Memory Management in Operating Systems

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Memory management in multiple operating systems

An operating system is responsible for assigning memory to processes so that processes can be executed. Broadly, this responsibility is defined as memory management, and operating systems handle memory management differently. Any operating system must do two things in order to handle memory effectively. First, an operating system must be able to allocate and free physical memory. Second, an operating system must have techniques in place to keep track of the location of programs in physical memory. Examples of the ways different operating systems handle memory management can be seen by evaluating the Linux and the Windows 7 operating systems.

In order to keep track of the locations of programs in physical memory, the Linux operating system employs virtual memory techniques. “The Linux virtual memory system is responsible for maintaining the address space visible to each process. It creates pages of virtual memory on demand and manages loading those pages from disk and swapping them back out to disk as required.” (Silberschatz, 2009, p. 823) It is evident that Linux uses a paging strategy with its virtual memory technique. When the Linux operating system attempts to execute a program, the operating system will not directly access the program from physical memory. Instead, it will access a table of virtual memory addresses that keeps track of physical memory locations. This virtual memory address will then reference the physical memory location of a program so that it can be placed for execution in the CPU.

The allocation of physical memory varies depending on the architecture of a computer, but with the Linux operating system, “the primary physical-memory manager in the Linux kernel is the page allocator.” (Silberschatz, 2009, p. 820) The page allocator carries the responsibility of dynamically freeing and allocating all physical memory. The page allocator is a primary tool of all memory...
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