Before the actual article: a quick question. Are any of you using DOS
version 5.0 ? If I've understood correctly, 5.0 changes the disk-layout
rather heavily. I doubt mtools can handle the new DOS partitions, and
possibly even the partition table has changed. Again, I'd be interested
to know if everything works fine with DOS 5.0.
Ok. Here is a short table:
Memory devices: Major = 1 (characted devices)
minor
0 /dev/ram - not implemented (never will be, I think: minix special)
1 /dev/mem - not implemented (easy, seldom used)
2 /dev/kmem - not implemented (easy, but I haven't done it)
3 /dev/null
4 /dev/port (implemented, but untested - don't play with it)
example: "mknod /dev/null c 1 3"
Floppy disks: Major = 2 (block devices)
minor = drive + 4*type, drive = 0,1,2,3 for A,B,C or D-diskette
type 1: 360kB floppy in 360kB drive (5.25")
2: 1.2M floppy in 1.2M drive (5.25")
3: 360kB floppy in 720kB/1.44Mb drive (3.5")
4: 720kB floppy in 720kB/1.44Mb drive (3.5")
5: 360kB floppy in 1.2M drive (5.25")
6: 720kB floppy in 1.2M drive (5.25")
7: 1.44M floppy in 1.44M drive (3.5")
Thus minor nr for a 1.44Mb floppy in B is: 1 + 4*7 = 29, and to read an
old 360kB floppy in a 1.2M A-drive you need to use minor= 0 + 4*5 = 20.
Example: "mknod /dev/PS0 b 2 28" (b for block: 2 for floppy, 28 for 1.44
in A)
Hard disks: Major = 3 (block devices)
minor
0 /dev/hd0 - The whole hd0, including partition table sectors etc.
1 /dev/hd1 - first partition on hd0
...
4 /dev/hd4 - fourth partition on hd0
5 /dev/hd5 - The whole hd1, again including partition table info
6 /dev/hd6 - first partition on hd1
...
9 /dev/hd9 - fourth partition on hd1
NOTE! Be /very/ careful with /dev/hd0 and /dev/hd5 - you seldom need
them, and if you write to them you can destroy the partition tables:
something you probably don't want.
The only things that use /dev/hd0 are things like "fdisk" etc.
NOTE 2!! The names for hd's are the same as under minix, but I think
minix orders the par...
