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Q82665: Causes of System Integrity Errors in Windows 3.1

Article: Q82665
Product(s): Microsoft Windows 95.x Retail Product
Version(s): WINDOWS:3.0,3.0a,3.1,3.11
Operating System(s): 
Keyword(s): 
Last Modified: 25-SEP-1999

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The information in this article applies to:

- Microsoft Windows versions 3.0, 3.0a, 3.1, 3.11 
- Microsoft Windows for Workgroups versions 3.1, 3.11 
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SUMMARY
=======

System Integrity errors are caused by unexpected CPU faults. The following
information provides a general overview of CPU fault causes. For more
information, refer to your Intel 80386 CPU manual or "The 80386 Book," by Ross
P. Nelson (published by Microsoft Press).

MORE INFORMATION
================

The following are some of the more common CPU faults:

- Invalid opcode

- Stack exception

- General protection (GP) fault

- Page fault

NOTE: Not all occurrences of these faults are invalid. Valid, expected faults
occur from all of the above except stack exceptions.

Invalid Opcode
--------------

An invalid opcode fault occurs when an instruction that is not legal is executed.
The most frequent cause of this invalid fault is executing a value that is not
an instruction.

Stack Exception
---------------

A stack exception fault occurs when an invalid stack operation is attempted. The
most frequent cause of this invalid fault is trying to PUSH or POP a WORD or
DWORD at an address that causes the operation to span across SP value 00000h or
0FFFFh. For example, attempting to POP a WORD with SP=0FFFFh, is attempting to
read one byte of the WORD at offset 0FFFFh and the other byte of the word at
offset 00000h. The CPU does not support this operation.

General Protection (GP) Fault
-----------------------------

Many things can cause a GP fault. As the name implies, this fault means something
was attempted that is not allowed because it would violate the protection
features built into the CPU. As with invalid opcode faults, a typical cause of
this invalid fault is executing garbage, but unlike the invalid opcode, the
instruction is legal; however, the particular form of the instruction is illegal
at the time.

Page Fault
----------

A page fault occurs when an access is made to memory that is not currently
mapped, (not currently available). The most frequent causes of this invalid
fault are wild pointer accesses to memory that is not legal to look at in the
current time frame. This is often a manifestation of "protection." For example,
a device wants to protect a piece of memory, always, or at the current time, so
that only that particular device can use it. It makes the memory unavailable by
using the paging features of the CPU so that any application that tries to read
or write to this memory will be stopped by an invalid page fault. This helps
prevent the wild pointer in the application from damaging critical information
in memory.

Additional query words: 3.00 3.00a 3.10 crash drwatson

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Keywords          :  
Technology        : kbAudDeveloper kbWin3xSearch kbWFWSearch kbZNotKeyword3 kbWin300 kbWin300a kbWin310 kbWin311 kbWFW310 kbWFW311
Version           : WINDOWS:3.0,3.0a,3.1,3.11

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