carlsson
Veteran Member
People sometimes report the ability to get a standard PC to take a 80 track floppy drive of the DD/QD variety, the ones that in native FAT12 format would hold 720K.
I have a couple of suitable drives but so far have failed to get them to work as 80 track drives. Most specifically I have a Mitsubishi MF503A-301ME which comes from a BBC Micro floppy drive (User Friendly Drive). It has a toggle switch on the front to select between 40 or 80 track mode.
My modern PC is an ASUS A7S333 with an AthlonXP 2000+. The board has a decent FDC, at least good enough to read and write foreign MFM formats with a 40 track drive. There may be more capable motherboards, but there certainly are less capable ones too.
Anyway, when I connect the Mitsubishi drive in 40 track mode to the PC, I can configure BIOS as a 360K drive, either A: or B: depending on which cable end I use. The drive is jumpered as DS1. In this mode, it works like just about any 360K PC drive when it comes to reading and I suppose writing floppy disks.
When I toggle it to 80 track mode, the problems occur. Since BIOS obviously doesn't have a suitable setting, I tried to fool it to accept the drive as a 5.25" 360K drive (BIOS error) or a 3.5" 720K drive (also BIOS error). In this case, I can press F1 to bypass the errors but it also appears to make the drives inaccessible as a whole.
I tried to set BIOS to 5.25" 1.2MB which is accepted by the computer (probably due to both QD and HD are 80 track drives) but whenever I try to access the drive from DOS, it reports errors.
So which way should I go ahead? Is the above behavior typical? Should I try to dig out another PC? I have various kinds from 386 to Athlon to try in case some BIOSes and chipsets are more forgiving and will try to address "unknown" formats until they physically fail.
Or should I rather look for a 1.2 MB drive which has been reported to at least read and in good cases write 80 track QD floppy disks? For reference, I have no false hopes of working with the 100 tpi PET/CBM formats, just some more traditional 640K MFM formats like the above mentioned BBC Micro, Philips P2000c (CP/M) and perhaps others.
I have a couple of suitable drives but so far have failed to get them to work as 80 track drives. Most specifically I have a Mitsubishi MF503A-301ME which comes from a BBC Micro floppy drive (User Friendly Drive). It has a toggle switch on the front to select between 40 or 80 track mode.
My modern PC is an ASUS A7S333 with an AthlonXP 2000+. The board has a decent FDC, at least good enough to read and write foreign MFM formats with a 40 track drive. There may be more capable motherboards, but there certainly are less capable ones too.
Anyway, when I connect the Mitsubishi drive in 40 track mode to the PC, I can configure BIOS as a 360K drive, either A: or B: depending on which cable end I use. The drive is jumpered as DS1. In this mode, it works like just about any 360K PC drive when it comes to reading and I suppose writing floppy disks.
When I toggle it to 80 track mode, the problems occur. Since BIOS obviously doesn't have a suitable setting, I tried to fool it to accept the drive as a 5.25" 360K drive (BIOS error) or a 3.5" 720K drive (also BIOS error). In this case, I can press F1 to bypass the errors but it also appears to make the drives inaccessible as a whole.
I tried to set BIOS to 5.25" 1.2MB which is accepted by the computer (probably due to both QD and HD are 80 track drives) but whenever I try to access the drive from DOS, it reports errors.
So which way should I go ahead? Is the above behavior typical? Should I try to dig out another PC? I have various kinds from 386 to Athlon to try in case some BIOSes and chipsets are more forgiving and will try to address "unknown" formats until they physically fail.
Or should I rather look for a 1.2 MB drive which has been reported to at least read and in good cases write 80 track QD floppy disks? For reference, I have no false hopes of working with the 100 tpi PET/CBM formats, just some more traditional 640K MFM formats like the above mentioned BBC Micro, Philips P2000c (CP/M) and perhaps others.
