what is virtual memory?

Answer 1

The answers I read so far are not quite right. Yes, RAM is Random Access Memory, which refers to the memory chip where computer programs are temporarily stored and run on, and often the space is not available to store all programs the system are currently running, and which virtual memory or harddrive space treating as RAM are used.

However, programs are not whole-saledly store on RAM. In run time, computer programs need to place parts of itself or the run time instructions on RAM in order for the CPU (central processing unit) to process the information. When the system (by which I meant operating system like windows) runs out of the space on RAM, it will start placing instruction information on the harddrive.

What gets to be placed on depends on its priority. If a set of instructions are not urgently needed, it will be placed on the virtual memory. However, when it is needed again, instructions with lower priority on RAM will be placed on virtual memory to make room for the needed instruction, which is where the swapping term comes from. Therefore, the bigger the RAM, the faster the computer become.

Also, there is something called cache right at the heart of CPU, which is the most often run instructions are placed, and where the all the instructions are truly processed. Cache becomes crucial in CPU performance, and they are usally much smaller than RAM. Last I heard (which is quite a while back), the pentiums have 128 K cache or so. Celeron processors have much lower cache, which is why it has lower performance than pentium processors.


XR

Answer 2

First, memory is where programs are temporarily stored, when you are running a program. For example, you open MIcrosoft Word. Let's say Microsoft Word is a 30MB program. Then, you would need to have 30MB of memory to run the program.

There are two types of memory: real and virtual. Real is random access memory, or for short...RAM. Most computers have at least 512MB of RAM, which means you can run up to 512MB worth of programs. Now, when you use up all of the 512MB, then this is where virtual memory comes into play. When you run out of RAM, then Windows will start using your hard drive space. This is known as virtual memory or swap space.

Virtual memory is bad because hard drives run slower than RAM, which will decrease overall performance. If you always hear your hard drive running, this means you are using virtual memory and it may be time to consider upgrading to more memory.

For most people, 1GB is sufficient for WinXP. For power users, they will go to 2GB. On the rare occasions, you might hear people go more, but this is more for servers or render farms for video game companies or movie companies.

Answer 3

Your computer uses what's called RAM (random access memory) to process all of the information that goes through it. RAM is contained in small chips that are plugged into the motherboard inside the computers case.

Microsoft windows usually needs much more space to work with than what your computer's RAM is able to provide so Windows will take a big chunk of your computer's hard disk (the place where you save all your files and programs) and use it in much the same way that it would use the RAM.. this is called virtual memory.

Answer 4

http://en.wikipedia.org/wiki/Virtual_memory