Virtual memory was introduced to help run more programs with limited memory. But in todays environment of inexpensive RAM, is it still relevant?
Since there will be no disk access if it is disabled and all the programs will be memory resident, will it not improve the performance and program response times?
Is there any essential requirement for virtual memory in windows apart from running more programs as stated above? Something windows internal not known to us.
The question is really what is the use of a pagefile considering how much memory modern computers have and what’s going on under the hood in the OS.
It’s common for the Windows task manager to show not much physical memory being used, but, your having many page faults? Win32 will never allocate all it’s physical memory. It always saves some for new resource needs. With a big pagefile vs small pagefile, Win32 will be slower to allocate physical memory to a process.
For a few days now I’ve been using a very small pagefile (200 MB fixed) in Vista with 3GB of addressable physical memory. I have had no crashes or problems. Haven’t tried things like large video editing or many different processes open at once. I wouldn’t recommend no pagefile since the OS can never shuffle pages around in physical memory leading to the development of holes. A large pagefile is fail-safe for people who wouldn’t know how to manually increase the pagefile if a low memory warning pops up or the OS crashes.
Some points: The kernel will use some of the physical memory and this will be shared through VM mapping with all other processes. Other processes will be in the remaining physical memory. VM makes each process see a 4GB mem space, the OS at the lower 2GB. Each process will need much less than the 4GB of physical memory, this amount is it’s committed memory requirement. When programming, a malloc or new will reserve memory but not commit it. Things like the first write to the memory will commit it. Some memory is immedietely committed by the OS for each process.