On 05/04/2012 09:19 PM, Spiro Trikaliotis wrote: > Hello, > > * On Thu, May 03, 2012 at 07:07:38PM +0200 Gerrit Heitsch wrote: >> I thought a floppy rotates at 300 rpm and not at 360 rpm? That would >> make it 5 rev / sec. > > It depends. Most PC floppy drives rotate at 360 rpm. For example, this > is mentioned at http://www.oldskool.org/disk2fdi/525HDMOD.htm. Yes, that's why a controller board that is supposed to work with them runs the controller chip not at 8 MHz for 5.25" DD but at 9.6MHz. Back when they used discrete crystals on the controller boards, you usually found a 16MHz and a 9.6MHz crystal there. 16MHz for HD (on 5.25" and 3.5") and (divided by 2) for 3.5" DD (since those were 300rpm) and 9.6MHz for DD on a 5.25" HD. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2012-05-04 20:00:31
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