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Sunday, July 1, 2012


I remember back in the early 1980’s, when personal computers were just becoming common, that a friend asked me a simple sounding question: ‘How do computers work?’  She wanted to know what was happening inside them to make them capable of doing what we asked of them. I didn't have a very good idea myself so when I tried to answer, I couldn't seem to get anywhere - it was a combination of my ignorance and her lack of any scientific background. It has kind of bothered me ever since and now that I have a rudimentary knowledge and can use links to the internet to fill in gaps, I have the temerity to try to at least throw a little light on the subject once more.

First, all computers run on electricity and work by means of switches that can either let electricity go through [that is represented as a 1] or turn it ‘off’ [that is represented as a 0]. So to understand what goes on inside a computer we must use the so-called ‘base two’ number system or ‘binary’ system. That means there are only two symbols for all numbers, 1 and 0. In the decimal system that we are used to, there are ten numerals - from 1 to 9 and, of course, 0.  We need 0 as a ‘place saver’.  Try adding 8 + 2.  There is no numeral for ten so we write     8 + 2 = 10 where the 1 in the second place means one ten. With that in mind, dealing with only two numerals is really the same.  Add 1+1, there is no numeral for 2 so we write 10 where the 1 in the second placed mens 2. You can click on the link for binary system for more of a tutorial. Not only numbers but letters and instructions can be programmed into computers as groups of 1’s and 0’s.  For instance when you press the letter 'a' on the keyboard the electricity is routed through to the agreed symbol for 'a', which is 01100001.

Next come transistors that are used as a switches in the computer.  The diagram to the right is like a transistor where the blue water represents the electric current. The water cannot flow from C [the collector] when the black plunger is blocking its way [the 0 position] but if water is forced into B [the base] it pushes the plunger up and lets the current [water] flow into E [the emitter]. The more we push water into B, the greater the flow into E.  The invention of transistors was key to the development of modern computers.  Without these tiny reliable devices, the integrated circuits used in powerful computers and smart phones would not be possible.

Lastly – at the heart of the computer are the electronic circuit boards or Integrated Circuits [IC].  They are made up of thousands of transistors, as well as resistors, capacitors, inductors and diodes. These electronic components are all connected by tracks that conducts current.  The combination of components allows all sorts of complicated operations to be performed and data to be moved from one place to another.  In an Intigrated Circuit the components are very small and interconnections are formed on the same material, typically crystalline silicon, often called a silicon chip.
Hope this throws a glimmer of light on a computer's inner workings - if you're interested in how computers work from a user's point of view, click on this highlighted website.     Rie 


  1. Excellent! Why don't you do a post on " algorithm?"

  2. Useful information shared..I am very pleased to study this article..Many thanks for giving us nice information.