Bits N Bytes

Computers operate on Bytes of information. What is a Byte? Lets define some terms.

Term	Abbreviation	= # BYTES	Precise size	Equals
BIT	none	1/8
BYTE	none	1	1	8 BITS
Kilobyte	K or KB	1,000	1,024
Megabyte	M or MB	1,000,000	1,048,576	1000 K or 1,000,000 BYTES
Gigabyte	B or GB	1,000,000,000	1,073,741,824	1000 M or 1 billion BYTES
Terabyte	T or TB	1,000,000,000,000	Who Cares?	1000 GB or 1 gazillion BYTES
Petabyte	P or PB	1,000,000,000,000,000	Too big to figure	1000 TB
Exabyte	E or EB	1,000,000,000,000,000,000	Wow	1000 PB
Zetabyte	Z or ZB	1,000,000,000,000,000,000,000	Unbelievable	1000 EB

One Bit is one on/off switch much like a standard light switch. Electricity flows when on and does not when off.

A byte is a bank of 8 bits. It is much like a dip switch in a garage door opener. A bank of 8 switches can create a combination of 256 different signals by turning on or off different combinations. What it really means to the average computer user is that a byte = one character on the keyboard. Below is a picture of a typical dip switch:

To see a chart of how the dip switch is set to represent the keyboard characters click here

Therefore, a Kilobyte (KB) represents 1000 text characters typed. Programming and graphics are more complex but still are represented by bytes.

A megabyte is 1,000,000 bytes or 1 million characters.

The following chart should help put it in perspective:

3.5 inch floppy = 1.44 MB or 1,440,000 bytes or holds about 80 pages of typing.

CD = 650 MB or 650,000,000 BYTES or the same as 450 disks. One CD can hold the text from the entire 20 volume Encyclopedia Brittanica (without pictures) . CD-R & CD-RW are the same as a CD.

DVD holds about 7 times as much as a CD.

Hard drives  = 3GB minimum up to over 200GB as of Jan 2003. The problem with bigger drives is the programs get bigger. Many programs today take 300 to 400 MB on the Hard Drive.

December 2009 update: I just bought a 1 TB drive for $112. I see ads now for 4 TB.