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Algorithm For Multi-Scrolling On A Display Terminal

IP.com Disclosure Number: IPCOM000053491D
Original Publication Date: 1980-Jan-01
Included in the Prior Art Database: 2005-Feb-12

Publishing Venue

IBM

Related People

Authors:
Stredwick, JB [+details]

Abstract

The algorithm described here is used to implement local scrolling by one or more lines on a display terminal. The display and consequently the contents of its refresh buffer are under control of a microprocessor. screen may be divided into multiple partitions, and each partition is bounded by left hand and right hand margin attributes. Each partition potentially has associated with it a scrolling buffer which contains that part of the presentation space data which is not currently in the viewport. The scrolling buffer for any partition is divided into two areas, Area A (above viewport) and Area B (below viewport), separated in memory by sufficient storage to contain a single row of characters for the partition plus the left hand margin attribute. This is represented diagrammatically in Fig. 3.