8.1 What is an Event Anyway?

An event is something of interest that occurs on the system or cluster. "Of interest to whom?" you might ask. Anyone, from the engineers who wrote the Tru64 UNIX and TruCluster Server products to everyday users, might have an interest in at least some of the events that EVM handles and dispatches. But EVM is not used for human interest alone. In fact, many applications use EVM to wait for events to occur and then act upon the information received. An event might be:

A system timestamp.
A task completed successfully.
A disk error occurred.
An application started.
A file system was mounted.
A system panic.

Let's see where events are defined and how to define our own.