5 1/4 controller?

Hardware questions and modifications

5 1/4 controller?

Postby jason » Thu Aug 28, 2008 2:16 pm

Does anyone know what I can use as a floppy controller that will work with the old double density 5 1/4" drives on a new system? I just realized my new system only handles one floppy drive and it only knows about 3 1/2" drives! :o . So unless I build an old machine back up again, I'm without a 5 1/4" drive to use to play around with my PCjr.

Any leads on USB 5 1/4" drives? All I've ever seen are 3 1/2" and from what I've read the new ones of those do directly to USB on the 3 1/2" drive itself, so I can't wire in a 5 1/4" , even if the on board controller knew what to do with it. Anyone know of any specific models of old USB drives I might be able to modify to work with a 5 1/4?
Thanks :),
Jason
jason
 
Posts: 35
Joined: Tue Aug 26, 2008 3:48 pm

Re: 5 1/4 controller?

Postby Brutman » Thu Aug 28, 2008 4:22 pm

I don't have specific model numbers, but if you find a floppy controller on a card it will probably suport 3.5 and 5.25 inch diskettes in both double density and high density formats.

The bigger problem is BIOS support. A 'normal' floppy controller doesn't have a BIOS chip on it, as the PC is supposed to know what to do with floppy drives already. It has been that way since the first IBM PC. If your BIOS doesn't support 5.25 inch diskette drives, you are hosed.

There might be a floppy controller with onboard BIOS. I know that there were some of these for the PC and XT designed to let you use high density diskette drives. I don't know if there are any current ones that give you 5.25" support.

Old USB drives are going to be a sticky problem too. I suspect that although electrically the 3.5 and 5.25 inch interfaces are nearly identical, the USB device onboard is going to expect an 80 track 3.5 inch diskette drive. I don't know how you would tell it that you have a 5.25 inch drive installed instead.

Your best bet is to keep a 'mothership' system around that has a 5.25" double density drive on it. You could use a 720K (double density) 3.5" drive on the PCjr, but there are some catches. (The PCjr BIOS only knows about 40 track drives, and you absolutely have to find 1MB or double density media.)

Mike
Brutman
Site Admin
 
Posts: 970
Joined: Sat Jun 21, 2008 5:03 pm

Re: 5 1/4 controller?

Postby jason » Sat Aug 30, 2008 6:19 am

How about a SCSI controller with a built on floppy controller? I think they have their own BIOS. Unfortunately the only one I had lying around was an old Vesa Local Bus card, lol. I'm trying to locate a PCI one through folks I know.
jason
 
Posts: 35
Joined: Tue Aug 26, 2008 3:48 pm


Return to PCjr Hardware

Who is online

Users browsing this forum: No registered users and 4 guests