Lisa Workshop: Eliminating LisaBug

For better or for worse, LisaBug is included in the Workshop in the form of
two files: SYSTEM.DEBUG and SYSTEM.DEBUG2. In version 1.0 of the software,
the mere presence of these two files enables the NMI key (non-maskable
interrupt) in the Office System. In later releases of the software, the
debugger may be invoked with the NMI key from the Workshop, or from the
Office System if you've come directly from the Workshop without first powering
down. It can be very distressing when uninitated users press the NMI key (the
minus sign on the keypad) and drop into LisaBug.

To deal with this problem with post version 1 software, power the system down
when you're done working in the Workshop and before you use the Office System;
alternatively, disable the debugger completely, as described below.

There are two ways to deal with this problem in version 1.0 of the Workshop:
change the NMI key code or disable the debugger. The first option is very
simple, but lasts only for the duration of the session. The next time you
boot your system, the NMI key code is reinitalized to the minus sign on the
key pad. To temporarily change the NMI key code for the session, use the
following procedure:

1. Enter the debugger by pressing the NMI key (minus sign on key pad).

2. Enter the command "NM 0" RETURN in response to the debugger prompt of
">". This sets the key code from hex 21 (the minus key) to hex 0 (no
key)*.

3. Type a "g" RETURN to go back to your starting point.

To respecify the NMI key, specify the key location--not the ASCII code
--for the character you want. The table listing the key codes is in the
Pascal Language Reference Manual.

To disable the debugger, you have three options:

A. Delete SYSTEM.DEBUG and SYSTEM.DEBUG2.

B. Change the names of the two files to something besides names starting
with SYSTEM.xxxx. (This allows for easy restoration at a later time.)

C. Transfer the two files to floppy, thus freeing up the disk space until
you wish to restore the debugger.

Note: you must reboot the system before these changes are effective.
Published Date: Feb 18, 2012