Subject: REALLY BIG DISKS ...
To: None <tech-kern@NetBSD.ORG, i386@NetBSD.ORG>
From: None <rvb@sicily.odyssey.cs.cmu.edu>
List: tech-kern
Date: 07/30/1998 22:41:08
This probably only applies to IDE disks.

I just got some dell machines with 9.4Gig disks.  First problem: I was
going to use partition magic to shrink the usoft stuff to make room
for NetBSD.  It turns out that this size disk uses FAT32X format; the
existing partition magic does not recognize this type.  So I must
clobber win98 and restore it ...

But the more interesting problem is that the disk reports (ATA
IDENTIFY) that it has only 16383 cylinders (2**14-1).  In the old
days, this was an IDE limit I think.  I don't have a new ATA spec
handy so if some kind sole could look up and see if there is a field
returned to IDENTIFY that indicates the true number of cylinders
that would be handy.  If there is not, then I guess the thing to
do is to regenerate the lp->d_ncylinders based on the d_secperunit
divided by the tracks and sectors per track.  Now the interesting
question is whether this fix is an x86 only hack, which belongs 
somewhere in disksubr.c or whether it is a generic IDE problem
that needs to be handled in ic/wdc.c after it does the IDENTIFY
command.

PS
I presume that the scsi disk don't have this nonesense and report the
true number of cylinders on truly large disks.