bus error

[dricci]

I have a Power Mac 8100/80 with two internal HDs, one 500MB and the other 250MB. On one of the drives I'm running 7.5.3, and on the other I was running 9.1. 9.1 was really slow, so I decided to downgrade. I booted from my 8.0 CD and formated the 9.1 HD, renamed it Mac 8.0 HD and installed. I then rebooted on the 8.0 HD and at startup I get "Sorry, a system error occured. bus error". I now get the same error when booting from the 8.0 CD. When I start with shift to turn off extentions, I have no problems on eather the CD or the HD booting. I tried reformating the HD and reinstalling 8.0, and the same thing happens, as well as the error when trying to boot from the CD.

I didn't have any problems booting 9.1 and I still don't have any problems booting the 7.5 drive. Any ideas what could be causing this bus error? I physically took out the 7.5 HD and tried booting with the same result, thinking there may have been a conflict. Thanks for your help!

 

[Dradts]

I've been having the same problems when I tried to downgrade from OS 9 to OS 8 on my old Performa 5300. I found several things that seemed to cause this error:

* DOWNGRADE UR HD DRIVER! (Most important in my opinion) Best thing would b to reformat ur OS 8 hd, overwrite all sectors wit 0's (zeros) and install OS 8's hd driver. Then run the OS 8 installer.
* Zap the Parameter Ram on System Startup
* Look for a system extension called "Macintosh Manager". If u can find it, remove it. If u can't find it, its probably not installed

Hope this will fix ur problems!
Cheers