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Introduction to Computer Science

You don't need to be an expert in computer science to be a good developer, but understanding how your programs run on the machine is essential in deeper understanding the concepts we will cover.

In the next short sections, you will learn how computer follows instructions, work with information, make decisions and repeat tasks.

Computers Are Not Magic​

Computer programs are just instructions for a computer to follow. Think of them as a recipe that contains step by step instructions that the computer will follow.

Once you see the code as steps your machine executes, its stops looking like magic

What Is Data?​

Data is "stuff" that computer works with and is usually grouped in 3 mayor categories:

  • Numbers (your age, price of the item or a score in a game)
  • Text (your name, a message, title)
  • Yes/No answers (is the light on?) A program takes this data and does calculations on them, moves them around and displays the result back to user.

Almost all programmes do just this. Move and calculate data to achieve some result

What Is an Actual Computer?

Computer is a machine consisting of many parts. We will focus on 3 main parts that play a vital role in executing our programmes.

These are:

  • CPU - Cemtral Processing Unit
  • RAM - Random Access Memory
  • Storage - HDD / SSD

CPU - Central Processing Unit​

This is the brain of your machine. Its responsible for executing instructions that your program gives it. The CPU understands instructions as tiny commands, like move this piece of data over here

CPU have a tiny bit of extremely fast memory called cache. As this memory is small, we also use RAM Memory

RAM - Random Access Memory​

This is very fast and fairly large peace of memory, that CPU uses to load your program while executing, so it has fast access to all data that it needs for the operation. RAM Memory data is deleted if power is lost. That's why we need another form of memory: Storage

Storage - HDD/SSD​

This is where your files, your programs, and everything else is stored, when not in use. This storage solution has the most capacity but it is also the slowest. Computer use this memory to store data permanently and it is not lost on power cut out.

What Is Hardware?​

Physical components that you actually see when you open a computer are called hardware. The ones listed above (CPU, RAM, Storage) are just some of the components you can have.

What Is Software?​

All programs are considered software. We cannot see these, but we do see work they do for us.

What Is Operating System (OS)?​

Operating system (OS) is a collection of sofware that manages hardware and applications by allocating resources.

Examples of operating systems are:

  • Windows
  • Linux distro
  • MacOS
  • Android

All computers, from your cellphone to huge servers all run some kind of operating system. Its essential peace that organizes and manages how hardware and software talk to each other.

How Do They Work Together​

When you run any program, your Operating System (OS) takes data stored in permanent storage and moves it into RAM so CPU can have instant access to it. CPU then executes instructions some program set.

Programming Languages​

Imagine you are trying to order food in a country where you don't speak a word of the local language. You can point at pictures, make hand gestures, or mimic eating, but miscommunications are bound to happen.

This is the exact problem we face with computers. At their core, CPU consists of billions of tiny electronic switches (just like a light switch but super tiny) that only understand two states: on (1) and off (0). Humans, on the other hand, communicate using complex spoken languages, abstract concepts, and logic. Writing instructions out of billions of ones and zeros is practically impossible for a human.

A programming language solves this. It acts as the ultimate bridge: a structured set of rules that allows us to write instructions in a way humans can read and write, which then gets translated down into the electrical impulses the computer can actually execute. Without programming languages, software as we know it simply couldn't exist.

At its core, a programming language is a set of instructions that enables humans to communicate with computers - using a series of symbols that serve as a bridge that allows humans to turn our ideas into instructions computers can understand. Like spoken languages, each language has its own unique syntax, structure, vocabulary, and even slang or shortcuts.

Python Programming Language​

Python is a versatile, high-level programming language designed with a clear philosophy: code should be as easy to read as it is to write. Because its syntax closely mimics the English language, it removes the "language barrier" between your ideas and the computer, making it an ideal choice for beginners and professionals alike.

What Can You Build with Python?​

Python’s flexibility allows it to thrive in almost every corner of the tech industry. Whether you are automating a small spreadsheet or powering a global social network, Python has the tools to handle it:

  • Web Development: Powering the back-end of modern websites using frameworks like Django and Flask.
  • Data Science & Math: Analyzing massive datasets, performing complex calculations, and generating visualizations.
  • Automation & Scripting: Writing "glue code" to automate repetitive computer tasks or manage system administration.
  • Software Tools: Creating desktop applications (GUIs), command-line tools, and even game prototypes.
  • DevOps & Infrastructure: Managing cloud deployments and streamlining software delivery pipelines.

Real-World Impact: You are likely using Python every day without knowing it. Reddit is built primarily on Python; Dropbox used it to scale from a prototype to a giant; and Instagram runs one of the world's largest deployments of the Python-based Django framework.

Recap

You have reached the end of this lesson. Before you go to next lesson, take a moment to answer following questions. If you do not know the answer, click on the question to read the answer.

For a deep dive into how computers run your programs, visit this article