Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ucbvax!hplabs!hpda!hpcuhb!hpindda!mintz
From: mintz@hpindda.HP.COM (Ken Mintz)
Newsgroups: comp.sys.ibm.pc
Subject: Re: How to write 360K disks in a 1.2MB drive
Message-ID: <4330094@hpindda.HP.COM>
Date: 6 Jul 88 20:06:21 GMT
References: <462@calvin.EE.CORNELL.EDU>
Organization: HP Technical Networks, Cupertino, Calif.
Lines: 24

> If you buy a copy of the COPYiiPC program, it includes a utility called
> BULKERAS.  This is a program that will completely blank out a disk.  It
> works with 1.2M drives as well...it's good insurance before you format your
> 360K disks.

  This leaves me thoroughly confused (again).  I understood that the 360K-
  disk-on-1.2M-drive problem was a physical limitation, namely that the 1.2M
  heads were narrower than the 360K drives and, thus, failed to overwrite all
  the magnetic fields.  (I suspect subsequent read success on a 360K drive
  would depend on the sensitivity of the read head.)

  Degaussing (bulk erasing) works only because it affects the entire magnetic
  surface, not just the track under the head.  But COPYiiPC would have to use
  the write heads of the drive to "erase" the disk.  Thus, I don't see how this
  could be 100% reliable.

  Is there something wrong with my understanding?

  BTW, since you mentioned COPYiiPC:  can it "copy" a 1.2M disk if all you 
  have is one floppy drive and a hard drive -- that is, without asking you
  to constantly switch floppies?  The ideal implementation would build a disk
  image in memory (if there's enough) or on the hard disk, then ask you to
  switch floppies.  Does it work that way?

Ken Mintz