18 Jan
2005
18 Jan
'05
7:31 a.m.
On Mon, 17 Jan 2005, Jim Leonard wrote:
Yep. DOS had only one quirk, though: If you wanted
to format a 720K disk in a
1440K drive, you had to specifically tell DOS to format as 720K. Otherwise, it
assumes you're going for 1.4, attempts it, and fails. You can choose /f:720
with later versions of DOS; use "/t:80 /n:9" for 3.x.
To add to the fun,...
SOME drives had a media sensor that would adjust the write current for HD
diskettes, others required that come from a signal from the controller.
The early PS/2 drives did NOT have a sensor. They would "successfully"
format a 720K diskette to 1.4M. (Reliability was less than perfect due
to 600 Oersted v 750 ) But then, when that disk was put into a
drive that had a sensor, the drive would have problems with it.