Computer - Random Access Memory

RAM (Random Access Memory) is used to store the result data, and program of the internal memory of the CPU. This is a read / write memory for storing data, until the machine is working. Once the machine is turned off, the data is erased.

In the RAM access time is independent of the number of other positions within the same memory address of each storage location is easy and the time required to reach. Data in RAM random access, but it is very expensive.

Is stored in the RAM when it loses volatile, i.e. the data, we turn off the computer, or if there is a power failure. Therefore, a backup power system (UPS), is often used and the computer. RAM is small, the amount of both in terms of its physical size and the data can be accommodated.

Are two types of RAM
Static RAM
Dynamic RAM

Static RAM (SRAM)

Digital still represent the contents of memory, as long as the power supply. However, the data when the power is down due to the volatile nature of the loss. Using 6-transistor static RAM chip and no capacitor matrix. Transistor does not require power to prevent leakage, so static RAM does not need to have to be refreshed periodically.

Because in the matrix of additional space, the same amount of storage space used by static RAM more than DRAM chip, so that the manufacturing cost is higher. Therefore,  static RAM  is used as a cache memory, and has a very fast access.

Dynamic RAM (DRAM)

In DRAM, unlike static RAM  must be constantly refreshed to keep the data. This is achieved by rewriting the data on a memory refresh circuitry done hundreds of times per second. DRAM memory is used in most systems, because it is inexpensive and small. All DRAM memory cell is a capacitor composed of them and a transistor.