2) Computer Fundamentals

1. Understanding a Computer

Definition

A computer is an electronic device designed to process data. It can perform a wide range of tasks by executing instructions, which can include calculations, data processing, and control over other devices.

Components

Computers consist of two main components:

• Hardware:
  • Physical parts that you can touch and see. Here are some key hardware components:
    • CPU (Central Processing Unit): Often referred to as the "brain" of the computer. It performs calculations and executes instructions from software. The CPU processes data by performing operations like addition, subtraction, and comparison.
    • RAM (Random Access Memory): This is temporary memory used by the CPU to store data and instructions that are currently in use. It is fast but volatile, meaning it loses all its information when the computer is turned off.
    • Storage Devices: These are used to permanently store data. Common types include:
      • Hard Disk Drives (HDD): Traditional storage devices that use spinning disks to read/write data.
      • Solid State Drives (SSD): Faster storage devices that use flash memory and have no moving parts.
• Software:
  • Programs that instruct the hardware on what tasks to perform. Software can be further divided into categories, such as:
    • Operating Systems (OS): These manage the hardware and provide services for other software. Examples include Windows, macOS, and Linux.
    • Application Software: Programs designed for specific tasks, like word processing (Microsoft Word), web browsing (Google Chrome), or gaming (Minecraft).

2. Fundamental Computer Concepts

Binary (0s and 1s)

Computers use the binary number system, which consists only of two digits: 0 and 1. This is the language of computers because it corresponds directly to the electrical signals inside the computer:

• 0 typically represents "off" (no current).

• 1 represents "on" (current flowing).

• Example:

  • The letter "A" in ASCII is represented in binary as 01000001.

• Image Suggestion: A chart showing binary representations of letters or numbers.

All data, whether it's text, images, or sounds, is ultimately represented in binary form within the computer.

Processor (CPU)

The CPU is the core component that executes instructions from software. It processes data using two main types of operations:

• Arithmetic operations (e.g., addition, subtraction).
• Logic operations (e.g., comparing two values).
• Example:
  • If a program asks the CPU to add two numbers (e.g., 2 + 3), the CPU processes this request and returns the result (5).
• Image Suggestion: An infographic showing how a CPU processes data.

The CPU operates at a high speed, measured in gigahertz (GHz), meaning it can perform billions of instructions per second.

Memory

• RAM (Random Access Memory):

  • Temporary memory that stores data and programs that are currently in use. When you open a program, it gets loaded from the storage into RAM for quick access. However, when you turn off the computer, all data in RAM is lost.
  • Example: When you open a web browser, the data for all open tabs is stored in RAM until you close them or shut down the computer.

• ROM (Read-Only Memory):

  • A type of permanent memory that contains essential instructions for starting up the computer. Unlike RAM, the data in ROM is not lost when the computer is turned off. It often contains the firmware, which is software that is closely tied to specific hardware and usually does not need to change.
  • Example: The BIOS (Basic Input/Output System) is stored in ROM, which helps boot the computer.

  Image Suggestion: A diagram explaining the difference between RAM and ROM.

3. Storage Basics

Files

A file is a collection of data or information that is stored on a computer. Files can come in various formats, including:

• Documents (e.g., .docx for Word documents).

• Images (e.g., .jpg, .png for pictures).

• Videos (e.g., .mp4, .avi for movies).

• Image Suggestion: A screenshot of a file directory showing different types of files.

Files are organized in directories (folders) on storage devices.

File Extensions

A file extension is a suffix at the end of a filename that indicates the type of file and tells the operating system which program should open it. For example:

• Examples:

• .txt: A plain text file.

• .jpg: A JPEG image file.

• .exe: An executable file that runs a program on Windows.

• Image Suggestion: An infographic illustrating common file extensions with icons.

4. .exe Files

Definition

An .exe file (short for "executable file") is a specific type of file used on Windows operating systems. When you double-click an .exe file, it tells the computer to execute the instructions within that file.

Function

• When an .exe file is opened, it loads the necessary instructions into RAM and begins running as a process in the CPU. This means the CPU starts executing the commands contained in that file, such as displaying a user interface or performing calculations.

• Example:

  • Opening notepad.exe launches the Notepad application, allowing you to write text.

• Image Suggestion: A screenshot showing a right-click on an .exe file in a Windows Explorer window.

Security Note

• Be cautious with .exe files downloaded from unknown sources, as they can contain malware or viruses that can harm your computer. Always download software from trusted sources.

5. Software Types

System Software

• System software is designed to manage the computer's hardware and provide a platform for running application software. The most common example is the Operating System (OS), such as Windows, macOS, or Linux. The OS manages resources, handles input and output operations, and provides a user interface.

• Image Suggestion: An image of different operating systems' logos.

Application Software

• Application software is designed to help users perform specific tasks. Examples include:
  • Word processors (e.g., Microsoft Word).
  • Web browsers (e.g., Google Chrome).
  • Games (e.g., Fortnite).
• Image Suggestion: A collage of various application icons.

These programs rely on system software to function and interact with the hardware.

6. Programs vs. Processes

Program

A program is a collection of instructions stored on a disk (e.g., in an .exe file). It is inactive until it is opened or executed. Think of it as a recipe that has not yet been cooked.

Example: Microsoft Word is a program that you can open and run.

Process

A process is what happens when a program is actively running in memory. When you open a program, the operating system creates a process for it, which includes:

• Allocating RAM for the program’s execution.
• Running the program's instructions in the CPU.
• Managing input/output operations for the program.

Image Suggestion: A diagram illustrating the difference between a program (on disk) and a process (in memory).

Once the program is closed, the process terminates, and the memory allocated to it is released.