Re: ROM 1 better than ROM 3?

[David A Lyons <dlyons@apple.com>]

In article <3b6p6d$2rd@news.service.uci.edu> Trangdaithi Hoang,
thoang@orion.oac.uci.edu writes:
> DOCVu 2.0 works fine on a ROM 3 as long as you don't move the mouse.
> Moving the mouse messes up the screen.  I've been told by a Digital
> Exodus member that DOCVu 2.0 doesn't access the mouse and that it
> might be caused by the differences in how the ROM 1 and ROM 3 shadow 
> memory.  There's also at least one new program in the works that has
> a similar graphics problem.  It also has a mouse problem with DOCVu
> 2.0 loaded.  The ROM 1 has no problems running these programs.

It sounds like the application is assuming that the Super Hi-Res
screen lives in bank $E1, which is not the case if shadowing is
enabled.  There's at least one GS technical note that talks about
this...the one that talks about CloseView compatibility...might have
"Universal Access" in the title.

You might or might not be able to get the app to work better by
removing CloseView from your system.  If that doesn't do it, the app
could be -asking- for shadowing in QDStartUp (in which case it would
be surprising if they were writing directly to the $E1 screen).

Yes, there are differences in how ROM 1 vs ROM 3 QuickDraw track the
mouse cursor.  It's not a problem with properly-written applications. 
ROM 1 always draws the cursor in bank $E1, but ROM 3 notices whether
Super Hi-Res shadowing is enabled, and if so it draws the cursor in
bank 1.

Dave Lyons
Mr Tangent