RFC 89 (rfc89) - Page 1 of 7
Some historic moments in networking
Alternative Format: Original Text Document
Network Working Group B. Metcalff
Request for Comments: 89 MITDG
NIC: 5697 19 January 1971
SOME HISTORIC MOMENTS IN NETWORKING
While awaiting the completion of an interim network control program
(INCP) for the MIT MAC Dynamic Modeling/Computer Graphics PDP-6/10
System (MITDG), we were able to achieve a number of 'historic moments
in networking' worthy of some comment. First, we were able to
connect an MITDG terminal to a Multics process making it a Multics
terminal. Second, we successfully attached an MITDG terminal to the
Harvard PDP-10 System thereby enabling automatic remote use of the
Harvard System for MIT. Third, we developed primitive mechanisms
through which remotely generated programs and data could be
transmitted to our system, executed, and returned. Using these
mechanisms in close cooperation with Harvard, we received graphics
programs and 3D data from Harvard's PDP-10, processed them repeatedly
using our Evans & Sutherland Line Drawing System (the E&S), and
transmitted 2D scope data to Harvard's PDP-1 for display.
The IINCP
Our experiments were run on the MITDG PDP-6/10 using what we have
affectionately called our 'interim interim NCP' (IINCP). Under the
IINCP the IMP Interface is treated as a single-user I/O device which
deals in raw network messages. The software supporting necessary
system calls includes little more than the basic interrupt-handling
and buffering schemes to be used later by the NCP. In short, the
user-level programs which brought us to our historic moments were
written close to the hardware with full knowledge of IMP-HOST
Protocol (BBN 1822). When the INCP and NCP are completed, these
programs can be pruned considerably (80%). The exercise of writing
programs which conform to IMP-HOST Protocol was not at all wasted.
Only now can those of us who are not writing the NCP begin to grasp
the full meaning of RFNM's and their use in flow control. The
penalties for ignoring an impatient IMP, for failing to send NOOPS
(NO-OPS) when starting up, and for blasting data onto the Network
without regard for RFNM's are now well understood.
The Multics Connection
Our quest for historic moments began with the need to demonstrate
that the complex hardware-software system separating MITDG and
Multics was operative and understood. A task force (Messrs. Bingham,
Metcalff