Date   : Tue, 18 Dec 1990 04:44:55 GMT
From   : amethyst!organpipe!astro.as.arizona.edu!tom@noao.edu (Thomas J. Trebisky)
Subject: uniform and 8 inch cpm formats on AT controllers

Michael_D._Sprague sprague.wbst311@xerox.com writes:
>
>> The 1.2M floppy format uses the same data-transfer rate as an 8" drive
>> (500Kbits/sec). This is also true for 1.44M drives.
>> 360K floppies use the standard 250Kbits/sec.
>Hmmm, I knew both of those, but what is the transfer rate for a quad density
>drive?  I assume 250K bits/sec?

I believe what is refered to as quad-density is also known as a 720k drive,
(the nomenclature is a bit sloppy, quad density means different things in
different contexts) and indeed has a 250kb/s xfer rate - the density being
acheived by higher track density (96tpi instead of the usual 48tpi).

BTW, for you transfer rate trivia freaks, did you know that a floppy written
on a 360kb drive and later read on a 1.2M drive (AT, HD 5.25in) has a xfer
rate of 300kb/s since the 1.2M drive rotates at 360 rpm, but the 360kb drive
rotated at 300rpm - this in part explains why you can read 360kb floppies on
such drives, but may have trouble writing to them (the other part is probably
the slimmer heads on the 1.2M drive).