CIS3355: Business Data Structures
Fall, 2008
 

What do bits have to do with computers??

Bits, or light switches, if you wish, are how the computer stores information.

Right. Light switches.
Controlled by little alien light switchers, right?

Basically, yes. 

It is how information is stored in RAM (Random Access Memory), the registers in the Central Processing Unit (CPU), and secondary storage (hard drives, CD-ROMS, etc). Both RAM and the CPU do contain little "light switches", and essentially act just the same as the light switches we have discussed in the previous tutorials. They are either 'on', or have electricty flowing through them, or they are 'off ' or have no electricty flowing through them (Actually, they always have electricity flowing through them, but the electricity is either high or low voltage; still a binary condition).

It might make a little more sense if we go back in time to the first computers.

The main memory (RAM) for the first computers were magnetic cores. A small ring, or core, originally about the size of a 'o' (the character 'o') on a printed page of paper, made of of ferrite (a ferromagnetic ceramic) could be magnetized in either of two opposite directions (clockwise or counterclockwise). Therefore such a core can be used for storing a bit of information. For almost 15 years, 'core' was  the most important memory device. These cores were the 'light switches' that were either 'on' or 'off'.

Sorry about the 'alien light switchers', but the voltage sent through RAM and the CPU were originally controlled by Vacuum Tubes (Generation I), Transistors (Generator II) and later by transistors embedded in silicon chips.

Therefore, we could say that a computer is essentially a collection of light switches (bits).

That's it? Light switches?

Yes and no. Certainly, there is much more: Busses to move the data, Logic gates, instructions, much more. But at the core of it all are the "light switches" (bits).

The main difference between what we we view as a light switch, and the messages it conveys, and a bit is how quickly we change the information it represents. Computers use electronic switches, as opposed to mechanical switches.

How quickly can we change the information represented?

That's coming up next.

Some good additional references include:

1.   How do Computer Clocks work?
2.   Binary Code: The Bits and Bytes Game
3.   An essay on bits, bytes

At this point in time, you should be able to Answer the following questions:

1. How are bits, or light switches, the basis of computers?
   
   It is how information is stored in RAM (Random Access Memory) and in the registers in the Central Processing Unit (CPU).
    
2. How were these "light switches" originally stored?
   
   The main memory (RAM) for the first computers were magnetic cores. A small ring, or core, originally about the size of a 'o' (the character 'o') on a printed page of paper, made of of ferrite (a ferromagnetic ceramic) could be magnetized in either of two opposite directions (clockwise or counterclockwise).
    
3. How was the voltage to these "light switches" controlled?
   
   The voltage sent through RAM and the CPU were originally controlled by Vacuum Tubes (Generation I), Transistors (Generator II) and later by transistors embedded in silicon chips.
    
4. How are computer switches different from "light switches"?
   
   The main difference between what we we view as a light switch, and the messages it conveys, and a bit is how quickly we change the information it represents. Computers use electronic switches, as opposed to mechanical switches.
    
5. Bits form the basis of:
   
   a.  RAM Storage
   b.  Secondary Storage
   c.  CPU Storage
   d.  a and c
   e.  All of the above
   
   Answer: e
    
6. RAM originally consisted of:
   
   a.  Transistors
   b.  Magnetic Core
   c.  Vacuum Tubes
   d.  Integrated Circuits
   e.  All of the above
   
   Answer: b
    
7. The difference betwen a light switch and an electronic switch is:

   a.  light switches are mechanical
   b.  electronic switches are slower
   c.  electronic switches rely on decibel regulation
   d.  a and c
   e.  All of the above
   
   Answer: a
    

8. The voltage sent to electronic switches is now controlled by:

   a.  Transistors
   b.  Magnetic Core
   c.  Vacuum Tubes
   d.  Integrated Circuits
   e.  All of the above
   
   Answer: d

   

   This page was last updated on 05/23/05