Difference between RAM and ROM

Parameter	RAM	ROM
Acronym for	Random Access Memory	Read Only Memory
Definition	It is the class of Computer data storage which takes roughly same amount of time to read or write data items regardless of the order in which data items are accessed.	It is the class of Computer data storage in which stored data can only be modified slowly, with difficulty or not at all.
Power Requirements	It can retain data if and only if power supply is on. Data gets lost on power failure. Hence data is stored temporarily.	It can retain data even if power supply is off. Data is stored permanently.
Types	SRAM (Static RAM), DRAM (Dynamic RAM).	Mask ROM, PROM (Programmable ROM), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM)
Reading Speed	Large RAM chips can be read very fast.	Reading speed for ROM is slow for this reasons ROM contents are copied to RAM or shadowed before it can be first used.
Writing	RAM can be written number of times and has no write cycle limitations.	Re writable ROMs can tolerate only a limited number of write & erase cycles before its insulation gets permanently damaged.
Area of Use	RAM is generally used for temporary storage of data for fast access. Computer, Mobile Phones, Printers etc.	ROM is generally used to store Firmware programs permanently. E.g. BIOS Setup, game console cartridges.