Byte (and bits)
Computers work on the basis of being able to distinguish between two states, for example on or off, 0 or 1, yes or no, heads or tails - however you want to describe it. The electronics in computers is designed to have these two options. Each electronic element that can either be on or off (0 or 1) is called a 'bit'. But only counting 0 or 1 on its own is rather restrictive (you might say it was a bit restrictive) so let's put two bits together and use them to represent a single number. Then we can have:
(0,0) = 0
(0,1) = 1
(1,0) = 2
(1,1) = 3
So now we can count from 0 to 3 by just using the values 0 and 1 - it's getting better. The general rule is that the range of numbers you can count is given by 0 to (2N-1) where N is the number of bits being used.
It is normal practice to put 8 bits together to represent a number. We can then count from 0 to (28 -1) or 0 to 255. Such a combination of bits is called a BYTE. Several bytes can be used together to represent even larger numbers. When we start talking about storing large amounts of numbers (or characters) we need some new words and we use prefixes to make them. A prefix is simply a group of characters attached to the front of another word which indicates a number. For instance, the prefix KILO means 1000. The word kilogram, therefore, means 1000 grams.
In computer-speak, the first word we come across is KILOBYTE, and immediately we hit a problem. Bits and bytes, and computers in general, like powers of 2 (4,8,16,32 etc) while in general life we much prefer powers of 10 (100,1000 etc.) - so what exactly is a kilobyte? It's a bit of a cheat actually. Computer language borrowed the 'kilo' prefix but then they fiddled it to mean 'about 1000', so that kilobyte actually means 1024 bytes. Why 1024? - well 210 = 1024, not 1000. Unfortunately it gets worse so that when computer people talk of 1 megabyte they actually mean:
210 x 210 = 1024 x 1024 = 1,048,576 bytes
- not all that close to a million bytes. How confusing!
What's the origin of the words bit and byte?
The word 'bit' dates back to 1948, when computers were just becoming modern machines. An article written by C.E. Shannon in a technical journal of the time credits J.W. Tukey with its first use. The word comes from 'binary digit', but it also means a 'small part'. A bit of a neat play on words, eh?! You might also imagine that since it deals with two things (0s and 1s) it is only fair the word contains the letters 'bi' as in bicycle and binoculars.
On the other hand it’s not clear where the word byte comes from. It means 'eight bits' and was probably first used by someone working at the computer firm IBM around 1964. One suggestion is that the word could have come from BInary digiT Eight? The letter ' I ' was then substituted by a ' Y ' to save any confusion with the word bit! Maybe you could come up with your own version of where the word came from?