Thursday, July 25, 2019

Operating system memory management Essay Example | Topics and Well Written Essays - 2500 words

Operating system memory management - Essay Example It takes place in the following steps: The mapping from one address space to another is termed as binding. For a program to execute it must be copied into main memory at a particular location. Many instructions use "fixed" addresses these must be bound to "fixed" locations in the memory. This binding of instructions and data to memory addresses Dynamic loading involves loading routines into memory only when required. This is done during execution. Dynamic loading reduces the memory requirements of large programs. This is especially the case if there is a large set of infrequently used routines. Dynamic linking is often used for libraries. Only a "stub" of the library is kept in the programs image. When a program calls one of these routines, the routine is loaded and linked into memory. All programs share the one copy of the same library routine. Dynamic linking requires the operating systems intervention as sharing between processes is required. Implementation is done through memory tables to keep track of both main memory i.e. real memory as well as virtual memory. Also there is a unit MMU(Memory management unit) that performs the following tasks: Sometimes there may be a shortage of main memory due to the size of various applications and also in some cases several active processes may need to share memory at the same time. In such cases partitioning of memory is done. Partitioning refers to systematic division of memory into blocks so that a process may be allocated to a block. This is of various types: 1. Fixed partition memory management: This is the simplest memory management scheme for multiprogrammed system. Here the memory is divided into fixed partitions. This is done when the system is initialized and won't be changed during the system operation. This again of two types: Single partition allocation: Here the user is provided with a bare machine and has full control of entire memory space. It's advantages are: Maximum

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.