Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.csd.uwm.edu!uakari.primate.wisc.edu!ames!sun-barr!newstop!texsun!texbell!bellcore!dduck!johno
From: johno@dduck.ctt.bellcore.com (John OBrien)
Newsgroups: comp.sys.sequent
Subject: Re: Sequent Machines, what are their strengths & weaknesses
Message-ID: <17580@bellcore.bellcore.com>
Date: 8 Sep 89 13:18:36 GMT
References: <1263@syma.sussex.ac.uk> <1309@syma.sussex.ac.uk> <218@runxtsa.runx.oz>
Sender: news@bellcore.bellcore.com
Reply-To: johno@dduck.UUCP (John OBrien)
Organization: The Joe Irby Bar and Grill
Lines: 74

Trevor,

	Some of your questions require a bit of detail.  I'll make these
as short as possible.  We can follow-up if you like.

In article <218@runxtsa.runx.oz> treval@runx.oz (Trevor Luker) writes:

>	I am interested to know more about 386 based sequent boxes.
>
>	1)	Do the sequent compilers produce truly parallel execution
>		of a particular procedure. (Producing multi-threaded execution
>		of loops etc.) or does the architecture simply allow multiple
>		processes to run in parallel (A la NCR 850).

	A couple of answers here.  The sequent architecture does automatic
	multiprocessing across the available processors.  The scheduler
	works quite well.  The "Parallel Processing" is not done
	automatically!  The Sequent compiler allows you to use library calls
	to implement calls to the parallel processing routines.  There are
	third party compilers that try to parallelize loops and such.
	But for anything of any complexity, it is up to the person writing
	the program to parallelize it.  This is not too difficult once
	you get used to using the library calls.  The effort needed to
	parallelize you rprogram is completely dependant on the complexity
	of your program.  The library routines are quite easy to use.
	
>
>	2)	I believe they run under Dynix. Is this compatible with "real"
>		(AT&T) unix. (5.3 / 5.4 etc)

	The parallel processing libraries are not available under the AT&T
	dynix (they soon will be).  DYNIX is a dual universe OS, running
	both BSD and AT&T.  The parallel processing libraries are available
	under the BSD universe.  The AT&T universe has few inconsistencies
	with standard AT&T 5.2.  However, all administration is BSD.
>
>	3)	Does the architecture "scale" correctly, ie does performance
>		increase linearly with the number of processes added?

	My tests say YES!!!
>
>	4)	The machine that I have seen has 2 dual-processor 386 boards
>		with each chip running at 16 MHz. Are there speed up (33MHz)
>		options available? What about 486 boards?

	I'm not aware of any clock speed-up options.  I'm sure the 486
	boards will be available sooner or later.  But I don't have
	hard info.
>
>	5)	What are your experiences with bug-fixes and customer-support?

	Very responsive!  Bug fixes have been shipped promptly.  CUstomer
	support is great (although, we had some trouble with the time
	difference between Oregon and the east coast (7 AM in NJ is 4 AM
	in Oregon and no one is awake.)
>
>	6)	Given a free choice, would you buy another one...

	Absolutely!!!!!!!!
>
>Thanks, treval

Your welcome.



John O'B


John J. O'Brien
ISCP (Integrated SCP)
ctt!johno or johno@ctt
RRC 4B-307
699-8788