More features for TOPS-10 LISP.

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

    The REE control character interrupt kludge seems
    not to be necessary--it is possible to get TOPS-10 to
    do interrupts on entering characters using
    the Software Interrrupt  System. ...
I suspect that using this would be extremely expensive
in practice on TOPS-10, especially those with limited 
physical memory.  Also, this feature may not be available on earlier
TOPS-10's (HIC would know about this).  Finally, I would hope
that it works better than the ^C-trapping kludge, which we tried and
which failed miserably.
Sorry for being a pessimist -- Quux