Computer Memory

Memory is an important part of a Computer system. A computer system comprises of two types of memory:-  Primary memory and Secondary memory.

Primary Memory

It is considered as the main memory of the computer system. It is temporary memory. The data and instructions that we are working while running programs are stored in Primary memory. It is regarded as the main memory as we need to store the data that we are working on until we proceed for the output. Primary memory has got specified slot in the Motherboard of the computer system. It is also known as volatile memory. Primary memory is expensive than secondary memory.

RAM(Random Access Memory), ROM(Read Only Memory), DRAM(Dynamic RAM), SRAM(Static RAM), FPM(Fast Page Mode Ram), EDORAM(Extended Data Out RAM), SDRAM(Synchronous DRAM), PROM(Programmable ROM), EPROM(Erasable Programmable ROM), EEPROM(Electrically Erasable Programmable ROM) etc are some of the types of primary Memory. It can be understood from the following table:-

Memory    Type	Use
ROM	BIOS, CMOS, Special Function Chips
RAM	Main Memory
DRAM	Chips on SIMM boards or Motherboard
SRAM	Used as external cache
FPM	Used in 486 or older motherboards
EDO RAM	Used on Pentium or later motherboards
SDRAM	It is used on 168 pin DIMM chips.
FLASH	It is on a memory card

                                                                     RAM                                           

                                                                        ROM          

Secondary Memory:-

Secondary Memory is the Permanent memory of the Computer system. It is also known as Auxiliary memory of the computer system. It can be connected externally to the Computer system. It can hold the data and instructions permanently for long term persistent storage. It is also known as non-volatile storage. Various types of Secondary memory are available in the market with varying storage capacities. Some of the exammples of Secondary memory are:-

i)                    Hard Disk: It comes of varying capacities . It is of two types external and internal.

ii)                   Floopy Disk: It can store only limited data, so it is not much popular nowadays.

iii)                 CD-ROM/CD-RW/DVD-ROM:- They are all use for secondary storage. They are known as Optical storage devices.

iv)                 USB flash drives:- They are popular now a days because it is portable, removable, compact, faster, reliable and easy for carrying datas. They are integrated with USB(Ubiversal Serial Bus) interface of computer.  Pendrive and memory card are USB drives. They are available in the market with varying capacities.