SUSPEND/GC bug: OPSYFT

[Jon L White <JONL at MIT-MC>]

    Date: 15 October 1981 22:31-EDT
    From: Jonathan A. Rees <JAR at MIT-MC>
    To: BUG-LISP at MIT-MC
    The location OPSYFT in list space is clobberred by the startup code
    that gets run after a suspend happens.  However, that list cell is
    subject to garbage collection; if it can get on the freelist (it can; 
    don't ask me how ...), the cell can get allocated for another use
    before the SUSPEND, and clobberred after.
What you probably did to get that cell gc'd was something like
(SSTATUS NOFEATURE TOPS20) -- that's about the only way to cause that
cell to be cut out of the features list.  At any rate, the correct
thing to do (which I've just done by editing the sources) is to
have the three critical status options (namely OPSYSTEM-TYPE, SITE,
and FILESYSTEM-TYPE) be in a non-reclaimable part of list space.