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implementation of memory management

_ Done through memory tables to keep track of both real (main) as well as virtual (secondary) memory

_ Memory management unit (mmu)

·        Identifies a memory location in rom, ram, or i/o memory given a physical address

·        Does not translate physical address

·        Physical address is provided by an address bus to initiate the movement of code or data from one platform device to another

·        Physical address is generated by devices that act as bus masters on the address buses (such as cpu)

·        Frame buffers and simple serial ports are slave devices that respond to the addresses

Simple Memory Management Schemes

_ Shortage of main memory due to

·        Size of many applications

·        Several active processes may need to share memory at the same time

_ Fixed Partition Memory Management

·        Simplest memory management scheme for multiprogrammed systems

·        Divide memory into fixed size partitions

·        Partitions fixed at system initialization time and may not be changed during system operation

·        Single-Partition Allocation