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From: jb10320@uxa.cso.uiuc.edu (Desdinova)
Newsgroups: comp.sys.apple2
Subject: Prizm Sucks!
Message-ID: <1990Dec1.082442.25195@ux1.cso.uiuc.edu>
Date: 1 Dec 90 08:24:42 GMT
Sender: news@ux1.cso.uiuc.edu (News)
Organization: University of Illinois at Urbana
Lines: 47

Derek Taubert and I were just working on porting some 3-D object viewer
software I wrote from an IBM RT to the GS.  We were having some problems
with the tool startup, so we figured since it was a desktop program we'd
compile it under Prizm and take advantage of the source level debugger.

Ha!

1) I loaded the file into memory (or so I thought).  Random bits of the
   file were trashed when I scrolled through the file.  First thing I
   figured was, "Well, maybe I have bad ram. My ramcard setup is pretty
   goofy."
2) So we looked thru all the blocks allocated to Prizm, to try and find
   the editor buffer so I could do some hand tests on the "bad" RAM.
   Much to our surprise, NONE of the blocks allocated to Prizm contained
   the file.
3) In a fit of impending anger towards what we imagined to be the worst
   programmer on the face of the earth, we did a bank by bank search of
   memory to locate the buffer. We found it. 
4) THE BLEEDIN' BUFFER WAS NOT ALLOCATED TO *A_N_Y_T_H_I_N_G*.  The file
   Prizm was supposed to be guarding was totally "free".  We verified this
   by making some toolbox calls (allocated the unallocated block just to make
   it 'ours', then trashing it to see the results- file go boom!) and
   by using MemoryBar to Compact memory.  Boom also.

So, to make a long story short, DON'T DEALLOCATE A BUFFER BEFORE YOU'RE
DONE WITH IT!!!!

I thought they taught that in my first year CS course, but maybe Mike
didn't attend an institution of higher learning (egads, even HIGH SCHOOL
level.)

Nothing personal, Mike.
Anyone have an Amiga for sale :-)
Or a shotgun?

Grrr... Unknown! I hope US SNAIL hurries up and gets that PMMU info to 
me so we can finally do some REAL programming with REAL tools on the GS.

Jawaid Bazyar
Derek Taubert

--
Jawaid Bazyar               | Blondes in big black cars look better wearing
Senior/Computer Engineering | their dark sunglasses at night. (unk. wierdo)
jb10320@uxa.cso.uiuc.edu    |      The gin, the gin, glows in the Dark!
   Apple II Forever!        |                             (B O'Cult)
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