The pc's operating system, utilizing a combination of hardware and software program, maps memory addresses utilized by a program, called digital addresses, into physical addresses in pc memory. Fundamental storage, as seen by a course of or task, appears as a contiguous handle area or assortment of contiguous segments. The working system manages virtual tackle spaces and the task of actual memory to virtual memory. Handle translation hardware in the CPU, sometimes called a memory management unit (MMU), mechanically interprets virtual addresses to bodily addresses. Software inside the working system could prolong these capabilities, using, e.g., disk storage, to offer a virtual handle house that can exceed the capacity of real Memory Wave Program and thus reference extra memory than is bodily present in the computer. The first advantages of virtual memory include freeing functions from having to manage a shared memory space, capability to share memory utilized by libraries between processes, increased safety attributable to memory isolation, and having the ability to conceptually use more memory than might be physically available, using the strategy of paging or Memory Wave segmentation.

Digital memory makes application programming easier by hiding fragmentation of physical memory; by delegating to the kernel the burden of managing the memory hierarchy (eliminating the need for this system to handle overlays explicitly); and, when every process is run in its own devoted deal with space, by obviating the necessity to relocate program code or to access memory with relative addressing. Memory virtualization will be considered a generalization of the idea of digital memory. Virtual memory is an integral a part of a modern computer structure; implementations normally require hardware help, typically in the form of a memory administration unit built into the CPU. Whereas not mandatory, emulators and virtual machines can make use of hardware help to extend efficiency of their digital memory implementations. During the 1960s and early '70s, laptop memory was very costly. The introduction of virtual memory offered an means for software program programs with giant memory demands to run on computer systems with much less real memory.

The financial savings from this supplied a robust incentive to switch to virtual memory for all techniques. The additional capability of offering digital tackle areas added one other stage of safety and reliability, thus making virtual memory even more attractive to the marketplace. Most modern operating methods that assist virtual memory additionally run each process in its own dedicated address house. Every program thus seems to have sole access to the digital memory. However, some older working systems (reminiscent of OS/VS1 and OS/VS2 SVS) and even trendy ones (comparable to IBM i) are single handle area operating techniques that run all processes in a single deal with space composed of virtualized memory. Embedded methods and other special-objective computer systems that require very quick and/or very consistent response instances could choose not to make use of digital memory due to decreased determinism; virtual memory programs set off unpredictable traps which will produce undesirable and unpredictable delays in response to input, especially if the lure requires that information be learn into primary memory from secondary memory.

The hardware to translate virtual addresses to physical addresses typically requires a major chip area to implement, and not all chips utilized in embedded systems embody that hardware, which is another motive some of these techniques do not use virtual memory. Within the 1950s, Memory Wave all bigger programs had to include logic for managing main and secondary storage, comparable to overlaying. Digital memory was therefore introduced not solely to increase primary memory, however to make such an extension as simple as doable for programmers to use. To permit for multiprogramming and multitasking, many early methods divided memory between multiple packages without digital memory, such as the UNIVAC 1107, PDP-6 and early fashions of the PDP-10, by way of base and bounds registers. The pc proposed by Güntsch (but never built) had an address area of 105 words which mapped exactly onto the 105 phrases of the drums, i.e. the addresses had been actual addresses and there was no form of oblique mapping, a key characteristic of digital memory.