ViewSys User's Guide

ViewSys Overview
ViewSys User’s Guide—526358-002
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Running ViewSys in NonStop Mode
impact on Measure is limited to the resources used by the program itself. Most of the
impact is the interprocessor communications necessary to gather individual processor
values. A moderate amount of arithmetic and the display code is performed in the
processor in which ViewSys executes. This version of ViewSys does not depend on
Measure recorders to produce the measurement data.
PEEK also uses the system tables accessed by ViewSys. ViewSys does not affect
PEEK statistics in any way. ViewSys might be slightly affected by the execution of a
PEEK INIT command, because this command initializes some of the counters used by
ViewSys. The impact to ViewSys is limited to only one measurement period.
Running ViewSys in NonStop Mode
Because ViewSys is an interactive terminal display utility, there is usually no need to
run it in NonStop mode. If an error causes ViewSys to terminate, simply restart it.
ViewSys can be run in NonStop mode by using the run time command, BACKUPCPU
n. However, it must be run as a named process. In NonStop mode, ViewSys
checkpoints only when the display mode is altered, using little system overhead. On a
switch to the backup process, the most recent display data is lost. NonStop coding was
implemented to provide display and monitoring continuity.