[comp.sys.mac.programmer] Bad slot numbers

fry@brauer.harvard.edu (D. Spotts Fry) (10/27/89)

A couple of weeks ago I posted code to use a VBL task tied to
a slot interrupt and a Mac II video card to do smooth
animation.  This involved calling GetVideoDefault() at the
beginning of the program to find the slot number of the
startup video card.

Since then, some program or init or other messed up my
computer's startup information so that GetVideoDefault was
returning a slot number of 96(!!), not in the required 9 to 14
range.  Passing 96 to SlotVInstall then failed.  

I used the Monitors cdev to fix things up, but my question 
is how should I program for this?  What should I do if I get a
strange slot number for the default video.  How does the
system handle it itself at boot time?

David Fry				fry@huma1.harvard.EDU
Department of Mathematics		fry@huma1.bitnet
Harvard University			...!harvard!huma1!fry
Cambridge, MA  02138