have read that the 4869-001 is only a 360K drive, is that correct, or does it depend on the controller?

Also, if I simply hook this 4869 up to a standard IBM PC floppy card (not one of the special ones), and set the motherboard switches to "3 drives", is this likely to work? I've read different things about that.
 
Yes, the -001 is the 360K; the -002 is the 1.2M. It should work; at worst, it's a matter of changing the drive select jumpers.

Early versions (e.g. 1.x and I think 2.x) of PCDOS assigned drive letters to floppy drives first, and then the hard drive(s). So a 3 floppy system would have floppy A B C and then the hard drive as D. Later (I think starting with DOS 3) it was 2 floppies for A and B, the hard drives, then the rest of the floppies.

On my 6 floppy tower, A and B are floppies, C and D are (SCSI) hard drives, then E F G and H are the other floppies. I have a parallel port Zip drive; I think it's assigned as drive I, but I'd have to check. Running MS-DOS 5.0.



So be prepared for some
 
I see. Thanks for the info!

I forgot to mention that my 5150 currently has the original Tandon 5.25" full height drive, and a 3.5" floppy (works as 720K), so I guess having the external show up as something else would work in this situation. The computer also has a C: drive (original half height Miniscribe 3.5" MFM hard drive) and can be assigned a D: drive (Parallel port CF Card reader).

I have read that the 4869-001 is only a 360K drive, is that correct, or does it depend on the controller?

Also, if I simply hook this 4869 up to a standard IBM PC floppy card (not one of the special ones), and set the motherboard switches to "3 drives", is this likely to work? I've read different things about that.

Jumpering the 5150 to 3 drives will NOT work with an unmodded 4869. The 4869 uses DS2 (1-4 scheme), so on a original IBM FDC it will appear as the 4th logical unit. You can either jumper the motherboard to 4 drives and have a phantom 3rd floppy, or load DRIVER.SYS /D:3 /F:0.

I have one connected to my 5150 right now using the DRIVER.SYS to provide it a drive letter after my hard drives.
 
Jumpering the 5150 to 3 drives will NOT work with an unmodded 4869. The 4869 uses DS2 (1-4 scheme), so on a original IBM FDC it will appear as the 4th logical unit. You can either jumper the motherboard to 4 drives and have a phantom 3rd floppy, or load DRIVER.SYS /D:3 /F:0.

I have one connected to my 5150 right now using the DRIVER.SYS to provide it a drive letter after my hard drives.
Thank you! I had read something about an odd drive-numbering issue with the 4869 elsewhere, but your post explained it much more clearly.

That's really awesome to hear that this should work if the system is simply jumpered to 4 drives. Having a missing drive isn't a big deal at all. It's not like other people use the poor thing. Though it seems like a no-brainer to use the driver.sys configuration you mentioned. Is there any reason not do to that?

I will test the drive out when I get a chance to crack the system open and switch the jumpers. Only problem with my IBM PC setup is that it's a pain to get into. With a monitor on top of a stand\surge-protector, on top of the system, and it's all on a small desk in the living room with no room for dismantling.

It's also nice to know I don't have to tie up one of my other (more rare) cards in the IBM, since that system pretty much does everything I need it to do with the original card.
 
You can modify the 4869 for standard drive select quite easily (which is what I do). See my blog post, part 1 and part 2, complete with photos from 10 years ago.

I use these 4869 boxes for both 5.25" and 3.5" drives and even have one set up to for a CF2 3" drive.
 
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