Wednesday, March 25, 2015

How do computer store data ?

All the data stored in computer - every word, picture, number and sound - is captured as a series of electrical pulses that are either on or off. A number system called binary is used to represent these pulses with "1" meaning "on" and "0" meaning "off".

A single binary digit, known as a "bit", switches a single switch on or off. By linking together these switches, the computer can carry out the complex operations we demand.

Bits and bytes

1 bit = a binary digit either 1 (on) or 0 (off).
1 byte = 8 bits
1 kilobyte =
1,000 bytes
1 megabyte = 1,000,000 bytes
1 gigabyte = 1,000,000,000 bytes
1 terabyte = 1,000,000,000,000 bytes

How much data?

10 bytes = one word
2 kilobytes = one typewritten page
100 kilobytes = a low-resolution photograph
1 megabyte = a short novel
2 megabyte = a high-resolution photograph
100 megabyte = 17 hour of digital music
10 terabytes = all the printed works in the US library of Congress (the world's largest library)