burleigh@cica.cica.indiana.edu (Frank Burleigh) (06/11/90)
I'm looking for a procedure to determine the type of diskette a
drive may contain (e.g., a media descriptor byte [360KB 5.25",
1.44MB 3.5", etc.]) whether or not the drive contains a diskette.
Some possibilities and their drawbacks:
1. DOS 32h provides the needed data, but it is a) undocumented;
b) doesn't work if there is no disk in the drive (and may not
work if a diskette is unformatted).
2. DOS 1ch (get drive data) returns a pointer to the media byte,
but again must interrogate a diskette, failing if there is no
diskette or (presumably) if the diskette is unformatted.
2. ROM BIOS 13h (sub 8h) (get drive params) looks promissing: it
returns a descriptor byte, but the notation in Duncan, 2nd
ed. says it won't work for floppy drives on PCs and PC/XTs.
In summary, I'd appreciate suggestions of/pointers to a C or C-
callable assembly procedure that will identify the type of
diskette a drive may contain without actually hitting a diskette.
Thanks in advance for your ideas.
--
Frank Burleigh burleigh@cica.cica.indiana.edu
USENET: ...rutgers!iuvax!cica!burleigh BITNET: BURLEIGH@IUBACS.BITNET
Department of Sociology, Indiana University, Bloomington, Indiana 47405