23 Mar
2010
23 Mar
'10
7:49 p.m.
On Tue, 23 Mar 2010, Brian Lanning wrote:
I'm arriving late to the conversation, so maybe I
missed something. High
density floppies have a square hole opposite the right protect tab up in the
corner. Most 3.5" floppy drives have a switch that detects this hole and
does (here's my hardware knowledge black hole) something different with the
media. 720k double density floppies don't have this hole.
Yes. Well, MOST drives. The "something different" is a change in the R/W
current level. Not ALL drives have that sensor. In the early PS/2 "1.44"
drives, that is controlled by a signal from the controller to the drives.
So you should be able to simply cover the holes with
tape or disable the
switch the right way and the drive will treat the media like a double
density disk.
Nope. That's the case with "360K" v "1.2M" 5.25".
3.5" is the same 135TPI for both.
From what I remember, there's issues with this
though. First, the
read/write head is thinner which I believe causes problems when
you put that
disk back into a real double density drive and one of the drives is slightly
misaligned. Also, I think the actual media may be different, as
in
different magnetic properties.
Yes. 600 Oersted v ~750 Oersted.