MIT provides MULTICS source and documentation (DPS-8 simulation)

Chuck Guzis cclist at
Wed Nov 14 23:04:50 CST 2007

On 14 Nov 2007 at 23:36, Roy J. Tellason wrote:

> Multi-user in an 8-bit context doesn't sound real terrific to me,  for some 
> reason,  though I don't see a problem with multiprocessing if it's done 
> right.

It could be remarkably good, but you have to work within the 
limitations of the architecture.  The x80 CPUs didn't have any good 
way to dynamically relocate code and data and had a fairly small 
addressing space.

We simply went to a (pcode-type) interpreter that serviced all of the 
users.  It cut down on redundant code and since we were executing 
BASIC programs, the speed penalty wasn't too awful.  

I received a note last week from a one-time customer in Japan who 
mentioned that they were talking about phasing out the old code 
they'd written back in the 80's for the system we wrote in 1979 for 
an 8085 (supporting 5 users) and later ported to SCO Xenix.  He 
remarked that they'd added to the programs over the years with no 
problems.  This is more than 20 years after the company offering the 
language went out of business.

I've still got the source code somewhere.


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