View of a circuit board that might be found inside of a computer
Computers shape our lives every day. The food on the shelves, this article on your screen, and the pencil on your desk were all affected by computers. Today most of the world is accustomed to computers' omnipresence in life, and they have changed the world in innumerable ways. Yet, the first computers took up an entire room, and could barely solve a quadratic equation. As the field of computer science grows and expands, the world will change again and again.
The first computers were only capable of the task they were built to do. A computer that solved quadratic equations could only solve quadratic equations. People soon realized that a computer that could only solve one task was neither efficient nor useful. Eventually, computer scientists realized that they could split computers into a few individual parts that could be programmed with software to carry out infinitely complex operations. This abstraction allowed for computers that could go from solving quadratics to sifting the internet in milliseconds.
A computer is made of 5 parts. These include the CPU, RAM, GPU, Storage, and the Motherboard. The first, and arguably most important part, is the CPU. The CPU is the Central Processing Unit, a silicon wafer capable of performing billions of calculations per second. Every CPU is made of transistors, tiny switches that are unfathomably small. Each of the transistors in a CPU is either on (1) or off (0) and somehow, and a seemingly arbitrary combination of 0s and 1s creates this brilliant webpage in front of you. While powerful, the CPU has little memory and cannot store all of the data required to run every open application on your PC. This is the RAM’s job, which stores most of the active data on your computer. RAM stands for Random Access Memory and allows the CPU to access the data it requires to perform complex calculations quickly. The GPU or Graphics Processing Unit generates the images you see on your screen. In many cases, the GPU is a part of the CPU, receiving data from it, operating on it, and storing the resultant screen data in the RAM. Then the screen loads the data from the RAM onto the display. Storage is where the majority of a computer’s data is stored (thus the name, of course). Last but not least is the Motherboard. The Motherboard is a plastic plate imprinted with wires. It connects all the parts of the PC together. Additionally, the Motherboard facilitates connections to Input/Output devices like speakers and USB ports.
So how does a seemingly random sequence of 1s and 0s become the electronic wonderland we immerse ourselves in today? Math. We, humans, count in base 10; we use 10 digits, 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. However, in the early days of computer science, this was impossible to do. Thus we made computers “think” in base 2, also known as binary. Base 2 has 2 digits, 0 and 1. Zero stands for “off,” and 1 stands for “on.”
Using binary, we can denote numbers in a form that is easy to produce with a computer. But how does a number become text? Similar to how we say that ‘A’ is the first letter in the alphabet, we can assign numerical values to non-numerical items. Every one or zero is a bit, a tiny unit of storage. Eight bits become a byte. Every byte of storage is assigned an address in the RAM and can be called upon for later use. While storing numbers as bits allows us to store large values, data is worthless if you can’t use logic to decipher it. Thus we turn to logic gates.
Every operation that a computer carries out uses logic gates. There are three logic gates, AND, OR, and NOT. An AND gate takes in two bits and returns 1 if they are both 1, and 0 otherwise. An OR gate takes in two bits and returns 1 if either or both of them are 1. A NOT gate takes in a bit and returns its opposite (Input: 1 Output: 0). But how does a computer add? Just like in base 10, addition happens digit by digit. To perform this calculation, the addition operation makes use of an XOR gate, AND gate, and some memory (To store the carry). XOR returns 1 if only one of its inputs is one. Take a look at the diagram and example below.
Byte: 00001010 ← Byte with a value of 10
Byte: 00001110 ← Byte with a value of 14
Digit: 76543210 ← The computer goes “backwards,” from right to left!
Digit 0 Carry = 0 Result = 00000000:
0 XOR 0 : 0 → Result = 00000000
0 AND 0 : 0 → Carry = 0
Digit 1 Carry = 0 Result = 00000000:
1 XOR 1 : 0 → Result = 00000000
1 AND 1 : 1 → Carry = 1
Digit 2 Carry = 1 Result = 00000000:
0 XOR 1 : 1 → Result = 00000100 → Carry → 1 XOR 1: 0 → Result = 00000000 , Carry = 1
Digit 3 Carry = 1 Result = 00000000:
1 XOR 1 : 0 → Result = 00000000 → Carry → 0 XOR 1: 1 → Result = 00001000
1 AND 1 : 1 → Carry = 1
Digit 4 Carry = 1 Result = 00001000:
0 XOR 0 : 0 → Result = 00001000 → Carry → 0 XOR 1: 1 → Result = 00011000
0 AND 0 : 0 → Carry = 0
From here the computer continues to carry on adding digit by digit, but that is not shown here because all operations henceforth would be identical to the first.
Result = 00011000 ← Byte with a value of 24, 10+14=24 (Addition successful Yay!)
Everywhere I go, I see people wondering if computers have stopped the progress of society. We first achieved flight in 1903. Just 66 years later, humans stepped foot on the moon. Fifty - three years have passed since then and human extraplanetary space flight is still a vision of the future. A teacher of mine asked me what we as a society have achieved after the dawn of the internet and high-speed computing. While human space exploration stalled, the reign of computers began. Fifty-three years ago we required humans to calculate orbital trajectories. Now, all it takes is a push of a button and a few seconds. In the last decade, we built computers that can mimic human language to the point at which one may forget that they are conversing with a machine. Today, I can spread my message to billions of people across the world in milliseconds. Computers have not stalled the progress of society. Computers are tools that allow us to change our world so fast that we don’t even realize it.
Computers are everywhere, and they are not going away any time soon. As the field of computer science grows, so will computers' presence in our lives. The computers of the future may replace transistors with qubits, electronic storage with DNA storage, and screens with a neural interface. At the time I am writing this article, the device you are using to read this article can process billions of instructions per second (If you are reading this in the near future, it may be trillions or more). That's more than enough power for a device to plot a trajectory to the moon. So why won’t it? Why does your PC oblige your desire to read this article? Programming. If hardware is the heart of a computer, software is the brain. Without programming, a computer is just an expensive lump of metal and plastic. The world of programming is a vast world filled with ingenuity and is a world that will be explored in our next article.
Post By: Armaan G.
Photo Credits: Alexandre Debiève
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