Caching disk controllers and 386 multiprocessor

[Jeff Tye sys adm]

In article <10 at aostul.UUCP>, steveb at aostul.UUCP (Steve Bogner) writes:
> 
> I am trying to put together a very high performance SCO Xenix
> system and would like to know if anyone out there has had
> experience (good or bad) with the caching disk controllers made
> by DPT (Distributed Processing Technologies).  They say you can
> have a hardware cache of up to 16 MB, reducing disk access to .6
> ms. 

I've been using and selling the DPT caching disk controllers for over
a year and a half. I highly recommend the product and the company. The
performance benefits are outstanding. I like them so much that I propose
them with every system I sell. The difference is like night and day.

Some tips on using them:

1)	Don't use it unless you have the RAM card with it. 512K is not
	enough by itself. Trust me. I've tried it in a variety of
	configurations and 2.5MB cache RAM or more is needed.

2)	Lower your disk buffers in Xenix to 256K when using the DPT card.
	You get more RAM for XENIX that way and the DPT does the rest for
	you.

3)	Use the DPT format utility and *NOT* the Xenix install format. DPT
	uses a special formatting algorithm that skews the sectors for 
	optimum performance.

>    Also, a company called Corollary makes a 386 multiprocessing
> board for SCO Xenix called the 386/mp.  Up to four 386's can be
> added to the server.  Has anyone actually done this?  I'm using
> the ALR 33/386 server with 16 MB of 80 ns RAM and Maxtor 4380E
> disks.  Please reply by e-mail.

You must use Corollary's motherboard in order to use their multiprocessing
capabilities. The AT buss is too slow for multiprocessing so Corollary
created a new AT compatible motherboard with dedicated 'C' buss for memory
and data transfers. It is a true multiprocessing buss with cache coherency
and all that stuff. Zenith is OEMing the product in their Z10000 (?) line.

-- 
Jeff Tye
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