priority scheduling

operating system Processes scheduling in which the

scheduler selects tasks to run based on their priority as

opposed to, say, a simple round-robin.

Priorities may be static or dynamic. Static priorities are

assigned at the time of creation, while dynamic priorities are

based on the processes' behaviour while in the system. For

example, the scheduler may favour I/O-intensive tasks so

that expensive requests can be issued as early as possible.

A danger of priority scheduling is starvation, in which

processes with lower priorities are not given the opportunity

to run. In order to avoid starvation, in preemptive

scheduling, the priority of a process is gradually reduced

while it is running. Eventually, the priority of the running

process will no longer be the highest, and the next process

will start running. This method is called aging.