External SCSI disks with SS20

[Hartwig Atrops <Hartwig.Atrops@t-online.de>]

Hi all.

I try to run an external SCSI disk box (3 disks) with a Sparcstation 20 
(Debian 3.0 Woody, kernel 2.4.18 SMP,  2 x SuperSparc II 75 MHz, no 
CDROM). Disk array: Sun P/N 595-3769-01, three 2GB disks (one slot is empty), 
narrow SCSI (50 pin).

The SS20 starts booting, linux bootup recognizes 4 SCSI disks: three times 
ST32550N (external) and a MAB3045S internal 4GB disk. External: SCSI ID 0-2, 
internal 3. This one is the boot disk. When I boot with the disk array 
powered down, the SS20 boots without problems.

With external disks on it ends up with:

   Kernel panic: VFS: Unable to mount root fs on 08:01
   Press L1-A to return to the boot prom
   spin_lock(f0209000) CPU#0 stuck at f00599a8, owner PC(f0027124):CPU(1)
   ... ( last line periodically repeated) ...

What is going wrong? Does my SS20 try to use an external disk as root 
filesystem? Which device is 08:01?

Thanks in advance,

   Hartwig