Multiprogramming with fixed partitions

Consider the warehouse example again, multiple jobs of different types (perhaps size) entering storage in different partitions

• Several users simultaneously compete for system resources
• switch between I/O jobs and calculation jobs for instance
• To take advantage of this sharing of CPU, important for many jobs to be present in main memory
• Allowing Relocation and Transfers between partitions
• Protection implemented by the use of several boundary registers : low and high boundary registers, or base register with length
• Fragmentation occurs if user programs cannot completely fill a partition - wasteful.

  
Figure 2: Multiprogramming - fixed partitions