Re: tlug: Fast/Ultra SCSI compatibility

["Yuri F. Anissimov" <youri@example.com>]

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tlug note from "Yuri F. Anissimov" <youri@example.com>
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> % I'm not too sure about mixing wide and normal SCSI, but normal/ultra
and
> % normal/fast work fine...
> 
>   If you put the narrow devices on the end of the chain it should 
>   work. Many of the newer wide devices have automatic termination
>   for both halves of the wide bus. When a narrow device is added, the
>   wide device will terminate the unused half and pass through signals
>   to the narrow device on the other half. I've done this with Sun
>   equipment, but I don't have any experience with PC based F/W
controllers.

With PC hardware it also works, SCSI is SCSI after all, but with the
addition of narrow device on wide chain, narrow SCSI communications will be
initiated only - the price is the performance penalties and necessity to be
more accurate with termination. On Mylex 960 RAID controllers it can hang
the bus though.
AHA3940W/2940W is more tolerant.
Yuri

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