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VRM Handling of Key Sequences

IP.com Disclosure Number: IPCOM000062388D
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Greenberg, MS: AUTHOR [+2]

Abstract

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.

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VRM Handling of Key Sequences

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. When the user releases the CNTL and ALT keys in order to interface with the Debugger, the VRM Keyboard Device Driver (KDD) receives no interrupt. The VM, which owned the virtual terminal when the CNTL and ALT keys were depressed, received notification of that via virtual interrupts. Upon exit from the VRM function, there needs to be a way to notify the VM that the CNTL and ALT keys have been released. Also, in the case where the key sequence is not for any VRM functions, the scan codes read must be available to the VM that owns the viewed virtual terminal. The solution to these problems is for the FLIH to set flags to...