Memory in Computer System

 Explain about memory in Computer System?
(or)
Write short notes on memory of a computer? (MAY 2009)

The Role of Memory

The term "memory" applies to any electronic component capable of temporarily storing data. There are two main categories of memories:

Internal memory that temporarily memorizes data while programs are running. Internal memory uses micro conductors, i.e. fast specialized electronic circuits. Internal memory corresponds to what we call random access memory (RAM).

Auxiliary memory (also called physical memory or external memory) that stores information over the long term, including after the computer is turned off. Auxiliary memory corresponds to magnetic storage devices such as the hard drive, optical storage devices such as CD-ROMs and DVD-ROMs, as well as read-only memories.

Technical Characteristics

(a) Capacity, representing the global volume of information (in bits) that the memory can store

(b) Access time, corresponding to the time interval between the read/write request and the availability of the data

(c) Cycle time, representing the minimum time interval between two successive accesses

(d) Throughput, which defines the volume of information exchanged per unit of time, expressed in bits per second

(e) Non-volatility, which characterizes the ability of a memory to store data when it is not being supplied with electricity

The ideal memory has a large capacity with restricted access time and cycle time, a high throughput and is non-volatile.