Browse Prior Art Database

Validity Mask Processing of Keystrokes

IP.com Disclosure Number: IPCOM000088995D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Prokop, CJ: AUTHOR

Abstract

In a keyboard input processing system, certain applications may require that some keystrokes be inhibited from processing and other keystrokes be included as a valid key group. This has been accomplished by providing multiple overlays on the keyboard distributor random-access memory area in order to specify empty and nonempty locator elements correct for the application. However, that technique is wasteful in that multiple and often redundant overlays are required.

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Validity Mask Processing of Keystrokes

In a keyboard input processing system, certain applications may require that some keystrokes be inhibited from processing and other keystrokes be included as a valid key group. This has been accomplished by providing multiple overlays on the keyboard distributor random-access memory area in order to specify empty and nonempty locator elements correct for the application. However, that technique is wasteful in that multiple and often redundant overlays are required.

The technique described herein provides for the allowance or inhibition of keystroke processing using a single completely defined keyboard distributor overlay and a group of validity masks which identify a key or grouping of keys that are allowed for subsequent processing or handling.

Rrferring to the figure, the depression of an entry key 1 selects an address in the keyboard distributor 2 which points to the key handler routine for the desired function. The keyboard overlay 3 provides the keyboard distributor 2 with all the possible keystroke processing and handling locator elements for the particular key group.

J key group validity masks 4 are provided which correspond to sets of the defined N locator element positions within the keyboard distributor area. For each unique, valid key group within an application area which allows the processing of N keystrokes, there exists G bits uniquely corresponding and identifiable to the G locator elements which are set to a...