Memory Management

March 7, 2014

Memory Management

Memory is one of the basic elements on a computer system. The memory allows the user to store data and programs. Memory management is the controlling, coordination and management of the computer memory (). The different memory types a computer has are a cache, main memory, and a disk used for virtual memory. Managing this memory will allow the user to access information faster. The memory management system is on the most important parts in the operating system. In this essay will be discussing the differences in memory management between Windows and Linux base operating system. Windows has implemented several technologies, for both resource allocation and security("Windows Memory Management", 2008). One of these technologies is Dynamic Allocation Space Layout Randomization, which all dynamically adjusts according to operation requirements. Windows uses virtual address space to make that could be bigger or smaller than the physical memory on the computer. Windows memory manager has two first-in-rank responsibilities("Windows Memory Management", 2008). The first is to translate, or map, a process’s virtual address space into physical memory so that when a thread is running in the context of that process reads or writes to the virtual address space, the correct physical address is referenced ("Windows Memory Management", 2008). This minimizes hackers’ threats to the computer system. Second on is paging some of the contents of memory to the disk when it becomes overcommitted (). This happens when there is a threat to the system or when the system code tries to use more memory. One vital service provided by the memory manager included memory-mapped files ("Windows Memory Management", 2008). This can speed up sequential file processing because the data is not sought randomly. It also provides capabilities for memory sharing between process. On a 32-bit Windows operating system uses 2GB for each processor and 2GB as virtual memory to map itself, device drivers that are configure to load, and to store the data that is maintain by the drivers and the operating system. Linux has developed similar strategies to solve the need for more memory than exist physically in a system. Virtual memory makes the system think to have more memory that it actually has by sharing it between competing processes as the y are needed. Linux memory management provides large address spaces, protection, memory mapping, fair physical memory allocation, and shared virtual memory. As the processor executes a program it reads and instruction from memory and decodes it ("Memory Management", 1999). By the decoding the instruction, it may need to fetch or store the contents of a location in memory. When this is done, the processor is always accessing memory either to fetch instructions or to fetch and store data. The virtual memory does not store virtual address in the physical memory, rather this virtual addresses are converted into physical addresses by the processor based on information held in a set tables maintained by the operating system. The system makes this transition easier by diving into pieces called pages. Mapping virtual to physical address this way the virtual memory can be mapped into the system’s physical pages in any order.
Windows and Linux have modern memory management system and have lot in common. Linux implements the virtual memory data structure in a similar manner to Unix. The two systems have originated differently. Linux takes simplicity against performance while windows go for the monetary benefits. Which helps develop more features for windows but more difficult to maintain and improve.

References
Memory Management. (1999). Retrieved from http://www.tldp.org/LDP/tlk/mm/memory.htm

Windows Memory Management. (2008). Retrieved from http://www.codeproject.com/Articles/29449/Windows-Memory-Management