Path: utzoo!censor!geac!jtsv16!uunet!tut.cis.ohio-state.edu!rls!randy
From: randy@rls.UUCP (Randall L. Smith)
Newsgroups: comp.sys.dec
Subject: Re: Questions on 5400 systems
Summary: dssi is no bus, no Jack Kennedy either.
Keywords: 5400, vax, risc, ultrix, 3000, dec
Message-ID: <356@rls.UUCP>
Date: 9 Aug 89 03:17:09 GMT
References: <106@pserv.UUCP>
Distribution: usa
Organization: A maze of twisty passages all alike in Columbus, Ohio.
Lines: 39

In article <106@pserv.UUCP>, stevem@pserv.UUCP (Steve Mestad) writes:
> Our sales reps state that the 5400 qbus can run 8 meg and disk io will
> be about 2.5 times better than on our Microvax II's.  Has anyone
> experienced this?  How fast do the dssi drives run....or is the kda a
> better way to go?

Dssi is far better because the i/o's do not go to the q-bus.  The controller
is "built-in" to the processor card.  Naturally, the disk connects directly
to the controller.  Since the QIO's and data don't travel over the bus, its
much faster. 

> How are the connections brought out?
>
> Does the 8 meg bus in the 5400 eliminate the use of existing cards due to
> its faster speed?
>
> Or do the third party 3000 series card run fine in the 5400??

The Q-bus is still in place and available for kda50's and other dog type
controllers.  The connections are either Q-bus or the dssi slots.  dssi is
bus-less, that is, it is *not* a bus.  It is a controller on the processor
card.  Once all the dssi slots are used, thats it.  No further expansion is
possible.  I think there are typically four dssi slots.  I am not familiar
with the 5xxx series.  A limitation of dssi is that only dssi drives can be
used with it.  The Q-bus can utilize SMD, ESDI, tapes, etc. 

> How about the Risc Ultrix?  Full of porting bugs or identical to the
> Vax Ultrix?  Third party applications getting ported or are they too busy
> or not interested.....

Don't know but a good question.  If anyone knows, I'd like to hear too.

Cheers!

- randy

Usenet: randy@rls.uucp
Bangpath: ...!osu-cis!rls!randy
Internet: rls!randy@tut.cis.ohio-state.edu