Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!linus!decvax!cca!ima!inmet!bhyde
From: bhyde@inmet.UUCP
Newsgroups: net.arch
Subject: Re: BBN C machine? - (nf)
Message-ID: <256@inmet.UUCP>
Date: Thu, 11-Aug-83 05:39:10 EDT
Article-I.D.: inmet.256
Posted: Thu Aug 11 05:39:10 1983
Date-Received: Fri, 12-Aug-83 16:53:00 EDT
Lines: 19

#R:ucbesvax:12800006:inmet:2500003:000:938
inmet!bhyde    Aug 10 17:26:00 1983

  Well, first there was the Arpanet and it was build using Honeywell
Sue minicomputers.  Then Honeywell went out of buisness making the
Sue and the arpanet code got too big for 16bit addresses.  Soo...
a microprogramable computer was spawned that had 20bit bus capacity
and it was set up to simulate the Sue.
  That machine is known as the MBB or microprogramable building block.
It can be expanded to have special hardware to help with instruction
decode and bus management and such.  The C machines are just such an
extention.  The instruction set is sort of tunned to be what sounds good
for C programs.  The nice feature in the design is that the registers
subprogramming calling instructions save and restore a few registers
for you.  
  The word size of the machine is 20bits, the bytes are 10bits, thus
the 10bit characters, who cares?
  Except that the BBN lisp machine was built in the same building they
share no common ground.