Microsoft KB Archive/70056

“Break Caused by NMI” Message Displayed by CodeView ID Number: Q70056

3.00 3.10 3.11 3.14 MS-DOS

Summary:

When running real-mode CodeView (CV.EXE) version 3.0 or later, the message “Break caused by NMI” may occur. This message is caused by a call to INT 2H (interrupt 02H is defined as the NMI – the nonmaskable interrupt).

INT 2H is usually invoked by a memory parity error, but it may also be generated by an add-on hardware debugger with a “break” switch. CodeView traps this interrupt and displays the above message in the command window. You can still continue to debug the program following the break.

To turn off trapping of the nonmaskable interrupt and 8259 interrupts, run CodeView with the /I0 option. To disable the trapping of the NMI only, use the /N0 option.