EMS Manual

EMS Components and Architecture
EMS Manual—426909-005
2-11
EMS Filters
The compatibility distributor has no interactive or programmatic command interface of
its own. It is controlled indirectly through commands to the primary collector. The
primary collector can be instructed, through its own commands, to change certain
parameters that affect the compatibility distributor.
Compared to other types of distributors, the compatibility distributor has a few simple
characteristics:

Its source of event messages is always the current primary collector log (or logs,
on a network)—not the saved log files.

The console prints or displays each message in the DSM display format. The pre-
EMS compatible format is not supported.

It has a selection criterion, CRITICAL-ONLY, which you can set to ON or OFF:

When CRITICAL-ONLY is ON, the compatibility distributor suppresses the
printing of certain operator messages on the operator console. This setting
decreases the number of noncritical messages displayed on the console,
particularly during a system load. The messages that are suppressed are
numbered operator messages, subsystem EMS, event number 6 (LDEV UP),
141 (CLIP DOWNLOADED), and 150 (CSS ACTIVATE PATH).

When CRITICAL-ONLY is OFF, the compatibility distributor displays all
messages.

You can set the selection criterion during system generation. If you do not set the
selection criterion at system generation, the value CRITICAL-ONLY ON is used as
the default. You can use EMSCCTRL to change the selection criterion after the
distributor is started.
EMS Filters
Every EMS collector and distributor (except the compatibility distributor) can use one or
more filters to determine whether to forward specific event messages to their
destinations. These filters can select messages in a way that is as detailed and
complex as you want. For example, you can design an alternate collector that filters
out all events of a certain type from its event log, a forwarding distributor that forwards
only critical event messages, a printing distributor that prints only action event
messages, and a consumer distributor that returns only Pathway event messages.
EMS collectors and distributors can use three types of filters.
Compiled Filters
You generate compiled filters from filter source statements contained in an EDIT file
written in the Event Management Service filter (EMF) language. You then compile this
filter specification to create the filter, which is returned as an object file. For details on
writing compiled filters, see Writing and Compiling Filters
on page 5-1. For full