Tunable parameters are system parameters which affect system behavior and capabilities. They are used to configure the kernel and the included features, to change their behavior, and adapt them to your needs. Typical examples of tunables are: maximum number of kernel objects, scheduler type and attributes for threads, or system clock frequency. Each system component or feature defines a number of these tunable parameters.
Static parameters are tunable parameters whose values are permanently set within a system image. Changing these values requires rebuilding the system image.
The procedure for assigning new values to tunable parameters is detailed in "Changing Tunable Parameter Values".
For some tunable parameters, an additional flexibility is offered: the ability to assign values to these parameters at various stages of system production and execution. These types of parameters are called dynamic parameters. These dynamic parameters define the system environment.
Dynamic parameters form a system-wide environment. A basic set of services allows this environment to be constructed and consulted within a system image, at boot time and runtime.
Compared to static parameters, dynamic parameters require additional target data memory in order to store their names and values.
The procedure for modifying dynamic parameters is detailed in "Modifying the System Environment".