From: seindal@diku.dk (Rene' Seindal) Subject: floppy reset called -- possible solution. Date: 10 Jun 1992 15:40:23 GMT
I used to get these floppy reset called messages a million times when I
tried to access floppies that wasn't high density. I had some 3.5"
720kb floppies I wanted to read.
After digging through the floppy driver I arrived at this: if you want
to use 720kb 3.5" floppies, create the devices
/dev/fdd0 major 2, minor 16 (a drive)
/dev/fdd1 major 2, minor 17 (b drive)
The floppy driver supports autodetection of media density through the
devices:
/dev/fdx major 2, minor 0 (a drive)
/dev/fdy major 2, minor 1 (b drive)
Using these last two devices will give you some kernel messages
indicating the size and density of the media in the drive.
Consequently, you can mix high density and double density floppies using
these devices, having the systems adapting automagically.
In general, the two low order bits of the minor number is the unit
number, i.e., support for up to four drives, and the remaining six bits
is the drive type. From the above, we see that type 0 is autodetect,
type 4 is 720kb floppies in a 1.44Mb drive, type 7 is 1.44Mb floppies in
a 1.44Mb drive, type 2 is 1.2Mb floppies in a 1.2Mb drive (5.25"). The
other types can be found in .../kernel/blk_dev/floppy.c, the table
floppy_type[].
The type of the media in a drive can be queried with a ioctl (FDGETPRM
?), found in .../include/linux/fd.h.
Rene' Seindal (seindal@diku.dk)