RAM is acronyms of Random access memory. It is used in computer to store the information. A random access memory allows data items to be retrieved in almost the same amount of time regardless of the physical location of data in the memory. In general the other data storage device including hard drive, DVD-RWs, CD-RWs, and the older memory devices, etc. takes more time to read and write the information from it, due to mechanical limitations like media rotation speeds and arm movement delays. But in the case of random access memory, it stores the data in integrated circuits. It is associated with volatile memory type such as DRAM, where stored information is lost after the power off.
There are other non-volatile also memory exist which allows user to random access for read operations, but do not allow to perform write operations. RAM can be classified in two types like static RAM (SRAM) and dynamic RAM (DRAM). In Static RAM, a bit of data is kept by making the use of the state of a six transistor memory cell. It is more costly to produce, but it is faster and requires less power compared to Dynamic RAM. Whereas dynamic RAM stores a bit of information by using a pair of transistor and capacitor. These transistors and capacitor together form a dynamic RAM memory cell.
These static and dynamic RAM are considered as volatile because after shutdown the system information saved in it get lost or reset. In modern OS, RAM capacity can be extended by employing a technique known as “virtual memory”. In this technique, a system hard drive portion is set aside for a paging file. This page file and physical RAM combination of the system total memory together. Let us consider an example, suppose your system having 2 GB RAM and 1 GB page file, and then system operating system utilizes total 3 GB memory.
RAM can be divided in a portion by using an application. This RAM partition act as a much faster compare to the RAM is known as a RAM disk. This RAM disk loses the saved information after the system gets shut down. There is another term related to RAM that is Shadow RAM. It is a copy of Basic Input /Output Operating System (BIOS) procedures from ROM into a special area of random access memory so that they can be accessed more quickly.