[962] in linux-scsi channel archive
Re: 2.0.0/2.0.25 oopses with buslogic 956C and two 4G seagates ...
daemon@ATHENA.MIT.EDU (Peter T. Breuer)
Sun Nov 17 16:16:25 1996
From: "Peter T. Breuer" <ptb@oboe.it.uc3m.es>
To: lnz@dandelion.com (Leonard N. Zubkoff)
Date: Sun, 17 Nov 1996 22:11:09 +0000 (WET)
Cc: linux-scsi@vger.rutgers.edu
In-Reply-To: <199611171953.LAA01108@dandelion.com> from "Leonard N. Zubkoff" at Nov 17, 96 11:53:30 am
X-Anonymously-To:
Reply-To: ptb@dit.upm.es
OK - You got me, but I have 10 mins before the last bus goes and I'll bite
on this one ... :-)
"A month of sundays ago Leonard N. Zubkoff wrote:"
> (thanks for the clue about what the adaptor bios setup message is
> referring to with "low and high bits". This is another wonderful piece
> of impenetrable jargon! Might you pass on a request for a better way of
> putting it through your connections in buslogic?)
>
> There is quite a detailed explanation of low and high byte termination, and in
> which cases each byte should be terminated, in the manual that came with your
> BT-956C. Please read that section again and see if you still feel there is a
> need for further documentation. Even the back of the BT-956C board itself has
> a summary of the possible narrow and wide connection options and which byte
> should be terminated.
There are 19 shelves of manuals behind me. I found a slim (thank god!)
buslogic manual wedged between solaris 2.5 desktop manuals and the
"SamTron" Color monitor. Surprisingly (not because it's you, but
because that's the way of manuals in general) you are quite right! The
explanation is comprehensible. It says, in a table with H/A Low (H/A
High) Byte Termination at the left:
+Turn only High Byte on when one 68-pin and the 50-pin connectors are
used, or when both 68-pin connectors are used and one is used for
8-bit devices
and more options like that. Although I understand what they mean, this is
literally gibberish. Supposing I want to connect up a scsi, I am supposed
to complete the instructions, which will oblige me to install one sort of
cable or the other, and then refer back through the book again looking
for what I have done with the cabling to see if there was something
else I should have done too!!
Your explanation, in contrast, was crystal clear. The high bits and the
low bits together are needed for wide scsi connections. I have wide,
therefore I should enable both. I don't need this mumble about cables
when I have exactly 5 mins to read the manual in before the bus goes,
and I have a meeting at 9am tomorrow, and tuesdays class to prepare ...
I suspect that manuals are put together by people who don't think
in abstractions. I have no idea what kind of cables I have and I am
not going to stand there with a microscope counting the pins. But
I have wide scsi. My suggestion is meant to be helpful - a naive but
informed user has tested their dialog screen and found it wanting. All
they have to do is put your excellent explanation in the help box. That
will increase the value of their product in a subtle way - it will make
it customer-friendly.
Peter T. Breuer
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