🚀 go-pugleaf

Xerox released MESA to universities in 1985.  I'm not sure what these
universities had to sign, but they were given full documentation (the
MESA programming language, the Pilot kernel operating system, and the
Tajo development environment).  Big corporate customers like Boeing
were also given these things.  At least 20 universities received a
grant of 20 machines or more, and the documentation.  One thing that
Xerox DID NOT disclose was the architecture of the Dandelion
processor, and the microcoded machine language for the MESA processor.
In the late 1970's this was something great, but in today's world of
megabyte programs it is something incredibly crufty, like the 8088.

Cedar is PARC's guess at the programming technology of the 1990's --
they started with MESA as the basis language.  MESA is a strongly
typed algorithmic language like PASCAL, with complexity that lays
between MODULA-II+ and ADA (incidentally, the DoD once asked Xerox to
disclose MESA, to avoid/help with the development of ADA.  Xerox in
its infinite wisdom decided to keep MESA a secret).  PARC added
features to give it the ability to be "type-safe".  These features
include garbage collection, string handling, and automatic compiler
checks for the "safe" subset of the language.

One of the unique things about MESA is that you can develop dangerous
non-safe code (e.g. memory smashing is possible), and then turn on the
safety checking and debug the danger out of your code.  The last thing
I heard was they were rewriting the Pilot O/S to be completely type-safe.
They were also working on a machine-independent version of the Cedar
language, called Mimosa.

Cedar is also the development environment that runs on dorados (about
the speed of a NeXT, with a turbo I/O system) .  There are some really
crufty things about this environment, and some other very beautiful
things.  For more information, see the many papers in the annual ACM
SOSP proceedings for the last 5 years. 

Some of the amazing things of Cedar include protocol compilers, user
interface compilers, and incredible configuration management software.
But it shows it age, with some baroque drawbacks (such as a wierd file
system like the Mac's MFS, general fragility/crashability, and
language drawbacks due to the stale hardware architecture).  The NeXT
user interface / development environment, which was recently written
from scratch by a development team that included many ex-Xerox
programmers, is probably cleaner and more desirable.

I was a developer in the Xerox XNS mail/clearinghouse team from summer
1984 to the summer of 1986.  Anyone wish to carry the story further?

Don Gillies, Dept. of Computer Science, University of Illinois
1304 W. Springfield, Urbana, Ill 61801      
ARPA: gillies@cs.uiuc.edu   UUCP: {uunet,harvard}!uiucdcs!gillies