Computers work with base 2 because switches can be either switched on or switched off just like your light switches. ON or OFF, that’s 2, so its base two. (We have 10 things on the ends of our two hands so we count in base 10, its as easy as that. If we had 8 fingers like the Martians we’d count in base 8 obviously).

Here is 2 raised to the power 8:

or:

or:

If you work out 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 you get 256

THIS IS CALLED ONE BYTE, there’s 8 BITS in a byte. That’s the INDEX, 8 above.

**Here’s a typical BYTE: 1 0 1 0 1 1 0 1**

Its a number in base 2, where you can only have the numbers 0 (which represents ‘OFF’) and 1 (which represents ‘ON’).

The different columns are similar (in fact **isomorphic **is the word, I love that word) to our normal (base 10) number system, but every column is worth twice as much as the one before, unlike base 10 where every column is worth 10 times more than the one before.

I just wanted to tell you about multiples of bytes, so here goes:

1 **byte** is 2 to the power 8

1 **kilobyte** is 2 to the power 10

1 **megabyte** is 2 to the power 20

1 **gigabyte** is 2 to the power 30

1 **terabyte** is 2 to the power 40

1 **petabyte** is 2 to the power 50

1 **exabyte** is 2 to the power 60

1 **zettabyte** is 2 to the power 70

1 **yottabyte** is 2 to the power 80

**1 yottabyte** is enough memory to store 250 trillion DVD’s

OK

and remember, that’s a pile of 80 crossed red rods if you call the red rod 2. I bet you can’t make one of them… However, is there another way using rods…? I’m not telling…

One of the most powerful computers at the moment is **TITAN**, built by Cray at Oak Ridge, and it can only store 17.59 terrabytes of information. How pathetic is that? (Got to admit, it’s pretty fast though….)

However the US government has a computer called **DAWN** which can simulate the brain of a rat, that’s coming on…. In another 20 years or so, there will be computers that can simulate the brain of a human….that’s **SCARY** and we’d better **WATCH OUT!**