Oscar Oberg writes:
[...]
> b) I'm getting SCSI (I assume) errors of this kind:
> 
> DMA incomplete: ntrans=8193/16384, lock=98
> si_dma_stop: timeout?
[...]                                                           
> Is this a software or hardware problem? I've recently installed a SCSI1
> CDROM, and I don't recall getting any of these errors before I did. If
> it's a problem w/ the CDROM, what could it be?

This is a software/driver problem. There are some real bugs/problems
in the NCR driver. One of them is that transfers get interrupted for
still unknown reasons and this results in this "DMA incomplete" message.
(BTW: ntrans is the number of bytes already transfered, second number 
is the number of bytes to transfer, lock-info is some internal value
and not related to this special problem.)

Because of these problems there's a "work-around" (ie. ugly hack) in 
the scsi-driver which busy-waits for some time after starting a transfer,
so that the transfer won't be interrupted. The wait-time is "calculated" 
out of the transfer size and some "don't-ask-me" constant. Since I 
"found" this constant on my VS2000 with one SCSI-disk, I assume that
the problems you see are caused by the CD-ROM. I assume that transfers
are slower and that the busy-wait phase is not long enough for that
device...

Anyways, the NCR/SCSI driver should be rewritten since these bloody
busy-waits slow down disk operations a lot. I hope I'll have some
spare time in june so that I can do that. Let's hope that these
problems disappear with a new driver.

Ciao,
	bertram

PS: If anybody else is interested in (re-)writing the SCSI driver,
    I would not mind...   ;-)