Path: utzoo!attcan!uunet!bywater!scifi!paladin!beal
From: beal@paladin.Owego.NY.US (Alan Beal)
Newsgroups: comp.arch
Subject: Re: Computer Architecture methodology
Summary: What is the story on the A-series machines?
Keywords: A Series, B6700
Message-ID: <550@paladin.Owego.NY.US>
Date: 11 Jul 90 01:16:36 GMT
References: <8533@canterbury.ac.nz> <14279@burdvax.PRC.Unisys.COM>
Distribution: comp.arch
Organization: The Design Committee
Lines: 37

I used to work on B7800s and A-series machines and I was wondering how
they are doing in the market place and what changes have been made in
the last 3 years.  The most powerful system I recall was an A-17 using
MCP/AS.  Is there now a more powerful machine?  Have the B1000 users
moved on to the A-3s and A-5s or to another architecture entirely?
The 32 bit scheme seemed to be a work around the 20 bit hardware
addressing limitations.  Is there any effort to increase the word
length from 48 bits or change the descriptor formats?  I read where
the global table allows a program to address 2**20 objects, each
up to 2**32 words.  Is that true?  What portion of this is implemented
in hardware and which in software?  I also read that the global
table decreased the amount of stack searching for copy descriptors.
How much does this offset the penalty of the extra indirection using
the global table?  Any other new hardware features on the A-series
machines?  Are they still selling well?

I really liked the operating system and the use of compilers instead
of assembly language.  However, the Algol compiler did not allow any
complex data types other than arrays.  Will this ever change?  My
last expereience was on MCP 3.6 and I am wondering how the MCP
has changed since then.  How well is the semantic database software
being accepted?  Any new developments in distributed computing?
Now that I have been away from the A-series machines, I find myself
missing it more and more every day.  What I wouldn't give again for a system
that displayed sensible error messages, told me exactly on which line
my program failed, provided easy multitasking and interprocess
communication facilities, and had an elegant job control language(WFL).
Oh, to the goood old days.  Before I leave, does Unisys still provide
the source code for the MCP and other software?  Are TCP/IP and
other non-Unisys protocols supported?

Thanks.

-- 
Alan Beal
Internet: beal@paladin.Owego.NY.US
USENET:   {uunet,scifi}!paladin!beal