EMS Manual

Standard Events
EMS Manual—426909-005
9-9
Production Requests Requiring Operator Attention
These system-wide resources are better monitored outside the subsystems and
applications (making an individual subsystem or application unnecessary) by monitor
programs such as the Object Monitoring Facility (OMF):

CPU (percent busy)

Disk files (percent file full)

Disk volumes (percent volume full)

Transaction response time (in units of time)
Subsystems, applications, and monitor programs that generate Usage Threshold
events should provide for each object a configured high and a configured low usage
level, which dictate when the Usage Threshold event for an object is reported. An
operator should be able to configure these levels to control the type of resources and
the levels at which their usages are reported.
The configured low level indicates the threshold level to which the object utilization
must fall before its usage is reported (for example, measuring free disk space). The
configured high level indicates the threshold level that the utilization of an object must
reach or exceed before its usage is reported. Usage of an object is first reported when
it reaches the configured high level, then when it drops below the configured low level,
again when it rises above the configured high level, and so on.
Toggling between the configured high and configured low levels prevents many
simultaneous events from being reported if the utilization of the object hovers around
one of these levels. This algorithm follows the one defined by ISO in the document
ISO/IEC 10165-2 dated August 1991: “Information Technology—Open Systems
Interconnection—Structure of Management Information—Part 2: Definition of
Management Information.”
Production Requests Requiring Operator Attention
When a subsystem or application cannot continue its work until the operator takes
some action, an event message should be issued. Subsystems and applications that
control or use mechanical peripherals often have such situations; for example, when
tapes need to be mounted or when printers run out of paper.
Use the Operator Attention Needed event to inform the operator of what needs to be
done. Use the Operator Attention Completed event to tell the operator that the action
situation has been resolved. A typical scenario:
1. A subsystem encounters a problem for which operator assistance is required.
2. The subsystem creates and sends an Operator Attention Needed event message,
specifying the service that needs attention and an ID identifying this request.
3. A management application, such as ViewPoint, retrieves the event message and
displays the message for the operator.