Int 00  - Zenith - ROM Debugger                                            [G]

Desc:  invokes the ROM Debugger when at the BIOS level; equivalent to
     pressing Ctrl-Alt-Ins on booting.

Note:  since DOS revectors INT 00, it is necessary to restore this vector to
     its original ROM BIOS value in order to invoke the debugger once DOS
     loads

See Also: INT 03"Columbia"