14 Mar
2005
14 Mar
'05
1:13 p.m.
On Mar 14 2005, 14:30, Randy McLaughlin wrote:
2.88 mb controllers use it one way, some 1.44mb drives
use it
another, some
5.25" drives use it for one thing other another.
1.44MB drives, ie 3.5" drives, do not need to be told what density to
use; they use the media sense to detect that from the holes in the
diskette. Therefore if they use pin 2 at all, they usually use it to
signal to the controller whether the media loaded is HD or DD.
--
Pete Peter Turnbull
Network Manager
University of York
14 Mar
14 Mar
3:04 p.m.
2.88 mb
controllers use it one way, some 1.44mb drives use it
another, some
> 5.25" drives use it for one thing other another. 1.44MB drives, ie 3.5" drives, do not need to be
told what density to
use; they use the media sense to detect that from the holes in the
diskette. Therefore if they use pin 2 at all, they usually use it to
signal to the controller whether the media loaded is HD or DD.
On the early PS/2s, IBM used both 720K drives, and ones that they called
"1.44M", that held 1.40625M (2*80*18*512)
Unlike everybody else in the world, IBM did NOT have a media sensor!
... and therefore used pin 2.
Using a 720 K diskette in one of IBM's 1.4M drives resulted in a not very
reliable 1.4M.
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