DOS feature on formatting disk

[Paul Koning]

>>>>> "Bjørn" == Bjørn Vermo <bv at norbionics.com> writes:

 Bjørn> On Tue, 18 Jan 2005 09:35:01 -0800 (PST), Dwight K. Elvey
 Bjørn> <dwight.elvey at amd.com> wrote:

 >> Hi DOS has an irritating feature when asked to format a disk. If
 >> track 0 is partially readable it will fail to format, even if you
 >> use the /u option.  I've been moving data from one machine to
 >> another and the source machine has a flaky drive. It sometimes
 >> trashes track 0.
 Bjørn> ...

 Bjørn> Any OS / file system has problems if track 0 is really bad,
 Bjørn> especially if sector 0 is bad.  

That's definitely not true.  For example, PDP11s use sector 0 for the
boot sector, bot not for anything else.  A disk that doesn't need to
be booted will work perfectly well with an unreadable sector 0.
Depending on the OS, there may be some other critical sector (sector 1
on RSTS, for example).  More sophisticated file structures have a
search rule, where the "superblock" can be found in one of several
places that are checked in order.

       paul