Jonathan Stone wrote:
> 
> But we can (and IMHO probably should) do better for either signle-disk
> systems or for SCSI controllers, like Adaptecs, where two fields of
> the C/H/S geometry is fixed for all disks on a given controller.

I don't understand that last sentence...

ahc0 at pci0 dev 10 function 0
ahc0: interrupting at irq 15
ahc0: aic7860 Single Channel, SCSI Id=7, 3 SCBs
scsibus0 at ahc0 channel 0: 8 targets
ahc0: target 0 synchronous at 20.0MHz, offset = 0xf
sd0 at scsibus0 targ 0 lun 0: <QUANTUM, XP34550S, LXY1> SCSI2 0/direct fixed
sd0: 4341MB, 5899 cyl, 10 head, 150 sec, 512 bytes/sect x 8890760 sectors
ahc0: target 2 synchronous at 20.0MHz, offset = 0xf
sd1 at scsibus0 targ 2 lun 0: <QUANTUM, XP34550S, LXY4> SCSI2 0/direct fixed
sd1: 4341MB, 5899 cyl, 10 head, 150 sec, 512 bytes/sect x 8890760 sectors

# disklabel -r sd0
# /dev/rsd0d:
type: SCSI
disk: qaII4550
bytes/sector: 512
sectors/track: 32
tracks/cylinder: 64
sectors/cylinder: 2048
cylinders: 4320
total sectors: 8847360

# disklabel -r sd1
# /dev/rsd1d:
type: SCSI
disk: qaII4550B
bytes/sector: 512
sectors/track: 10
tracks/cylinder: 150
sectors/cylinder: 1500
cylinders: 5899
total sectors: 8848500

I disklabeled them differently as sd0 had a bootable DOS partition

#        size   offset    fstype   [fsize bsize   cpg]
  h:  1535968       32       MSDOS                        # (Cyl.   0*- 749*)

on it, whereas sd1 is entirely NetBSD

#        size   offset    fstype   [fsize bsize   cpg]
  a:   205500        0      4.2BSD     1024  8192    16   # (Cyl.   0 - 136)

They are still both on the same Adaptec controller..

Cheers,

Patrick