This is a well known problem that has plagued many of us. See:
http://www.geocrawler.com/archives/3/483/2000/6/0/3924400/
http://www.geocrawler.com/archives/3/483/2000/8/0/4133556/

So as of today, I am still living with the 20000205 kernel.
If you manage to get around this, there are many people on 
the list who would be happy to learn more about it.

Jake

> This is on a 7500, with the CD-ROM plugged into the "internal" MESH SCSI
> bus. I can load almost any kernel from floppy or a SCSI drive on either bus
> (MESH "internal" or NCR "external").  Once it gets to the point of probing
> the SCSI busses for devices, it always fails in one of two ways.  The first
> failure method is an endless stream of mesh timeouts.  The other failure
> method is a few errors and incorret info about the CD-ROM, but it suceeds
> in booting to the point of prompting for a root device.  Here's what the
> output looks like:
> 
> [...]
> mesh0 at obio offset 0x18000 irq13: 50 MHz, SCSI ID 7
> scsibus1 at mesh0: 8 targets, 8 luns per target
> [...]
> scsibus1: waiting 2 seconds for devices to settle...
> probe(mesh0:3:0): Sense Error Code 0x0
> sd0 at scsibus1 target 3 lun0: <,  , > SCSI0 0/direct fixed
> mesh: timeout state=3
> mesh: resetting dma
> [repeat]
> sd0: could not mode sense (4/5); using fictitious geometry
> mesh: timeout state=3
> mesh: resetting dma
> 
> The kernels I tried are:
> <ftp://ftp.netbsd.org/pub/NetBSD/NetBSD-1.5_ALPHA2/macppc/binary/sets/kern.tgz>
> <ftp://ftp.netbsd.org/pub/NetBSD/NetBSD-1.5_ALPHA2/macppc/installation/floppy/bo
> ot.fs>
> <ftp://ftp.netbsd.org/pub/NetBSD/arch/macppc/snapshot/20000620-1.5/binary/kernel
> /netbsd.GENERIC.gz>
> <ftp://ftp.netbsd.org/pub/NetBSD/arch/macppc/snapshot/20000620-1.5/installation/
> netbsd.ram.gz>
> <ftp://nandra.iri.co.jp/pub/NetBSD/macppc/netbsd.hfsboot>
> 
> The CD-ROMs I tried are a Teac 12x from a PowerComputing PowerCenter Pro
> and an "Apple" brand 12x from a 7300.  I've never had any other problems
> with either of these two CD-ROM drives.
> 
> Any suggestions?
> 
>   -- MW
> 
>