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Keystroke-Filtering Method for IBM Personal Computers Disclosure Number: IPCOM000064403D
Original Publication Date: 1985-Jul-01
Included in the Prior Art Database: 2005-Feb-18

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Bracht, CJ Fichtner, LG [+details]


A method is described for filtering keystrokes on the IBM Personal Computer (PC) in which a software routine determines if a keystroke is typamatic by reference to the "timer tick interrupts" of the PC. The IBM Personal Computer hardware supports all keyboard keys as typamatic. This means that once a key has been depressed, 'keystroke data' for the particular key will continue to be generated approximately every 100 milliseconds. This function can cause a problem when the operator is using certain outboard keys. An example would be when the operator is typing in the "text" mode and wants to page forward multiple pages. If the application is processing keystrokes slower than the hardware typamatic rate, this results in a number of keystrokes being queued.