Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!pasteur!agate!labrea!polya!rwilson
From: rwilson@polya.Stanford.EDU (Randy Wilson)
Newsgroups: comp.sys.mac.programmer
Subject: System 6.0 and 2nd screen
Message-ID: <3316@polya.Stanford.EDU>
Date: 20 Jul 88 08:03:29 GMT
Reply-To: rwilson@polya.Stanford.EDU (Randy Wilson)
Organization: Stanford University
Lines: 22

I have been writing a Mac video game for some time, and just got around to
testing it on system 6.0.  When it starts writing to the 2nd graphics screen,
it crashes, id=02.  It turns out that BufPtr is in the middle of the 2nd
screen, so I assume I am trashing info in high memory; it worked on all 
previous systems.  Further, the launch call to allocate the 2nd succeeds, and
moves globals, etc down as if clearing the way to use the 2nd, but still
dies.

I have the Ramcache off and am using no INITs other than the ones in the
system as distributed.

Does anyone know what Apple has put in high memory?  Have they finally made
good on their threat to mangle programs that use the 2nd screen?  If so, why
do they allow the Launch call to succeed, instead of failing there??  Is
there a way around this problem?  

If I can't fix this, I'll have to just tell people to use another version of
the system file, unless they're on a II (it works fine there, since it
follows all rules on the II).

Thanks in advance,
Randy
rwilson@polya.stanford.edu