System Launch and Monitor (SLM)

Runs on:

QNX Neutrino

Description:

System Launch and Monitor (SLM) is started early in the boot sequence to launch complex applications consisting of multiple processes that must be started in a specific order.

SLM is a utility controlled by a configuration file. The configuration file specifies any interprocess dependencies, the processes to run, and the process properties. For example, suppose a multimedia application needs the services of the audio subsystem and the database server, which in turn requires the Persistent Publish/Subscribe (PPS) service. When SLM learns of these one-way dependencies when reading the configuration file, the service internally constructs a directed acyclic graph (DAG). The DAG represents the workflow of the underlying processes and is sorted to produce a partial ordering for scheduling the processes so that all control-flow dependencies are respected. In this example, SLM would first verify that PPS is running before starting the database server, and then check that the database server is running before starting the multimedia application.

For more information about how to use SLM, see slm in the Utilities Reference.