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Deferred Update of Cursor-Dependent Fields on Unintelligent Display Stations

IP.com Disclosure Number: IPCOM000060451D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 13K

Publishing Venue

IBM

Related People

Hart, RJ: AUTHOR [+4]

Abstract

This invention provides the capability of displaying cursor-dependent status fields on dependent display stations without severely degrading performance. In a word processing environment, there are a number of fields on a display screen that need to be updated based on the cursor position. However, updating these fields on each keystroke potentially causes an unacceptable performance burden on the I/O processor (Work Station Controller (WSC) if the operator is keying at a fast rate. If updating these fields is deferred until the cursor has come to rest for a small period of time (100 to 200 milliseconds), the performance burden is considerably reduced at the expense that the fields are not always current.

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Deferred Update of Cursor-Dependent Fields on Unintelligent Display Stations

This invention provides the capability of displaying cursor-dependent status fields on dependent display stations without severely degrading performance. In a word processing environment, there are a number of fields on a display screen that need to be updated based on the cursor position. However, updating these fields on each keystroke potentially causes an unacceptable performance burden on the I/O processor (Work Station Controller (WSC) if the operator is keying at a fast rate. If updating these fields is deferred until the cursor has come to rest for a small period of time (100 to 200 milliseconds), the performance burden is considerably reduced at the expense that the fields are not always current. This is acceptable in a power-typing mode, since the operator is looking at the text to be keyed in, or the words just typed on the screen, and not at the fields that are dependent on the cursor position. The implementation of this function on the System/36 WSC is called Deferred Function (DF). This deferred function is used to update three fields on a word processing screen, the audit window, the scale line, and the line number. All of these fields are sensitive to the cursor position and both need to be updated frequently. During normal keystroke-processing operations, the WSC polls the displays for keystrokes every 32 milliseconds. If a scan code is received in response to the poll, indicating a key has been pressed on the display station keyboard, the scan code is processed by the WSC keystroke-processing logic. If no scan code is returned (no key has been pressed in the last 32 milliseconds), a count called the DF count is incremented. This count effectively indicates the amount of time the operator has not pressed any key in increments of 32 milliseconds. The count is compared to a trigger constant to determine whether the DF f...