Machine stories are about machines. Period. No drama, suspense or fantasy — just plain simple machines, and how they work. To get this started, the simple machine that humans think of are complex is what will be covered in this story. The computer!

This story is part of a trilogy which takes us through this simple machine's journey.

Computers are not magical. Yes they can beat humans in chess, go, or jeopardy, but it is not a mysterious being that can do multiple things at the same time. It’s just a simple machine no different than a light switch and can only do a very few things: it’s just that they are incredibly fast and tiny. They are good at doing specific simple things one after another in an orderly sequence as they are told in a consistent manner without getting bored. No questions asked!

If their specific simple task is to ask questions, then questions will be asked. A computer’s super power is its speed, not complexity.

Computers work on electricity and electricity travels at the speed of light, which is around 299,792 kilometres per second. Electricity travels through wires at around 1/100th the speed of light due to the weight of the electron streams. So it would take approximately 2 minutes to turn on a light bulb in the moon connected by a long pair of wire from earth. This speed allows a google search result to be returned in a fraction of a second. Hence the human’s obsession with the computer since they prefer their search result displayed instantly, not mailed to them a few days later.

What a computer can do hasn’t changed since it’s birth (1940). It still does the same few simple things, except that it has gotten faster, tinier, and cheaper.

 They are made of a few parts with a specific mission combined together to form a machine that helps humans.

Computers operate in binary and only understands two possible states: “on” and “off”, which is called a bit. The bits in a computer either has electricity (on) or not(off). There is no gray area. The only thing that has to move in a computer is electricity and the flow of this electricity is controlled by transistors (diagram below). The only decision this machine takes is to turn “off” or “on”, very similar to a light switch!.

How a machine works is usually understood by looking inside it. Different chips, plugged into a board is what can be seen if a computer is opened. Yes! looks can be deceiving, unlike a mechanical machine, staring inside a computer either gives you a headache or itchy red eyes (if you're allergic to dust) but the electric signal travelling through these chips cannot be seen.

In order to make it simple for humans, the parts of the computer made with these chips are characterized by giving them a name and its own symbol. These parts are connected into something else that also gets a name and another symbol. It keeps going until its done and the name given to the final product is "computer" and the symbol somewhat looks like this --> 💻.

Today’s computers use billions of tiny transistors to perform calculations by forming basic logic components called gates (not the founder of Microsoft) and it symbols are represented below.

The basis for computer logic was formed by George Boole a long time ago (1851-1864), which helps computers form an opinion (true / false) on the inputs presented to it. A logic gate might sound complex, but it is a simple electric circuit with two inputs and an output. It receives two incoming electric currents, compares them, and decides to generate a new outgoing electric current depending on the truth it finds. The most common gates called AND, OR, NOT, XOR (Exclusive Or), NAND (NOT AND), and NOR (NOT OR). A logic gate is like an admission office to a school that enforces these simple rules:

 Student admitted if excellent grades in Math and Science

 Student admitted if excellent grades in Math or Science or both

 Student admitted if excellent grades in Math or Science but not both

Student neither good in Math or Science but excellent in sports

Gates are the only thing that is required to build a computer, but a lot of them have been wired together to make something purposeful. One or more NAND gates is what makes a computer do what it could. Typically, standard logic gates are available in 14 pin or 16 pin DIL (dual in line) chips.

The TTL 7400 chip, containing four NANDs. The two additional pins supply power (+5 V) and connect the ground


By Audrius Meskauskas - Used GFDL images from 

Most complex math operations such as addition, subtraction, repeated addition (a.k.a multiplication), and repeated subtraction (a.k.a division) can be achieved by creatively assembling these gates in a circuit, where one output can be connected to input of one or many gates.

Now that the most complicated part of this simple machine's design has been covered, we'll be exploring its memorization skills in the sequel.

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