Browse Prior Art Database

Forward And Backward Edge Trigger Entry Fields

IP.com Disclosure Number: IPCOM000102627D
Original Publication Date: 1990-Dec-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 89K

Publishing Venue

IBM

Related People

Eagen, ST: AUTHOR [+3]

Abstract

In a computer system with work station controllers (WSCs) which control the attachment of non-programmable terminals (NPTs), generally neither NPTs nor WSCs support local scrolling of additional panel data outside the display screen. Therefore, scroll up/down or scroll left/right keys are used when the panel contains more rows or columns than would fit on the NPT display screen. Users then must switch back and forth between the primary keys used for the particular application and scroll keys. This article describes how the NPT display data stream and the work station controller can be enhanced to provide automatic scrolling requests to an application.

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This is the abbreviated version, containing approximately 52% of the total text.

Forward And Backward Edge Trigger Entry Fields

       In a computer system with work station controllers (WSCs)
which control the attachment of non-programmable terminals (NPTs),
generally neither NPTs nor WSCs support local scrolling of additional
panel data outside the display screen.  Therefore, scroll up/down or
scroll left/right keys are used when the panel contains more rows or
columns than would fit on the NPT display screen.  Users then must
switch back and forth between the primary keys used for the
particular application and scroll keys.  This article describes how
the NPT display data stream and the work station controller can be
enhanced to provide automatic scrolling requests to an application.

      The figure illustrates the flow of display panel data between
an application program and a NPT in a typical system.  The host
display data manager builds a physical data stream representation of
a display panel and passes it to the WSC for presentation.  The WSC
controls the physical attachment of multiple NPT devices.  Each NPT
consists of a keyboard and display monitor and has limited processing
capability.

      Entry fields are defined in the NPT data stream by using Start
Field (SF) orders.  The SF order can contain one or more optional
Field Control Words (FCWs).  The forward or backward edge trigger
entry field functions are provided by enhancing the NPT data stream
to include two new FCWs.  The WSC will inform the host when a forward
or backward field exit occurs in the direction specified for an edge
trigger entry field.  Applications or a typical operating system can
then define when a specific entry field exit should cause an
automatic scrolling request back to the application or operating
system.  The display screen can then be updated with additional panel
data scrolled in the direction indicated.  Note:  both forward and
backward edge trigger FCWs are allowed for an entry field.

      WSC support for the forward and backward edge trigger functions
involves the following:
-  The WSC will accept the forward and backward edge trigger F...