Browse Prior Art Database

SCREEN REFRESH METHOD

IP.com Disclosure Number: IPCOM000023587D
Original Publication Date: 1978-Apr-30
Included in the Prior Art Database: 2004-Mar-31
Document File: 2 page(s) / 277K

Publishing Venue

Xerox Disclosure Journal

Abstract

As is known, it is necessary to "refresh-data displayed on a CRT since the persistence of the data is low, Typically, the data is refreshed about 60 times per second, In accordance with this disclosure, the main memory 12 of a display-type computer system 10 also including a CRT display 14 has an address table containing 24 addresses. Each address points to a stream of data bytes also stored in memory and which represents anywhere from 1 to 1920 (whole page) char-acters, There are 80 characters per line and 24 lines per page display. If the data stream pointed to for a particular address has less than 80 characters, a carriage return byte is stored at the end of the data stream. In this manner, the next address in the table is immediately consulted for display of the next line(s) of characters,

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 77% of the total text.

Page 1 of 2

XEROX DISCLOSURE JOURNAL

SCREEN REFRESH METHOD
ProposedGeorge L~ Powers Classification

U~S. C1~ 315/1
Int, C1~ HOlj 23/34

As is known, it is necessary to "refresh~ data displayed on a
CRT since the persistence of the data is low, Typically, the
data is refreshed about 60 times per second,

In accordance with this disclosure, the main memory 12 of a
display~type computer system 10 also including a CRT display
14 has an address table containing 24 addresses. Each address
points to a stream of data bytes also stored in memory and
which represents anywhere from 1 to 1920 (whole page) char-~
acters, There are 80 characters per line and 24 lines per page
display. If the data stream pointed to for a particular
address has less than 80 characters, a carriage return byte is
stored at the end of the data stream. In this manner, the next
address in the table is immediately consulted for display of
the next line(s) of characters,

If the first address points to the entire page of 1920 char~
acters, then no carriage return byte is used as the characters
will be displayed serially with automatic carriage return,
The purpose of using a carriage return byte with a data stream
less than 80 characters is so the entire line need not be
scanned if only 20 or 30 characters, for example, have to be
displayed,

7/0

Volume 3 Number 2 March/April 1978 109

[This page contains 1 picture or other non-text object]

Page 2 of 2

SCREEN REFRESH METHOD (Cont~d)

When the last address in the table is consulted or the ent...