On Sun, 16 Aug 1998, Michael Richardson wrote:
>   I just added a new drive to my file server. A 4Gb Quantum VIKING (SCA
> with an adaptor to Ultra+Wide).
>   My suspicion is that there is some parameter that needs tuning on
> the NCR driver.... I have 6 devices, counting LUNs and adaptor, 8.
> The system hangs at the end of the boot sequence with:
> ncr0: no ccb.
> sd3: not queued, error 5

I don't know of any limitation in the NCR driver on the number of
devices you can have... it sounds like it might be SCSI chain problems.
Ultra SCSI is pretty picky about cabling; your chain might be too long.
I think the limit is about 1.5 meters-- less if you have many devices.
Perhaps reducing the max bus speed to 10MHz would help... "options
SCSI_NCR_MAX_SYNC=10000". You may also need to reduce the speed in the
'875 BIOS to get the boot blocks to work reliably.

What I do is use a cheap (~$30) 53c810 for my external devices and
CDROM, and only use the 875 for my (two) internal UltraWide drives.
-- 
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