This is the memory that the computer uses for storing the programs and their data while working on them. So, if you are drafting a letter using a wordprocessor, say MS-Word, you are working with a document loaded into the RAM. To store your letter for later use, it has to be saved on the hard disk. Later, you can retrieve it from the disk and continue working on the document. Thus, RAM functions as a scratch pad for the computer and is sometimes called the scratch pad memory.
RAM has the following characteristics:
- Data within the RAM can be read or modified, i.e. you can either read from the RAM or write onto it. Hence it is called read/write memory.
- The contents of the RAM are lost when the computer is switched off. Hence, the RAM is said to be volatile.
The capacity of RAM can vary from 640 KB to 64 MB and more, depending on the number of memory chips installed, which in turn depends on the capacity the microprocessor can handle. The RAM size is an important parameter in determining the size and complexity of problems that a computer can handle. When people refer to the amount of memory that a computer has, they are talking about the amount of RAM available.