those computer users who are lucky enough to catch the glorious heyday of systems based on the 8086-compatible processors are very well aware of how at that time the important amount of memory installed.The score was literally kilobytes: to exceed the basic 640 kbps and reach the "fantastic" 736 KB to acquire any special external extension, which is a hefty fee in a relatively large-sized housing.However, computer technology has evolved quickly and soon the psychological barrier of 1 megabyte was passed.RAM modules are much smaller, also appeared processors using it to the fullest.Not lagging behind, and applications.A landmark event was the output Vindovs third version, in which the use of virtual memory.However, these were only tentative steps in the direction that would become standard on all operating systems.
What is virtual memory?Imagine two identical computer running Windows 3, only one has 1 MB of memory, and the other - 2 MB.To select software applications based on the volume - to condemn programmers hard work, because they need to optimize their products for 1, 2, etc.megabyte.Create a program designed for a standard minimum of 640 KB - it means to give up some opportunities, "drive" application framework.A focus on the 2MB - to lose potential customers who have computers for only 1 MB.It is understood and Microsoft, therefore proposed a mechanism, called "virtual memory".Programmers no longer need to know how much is installed in each computer.Of course, some restrictions, nevertheless, take into account, but the overall concern about how to "make friends" demanding applications and components of the computer took over the operating system.No miracles here, of course, does not occur.The principle of operation is extremely simple.
Take for example the case when the computer is started with 1MB application developed under 2MB.Part of the volume occupied by the system itself, therefore, from 1 MB available to the user only 500 kb (suspended).Run the application.If the virtual memory is enabled or disabled, the program occupies 500 kb and exits, giving a message about the error.But a completely different if the mechanism is included: doing the very same 500 kb, if the following query is a memory, the data block is written to a special file on the disk, freeing up the volume in RAM.The application mechanism of "transparent."In fact, virtual memory - it is part of the task, but not placed in the chips and disk space.This decision turned out to be so successful that still are working on its improvement.So, in recent Vindovs 8 to the already familiar swap file added pagefile swapfile, intended only for metro applications.
Sometimes, users may see a system message that the virtual memory ends.How to explain it in the light of the above?Moreover, it is not clear, given that the free disk space on your hard drive can still be.One of the most likely reasons for this lies in the wrong configuration of the mechanism of virtual memory.Although the default, the system selects the automatic control the size of the paging file is allowed manual control to specify a rigid framework.Is it necessary to do so or not - each user chooses their own, but if an error occurs due to a lack of volume will have to raise the upper limit allowed.This is configured in the Performance Options (can be accessed via the "My Computer" or from the control panel).
