Virtual Memory: An extension of the computer’s physical memory, virtual memory is a memory area that is created by the operating system (Windows, DOS, Linux, etc.), on the hard disk. This technique used by multitasking operating systems is simply for the management of memory. In this addressing system, non-contiguous memory is addressed as contiguous memory, and is referred to as virtual memory address space.
Page memory systems use virtual memory addressing. The operating system divides virtual Memery into pages, and each page is allocated a fixed address on the hard disk. When the page is needed, the operating system copies it from the disk to main memory, thus converting virtual addresses to real addresses.
Low Virtual Memory: Virtual memory is much slower and less accessible than actual RAM Memmory. When the computer does not have sufficient RAM, the system over-clocks, as it has to constantly swap RAM information. This process is called ‘thrashing’, and the computer becomes slow and less responsive. ‘Thrashing’ usually occurs in computers having 32-64 MB RAM, and hence, in such computers, the virtual memory settings are placed at a high level. If a user gets a low virtual memory error message, it indicates that the system may have used all the RAM and virtual memory in it.
Sometimes, badly designed programs do not return their working memory space to the operating system, which results in the system crashing or collapsing. In such a case, the operating system allocates more virtual memory as soon as the system is restarted. And sometimes, programs requiring a large amount of memory, may fail to run or load, because the operating system may have failed to recognize or ascertain the available space. Then, it is advisable for the user to manually allocate the virtual Memroy.
Increasing Virtual Memory and Computer Setting: If the measures mentioned above are not relevant or sufficient, and the operating system constantly displays the ‘Your system is low on virtual memory’ message, the user should not panic. The operating system can be manually configured to automatically manage the virtual memory.
In the case of Microsoft Windows XP, The following steps should be followed:
- Click on the ‘Start’ button on the desktop to get to the Control Panel from Settings.
- Click on Performance and Maintenance, and then click on System Management.
- Click on the Advanced tab.
- Under Performance, click Settings.
- Click the Advanced tab.
- Under Virtual memory, click Change.
- Under Drive [Volume Label], click the drive that contains the paging file (virtual memory) settings that one would want to change. In most cases, the changes are done on the ‘C: drive’.
- Click to select the “System managed size” option. Change the Initial size value and the Maximum size value to a higher value and then click Set.
- Click OK three times and restart your computer.
When the user allows the operating system to manage its virtual memory, it uses the optimum amount of unused hard disk space to be used as virtual Menory. This is done by automatically shrinking or enlarging the paging file as required. If that doesn’t solve the low virtual Momory problem, increasing the physical memory will finally solve it.