Types of

Memory

TYPES OF MEMORY

• Cache Memory• Primary Memory• RAM• ROM

• Secondary Memory• Sequential Access

Devices• Random Access

Devices

CACHE MEMORY

Characteristics•Cache Memory is building block of a computer which is used to improve overall performance of a processor by minimizing the memory processor speed mismatch.•It is a small memory between main memory and CPU •Act as a high speed buffer between them.•Use to store very active data temporarily.•Extremely Fast.•Access time is closer to the speed of processing of CPU.

Advantages•Faster than main memory.•Consume less access time.•Stores a program that can be executed within a short period of time.

Disadvantages•Cache memory has limited capacity.•Very Expensive.

Primary Memory

Characteristics•Primary Memory is made up of several small storage areas called locations or memory cell.•Consist of Integrated Circuit(IC) chips connected or attached to mother board.•They are semiconductor memories.•It is used to hold the program being currently executed in the computer, the data being received from the input unit, the intermediate and final results of the program.•It is temporary in nature.•Data is lost when power supply to system is off.•Primary Memory is volatile in nature.•Faster and costly than secondary memory.•It is also known as main memory.•It is working memory of a computer. A computer cannot run without primary memory.

Advantages•Faster than secondary memory.•Working memory of a computer.

Disadvantages•Volatile in nature•Expensive•Limited capacity.

Types of Primary Memory•RAM(Random Access Memory)RAM is a memory scheme within the computer system responsible for storing data on a temporary basis, so that it can be promptly accessed by the processor as and when needed. It is volatile in nature, RAM stores data randomly and the processor accesses these data randomly from the RAM storage.•ROM(Read Only Memory)ROM is a permanent form of storage. ROM stays active regardless of whether power supply to it is turned on or off. ROM devices do not allow to modify the data stored. Data can only be accessed and read by the user, cannot be alter or modified.

Secondary MemoryCharacteristics•Secondary memory is used like an archive. It stores several programs, documents, databases on permanent basis.•It is non- volatile in nature.•Data is stored permanently even if computer is switched off.•It is backup memory of computer.•Used as supplement to main memory.•It is slower and cheaper as compared to primary memory.•Also known as auxiliary memory

Advantages•Stores data on permanent basis.•Less expensive.•Storage capacity larger than that of primary memory•Non-volatile in nature.•Used as backup memory.

Disadvantages•Slower than primary memory.•Cannot store data of ongoing running programs.

Types of Secondary Memory•Sequential Access Storage DeviceIt is a class of data storage devices that read their data in sequence and the time for access depends on the location of the data desired. For e.g. Magnetic Tapes.

•Direct Access Storage DevicesIt is also called random access devices. It allows stored data to be accessed in any order in very nearly the same amount of time for any storage location or size of memory device. In case of direct access devices data can be accessed in a random manner. Magnetic disks like Hard Disks and Floppy Disks and Optical Disks like CD-ROM and DVD-ROM are examples of direct access storage devices.