Backups of Distibution Floppies

[Chip Rosenthal]

In article <752 at mccc.UUCP> pjh at mccc.UUCP (Pete Holsberg) writes:
>I have Microport V/386 and a friend has SCO Xenix/386, and we were both
>wondering how to make backups of the distribution floppy disks?  Can you use
>DISKCOPY or are they *NIX-formatted disks?  If the latter, are they mountable,
>or are the files tar/cpio archives?

There is no such thing as a "unix-formatted" disk.

You have to realize that there are two levels of formatting for magnetic
media:  physical formatting and logical formatting.  Physical formatting
is where, in the case of disks, you lay down the sector/track info.  It
is mainly a function of hardware[1].  The logical formatting is a function
of what you are doing with the disk.  Cpio archive?  DOS filesystem?  etc.

When you do a "format", whether it be under DOS, XENIX, Microport or
whatever, you are putting down the physical format.  The DOS FORMAT command
then goes on to put other goo on the disk, like boot and fat blocks[2].
Under unix, this is broken out in a seperate step called "mkfs".

If you've got a utility which just copies the raw data on the disk, then
it matters not what the logical format is, just that the physical format
be understood.  Under DOS you've got DISKCOPY.  Under unix, there's dd.

In the case of XENIX 386 on 96tpi floppies, the N1 floppy is a mountable
filesystem.  The rest are tar archives.  But they are all boil down to
15 sector 79 track disks with goo on them.  (As do DOS format DSHD
floppies.)  DISKCOPY or dd will work just fine.

[1] Of course it is possible to do strange things, like throw on a track
    with am unusual number of sectors.  This is the basis of some DOS
    copy protection schemes.

[2] On hard disks, the DOS FORMAT command *only* puts down the goo.  The
    so called low-level format lays down the physical formatting.
-- 
Chip Rosenthal / chip at vector.Dallas.TX.US / Dallas Semiconductor / 214-450-5337