RAMRAMstands for Random Access Memory, and is one of the two basis types of computer memory. It is considered to be the computer's main memory, because it is directly accessible by the CPU (Central Processing Unit).
The two types of computer memory built from semiconductor integrated circuits (IC) and located on the motherboard are RAM (Random Access Memory) and ROM (Read-Only Memory). As noted above, RAM is a computer's main memory. When a computer is first started, the RAM is responsible for supplying the CPU with memory for initializing the computer's systems. In fact, any activity which is accomplished spontaneously (such as striking the keys of a keyboard) is temporarily stored in the RAM.
RAM differs from ROM in that the CPU can read information out of the ROM, but cannot write to it as it can with RAM. Information such as certain embedded parts of operating systems are stored in a ROM chip by manufacturers. Another important distinction is that the information in the RAM gets lost when its power supply is turned off (normally the main power supply of the computer), whereas information storage in the ROM is independent of electrical power supply. RAM can be accessed in a nonsequential order by electronic switching among different memory locations without increasing access time. This distinguishes it from other non-IC memory devices such as a magnetic disc or hard drive, where it is faster to access locations sequentially because the drive head has to be physically moved to another disc location. The counterpart of the hard drive is the CD-ROM.
If the electricity goes out before you have saved a file, the file will probably be lost forever because the RAM is responsible only for quick, executable commands. When a program is launched, it must be copied from the secondary memory (ROM) to the main memory (RAM) in order for the computer to run it.
RAM memory is associated with the computer's memory chip, while ROM describes the memory available on a hard or floppy disk. There is a good reason for having these two types of memory. A computer chip works much faster than a computer disk; if a disk were responsible for providing the CPU with memory, it would take much longer to run programs.