How many gigs (GB) in your iPhone? Hard Drive? MP3 player, Video card? We don't talk much about bits and bytes anymore. All our gadgets and great stuff appear to work with a kind of magic or mystical NERD stuff. It seems way too complex to worry about unless you're an engineer or worse yet an actual NERD!!
While our high tech IS complicated, a few simple ideas can take away some of the mystery (and for some, a hidden fear of all the gadgets).
First, computers are not smart. In fact they're really dumb. About the only thing they can do is see whether the electric is on or off. It's like the light switch on the wall, you turn it on or off and that's it. That's the extent of "computer intelligence" What makes our gadgets look smart, are the clever ways engineers and scientists figured out how to use this "is it off?, or is it on?" binary way of thinking. You could say that OFF is nothing or zero (0), and ON is one (1). This on/off switch is called a "bit" of information. Taking this a little further, people put together 8 of these bits or switches and started the thing called "bytes".
The thinking went like this; "Well if we took 7 switches (later 8) that can be OFF or ON, we could assign a different meaning to each of the combination's of off and on" (see ASCII). So for example, if we turned on only the first and the last of 8 switches, and put the middle six off, we could agree to say that means the letter "A". With 8 switches you could have 256 different combination's, enough for all the letters, numbers, and other useful characters. That was a big help in getting us started making computers useful for more than just crunching numbers.
OK that's kind of interesting, but what happens if you turn the computer off? If we're talking about light switches, when you turn off the electric all the switches will loose their off/on information. So where's my "A", last tweet, email or sms? Well in some ways, they do go away. These electric switches (Logic gates) really do exist in most devices and they're the part we call RAM chips. All the memory in RAM gets lost when there's no juice.
Not wanting to loose all that precious information like our "A", we need something else. Several types of neat gadgets were developed to hold onto your tweets even when the lights go out. We need a way to remember which switches were off or on, when you turn the computer on again. One of the earliest ideas was to make little groups of 8 magnetic spots on a metal disk. These groups use the same "ASCII, byte" idea as RAM. If spot one is magnetized, the next 6 are not magnetized, and the last is, then... Wow, there's an "A". We saved your "A" on the thing we call a hard disk! Whenever you save something on your computer it magnetizes lots of little spots on a spinning metal disk called a hard drive. Whenever you want to retrieve that really important "shout out" to your BFF, the computer will read which spots are magnetized or not, turn on the matching switches and presto - your "A" is back. Floppy disks work with magnetism in the same way.
There are some other ways to save your "A". Since all our digital devices use the same "Byte" idea, it's always a case of figuring out how to hold on to a bunch of 0's and 1's. CD's and DVD's for example, have shiny surfaces that reflect light. If you would burn a tiny spot with a strong laser beam it wouldn't be as shiny and couldn't reflect light very well. So the zero and one are back! Shine a light (laser) on a spot and if it reflects... Yeah! a ONE! no reflection? You're a ZERO!
Putting it together, The electric switch, magnetic spot or burn on a CD are "Bits" and represent zero and one. Hmm, So that's why we say "Burn a CD"? 8 bits together in any form and you've got a "Byte". What does that mean? Think about your 16GB iPod... Do you know how many little switches it has? The G = "Giga" , means billion, the B = "Byte", means 8 switches or spots. So your little gadget actually has 16Gigs x 8 bits, or 128 Billion little switches inside!
The next time you start typing "YO!" You've just turned 24 switches off and on like this:
Y O !
101 1001 - 100 1111 - 010 0001
Now next time, believe it or not, it's those same dumb zeros and ones, used in really smart ways, that give us digital pictures and our uTube videos, but that's a story for another time.
