Re: IFU on 3600

["K. Mark Alexander" <kma@samson.cadr.dialnet.symbolics.com>]

    Date: Fri,  2 Dec 88 14:05:08 EDT
    From: MILLER@vax.cam.nbs.gov

    In response to discussion about 3600's with IFU.
	    We've got an older 3600 which we upgraded with the IFU around
    Rel 6.1 time.  After the initial period of board swapping, it worked
    fine and the performance gain was, all in all, worthwhile (although it
    wasn't quite the 50% implied). 
	    However, after Genera was installed, we started getting
    mysterious bugs similar to what you are experiencing: After a number of
    hours of hard symbol (and number) crunching, the machine would go into
    the debugger. It was always the same error; a NIL ended up in the
    arglist where a number had been in the internal function
    SI:ARITHMETIC-FUNCTION-PLUS-BIGNUM-BIGNUM. I really can sympathize with
    the `Frustration factor': I came in many a morning expecting to see
    wonderful results from an overnight run and !)@#*)!@*#.  The bugs went
    away when I rebooted Rel 6.1 (ugh).
	    Happy ending: Nobody seemed to have a clue at Symbolics or
    elsewhere what it might be, but Dave Plummer came up with a suggestion,
    bless his heart. It seems that swapping boards randomly missed the
    point. There existed, at that time, a magical list of `compatible' rev
    levels for various boards.  With CPU board ver. X and Foo board ver. Y,
    then you should use IFU board ver U, and XSQ board V. In hindsight it
    seemed obvious, but in foresight it apparently wasn't. In any case, the
    machine has been working like a charm ever since. Except the console is
    flaky again, but thats another story....
			    Bruce Miller
			    MILLER@VAX.CAM.NBS.GOV

GREAT! Where do I find this magic list of `compatible' rev levels?