Prose samples by Robert Elton Maas <rem@BTR.Com>
Technical proposal


%% 79C07A.SUZ (19k, 1979) Proposed amendment to PCNet protocol

BACKGROUND

Two years ago (1977), Ron Crane designed most of the PCNet protocols,
from the telephone-manager interface up to the server-process interface.
Most of this was written up in PROTO PB1, but a few handwritten notes
were never transcribed because we never agreed about accepting his
proposed methods.  Part of this not-yet-accepted protocol concerns
algorithms for changing from Radix-41 to binary.  Of a similar nature,
but not even designed to date, are (1) change of baud rate (2) operation
in half-duplex 8-bit-binary mode.  This proposal is aimed at filling
these three gaps as well as changing the full-duplex 8-bit-binary mode
so that all modes are as compatible as possible, thus reducing the amount
of alternative code that must be written to handle all modes.


BINARY HDX TURNAROUND

Upon seeing turnaround from the other node, the first thing transmitted
shall be five (5) atsigns.  The first two may overlap with the trailing
turnaround characters from the other node, due to 3-out-of-5 majority
logic in detecting turnaround, but the last ones should be visible to
the other node, thus guaranteeing the UART is properly synchronized for
the LTBs to follow.  At the very end of a transmission, if HDX mode is
still in effect, five (5) brackets shall be transmitted, of the open flavor
"[" if node #1 is ending transmission, of the close flavor "]" if node#0
is ending transmission.  These brackets shouldn't be sent until a moment
before the node is ready to begin listening for the other node's subsequent
transmission.  (At most 5 character-times should elapse from starting the
third bracket until the node is all ears listening for the other node's stuff,
three of which are consumed by those three brackets and the remaining 2 of
which may be cpu time getting set up for reading.)  Note that HDX turnaround
(atsigns and brackets) is defined here the same as for Radix-41 transmissions.


%% End of sample of technical proposal