Andy Tanenbaum
Wiskundig Seminarium
  der Vrije Universitet
De Boelelaan 1081
Amsterdam-11
NETHERLANDS

Dear Mr. Tanenbaum:

Thank you for your letter of November 7.
I am enclosing a copy of the
paper by me and Ken Thompson whose abstract you read;
it gives a fairly complete picture of the nature
of the implementation.
No more detailed descriptions have yet been released,
although UNIX is being made available
through a Western Electric Company license to educational
institutions.

As the paper indicates, UNIX is indeed written in a home-grown
systems programming language called C.
As the paper indicates, earlier versions of the system were written
in assembly language.
We are extremely happy with the new system,
which is only one-third larger than the old and considerably
more powerful.
Its modest growth is attributable both to a good compiler
and to better understanding
of the organization of the routines and the data involved.

				DMR
