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Browse Prior Art Database

Addressing Multiple Planes On Fixed Function Terminal

IP.com Disclosure Number: IPCOM000099723D
Original Publication Date: 1990-Feb-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Akiyama, AA: AUTHOR [+3]

Abstract

Described is a scheme for controlling multiple buffers within a display. A command addressing mode is defined to allow common operations for display buffers.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Addressing Multiple Planes On Fixed Function Terminal

       Described is a scheme for controlling multiple buffers
within a display.  A command addressing mode is defined to allow
common operations for display buffers.

      In fixed function terminals, it is common to have multiple
planes of data to represent each character position on the physical
screen. A plane which contains code points for the characters to be
displayed on the physical screen is referred to as a presentation
space (PS).  Additional planes which contain visual characteristics
of the characters in the PS (such as underscore, blink, highlight)
are referred to as extended attribute buffers (EABs).  It is not
uncommon for fixed function terminals with color to have a PS and two
EABs--one for base attribute quality (underscore, blink, etc.) and
one for color quality (red, blue, etc.).

      The traditional way to manipulate data, read data, or write
data to the PS or EAB is to encode within the command byte which
plane the command is to operate on.  Each command operates on only a
single plane at once.  In order to manipulate data in the PS and
EABs, multiple commands are sent to first manipulate the data in the
PS and then to manipulate the data in the EABs.

      For many situations, the data manipulation to be performed on
the PS and the EABs is identical.  EAB data and PS data are really
tied together, that is to say that an EAB character at a certain
row/column position within the EAB has meaning with the PS character
at the same row/column position within the PS.  Therefore, when
performing data manipulation (moves, inserts, d...