[CentOS] floppy drives

John R Pierce pierce at hogranch.com
Mon Apr 8 17:22:28 UTC 2013


On 4/8/2013 9:57 AM, m.roth at 5-cent.us wrote:
> OH! I thought, since the m/b is from '05 or '06, that it would detect the
> floppy drives, but*that*  I need to look at. Thanks!

the floppy interface was really low level.    all parallel signals, like 
select drive, step, direction, head select, serial data, clock, write 
enable, and a status line for home, and index (the hole in the disk that 
said its at sector 0).

the ONLY way to detect a drive is connected was to STEP outwards 100 
times, checking for the 'home' status each time, this takes several 
seconds per drive.   AFAIK, there was no way electrically to tell the 
difference between drive types, unless there's a reliable disk in the 
drive.   so the BIOS's pretty much stopped doing the 
auto-home-and-detect thing early on when floppies became optional 
because it was /so/ slow and added significant time to POST.   and even 
from the very beginning, you have to configure the BIOS for the drive 
types (heck, early hard disks had to be configured in the BIOS too)



-- 
john r pierce                                      37N 122W
somewhere on the middle of the left coast




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