Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uunet!munnari.oz.au!murtoa.cs.mu.oz.au!murdu!ucsvc!u5533129 From: U5533129@ucsvc.ucs.unimelb.edu.au (CARDIOLOGY, R.M.H.) Newsgroups: comp.sys.ibm.pc Subject: Re: Formatting 1.2 Meg disks to 360K question Message-ID: <455@ucsvc.ucs.unimelb.edu.au> Date: 14 Jan 90 22:31:22 GMT References: <3226@ucrmath.UCR.EDU> <7715@nigel.udel.EDU> <25AD7F7A.26599@maccs.dcss.mcmaster.ca> Organization: The University of Melbourne Lines: 21 In article , jacobs@cs.utah.edu (Steven R. Jacobs) writes: > Now I'm sure you will point out that the 1.44M microfloppy drives will > format/read/write data at 720K. The reason that this works is that the > data is _exactly_ twice as dense, so that the 1.44M drive can write the > data on two neighboring tracks to make it look like 720K data. This is > not possible with the 1.2M drive, since 1.2M is not an integer multiple > of 360K (there are probably other complications as well). This is BULLS**T! The greater density of a 1.44M floppy comes from writing more sectors per track, not from using any more tracks. 1.44M, 1.2M and 720k disks all use 80 tracks, with 18, 15 and 9 sectors per track (x2 sides) each. 360k disks use 40 tracks x 9 sectors / track (x2 sides). As far as I know, no one does writes to adjacent tracks. I don't know whether this would work, but it would be very easy to do (with a small TSR on int 13). Does anyone know any more about this? Peter S.