Computers and Microprocessors – Explained

Today world is supremely and finely based on technology, we all know that today’s modern era would be completely in a different “universe” without the amazing computers that have started this Information Technology era. The very first “computer” device was an analog one designed by Charles Babbage in the 1820’s that could compute additions, multiplications, divisions, etc and incorporated basic memory and a central control unit. On the other hand, the very first “digital computer” that could be programmed was invented by Konrad Zuse, the Z1, in 1936 that could compute binary. And finally the very first microprocessor was the Intel 4004 a 4-bit CPU introduced in 1971 that completely revolutionized the idea of a more compact computer.

Now, to clear up some of the terminology here, a computer is a whole system that works together to run a set of instructions (a program), a processor is the Central Processing Unit (CPU) of the computer system that executes and processes inputs for outputs (a microprocessor  is a processor made to fit on a small area or a chip) and a SoC or a system on a chip that has all components of a computer built onto a chip, the most advanced form of a computer to this date in 2017.

For a computer processor to work, a form of a semi-conductor must be used.This is because all the primary protocol and all the interactions among components that occur are through on and off electrical currents in a circuit board. The 1’s and 0’s also known as binary digits are representations of on (1) or off (0) wires on a chip, the main form of communication for a computer (all the little dark green shades and lines seen on a motherboard such as the one on the image are circuits that are made of conductive silicon).

The concept stated above is the idea behind how a computer interprets information, the basics. The goal of a CPU inside a computer is to perform operations with numbers that the software might command and output them to external devices such as monitors, drives, etc. Such operations are all conducted in the ALU (Arithmetic Logical Unit) of CPU where all arithmetic (algebra) operations are performed. The ALU receives information from a form of storage and the Control Unit of the CPU orders it to perform a designated operation, the way numbers are added or multiplied in an ALU is a very tricky concept to understand but I will try to explain it at the most basic level:

For the CPU to perform operations, it uses a semiconductor device called the transistor. The transistor is a device that uses silicone with added substances to amplify current or act as an motionless switch, in a computer it serves the most important role of a switch. Silicone (+4) is injected with two types of elements to increase or decrease conductivity in a process called doping .

In N-type doping, phosphorus (+5) is integrated in the silicone and due to its one extra valence electron causes a net move of free electrons.
In P-type doping, boron (+3) is integrated in the silicone and due to its lack of a valence electron creates extra spaces for electrons (holes).
Using a combination of these layers, electrons can be made to move or stop within this device (a switch) with the application of a voltage.

Well how do computers use this concept to perform operations on numbers? Well at the very base of the tree, these on and off transistors act as 1’s and 0’s to the computer and using them we can create protocols called a logic gates:

These logic gates are classified for various commands, for example:

AND command: (A and B are transistors and X is an output device(light bulb). If the two transistors are in series with the bulb we can witness the following 3 scenarios based on how we distribute the voltage:
(A/ON)-in series with-(B/ON)–output to–(X/ON)

(A/ON)-in series with-(B/OFF)–output to–(X/OFF)

(A/OFF)-in series with-(B/ON)–output to–(X/OFF)

 

 

Along with the AND command an ALU has thousands of transistors set up for more complex commands too (like OR, NOR and IF). They help the ALU in figuring out what outputs are made from 0’s and 1’s as inputs, since only two outputs are possible 1 or 0. This is the processing part of a CPU, since numbers and letters are stored as a set of binary (for ex: G=0110010001..  or 324=100001101010..), this method allows the addition of these 1’s and 0’s leading to a new combination of binaries which is mapped to a specific unique number/letter. The frequency at which all these operations occur at is controlled by one “god” wire called the clock, this speed is the CPU’s clock speed and nowadays these clock speeds have reached the Gigahertz (Ghz) or about 1 billion times (rounds of operations) per SECOND.

And that is pretty much about it for how at the basic level the CPU processes stuff. It works with other components such as the RAM (primary storage) and secondary storage. The RAM (Random Access Memory) stores data (0’s and 1’s) in various addresses and is directly communicating with the CPU at a speed usually slower than the clock speed. The CPU orders an address and sends it to the RAM ( with an enable wire turned on) and RAM sends whatever was stored in that address back to the CPU. CPU then processes something and sends it to be stored back in RAM or sends it to an external device (mouse, monitor, etc)

 

 

 

Sources:

https://computer.howstuffworks.com/pc.htm

Youtube channel: “In One Lesson”

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