BBN PDP-11 V6 Unix with C TCP/IP
(from Noel Chiappa)

  This is an early TCP/IP Unix system written at BBN. It was not the
  first TCP/IP Unix; that was one done at BBN in MACRO-11, based
  on a TCP done in MACRO-11 by Jim Mathis at SRI for the TIU (Terminal
  Interface Unit).

  This networking code is divided into three main groups. First there is
  code for the kernel, which includes IPC enhancements to Unix, including
  Rand ports, as well as further extensions to that done at BBN for the
  earlier TCP - the capac() and await() calls. It also includes a IMP
  interface driver (the code only interfaced to the ARPANET at this point in
  time). Next, TCP is implemented as a daemon which ran as a single process
  which handled all the connections. Finally, other programs implement
  applications; TELNET is the only one provided at this point in time.

  A modest amount of documentation is available in the 'doc' directory;
  included are the original NROFF source to the two Rand publications
  about ports, and several BBN reports.

  The original port code was written by Steven Zucker at Rand; the extensions
  done at BBN were by Jack Haverty. The TCP was mostly written by Mike
  Wingfield, apparently with some assistance by Jon Dreyer. Dan Franklin
  apparently  wrote the TELNET.

  For more information about this system, see:
  - "Interprocess Communication Extensions for the UNIX Operating System:
  I - Design Considerations", Rand Corporation, Report R-2064/1-AF, June 1977.
  - "Interprocess Communication Extensions for the UNIX Operating System:
  II - Implementation", Rand Corporation, Report  R-2064/2-PR, April 1977.
  - "UNIX TCP User's Guide", Bolt Beranek and Newman Inc., Report No. 3724