Most of us are aware that "disklabel" can be used to query
a Brand-X disk for its geometry information, and use that
to create a sensible disk label.
One thing I've wondered about for a long time, though (and
my attempts to RTFM haven't provided an answer) is whether
it's important (and, if so, how important) that things like
the rpm value and the {track,cylinder}skew values be right.
The reason I'm curious is that the rpm value being assigned
to a drive is often incorrect. I have quite a few 5400 and
7200 rpm drives which "disklabel" seems to assume are 3600.
And sometimes, the rpm values that "disklabel" assigns have
been totally absurd numbers.
The trackskew and cylinderskew numbers in the disk label are
zero for all our drives (both DEC and non-DEC) which live on
our 3.2c systems. Interestingly, all our disks (again, both
DEC and non-DEC) attached to our 4.0c systems seem to have a
sensible (or, at least, nonzero) setting for the skew values.
Also, all disk labels on our 4.0c systems have a correct rpm.
Was the v3.2 version of "disklabel" buggy, in the sense that
it didn't bother with the skew values, and often got the rpm
wrong?
If "newfs" will lay out a better-optimized filesystem if all
the information in the disk label is accurate, then I really
ought to be correcting the bad values after "disklabel" gets
run, before running "newfs". But if it doesn't matter, then
there's no point in bothering ...
Mark Bartelt 416/978-5619
Canadian Institute for mark_at_cita.utoronto.ca
Theoretical Astrophysics
http://www.cita.utoronto.ca/~mark
"Nur eine Waffel taugt!" -- Parsifal, in an Eggo commercial
Received on Wed Apr 29 1998 - 19:18:27 NZST