lane@dalcs.UUCP (John Wright/Dr. Pat Lane) (08/11/88)
While we're on the subject (again), I've been wondering if, when I reformat
a 360K disk using FORMAT A:/4 (actually that's a 354K disk!) in a 1.2M drive
and the disk has been previously formatted and/or written on by a regular
low density drive, am I not leaving part of the wider low density track on
the disk and might I not have trouble reading the information written by the
1.2M drive on a low density drive? Does this not imply that once a disk has
*written* on by a low density drive, it has been "soiled" and probably should
not be re-formatted and used on a 1.2M drive, not at least, if the disk is to
be readable by both types of drives? I assume, of course, that when I format
on a low density drive, I completely erase any 1.2M information and the disk
is the same as if it had never been written on.
Then I was wondering if I could use one of those "Bulk Erase" programs that
purport to erase all info including formatting, to erase low density disks
before I re-format them on my 1.2M drive and if this would prevent any
future problems using these disks between the two drive types. Would the
bulk-erasing have to be done on a low density drive to erase the low density
tracks or would it still work on a 1.2M drive?
John Wright ///////////////// Phone: 902-424-3805 or 902-424-6527
Post: c/o Dr Pat Lane, Biology Dept, Dalhousie U, Halifax N.S., CANADA B3H-4H8
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--
John Wright ///////////////// Phone: 902-424-3805 or 902-424-6527
Post: c/o Dr Pat Lane, Biology Dept, Dalhousie U, Halifax N.S., CANADA B3H-4H8
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Uucp: lane@dalcs.uucp or {uunet,watmath,utai,garfield}!dalcs!lane kevin@iisat.UUCP (Kevin Davies) (08/12/88)
In article <2972@dalcs.UUCP>, lane@dalcs.UUCP (John Wright/Dr. Pat Lane) writes: > While we're on the subject (again), I've been wondering if, when I reformat > a 360K disk using FORMAT A:/4 (actually that's a 354K disk!) in a 1.2M drive > and the disk has been previously formatted and/or written on by a regular > low density drive, am I not leaving part of the wider low density track on > the disk and might I not have trouble reading the information written by the > 1.2M drive on a low density drive? Does this not imply that once a disk has > *written* on by a low density drive, it has been "soiled" and probably should > not be re-formatted and used on a 1.2M drive, not at least, if the disk is to > be readable by both types of drives? I assume, of course, that when I format > on a low density drive, I completely erase any 1.2M information and the disk > is the same as if it had never been written on. > What you've said above is correct, especially about a disk that has been formatted under 360K format and then later on a high density drive. In order to use a disk that has previously been formatted and used on a 360K drive, you have to remove *everything* to make it appear like a new disk that has not been touched. I don't think one of those Bulk Erase programs will work that great since you are relying on the head technology again (reguire the larger head of the 360K). I've used these magnetic bulk erasers and normal magnets to erase a disk and they work perfectly, but you *must* keep it away from important disks ! By keeping these ideosyncrises in mind, you should not have any problems moving a disk between the 2 drive types. -- Kevin Davies International Information Service (IIS) UUCP: {uunet,utai,watmath}!dalcs!iisat!kevin Bitnet/Uucp: kevin@iisat.uucp Arpanet: kevin%iisat.uucp@uunet.uu.net
lane@dalcs.UUCP (John Wright/Dr. Pat Lane) (08/15/88)
last week, I posted the question: If you have a disk written on by a 360K
drive and re-format it with a 1.2M drive, are parts of the 360K track left
on the disk that could cause problems if the disk were subsequently read on
a 360K drive (Hmm.. that was much better phrased than my original question!)
I also asked if software "bulk erase" programs would be effective in
preventing these problems and if so would they be equally effective if used
on a 1.2M drive.
I got got two contradicting answers. One fellow posted, saying my fears were
founded, and that only a magnetic bulk eraser (or just a magnet) would re-
cycle a 360K disk for 1.2M use. Another fellow mailed and said that floppy
drives use a "tunnel erase" and that on formatting (and maybe all writes) on
a 1.2M drive, any 360K track stuff is erased. If I understood him correctly,
the only rason you get the 360K/1.2M problem is drive mis-alignment.
Well, them's the breaks, eh...
I was ruminating on the question and wondered if the 1.2M drives write every
second track in 360K mode, and if they start track 0 at the same diameter on
the disk then the situation would not be, as it is usually pictured:
///////////////////////// /////////////////////////
// residual 360K track // /////////////////////////
///////////////////////// // residual 360K track //
\\\\\\\\\\\\\\\\\\\\\\\\\ /////////////////////////
\\\\\\\ 1.2M track \\\\\\ but: /////////////////////////
\\\\\\\\\\\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\\\\\
///////////////////////// \\\\\\\\ 1.2M track \\\\\\
// residual 360K track // \\\\\\\\\\\\\\\\\\\\\\\\\\
///////////////////////// \\\\\\\\\\\\\\\\\\\\\\\\\\
(these drawings not to scale!)
If the latter is the case, it would seem it me, that it would be possible
for the 1.2M drive to write pairs of identical concentric tracks (instead
of skipping every second track) and thus produce a 360K disk that is
identical to one written on a 360K drive.
I suppose there's a real good techno-reason why this won't work but if
it did it would solve this whole 360K/1.2M mess, wouldn't it?
Any comments?
--
John Wright ///////////////// Phone: 902-424-3805 or 902-424-6527
Post: c/o Dr Pat Lane, Biology Dept, Dalhousie U, Halifax N.S., CANADA B3H-4H8
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