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Updating of Displayed Data From a Shared Data Store

IP.com Disclosure Number: IPCOM000100046D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Dickson, DW: AUTHOR [+2]

Abstract

In a windowing system that supports a number of in- tegrated applications, there is the need to update the display of variables held in a shared data store. In the system described here, all the applications run on a single thread of control such that user input is accepted only when all applications have completed processing. This point in time, at which the system drops into a wait state waiting for user input, is called the 'Wait State'. An application can define a field within one of its windows, specifying that a stored variable is displayed. Immediately before the Wait State is entered, the display manager checks every field on the screen and updates it if it is displaying a variable whose value has changed since the last Wait State. This relieves applications of the burden of keeping displayed values up to date.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 66% of the total text.

Updating of Displayed Data From a Shared Data Store

       In a windowing system that supports a number of in-
tegrated applications, there is the need to update the display of
variables held in a shared data store.  In the system described here,
all the applications run on a single thread of control such that user
input is accepted only when all applications have completed
processing.  This point in time, at which the system drops into a
wait state  waiting for user input, is called the 'Wait State'. An
application can define a field within one of its windows, specifying
that a stored variable is displayed.  Immediately before the Wait
State is entered, the display manager checks every field on the
screen and updates it if it is displaying a variable whose value has
changed since the last Wait State.  This relieves applications of the
burden of keeping displayed values up to date.

      Every variable has a 'changed' flag associated with it, which
is set to 'true' by the data manager when the variable is updated.
There is also a function of the data manager to reset ALL 'changed'
flags to 'false'.  The display manager tests the 'changed' flag of a
variable to determine whether the variable has changed.  It uses this
test immediately before the Wait State, when it is testing every
field on the screen, and updating as necessary.  After the screen has
been updated, the display manager calls the data manager function to
reset all 'changed' flags.  This is th...