[rescue] Dead AXi?

[Big Endian]

>High-byte terminating convertors are best used for just two things:
>1. (most useful) putting a wide drive on a narrow bus.  The termination of
>the high byte at the drive's interface does wonders on many drives to get
>them to negotiate down to narrow.
>2. (less useful) reducing a Wide SCSI host adapter channel to narrow right as
>it comes off the card, assuming that the card is an older one that doesn't
>support high-byte autotermination well (or at all).

#2 is essentially what I'm doing here.  The only thing on this bus is 
the cdrom.  I'm using a high terminated wide-narrow and the drive 
terminator for the low bits.

>If you are going to share a bus between wide and narrow devices, the best bet
>is not to attempt to reduce the bus half-way down the run (in my experience).
>Every adapter you add in-line creates impedence mismatches and generates
>signal reflections (however small they may be). the best bet is to cable the
>entire run as wide with active *external* termination at the end, and then
>put un-terminated wide->narrow adapters in between the ribbon cable and your
>narrow devices.  Yes, on-the-drive termination works, but I have had problems
>with it before, where I have never had problems with a separate active
>terminator.

Unfortunately I don't have the greatest collection of wide scsi gear 
here at work.  I do have terminated and unterminated converters but 
no pure terminators.

>This arrangement minimizes signal distortion at the far end of the bus, and
>provides the most sure and proper termination of the bus.
>
>to Illustrate: (R=Ribbon, C=Connector)

more like:

C (host adaptor, assume terminated)
R
R
R
R
R
R
R
R
R
R
C (ultraplex w/ adaptor)

----

daniel
-- 
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"Fragile. Do not drop." -- Posted on a Boeing 757.