Memory

Random Access Memory (RAM)
This type of memory where any byte of memory can be accessed at random without having to go through each previous byte first. Because the information stored is randomly accessible instead of having to read it sequentially like a CD you are able to read and write data to RAM much faster then other storage devices.

RAM is volatile memory which mean that it must be powered in order to store information, any information stored when the power is cut will be lost.

The main types of RAM are: most common type as it is cheaper and needs to refreshed thousands of times a second.
 * DRAM (Dynamic Random Access Memory) – This is the

is faster as it doesn’t need to be refreshed but is more expensive.
 * SRAM (Static Random Access Memory) – This type

Read-Only Memory (ROM)
During manufacturing data is written to ROM it cannot be erased or rewritten only read from which can be useful for security systems as hackers cannot alter vital program code, but updating software on ROM requires the storage device to be replaced.

ROM is non-volatile memory which means that it retains its contents when it loses power making it suitable to store programs such as BIOS.

Programmable Memory
PROM (Programmable Read-Only Memory) is manufactured blank instead of pre-programmed like ROM and you must use a special programmer to write the data. Without the PROM programmer you are only able to read the data and not alter it in any way.

EPROM (Erasable Programmable Read-Only Memory) is similar to PROM as it is produced blank and you use a programmer to write to the PROM although if you expose it to ultraviolet the data is erased.

EEPROM (Electrically Erasable Programmable Read-Only Memory) is also erasable but with the use of an electrical charge instead of ultraviolet light making it easier to use for digital storage.

Cache Memory
Cache memory is typically integrated directly into a device such as a CPU or storage drive, it can be accessed faster than most storage devices such as the CPU accessing data from the ram. The basic purpose of cache is to store program instructions that are frequently used by software during operation.