RFC 49 (rfc49) - Page 1 of 5

Conversations with S

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NWG/RFC 49      Conversations with Steve Crocker (UCLA)

                          Edwin W. Meyer, Jr.
                            MIT Project MAC
                             April 25, 1970


   (Both my personal opinions and those that I believe represent a
   consensus of the Network Working Group at Project MAC are presented
   here.  The pronouns "I" and "we" are used to distinguish between
   these.)


On April 21 and 23 Thomas P. Skinner and I had telephone conversations
with Steve Crocker at UCLA relating to the network protocol,
specifically regarding our proposal in NWG/RFC 46.  The following items
were discussed.  (I hope that Steve will pardon me if I happen to
misparaphrase him.)

1) Steve stated that he felt that a need for dynamic reconnection would
later be recognized by the network participants.  However, because of a
lack of consensus, it will not be included in the initial
implementation.  (We at Project MAC favor this approach of not including
it initially.)


2) Steve supported the implementation of the INT network command
described in NWG/RFC 46.

This command allows a process that has agreed to accept interrupts over
a socket connection to be reliably interrupted by the process at the
other end.  The interrupt causes a process to abey its current execution
and execute a procedure that it has specified as the INT handler.  (The
NCP does not specify the INT handler.  That is the function of higher
level protocols.)

The INT command is designed specifically for use by a third level User
Control and Communication (UCC) protocol to implement a "quit" signal.
Under such a protocol, both the requestor and the created process agree
that an INT related to a specific socket connection and transmitted over
the NCP control link to the created process is the standard "quit"
signal.  The created process provides an INT handler that implements
this "quit" function.  (This does not preclude a different
interpretation of INT by other third level protocols.)

Although many systems implement the "quit" as a control character in the
Teletype input stream, systems such as CTSS, Multics, and others
implement it as a 200 ms spacing on the line.  We at MAC think that the
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