Information is stored and processed in computers as electrical signals. A computer contains thousands of electronic circuits connected by switches that can be in one of the two states: ON and OFF. To represent these two conditions we use binary notation in which 1 means ON and 0 means OFF.

This is the only way a computer can 'understand' anything. Each 1 or 0 is called a binary digit or bit.

Is and 0s are grouped into eight-digit codes called bytes. Thus, each character in a keyboard has its own pattern of eight bits. For example, 01000001 for the letter A and 010000010 for B.

To describe the RAM memory, the storage capacity of disks and size of any application or document we use kilobytes (KB), megabytes (MB) and gigabytes (GB). 1 KB is 1,024 bytes, 1 MB is equivalent to 1,024 KB, and 1 GB is 1,024 MB.

Answer the questions.

1.  How many digits does a binary system use? What is a 'bit'?

2.  How is a collection of eight bits called?

3.  One kilobyte (1K) equals 1,024 bytes.

       Can you work out the value of these units?   (kilo-:one thousand)

1 megabyte = .......... bytes/1,024 kilobytes               (mega-:one million)

1 gigabyte = .......... bytes/1,024 megabytes                   (giga-:one thousand million)