1. Introduction: Demystifying the Magic

Computers often appear magical-throw some metal and silicon in a box, and suddenly, complex tasks are performed. But beneath the surface, everything is grounded in physics, logic, and mathematics15.

2. The Heart of the Computer: The CPU and Transistors

At the core of every computer is the Central Processing Unit (CPU), a tiny chip made from silicon. This chip contains billions of transistors-microscopic switches that can be turned on or off, representing binary states 1 and 0 2. These binary states form the fundamental language of computers, known as the binary system 12.

  • Transistors act as switches or amplifiers, controlling the flow of electrical signals. Modern CPUs pack billions of these into a single chip, enabling rapid, complex computations2.
  • Binary System: Each transistor's state (on/off) encodes a single bit of information12.

3. From Bits to Bytes: Storing and Representing Data

  • Bit: The smallest unit of data, representing a 0 or 1.
  • Byte: A group of 8 bits, allowing for 256 unique combinations (2^8)1.
  • Binary Numbers: Each bit in a binary number represents a power of 2. For example, 1000101 equals 69 in decimal3.
  • Hexadecimal: Because binary is hard for humans to read, computers often use hexadecimal (base-16), where one digit represents four binary bits, making it easier to interpret large binary numbers3.

4. Logic Gates and Boolean Logic

  • Logic Gates: Built from transistors, these basic circuits perform operations based on Boolean logic (AND, OR, NOT, etc.), enabling computers to make decisions and perform calculations4.
  • Boolean Logic: Uses true/false (1/0) values to process logical statements and control data flow in circuits4.

5. Representing Characters: Character Encodings

Computers must also handle text, not just numbers. Character encodings like ASCII assign binary values to characters (e.g., "A" = 65 in ASCII), allowing computers to store and display text1.

6. Operating System and Machine Code

  • Operating System Kernel: The core software (like Windows, Linux, or macOS) that manages hardware and software interactions, using device drivers to communicate with hardware components 1.
  • Machine Code: The lowest-level instructions, written in binary, that the CPU executes directly 1

7. Memory and the Fetch-Decode-Execute Cycle

  • RAM (Random Access Memory): Temporary storage for data and instructions, organized as a grid of addresses, each holding one byte1.
  • Instruction Cycle: The CPU repeatedly fetches instructions from memory, decodes them, executes them, and stores the results-a process called the fetch-decode-execute cycle.

8. CPU Speed, Cores, and Threads

  • Clock Speed: Modern CPUs perform billions of cycles per second, synchronized by a clock generator.
  • Cores and Threads: CPUs often have multiple cores, each capable of handling separate tasks in parallel. Threads allow each core to switch between multiple tasks quickly1.

9. Programming Languages and Abstractions

  • High-Level Languages: Programming in raw machine code is impractical, so we use languages like Python or C, which are compiled or interpreted into machine code1.
  • Shells and Interfaces: The kernel is accessed via shells (command-line or graphical interfaces), making it easier for users and programs to interact with the system1.

10. Variables, Data Types, and Memory Usage

  • Variables: Named storage locations for values.
  • Data Types: Include integers, floating-point numbers (for decimals), characters, and strings. Different types use different amounts of memory (e.g., an integer typically uses 4 bytes)1.
  • Floating-Point Numbers: Allow for a wide range of decimal values, but can introduce rounding errors due to binary approximations1.

11. Data Structures: Organizing Information

  • Arrays: Fixed-size collections of elements, efficient for indexing.
  • Linked Lists: Flexible, dynamic structures where each node points to the next, but slower for random access.
  • Stacks (LIFO) and Queues (FIFO): Specialized structures for managing ordered data.
  • Hash Maps/Dictionaries: Store key-value pairs for fast lookups, using hashing to determine storage location; collisions are handled with techniques like linked lists.
  • Graphs and Trees: Graphs model networks, trees provide hierarchical organization (e.g., binary search trees for fast searching)1.

12. Algorithms and Optimization

  • Algorithms: Step-by-step procedures for solving problems.
  • Functions and Recursion: Functions encapsulate algorithms; recursion allows functions to call themselves, requiring a base case to prevent infinite loops.
  • Memoization: Caching results to avoid redundant computation.
  • Big O Notation: Describes how algorithm performance scales with input size (e.g., O(n) for linear time, O(n!) for factorial time)1.

13. Why This Knowledge Matters

Understanding the layers-from transistors and binary logic up to programming languages and algorithms-gives you a solid foundation for software engineering, system design, and troubleshooting15. Whether coding, designing, or debugging, this knowledge is invaluable.

References

  1. . Computer Science in 17 mins
  2. https://www.explainthatstuff.com/howcomputerswork.html
  3. https://sage-advices.com/what-does-a-transistor-do-in-a-cpu/
  4. https://dev.to/m_mdy_m/understanding-number-systems-binary-decimal-hexadecimal-and-beyond-55i4
  5. https://www.savemyexams.com/igcse/computer-science/cie/23/revision-notes/10-boolean-logic/boolean-logic/logic-gates/
  6. https://artsandculture.google.com/story/how-computers-work/DgWBfSPf_sFSow
  7. https://www.youtube.com/watch?v=fOcoLKHeOTI
  8. https://www.techtarget.com/whatis/definition/ASCII-American-Standard-Code-for-Information-Interchange
  9. https://www.techtarget.com/searchdatacenter/definition/kernel
  10. https://softwareg.com.au/blogs/computer-hardware/how-does-ram-and-cpu-work-together
  11. https://www.fortra.com/resources/articles/modeling-multi-threaded-processors
  12. https://www.linkedin.com/pulse/how-do-computers-work-sam-frymer
  13. https://newsroom.intel.com/wp-content/uploads/2024/05/tech101_transistors_vis3_v01-1024x779.gif?sa=X&ved=2ahUKEwiZufukq_2MAxUva_UHHXUXAh4Q_B16BAgEEAI
  14. https://informatecdigital.com/en/Number-systems-in-computing-binary-decimal-and-hexa/
  15. https://byjus.com/jee/basic-logic-gates/
  16. https://cs50.harvard.edu/ap/2020/assets/pdfs/ascii.pdf
  17. https://www.scaler.com/topics/kernel-in-os/
  18. https://www.livewiredev.com/the-relationship-between-ram-and-cpu-performance/
  19. https://shardeum.org/blog/cpu-cores-and-threads/
  20. https://www.reddit.com/r/computerscience/comments/ljfcm3/how_computers_work_the_basics/
  21. Exploring How Computers Work