)(n.) An imaginary memory area supported by some operating systems (for example, Windows but not DOS) in conjunction with the hardware. You can think of virtual memory as an alternate set of memory addresses. Programs use these virtual addresses rather than real addresses to store instructions and data. When the program is actually executed, the virtual addresses are convertedinto real memory addresses.
The purpose of virtual memory is to enlarge the address space, the set of addresses a program can utilize. For example, virtual memory might contain twice as many addresses as main memory. A program using all of virtual memory, therefore, would not be able to fit in main memory all at once. Nevertheless, the computer could execute such a program by copyinginto main memory those portions of the program needed at any given point during execution.
To facilitate copying virtual memory into real memory, the operating system divides virtual memory into pages, each of which contains a fixed number of addresses. Each page is stored on a diskuntil it is needed. When the page is needed, the operating system copies it from disk to main memory, translating the virtual addresses into real addresses.
The process of translating virtual addresses into real addresses is called mapping. The copying of virtual pages from disk to main memory is known as paging or swapping.
- virtual network computing
Through the use of software VNC, acronym for virtual network computing, makes it possible to interact with a computer from any computer or mobile device on the Internet. VNC software provides cross-platform support allowing remote control between different types of computers. To use VNC you must have a network TCP/IP connection, a VNC server and […]
- virtual printer
A file containing a set of attribute values that describe the data stream for a printer. Before a print job can be placed in a queue, a virtual printer definition must exist for both the print queue and the queue device.
- virtual private server
Abbreviated as VPS, the term virtual private server is used interchangeably with virtual dedicated server (VDS). See virtual dedicated server (VDS).
- virtual reality
An artificial environment created with computer hardware and software and presented to the user in such a way that it appears and feels like a real environment. To “enter” a virtual reality, a user dons special gloves, earphones, and goggles, all of which receive their input from the computer system. In this way, at least […]
- virtual router
(n.) An abstract object managed by VRRP that acts as a default router for hosts on a shared LAN. It consists of a Virtual Router Identifier and a set of associated IP addresses across a common LAN.