camargo@cs.columbia.edu (Francisco Camargo) (04/21/89)
Hi there, Maybe someone has had these problems before and could help me: 1- A Sperry-Rand AT Compatible with a 1.2Mb High Density Floppy Drive. When I boot it with its original MS-DOS v3.1 (customized for Sperry), I have no problems at all with the machine. When I boot it with either IBM PC-DOS v3.3 or a generic MS-DOS v.3.3, the the floppy drive becomes unstable and most times it fails in formating/writing 1.2Mb floppies. When formating, it reports an error as if the track 0 were bad, or invalid media is loaded. The problem is intermitent, and, if I run diagnostics for the drive, it acuses no problem. I believe that PC-DOS and MS-DOS v3.3 update some drive parameter table with timing constants that the machine cannot handle. Is there anyway to modify such constants (if this is indeed the source of the problem). I even tried to use "drivparm=/D:0/F:1/H:2/C/S:80/T:15" with no positive result. And, as funny as it can be, the drive works fine with 360K disks. 2- A similar problem with another AT-Compatible, using a VIP motherboard with Phoenix BIOS, running at 10Mhz, 1-Wait state. Here the problem is a bit worse, in respect that I don't have any version of any DOS which makes the machine work well all the time. In the Sperry case, I at least have the customized MS-DOS 3.1 which works. Again, when running diagnostics, I get no errors in the driver, but it will never reliably format a 1.2Mb floppy. And again, it works fine with 360K floppies. Does anybody have any clues ? I'll be in great debt if you could send your comments to "camargo@cs.columbia.edu". Thanks. /Francisco A. Camargo camargo@cs.columbia.edu