Computer memory refers to either of two types of computer storage. Volatile memory refers to RAM that needs to be constantly refreshed to be retained. Static memory is permanent storage that is retained even after the computer is turned off.

RAM or Random Access Memory is volatile memory that is erased when the power goes off. Program instructions and data held in RAM can be accessed and saved much more quickly than that held in permanent storage. Therefore, files needed to run a program and data that is being processed are held in RAM while they are in use. The amount of RAM you need depends at least partly on the operating system( a program that directs all the basic functions of a computer such as accepting commands from a keyboard, displaying input on a monitor screen, and controlling disk drives and some other peripheral devices) you select as well as the type of programs you intend to run.

When you boot up the computer, in other words turn it on, the operating system or part of it is loaded into the RAM along with a variety of utilities required for normal operation. Therefore, programs and data are loaded into what's left. As little as 2MB(megabytes) total will suffice for most DOS( disk operating system-a proprietary program that controls all the basic functions of a computer) programs. In a Windows 3.x environment, 4MB is the recommended minimum, but 8MB runs far better.

Beyond operating system demands, the amount of RAM required depends on the applications to be run. For example, heavy graphics, real time video, and such need more RAM to keep things from slowing to a crawl or stop. Generally, off-the-rack machines come with 8 to 16MB, more than enough for a general purpose computer.

With improved handling of memory, reduced access times, and lower cost have conspired to make larger amounts of RAM practical. Which in turn has given programmers free rein to add more bells and whistles. This also helps programmers to become more creative in writing programs that require more RAM. There is reason to believe that this trend will continue.