RAM stands for Random Access Memory. It is a type of computer storage device that takes the form of microcircuits or integrated circuits which facilitate the storage of data. These ICs can be accessed in any order explicitly or at random.
The word “random” means any piece of information can be returned in a constant time or disseminated through the memory. Its physical location and its relation to any other pieces of information inside the RAM will not have any effect.
It can also be related to volatile types of memory, where information can be lost if the power is switched off.
Types of Random Access Memory
The following are the types of RAM and their descriptions:
Dynamic Random Access Memory (DRAM)
DRAM stands for Dynamic Random Access Memory. It has the capacity to store each bit of data in a separate capacitor within a microcircuit.
It is a highly volatile memory device because data can be lost when the power supply is removed. It is called dynamic because of its refresh requirement. Since real capacitors leak charge, data can ultimately fade unless the capacitor charge is refreshed from time to time.
DRAM is beneficial because of its structural simplicity. It requires only a capacitor and one transistor per bit, compared to six transistors used in SRAM (Static RAM).
Static Random Access Memory (SRAM)
SRAM stands for Static Random Access Memory. It is the most widely used RAM today. It is a type of semiconductor memory where data is stored in a state of a flip-flop.
Like DRAM, SRAM is also a volatile memory device which can lose information when the power supply is cut off. However, SRAM exhibits data remembrance wherein data can still be recovered for a short time after power-off.
The term static specifies that it doesn’t need to be periodically refreshed unlike DRAM. It uses a bi-stable latching circuitry (electronic circuit that has two stable states) to store each bit of data.
Flash memory is a non-volatile computer memory, which means that it can be electrically reprogrammed and erased. It is a specific type of Electrically Erasable Programmable Read-Only Memory (EEPROM or E2PROM).
The cost of a flash memory is less expensive compared to other byte-programmable EEPROM. Hence, it has become the leading technology for storing non-volatile, solid-state information.
It is primarily used in portable music players, mobile phones, personal digital assistants, digital cameras, laptop computers, scientific calculators, memory cards, game console, and USB flash drives.
Erasable Programmable Read-Only Memory (EPROM)
Erasable Programmable Read-Only Memory or EPROM is a type of non-volatile computer memory integrated circuit. It has the capacity to retain data when the power supply is switched off.
It uses floating-gate transistors that are individually programmed by an electronic device. It provides higher voltages compared to other commonly used electronic circuits.
Once it is programmed, EPROM can only be erased by exposing it to strong ultraviolet light with a wavelength of 235 nm for optimal erasure time.
Read-Only Memory (ROM)
Read-Only Memory, simply known as ROM, is a type of storage device used in computers and other electronic media.
The pieces of data stored in ROM are not very easily or quickly modified. It is primarily used to distribute firmware, which are software applications closely tied to a specific hardware and are not likely to require recurrent updates.