Memory of Computer
Memory is an integral part of every computer. It is used for storing data and programs which can be used at a later time, whenever required. For the sake of understanding, imagine memory to be like an array of switches as shown below
The switches in the array are organized in a number of rows each having 8 columns. Thus, each row has 8 switches. Each switch can either ON or OFF at any instant of time. This means that the switches that constitute a memory are two state devices i.e. ON and OFF. In the ON state a switch may be thought of representing a 1 and in OFF state a 0. Thus, each switch may be thought of as a smallest unit of memory capable of storing a 0 or 1 and it is called as a bit. As represented in the above table each row has 8 switches i.e. at any instant of time, a particular row of switches may represent a pattern say 01011011 called a word. A group of 8 bits is called byte. A world length may be more than 1 byte, depending on the type of CPU. Variety of CPU’s are there which handle word lengths from 1 bytes to 8 bytes.
Normally a single alphanumeric character requires 1 byte if memory for its storage.
The size of memory is specified in terms of BYTES. When the memory size is large, it is specified, for convenience, in multiples of BYTE as shown below.
1 Kilo Byte (KB) = 2^10 Byte = 1024 Bytes.
1 Mega Byte (MB) = 2^10 KB = 1024 KB
1 Giga Byte (GB) = 2^10 MB = 1024 MB