Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!ariadne!theseas!terry From: terry@theseas.ntua.gr (Eleftherios Simotas) Newsgroups: comp.sys.ibm.pc.hardware Subject: Re: 360K in 1.2M drives Message-ID: <1265@theseas.ntua.gr> Date: 7 Mar 91 12:38:11 GMT References: <1991Mar1.155859.16874@cbnewsc.att.com> <20713@shlump.nac.dec.com> Organization: National Technical University of Athens Lines: 33 gettys@yacht.enet.dec.com (Bob Gettys) writes: > One way to re-use a floppy without getting into this problem is to bulk >erase it with a bulk tape eraser. This destroys the 360k info allowing >the 1.2meg sized info to be visible without the old 360k info in the >"background". > Typically (but not always!) you can use a virgin (or a reborn virgin >via bulk erase) floppy to take data from a 1.2meg drive to a 360k drive >if the disk is formated as a 360k disk with the 1.2meg drive. This lays >down the narrow track without the interference of the wide track in the >background. When it won't work it is the result of the signal (remember, >there is less of it) is tto weak for the particular 360k drive you are >trying to read it on. I've wondered about the ability of a 1.2meg drive being able to reliably write info on 360k disks even if they have been used in a 360k drive. I am aware of the head width differences resulting in a 1.2meg drive overwriting only part of the track written by a 360k drive. Couldn't this problem be overcome by having the 1.2meg drive write every track twice ? (now it skips every other track when writing 360k format). I have done a bit of low level programming on PC's but I am not in position to write such a utility just to see if it would work. There is also the problem of signal strength. The 360k drives have much larger write currents resulting in a stronger signal. The 1.2meg ones having to cope with much higher bit densities use lower write currents coupled with better signal detection electronics. So there is a chance even by double writing the tracks that the 360k signal will still peek through. > /s/ Bob Gettys