IWM(4) | Device Drivers Manual (mac68k) | IWM(4) |
iwm
, fd
—
floppy disk driver for IWM and non-DMA SWIM
controllers
iwm0 at obio?
fd* at iwm0 drive ?
The iwm
driver interfaces to the built-in
and external floppy disk drives on the Macintosh. It supports double-density
media, written in Apple's proprietary GCR format. Currently, there is no
disklabel support for the floppy drives. Instead, the
iwm
driver sets up a fake in-core disklabel, using
the minor device number to select from the supported disk formats.
The following formats are supported:
Partition | Size | sides | tracks | sectors/track |
a | 800Kb | 2 | 80 | 10 (default) |
b | 400Kb | 1 | 80 | 10 |
c | 800Kb | 2 | 80 | 10 |
(The above table describes the logical mapping as implemented by the driver; the physical layout of GCR floppies has 8..12 sectors per track.)
The iwm
driver does currently not support
floppy disk formatting.
Apple Computer, Inc.: "Inside Macintosh", Vol III-33f. (Addison-Wesley)
Apple Computer, Inc.: "New Technical Notes DV 17 - Sony Driver"
Neil Parker: "iwmstuff"
The iwm
interface first appeared in
NetBSD 1.4.
Hauke Fath put together the beginnings of the
iwm
driver in 1996 from the sparse documentation in
"Inside Macintosh", Neil Parker's "iwmstuff"
documentation for the Apple IIgs and a long, hard look at the .Sony
driver.
The FFS code is incapable of dealing with a varying number of sectors per track. We have to fake a mapping and so lose FFS support for hardware parameters like transition times.
The driver only supports an obsolete format.
June 6, 1998 | NetBSD 10.99 |