[debian-knoppix] Boot floppy size formats and Win32 issues
Sorry, but I can't copy&paste the mail body (I just subscribed for this
mail, I read the posting on the web...)
The so-called Microsoft-DMF format has the following special
configuration:
1680K, which means 80 tracks, 21 sectors/tracks, doublesided;
(which requires interleaving (automatically triggered by virtually all
formatting utilities))
16 entries in the root dir, cluster size is 2048 (or 1024);
Media Byte 240 for compatibility reasons (tells DOS "I'm a hdd")
(With that, no special TSR is needed for "DOS" to recognise the format)
So formatting a dmf-disk with fdformat for dos (where I found the
description long, long ago in Version 1.6 (only 1.8 available now)) would
look like this:
fdformat a: /c:4 /d:16 /h:2 /i:1 /m:240 /s:21 /t:80
2048b/s
16 files
DD
interleaving (just to be sure)
media byte
21 sectors
80 tracks
with optional /g:xxx /x:xxx /y:xxx for faster access (for
customizing tha gap between sectors and the shifting of sectors
when changing head/track) (although the interleaving will prevent
substantial gain), but which depends on the actual floppy drive, so just
ignore that. (Anyway, all modern floppy drives seem to be optimized for
the slow "default" formatting produced by windows and are all quite slow
(gone are the times when I read or wrote a whole 1.44MB disk in 48s...)
And _every_ floppy drive which is not broken should easily read and write
those, although quite slowly if the disk wasn't preformatted with any
other settings. But I can't find any disks which aren't pre-DOS-formatted
any more, so I just format them 2 times just to be sure. That works fine
for me, but some obscure or old floppy drive might get into trouble if the
gaps aren't 100% unformatted (not magnetised). So it seems to be best to
stick with 1.44MB for as long as possible.
And I don't know if this configuration can somehow be obtained with
mkdosfs (especially the media byte).
Hope that helps,
Tim Botzelmann
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