On Tue, 10 Mar 2020, vinton cerf via Internet-history wrote:
>
> The Stanford first TCP implementation was done in BCPL by Richard Karp.
> Another version was written for PDP-11/23 by Jim Mathis but not clear in
> what language.
MACRO-11. We adapted it for our EPOS operating system on the PDP11/45
at ISI.
-- Steve