Path: utzoo!mnetor!uunet!mcvax!ukc!its63b!hwcs!zen!jules
From: jules@zen.UUCP (Julian Perry)
Newsgroups: comp.sys.hp
Subject: Re: hp9000 ser. 500 hpux
Message-ID: <1186@zen.UUCP>
Date: 18 Mar 88 18:15:06 GMT
Reply-To: jules@zen.UUCP (Julian Perry)
Organization: Zengrange Limited, Leeds, England
Lines: 86

[irf@kuling.UUCP (Bo Thide):]
>What's annoying about the 500 series is that the software is not being kept
>up-to-date, no TCP/IP, no X Windows, no troff (!!), no (supported) tplot, 
>plot, graph etc, and the hardware (CPU, RAM, interfaces) is VERY expensive

We agree, it's a shame to throw out 500's just because they're not the latest
hardware; they were good in their day.

>Our new 350 is much faster but I doubt that it is a good replacement as
>a central computer for our whole institute.  We don't even think an 800
>series can compete with a 500 with 2 or 3 computers in terms of multi-user
>capablility.  Was the experience with the 500 series so bad that HP has
>given up that idea?

Yes we think the 350 is great (ours is SRX-ed) and fast but we wouldn't
really recommend 10-15 users...single user is much better.  :-)

Let us put you right on this matter of an 800 not coping with 10-15 users,
the 800 series is VERY fast...we had a network of 3 series 500's (total
of 6 processors (mainly Focus II's), 12MB RAM, 4 discs, 30ish users) and
we thought they were fast till we replaced the lot with a 16MB 840.

We always got complaints about the interactive performance of the
500s once more than 10-15 users got going, but now other users'
activity is virtually unnoticeable.

For example, a single TeX or LaTeX nearly stops a 500 but I ran 39
simultaneous LaTeX's (text~300K, data~600K) on the 840 and it hardly 
slowed down at all!

[zaphod@deepthot.UUCP (millions of atoms of Lance):]
>Our main application of our 2 CPU 9000/550 is data collection, at
>1am a schedular starts up that phones 50 PC's around North America
>and exchanges data with them. The only action between the two machines
>is the simultaneous of information (grouped together as a single file).
>To save time we have multiple modems, allowing concurrent sessions.

>When we went from one modem/session-at-a-time to two, we noticed a
>definite throughput increase (sessions acheived/ time period) .
>when we went from two to three, we did not not an improvement, but
>rather a decrease in thoughput as communication sessions began to
>time out while two CPU tried to do three i-o intensive operations.
>[...]
>to acheive even better throughput, we are tacking in a third CPU.
>[...]
>on applications such as ours (concurrent near-identical sessions),
>a multi CPU machine is a neccessity.

Strictly speaking you would need multiple CPU's to get the best
performance with multiple processes, but in reality a single fast CPU is
sufficient.....the series 800 is FAST.  We have found NO tasks at which
the 500's are faster.  The 840 version of HP-UX has features to make it better
than the 500 version when running multiple processes -- kernel pre-emption,
real-time extensions and BSD fast file system, etc..

[jim@cs.strath.ac.uk (Jim Reid):]
>In article <672@kuling.UUCP> irf@kuling.UUCP (Bo Thide) writes:
>>............. So the logical question here is:  Why doesn't HP have a
>>multi-CPU 800?  Was the experience with the 500 series so bad that HP has
>>given up that idea?
>
>No, it's probably because building closely-coupled multiprocessors that
>use RISC (eg the 800 series CPU) isn't easy.

Just because it isn't easy doesn't mean it can't be done.

HP Precision Architecture allows assist hardware to enhance system
performance; for example, current 800 series use as a co-processor
the floating-point chips found on the FOCUS II board (according to HP Journal).  
Additionally, multi-processing is supported in HP-PA "to provide
incremental performance via distribution of the system workload over
multiple CPUs, or can be configured redundantly to provide fault-tolerance".
"Software is still responsible for maintaining consistency for I/O,
for modifying instructions and for virtual address mapping."  (HP
Precision Architecture Reference Manual)

After all, look how smootly HP made the multi-CPU 500s perform.   :-)


Jules and Frank [the spectral defenders of the faith]

-- 
IN-REAL-LIFE:  Julian Perry           
E-MAIL:        jules@zen.co.uk || ...!mcvax!ukc!zen.co.uk!jules
PHONE:         +44 532 489048 ext 217
ADDRESS:       Zengrange Limited, Greenfield Road, Leeds, England, LS9 8DB