RAM is an acronym for “Random Access Memory”. As the name “Random Access” suggests it implies that you can at any given time access any memory cell directly. It is also known as the “temporary memory” i.e. it holds the data only for a limited period of time, meaning when the system is shut off then the memory is lost.
How RAM works?
RAM is filled with many microscopic capacitors. These capacitors either are charged or they don’t hold any charge. If a capacitor is charged then it is given the value -1 and if it doesn’t hold any charge then it is assigned the value - 0. Suppose we have capacitors lined up and we end up having a combination “0100001” which represents A, or if we have combination “01100010” which say represents “B”.
This way every different combination can represent different characters. So we can have a bank of distinct capacitors to represent any transaction or application of the PC.
Each 1 or 0 is called a “Bit” and eight “Bits” together form a “Byte”. One million “Bytes” forms One Megabyte. Thus when we use the term like RAM storage of this computer is 512 MB it means that your RAM can represent 512 * Million characters. So the RAM storage on the computer is directly proportional to number of applications you can run your system.
Types of RAM
RAM stores the data either in the form of Flip-Flop as in SRAM (Static-RAM) or as a charge in the capacitor like in DRAM (Dynamic RAM), EPROM (erasable programmable read only memory), Flash memory, EEPROM (electrically erasable programmable read-only memory)
Another type is ROM (read only memory) that has permanently enabled/disabled transistors by using a metal task.
Traditionally SRAM and DRAM were used in most of the computers, but nowadays most of the products coming in the market such as music players and palmtop computers. use FLASH memory because it is non-volatile and the data can be electrically erased and reprogrammed. FLASH memory is further divided into NAND and NOR memory.
NOR type truly conducts the random access and is widely used as ROM. NAND does not support random access but is used for bulk storage like USB hard-drives.
Sometimes when your system runs out of RAM then it performs a certain function called “Swapping”. What happens during swapping is that area of your hard-drive is used as additional memory, but excessive use of Swapping may cause problems for your system because hard-disk memory is much slower than RAM. So, this excessive use of area of main memory as RAM can cause “Thrashing” which my cause your system to crash.
You can also partition portion of RAM, this allows RAM to act at a much faster rate and as a separate hard-disk.
