Generalized multiprocessing and multiprogramming systems

• Authors: A. J. Critcklow
• Venue: AFIPS '63 (Fall) Proceedings of the November 12-14, 1963, fall joint computer conference
• Year: 1963

In this paper, the following definitions have been followed: 1. Multiprogramming---the time-sharing of a processor by many programs operating sequentially. Many programs are available and in memory but only one program is actually being executed at a given time. Control of object programs is provided by a supervisory control program. Thruput is highest when many programs can be interleaved to use hardware most efficiently. In general, the time required to complete a selected program will be increased over single program operation. 2. Multiprocessing---independent and simultaneous processing accomplished by the use of several duplicate hardware units. Specifically, duplicate logical and arithmetic units are assumed, although systems with separate input-output channels can also be said to be multiprocessors. Note that "processors" do not include storage units while "computers" do. (Table 1.2.2) 3. Scheduling---is the determination of the sequence in which job programs will use the available facilities. Scheduling assignments are based on the availability of all required facilities, the priority of the job program and the relative priorities of other programs. Scheduling algorithms aim to optimize performance of the system with respect to chosen goals. 4. Allocation---is the assignment of particular facilities: core memory, tapes, disk files to a job program. 5. Interrupt and Trapping are considered synonymous. Both mean the ability, provided by hardware, to monitor particular conditions in the system during execution of all other operations and to provide an alarm signal which can interrupt a processor to obtain required action. Program interrupts or Intentional interrupts are really branching operations which sometimes use the alarm signal hardware.