when I played with netbsd/xen, I had the same kind of problem.
what I did, is write the right root device in the kernel config.
see the example in GENERIC :
#config         netbsd  root on sd0a type ffs

using wd0a, in my case, solved the problem.

On Fri, Jan 07 2005 - 02:08, Julien Aube wrote:
> Hi, 
> 
> Sorry to bother the list with such a problem, but I read pratically all
> the doc I could find without success. 
> 
> I've just installed NetBSD 2.0 (but the same problem also show up on
> 1.6.2) on an Ultra2, the boot disk beeing on a QLogic SCSI card.
> Everything runs fine , but at each boot, I have the following message :
> 
> scsibus0: waiting 2 seconds for devices to settle...
> scsibus1: waiting 2 seconds for devices to settle...
> sd0 at scsibus1 target 4 lun 0: <SEAGATE, ST19101W, 0014> disk fixed
> sd0: 8683 MB, 6576 cyl, 16 head, 169 sec, 512 bytes/sect x 17783240
> sectors
> sd0: sync (50.00ns offset 8), 16-bit (40.000MB/s) transfers, tagged
> queueing
> can't determine root device     <-------------
> root device (default isp0):
> 
> And then it waits until I simply give it "sd0a" (the drive that has been
> detected just above). Then it ask me the dump device, preloaded with the
> default "sd0b" which is fine, and so on with the filesystem (generic)
> and the init path. 
> At this point the boot continue normally.
> 
> My question is : How do I specify these information to NetBSD ?
> I mean, I've tried on the command-line "a la linux" root=sd0a, I've ran
> installboot. Do I have to recompile the kernel just for that ?
> 
> Note : I do not have the "-a" flag on the boot-file variable of the boot
> monitor. It read just "netbsd".
> 
> Thank you !
> 
> Julien Aube 
> 
> 

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