computer RAM (random acess memory)

(Random Access ) is the internal of the for storing , program and program result. It is read/write which stores until the machine is working. As soon as the machine is switched off, is erased.
Access time in is independent of the address that is, each storage location inside the is as easy to reach as other locations and takes the same amount of time. in the can be accessed randomly but it is very expensive.
is volatile, i.e. stored in it is lost when we switch off the or if there is a power failure. Hence a backup uninterruptible power system(UPS) is often used with computers. is small, both in terms of its physical size and in the amount of it can hold.
is of two

Static (SRAM)
Dynamic (DRAM)

Static (SRAM)

The word static indicates that the retains its contents as long as power is being supplied. However, is lost when the power gets down due to volatile nature. SRAM chips use a matrix of 6-transistors and no capacitors. Transistors do not require power to prevent leakage, so SRAM need not have to be refreshed on a regular basis.
Because of the extra space in the matrix, SRAM uses more chips than DRAM for the same amount of storage space, thus making the manufacturing costs higher. So SRAM is used as cache and has very fast access.

Characteristic of the Static

It has long life
There is no need to refresh
Faster
Used as cache
Large size
Expensive
High power consumption

Dynamic (DRAM)

DRAM, unlike SRAM, must be continually refreshed in order to maintain the . This is done by placing the on a refresh circuit that rewrites the several hundred times per second. DRAM is used for most system because it is cheap and small. All DRAMs are made up of cells which are composed of one capacitor and one transistor.