NOTE: These notes are adapted from those of Allan Gottlieb, and are reproduced here with his permission.

================ Start Lecture #5 (Feb. 5)

Scheduling (Continued)

Selfish RR (SRR, **, SRR, **)

Highest Penalty Ratio Next (HPRN, HRN, **, **)

Run the process that has been ``hurt'' the most.

Multilevel Queues (**, **, MLQ, **)

Put different classes of processs in different queues

Multilevel Feedback Queues (FB, MFQ, MLFBQ, MQ)

Many queues and processs move from queue to queue in an attempt to dynamically separate ``batch-like'' from interactive processs.

Theoretical Issues

Considerable theory has been developed.

Medium-Term Scheduling

In addition to the short-term scheduling we have discussed, we add medium-term scheduling in which decisions are made at a coarser time scale.

Long Term Scheduling

Creating a process

See Tanenbaum pp. 691-696 for Unix; pp. 799-800 for Window.

2.2: Interprocess Communication (IPC) and Process Coordination and Synchronization

2.2.1: Race Conditions

A race condition occurs when two processes can interact and the outcome depends on the order in which the processes execute.