PCs that support only one floppy drive in hardware

Chuck Guzis cclist at sydex.com
Tue Oct 11 10:44:04 CDT 2005


On 10/11/2005 at 9:24 AM Sridhar Ayengar wrote:

>How about SCSI floppy drives?

The problem with SCSI floppies is essentially the same--addressing is on a sector number basis, not CHS.  So the drives have limited format recognition capabilities.  I've never seen a 5.25' SCSI floppy, though at one time SMS marketed a SCSI-to-FDC conversion board.  But that was many years ago in the early days of SCSI, so it probably wouldn't work on a modern SCSI adapter.  Perhaps the SCSI firmware in a stock Teac FD-235S could be tweaked, but the drives are pretty hard to come by.

Although a stock USB drive is pretty brain-dead, it should be noted that the SMSC USB floppy chip (USB97CFDC2-01) does have the option of attaching a user-supplied external serial EEPROM for custom support.  According to the SMSC website, an evaluation board was produced for the first version of this chip (USB97CFDC), and, judging from the schematic, attached to a legacy floppy interface.  It'd be interesting to get a couple of the boards and see if the chip could be made to drive a 5.25" drive and how much flexibility is incorporated in the chip (e.g., can FM-encoded diskettes be read?).  Of course, host-side drivers would have to be written to handle an expanded interface, but it still might be an interesting exercise.

Cheers,
Chuck







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