On Sat, 25 Apr 1998, Brian C. Grayson wrote:

:   changing fd.c some.)  There are at least 4 such
:   formats that are handy:

You missed 880K (80/2/11) and 1760K (80/2/22), the Amiga formats, which are
MFM and _can_ be read and written on most--though not all--PC floppy
controllers.  If these were added, the Amiga driver, though not the same
code, could share a new major number suited for the new format layout.

:   The only bad news is that changing the minor numbers to
: use more bits for format (and less for drive, but how many
: people really have 2^5 floppy drives on one machine?)
: would break compatibility with earlier /dev directories
: for any of the new /dev files.  One solution would be to
: have two different majors for the fd:  the compatibility
: one, with its 5/3 split of minor, and a new extended
: floppy major, with a split of 3/5 or 2/6 or 2/5 with one
: bit for some flag or other goody, that does all the nifty
: special format stuff.

I'd prefer the latter, and whilst creating the new floppy major device, it
should be moved to a major number uniform across all platforms which use
that driver.

:   Would a similar larger block size buy us as much
: additional capacity from either ZIP disks or hard
: drives?

No.  Zip disks and hard drives (basically one and the same with one
removable and one not) give a sector-by-sector interface to the CPU, not a
raw media interface where you can twiddle the format.  Additionally, the
encoding of modern hard drives is no longer MFM, and is much more set in
stone.

-- 
-- Todd Vierling (Personal tv@pobox.com; Bus. todd_vierling@xn.xerox.com)