EMS Manual

EMS Components and Architecture
EMS Manual—426909-005
2-7
Event Message Collectors
Event Message Collectors
EMS supports two types of event message collectors.
Primary Collector ($0)
Each system (or node) has only one primary event message collector, named $0. The
primary collector, initiated at system generation, provides a central collection point for
all events from all subsystems in a system. $0 uses the $ZOPR process to perform
waited operations. $ZOPR is a continuous process that, like $0, exists on every node
and is initiated at system generation. $ZOPR has no user interface and is used only as
described here.
Alternate Collectors
Alternate collectors offer an alternative to the central collection point provided by the
primary collector, $0. Alternate collectors provide functions similar to those supplied by
$0, but each alternate collector maintains its own log files. The separation of events
into several log files speeds up event processing because a network application
program does not have to read a single large file containing many events unrelated to
that application.
Some features of alternate collector usage are:

One or more alternate collectors can be started on a system.

An alternate collector is typically started by entering a TACL RUN command.

An alternate collector is a named process (or process pair) with a name you define
when you initiate it.

An alternate collector accepts EMS events sent to it rather than to the primary
collector.

An alternate collector writes tokenized events to a log file. This file is identical in
structure to the log files maintained by the primary collector.
Event Message Collector Functions
The primary and alternate collectors provide:

Subsystem support

Pre-log filtration (PLF)

Log file management

Distributor support