VRM Handling of Key Sequences
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
By setting flags, the level 0 First Level Interrupt Handler (FLIH) of a Virtual Resource Manager (VRM) can indicate to a Virtual Machine (VM), which has received interrupts on the depression of the CNTL and ALT keys, that the keys have been released or, in the case where the VRM has determined that the key sequence does not request any VRM function, the third key scan code can be sent to the VM. Depressing the CNTL-ALT-PAUSE keys concurrently causes the system to reboot. Depressing CNTL-ALT and any other key than PAUSE concurrently causes the keyboard controller to generate a level 0 interrupt request to the central processor. The VRM level 0 FLIH gets control and reads the keyboard interface saving each scan code read. A function, such as the VRM Debugger, uses the keyboard as its input device in a non-interrupt mode.