langer@gibbs.uchicago.edu (Steve Langer) (04/23/91)
Hi --
Can anybody verify this? I think I've found a bug in the 6.0.5
system software. Following the following procedure crashes
my Mac (a IIcx with Apple's 13" RGB Monitor and 8 bit video).
The problem persists when all inits are removed. I disconnected
my hard disk and booted from a newly made system floppy and
it still crashes. I tried it on a Mac II with the same result.
Here's the procedure. If someone could try it out and tell me that
I'm not crazy, I'd appreciate it.
1) (Optional) Make a system floppy with no extras.
2) Boot with multifinder, either from the hard disk or the floppy.
3) Open the control panel.
4) Change all the white pixels in the background pattern to gray.
(Double click on the green square to bring up the color picker,
click in the center of the wheel to make it gray, click OK, then
click on all the white pixels in the desktop pattern.)
5) Close the control panel.
6) Open the control panel.
7) Choose the Monitors cdev.
8) Choose Undo from the Edit menu. This crashes the machine.
In step 4 the particular pattern chosen seems to be important. Just
creating a random pattern does not usually lead to a crash. The recipe
given for creating a gray pattern always leads to a crash, as far as
I can tell.
In step 7 you can substitute some (but not all) other cdev's. I know
that ApplicationMenu also crashes.
In step 8 I think that any command from the Edit menu will work. I always
used Undo when looking for the problem just to be consistent. (I know that
there's no reason to Undo something in the Monitors cdev, but I was being
clumsy the day I first discovered this.)
The important thing seems to be the state of the background pattern when
the control panel is opened. If you boot the machine with a bad pattern
and change it to the standard black and white checkerboard, it will still
crash on steps 7 and 8, unless you close and reopen the control panel.
Comments? Does this happen with 6.0.7? With 6.0.x (x < 5)? With 7.0?
-- Steve (langer@control.uchicago.edu)