What is multiprogramming?

Multiprogramming: The management of many processes within a single processor system. Operating systems such like UNIX provide multiprogramming for shared single processor systems. In the single-processor multiprogramming system processes are interleaved in time to yield the appearance of simultaneous implementation. It is the essential theme of modern operating systems

The introduction of multiprogramming brought concerning the ability to share resources among users. Sharing engrosses not only the processor but also the following

• Memory
• i/o devices such as printers and disks
• programs
• data

In a multiprogramming environment guard of main memory is essential. The concern isn't only the security but as well the correct functioning of the various processes that are active if one process is able to inadvertently write into the memory space of another process then the latter process may not execute properly.

Effects of ultiprogramming on resource utilization Multiprogramming

Processor use                      33%

Memory use                        67%

Disk use                              67%

Printer use                           67%

Elapsed time                       15 min

Throughput time                 12 jobs/hr

Mean response time            10 min