“…By limiting the number of active jobs in this class, control can be exercised over the number of concurrently active time sharing tasks. 6 Although this work appears to deal with job selection in a 'typical' batch system, in fact it deals with job selection in any system with limited resources. For example, in a virtual memory system which supports multiprogramming, jobs typically move through the waiting, ready and active states as described above, and there is usually an equivalent of the virtual processor, which serves as an agent which controls one active job.…”