PRB: Encountering an INT 01 with WDEB386

ID Number: Q64123

3.00

WINDOWS

Summary:

SYMPTOMS

When debugging an application with WDEB386, the program halts on a

breakpoint at an INT 01 instruction.

CAUSE

An INT 01 is coded into Windows in the Fatal_Error_Handler. This

interrupt is hit when some device driver is doing a fatal exit. The

INT 01 is there to make the debugger useful when diagnosing the

fatal error. INT 01 in virtual devices (VxDs) are generally ignored

(treated as NOP instructions) in the retail version of Windows.

However, if the debugger is installed, the system breaks into the

debugger.

RESOLUTION

Diagnose and correct the cause of the fatal exit.