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From: barry@PRC.Unisys.COM (Barry Traylor)
Newsgroups: comp.arch
Subject: Re: Computer Architecture methodology
Summary: A Series (B6700+) Hardware/software Integrated
Keywords: A Series, B6700
Message-ID: <14279@burdvax.PRC.Unisys.COM>
Date: 27 Jun 90 04:10:30 GMT
References: <8533@canterbury.ac.nz>
Distribution: comp.arch
Organization: Unisys Corporation, Paoli Research Center; Paoli, PA
Lines: 41

In article <8533@canterbury.ac.nz> PHYS169@canterbury.ac.nz (Mark Aitchison, U of Canty; Physics) writes:
>A little question: do the hardware architecture designers primarily strive to
>make conventional programs and operating systems run well (fast and lean, etc)
>or to make hardware race as fast as possible - independant of ideas of what
>software will run on it (i.e. say "It's up to the software guys to make the
>best of my hardware")?
>
>I know lots of people will have ideas on what they *ought* to do, and looking
>back with the aid of folklore, we can see what happened on occassions in the
>past, but I am hoping some present-day architure people (not just building
>block assemblers) will be able to reply with their design philosophy.
>
>Ta muchly,
>Mark Aitchison.

The B6700 and its successors have all been designed as integrated
hardware/software systems.  There is really nothing in the instruction set
that is not in fairly common use by the compilers.  Admittedly, certain
instructions exist so that the operating system can control the machine,
but as far as I know, there are no instructions in there that are there
just because "the hardware folks thought it would make the machine scream."
The reality of integration came about and has been maintained in the
absence of an assembly language.  The architecture of the machine is
largely driven by a combination of requirements from Cobol, Algol and
Fortran.

In recent history, we have been working on ways to make commonly used
instructions run faster, and there have been some attempts to bend the
software to work with some ill concieved hardware instructions, now
obsolescent.

In the architecture group, there are about 4 hardware engineers, 3 operating
system programmers and 4 to 6 compiler programmers.  Transient personnel
typically bring the group up to 20 at any given time.  Occasionally
hardware wants to make changes.  Occasionally software wants to make
changes.  All changes typically require a full consensus of the
architecture group before they are implemented.

Barry Traylor
barry@prc.unisys.com
Unisys Large A Series Engineering (operating systems programming)