TOPIC
After installing Mac OS 8.5, my computer now crashes with a System Error Type 7. If I start up the computer with extensions off, it runs fine. What is wrong?
DISCUSSION Solution Most of the reports of this type have involved third-party extensions. Normal extension troubleshooting will usually find the problem extension. Contact the vendor of the software regarding compatibility and upgrades. You can probably work around the problem by enabling virtual memory. Explanation An Error Type 7 is a privilege access error and is generated when trying to execute a privileged instruction on the emulated 68k processor when the processor is in user mode. Privileged instructions require the processor to be in supervisor mode. Mac OS 8.5 changed the state of the processor. With virtual memory disabled, the emulated 68k processor runs in user mode. In previous versions of the OS, the emulated 68k processor ran in supervisor mode with virtual memory disabled. Software that tests whether virtual memory is disabled or enabled and then assumes what state the processor is in based on this may crash. Enabling virtual memory may be a successful workaround, since the emulated 68k processor always runs in user mode with virtual memory enabled. The software should check the state of the processor before making privileged calls. For a more detailed explanation of this change, please see Tech Note 1142. (In particular, the General section of the chapter titled, "Inside the System File.") The following article can help you find the Tech Note mentioned here: Article 24493: " Apple Tech Notes: What They Are, Where To Find Them " |
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| Document Information | |
| Product Area: | Mac OS System Software |
| Category: | Mac OS 8.5 |
| Sub Category: | Troubleshooting |
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