Re: XL1200 Blasts thru FEP

[AI.gadbois@MCC.COM (David Gadbois)]

    Date: Fri, 4 Jan 91 13:40 CST
    From: ian@iexist.att.com

    I'm wondering if other XL1200 (or maybe Ivory in general) users are
    experiencing the phenomenon where the machine errors and blasts all
    the way thru the FEP, just as though the power had been cycled. The
    problem seems to be reproducable and related to some my code.
    Several (buggy) programs have manifested this behavior. It always
    happens in the same place (as far as I can tell given the effect). I
    may well be blowing the stack, but this sort of thing used to plop
    you in the debugger, where at least you had a clue as to where you
    were and what might be the problem.  I get no warning, just CRASH!

I have seen it on an XL400 under 8.0.1.  It is caused (reproducibly) by
passing a string argument to SI:HALT, as in

    (SI:HALT "Continue
")

Such forms are used by Rich Cohen's World Maker code.  The crash is
pretty spectacular.  Apparently, Lisp is passing a bogus string pointer
to the Ivory FEP.  This used to work on the Ivories and still does on
the 36xxs.  I have not heard back from customer service yet on their
progress in fixing this annoying bug.

--David Gadbois