Understanding Computers

Introduction

• Computers seem like magic but are based on logical principles.
• Inside a PC: Central Processing Unit (CPU) made of billions of transistors.
• Transistors can be either on or off representing 1 or 0 (binary).

Basic Concepts

Bits and Bytes

• Bit: Single binary value (0 or 1).
• Byte: Group of 8 bits, can have 256 different combinations.
• Binary Counting: Used to store information.

Binary and Hexadecimal

• Binary system: Based on powers of 2.
• Hexadecimal: More readable than binary, uses digits 0-9 and letters a-f.

Logical Operations

Logic Gates

• Built using transistors, represent logical statements (AND, OR, NOT).
• Basis for complex calculations using Boolean algebra.

Character Encoding

• ASCII: Assigns binary numbers to characters.

Software and Hardware Interaction

Operating System Kernel

• Examples: Windows, Linux, Mac.
• Manages hardware and applications, uses device drivers.

Memory and Storage

• RAM (Random Access Memory): Temporary storage for data and instructions.
• Four-step machine cycle in the CPU: Fetch, decode, execute, and store.

Programming Basics

Programming Languages

• High-level languages make programming easier by abstracting machine code.
• Examples: Python (interpreted), C (compiled).
• Variables, data types, arrays, and more.

Pointers and Memory Management

• Pointer arithmetic and memory allocation.
• Heap: Dynamically managed memory area, prone to memory leaks and segmentation faults.
• Garbage Collection: Manages memory automatically in high-level languages.

Data Structures

Arrays and Linked Lists

• Array: Contiguous memory, fixed size.
• Linked List: Nodes pointing to other nodes, dynamic size.

Specialized Data Structures

• Stack: Last in, first out (LIFO).
• Queue: First in, first out (FIFO).
• Hash Map: Key-value pairs, uses hash functions to assign keys to indices.
• Graph: Nodes connected by edges.
• Tree: Hierarchical structure, special case of graph.

Algorithms and Complexity

• Algorithms are step-by-step problem-solving instructions.
• Functions and recursive functions.
• Time and space complexity (Big O notation).
• Approaches: Brute force, divide and conquer, etc.

Advanced Topics

Machine Learning

• Teach computers tasks without explicit programming.
• Uses training and test data to build models.

Computer Networks

• Internet consists of interconnected computers via physical cables.
• Uses IP addresses and protocols like TCP/IP.
• Web: HTTP, URLs, DNS, client-server model.

Databases

• Relational Databases: Use tables, primary keys, and foreign keys.
• SQL: Language for database operations.
• Security: Prevent SQL injection attacks.

Summary

• Understanding these concepts requires practical application.
• Brilliant.org offers interactive lessons on these and many other topics.