Browse Prior Art Database

Use of a Line Image Buffer in Controlling Unintelligent Display Stations

IP.com Disclosure Number: IPCOM000060428D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Applegate, RL: AUTHOR [+4]

Abstract

This invention provides for using a data-processor oriented dependent display station for word-processing functions in a manner that optimizes the overall performance of the displays. Host processor 10 contains the word-processing programs. Work- station controller (WSC) 20 holds part of the document, and communicates with host 10 by channel 11. WSC 20 is an I/O processor, and controls display terminals 30. Since many word-processing functions are line oriented, the WSC microcode that supports these functions maintains a memory buffer which contains the contents of the line the cursor is currently positioned on. This buffer, the Line Image Buffer (LIB) 21, is only updated when the cursor is positioned on a new line and a key is pressed that requires knowledge of the data on the line on the screen.

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Use of a Line Image Buffer in Controlling Unintelligent Display Stations

This invention provides for using a data-processor oriented dependent display station for word-processing functions in a manner that optimizes the overall performance of the displays. Host processor 10 contains the word-processing programs. Work- station controller (WSC) 20 holds part of the document, and communicates with host 10 by channel 11. WSC 20 is an I/O processor, and controls display terminals 30. Since many word-processing functions are line oriented, the WSC microcode that supports these functions maintains a memory buffer which contains the contents of the line the cursor is currently positioned on. This buffer, the Line Image Buffer (LIB) 21, is only updated when the cursor is positioned on a new line and a key is pressed that requires knowledge of the data on the line on the screen. The status of the LIB (current or obsolete) is indicated by a bit named Line_Image_Obsolete. This bit is set on whenever the cursor is moved to a different line. Every microcode module that processes keystrokes for the display checks this bit before using the contents of the LIB. If the bit is on, a module is called that updates the LIB by reading the line the cursor is on from the display screen into the LIB. The Line_Image_Obsolete bit is required to avoid updating the Line Image Buffer (which is a performance degrading operation) when not necessary. For example, if the LIB is current from a prev...