Browse Prior Art Database

Intelligently Choosing Number And Size of Reads From a Display

IP.com Disclosure Number: IPCOM000101803D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 127K

Publishing Venue

IBM

Related People

Kiel, HG: AUTHOR [+3]

Abstract

Work Station Controllers (WSCs) provide attachment of multiple work stations to a host processor. Work stations can include displays, printers, or other types of devices. When a user at a display work station presses a keystroke requiring host processing (Enter, Roll Up, PF7, etc.), the WSC typically reads portions of the display screen into WSC memory, formats the data, and sends the formatted data to the host. This article describes how desired portions of the display screen can be grouped and read in a single read by including extra data between the desired portions of the display screen. Intelligently choosing the number and size of reads results in improved performance.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 50% of the total text.

Intelligently Choosing Number And Size of Reads From a Display

       Work Station Controllers (WSCs) provide attachment of
multiple work stations to a host processor.  Work stations can
include displays, printers, or other types of devices. When a user at
a display work station presses a keystroke requiring host processing
(Enter, Roll Up, PF7, etc.), the WSC typically reads portions of the
display screen into WSC memory, formats the data, and sends the
formatted data to the host.  This article describes how desired
portions of the display screen can be grouped and read in a single
read by including extra data between the desired portions of the
display screen.  Intelligently choosing the number and size of reads
results in improved performance.

      Work Station Controllers (WSCs) support multiple work stations
(W/S) using some type of W/S communication protocol.  Work stations
can include displays, printers, or other devices.  The function of
the WSC is to process host data streams, translate and process
keystrokes, build formatted data streams to be sent to the host,
etc..  A typical local WSC and attached work stations is shown in the
figure.  This disclosure also applies to remote WSCs (which are
attached to the host processor via a communication line instead of
system bus).

      When a user at a display presses a keystroke requiring host
processing (Enter, Roll Up, PF7, etc.), the following typically
occurs:
-  The WSC reads portions of the display screen into WSC memory,
formats and sends the data from the display screen to the host.
-  The host processor interprets the formatted data from the display
and sends a data stream to the WSC to build a new screen on the
display.
-  The WSC processes the data stream and writes the new screen to the
display.

      The sum of the time required for the above three steps is
frequently called display response time.  Previous WSCs have read
each input field into WSC memory, formatted the data, then proceeded
to read the next input field.  Each read has significant overhead and
the reads were a significant portion of the display response time.

      A display screen is divided up into input fields (the user is
allowed to key in these areas) and output areas (the user is not
allowed to key in these areas).  Input fields and output areas are
intermixed on the display screen.  When the user presses a keystroke
requiring host processing, the WSC reads the input fields from the
display screen into WSC memory, formats the data, and sends the
formatted data to the host for processing.  Depending of the type of
read command used, only modified input fields may need to be read;
unmodified input fields are then treated like output areas.

      Using this disclosure, the WSC reads input fields from the
display into WSC memory in groups, reading some output areas between
input fields along with the input fields. This can significantly
improve performance by reduc...