Computer Operating Systems – Virtual Memory Defined
Abstract
Computer operating systems are made up of a chorus of technologies and machinery that sing in unison for productivity and communication. Although there are many types and designs of OSs they are similar in how they perform and produce. The functions by which an OS operates contain basic task oriented duties that manage the resources that include; CPU, hardware, software, drivers, memory, etc. One such part or aspect of a OS which is vital to the successful operation is Virtual Memory, which expands the memory resource at a higher level for running programs simultaneously. This paper will discuss the important aspects of Virtual Memory, and how it allows for better computing and productivity.
Virtual Memory Defined
The concept of “virtual memory” means that it appears to be transparent when it actually is not. It differs from “real” memory in the sense that it is not run as a chip (hardware), but a file on the hard disk that contains many of the needed blocks of address memory to be called for reading. If the OSs main memory were running multiple applications with limited disk space, a virtual memory manager will take on the task of creating virtual space on the hard disk for temporary storage and use. “With virtual memory, all address references are logical references that are translated at run time to real addresses. This allows a process to be located anywhere in main memory and for that location to change over time.” (Stallings, 2009) Virtual memory is employed by automatically translating addresses for quick reading by the program and caching that information for re-use. It takes very little time (usually) to access this information, and makes it less time consuming for the CPU. Although the concept is a reliable one, it becomes more problematic if the main memory is taxed to its limit.