•first-come-first-served (FCFS);

•first-in-first-out (FIFO)—often seen as a fair rule, especially by the customer, but in practice it leads to overall inefficiency;

•earliest-due-date (EDD) first—the job due out first is processed first: this ignores arrival times and processing times;

•shortest processing time (SPT) first—an ideal method for getting small jobs out of the way and minimizing work in progress, but it can make large jobs late and it ignores due dates and arrival times;

•longest processing time (LPT) first— this tends to increase work in progress and to make short jobs late;

•truncated shortest processing time (TSPT)—jobs that have been waiting longer than a predetermined time are given priority (if no work has been waiting long, SPT rules apply);

•critical ratio (CR)—this is the ratio of the time until the due date to the processing time: jobs with the lowest CR are processed first.