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Memory Managment

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Submitted By trobinson43
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Pages 4
Markus Robinson
Memory Management
James Welti, Jr.
POS/355
July 10, 2015

Memory Management
And Its Requirements

Memory management is the act of managing computer memory at the system level. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed. Memory needs to be allocated to ensure a reasonable supply of ready processes to consume available processor time. Memory management also involves subdividing memory to accommodate multiple processes. This process, involving controlling and coordinating computer memory, assigns portions called blocks to various running programs. By doing this the overall system performance is optimized to its maximum performance. Memory management resides in hardware, the operating system, as well as in programs and applications.
Within hardware, memory management involves components that physically store data. The components that are involved in memory management include random access memory (RAM) chips, memory caches, and flash-based solid-state drives (SSDs). As users demand change, memory management involves the allocation and ongoing reallocation of specific memory blocks to individual programs in the operating system. By combining two related tasks, known as allocation and recycling, application memory management ensures the availability of adequate memory for the objects and data structures of each running program. One part of the memory management called the allocator assigns a block to a specific program when the program request a block of memory. Memory blocks will become available for when a program no longer needs the data. This task can be done manually by the programmer or automatically by the memory manager.
When it comes to memory management there are requirements that are involved. These requirements include, relocation, protection, sharing, logical organization, and physical organization. With relocation the programmer does not know where the program will be placed in memory when it is executed. While the program is executing, it may be swapped to disk and return to main memory at a different location. Memory references must be translated in the code to the actual physical memory address when addressing requirements for a process. with protection process this should not be able to reference memory locations in another process without permission. Is it possible to check absolute addresses compile time And these processes must be checked at run time. Memory protection requirement must be satisfied by the processor (hardware) rather than the operating system (software). The operating system cannot anticipate all of the memory references a program will make. When it comes to memory sharing requirements several processes must be allowed to access the same portion of memory. It is better to allow each process access to the same copy of the program rather than have their own separate copy. Logical organization management is where programs are written and modules. These models can be written and compiled independently. They are different degrees of protection given to each module and these include read-only and execute-only. Logical organization management also allows for the sharing of modules among processes. With physical organization management, The programmer does not know how much space will be available. Memory available for a program plus it's data may be a sufficient. Overlay allows various models to be assigned the same region of memory.
Another aspect of memory management is fixed partitioning. Fixed partitioning involves partitioning the available primary memory into a number of regions with each region having a fixed size, different regions potentially having different sizes. Any process who size is less than or equal to the partition size can be loaded into an available partition. If all partitions are full, the operating system can swap a process out of a partition. A program however may not fit into a partition. The programmer must then design the program with overlays. Fixed partitioning in main memory is an efficient. Any program, no matter how small, occupies an entire partition. When there is memory left over that does not fit perfectly this is called internal fragmentation. Partitioning brings along another aspect of memory management called placement algorithm. In equal-size partitions because all partitions are of equal size, it does not matter which partition is used. In unequal-size partitions, processes can be assigned to the smallest partition within which it will fit. Processes are assigned in such a way as to minimize wasted memory within a partition.
Understanding memory management helps significantly when dealing with the management of a computer's physical memory or random access memory (RAM). Memory management provides protection by using two registers, a base register and a limit register. Understanding the requirements for memory management will help you through learning other aspects of information technology.

References

Rouse, M. (2012). Memory management. Retrieved from http://whatis.techtarget.com/definition/memory-management Memory managment. (n.d.). Retrieved from
http://www2.cs.uidaho.edu/~krings/CS240/Notes.F13/240-13-19.pdf

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