- SCHED_FIFO - standard priority.
- Higest priority.
- No time-slice
- "supervisor" processes only
- SCHED_RR - priority round robin.
- Highest priority RR runs for 1 time slice.
- "supervisor" processes only
- SCHED_OTHER - time-sharing
- POSIX 1003.4
- All Linux user processes
- Higest priority.