TOPS-20 Interrupts

[GLS at MIT-AI (Guy L. Steele, Jr.)]

^S is weird in thhat it is BOTH an inteerrupt character and a macro
character.  I forget whether this is difficult or impossible to
do on a -20.  In any case, it is like ^W as an interrupt character
and like ^V and then a TERPRI as a macro character.  It should not
affect ^Q -- a primary use of it is to "turn off output until
my UREAD file is loaded" after seeing the first few bits of output.
JONL is of course correct in seying that ^Q should not be an interrupt
character.  (There is some question in my mind as to whether ^R and
^T should be interrupt characters as well!  But soomeone else can
argue thhat -- I don't care too much.)