Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!sun-barr!sun!chiba!khb
From: khb%chiba@Sun.COM (Keith Bierman - SPD Languages Marketing -- MTS)
Newsgroups: comp.arch
Subject: Re: Criteria for comparing RISC processors
Message-ID: <105001@sun.Eng.Sun.COM>
Date: 16 May 89 05:07:36 GMT
References: <2368@ogccse.ogc.edu> <1464@cfa.cfa.harvard.EDU> <141@dg.dg.com> <156@dg.dg.com> <658@pitstop.West.Sun.COM> <165@dg.dg.com>
Sender: news@sun.Eng.Sun.COM
Reply-To: khb@sun.UUCP (Keith Bierman - SPD Languages Marketing -- MTS)
Organization: Sun Microsystems, Mountain View
Lines: 72

In article <165@dg.dg.com> mpogue@dg.UUCP (Mike Pogue) writes:
>
>  Some interesting points.  However, Sun (of all the vendors) has
>the BIGGEST problem with vendor-to-vendor compatibility.
>
>  Yes, Sun went to multiple vendors, but MIPS and the 88K can 
>guarantee a much better compatibility story, because they don't
>have (for example) three DIFFERENT implementations of multiprocessing.

????

So far (as best I can tell) Sun has the most experience in this
particular area. Multiple FPU's (two weitek's and a TI), third party
system clone (Solb), not to mention numerous internal projects ....
and folks like Primsa (hate to always use them as an example; but they
were nice enough to leak some details to the press, so I am free to
repeat what has already been published :>) who presumably have plenty
of Sun 4/2xx and 1xx and perhaps some of the newer boxes to keep
themselves honest .... 

So far binaries migrate as desired. I assume that the 88K will have
this property ... but so far there is limited proof.

MIPSco 's customers cannot generally move binaries from Ardent's to SG
to MIPS to DEC.

This is not necessarily bad; but it does appear to be case currently.


>  And when latency changes on a Functional Unit (like floating point)
>in the future, the 88K register scoreboarding will allow performance
>increases WITHOUT CHANGING THE BINARY.

Yes. 

>
>  Sun networks ALREADY have a massive problem with Sun/3 and Sun/4
>binaries required for everything you use.

Don't forget the 386i !!

With some "clever" sysAdmin work the "problem" is invisible to most
users (modulo disk space requirements). I am no SysAdmin expert, but I
often work with all three arch. and various flavors ... and hardly
ever care (except when I am checking up on the compiler quality). 

Over time the cleverness should be eliminated and bulit into tools. 



>Neither MIPS nor the 88K
>have this problem.
>

In any case, as John pointed out, SPARC does not have this problem
either. Sun, as a whole, does because our customers want three
different instruction sets for their own reasons ... who are we to
argue with them ?

btw: does DG intend to drop the MV series ?  How is DG better off than
     Sun ? Is the 88K really binary compatible with the
     Nova and the MV4000, 8000, 10000, etc. ?



>My opinions are my own....


Keith H. Bierman      |*My thoughts are my own. Only my work belongs to Sun*
It's Not My Fault     |	Marketing Technical Specialist    ! kbierman@sun.com
I Voted for Bill &    |   Languages and Performance Tools. 
Opus  (* strange as it may seem, I do more engineering now     *)