> For the complete documentation index, see [llms.txt](https://riteshs4hu.gitbook.io/infosec-notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://riteshs4hu.gitbook.io/infosec-notes/computer-fundamentals.md).

# Computer Fundamentals

## What is a computer?

A computer is an electronic device that accepts input, processes it, and produces output under the control of the user.

### **Hardware**

Hardware refers to the physical components of a computer that can be touched.\
**Examples**: CPU, monitor, mouse, etc.

### **Software**

Software encompasses all logical concepts and processes that cannot be physically touched.\
**Examples**: Operating Systems (OS), DOS, Windows, etc.

#### **Types of Software**

1. **System Software**:
   * Responsible for managing hardware and system resources.
   * **Examples**:
     * Operating Systems (OS)
     * BIOS
2. **Application Software**:
   * Designed to perform specific tasks or functions for the user.
   * **Examples**:
     * VLC Media Player
     * MS Paint
3. **Utility Software**:
   * Provides additional functionalities for system maintenance and security.
   * **Examples**:
     * Antivirus software
     * Firewalls

***

### **Input Devices**

Devices used to provide input to a computer system include:

* Keyboard
* Mouse
* Microphone
* Thumb scanner

***

## **Operating System (OS)**

An **Operating System (OS)** is a collection of programs that acts as an intermediary between computer hardware and software. It enables communication and coordination between users and the computer hardware.

#### **Key Layers of an OS**

1. **Windows Workflow**: USER → Application → OS → Hardware
2. **Linux Workflow**: USER → Shell → Kernel → Hardware

#### **Functions of an Operating System**

1. **Process Management**:
   * Handles process execution, including multitasking, scheduling, and termination.
2. **Memory Management**:
   * Manages system memory by handling allocation and deallocation, ensuring efficient usage.
3. **I/O Management**:
   * Facilitates input and output operations, enabling interaction with devices such as keyboards, screens, and printers.

***

### **Internet**

The **Internet** is a global network connecting billions of computers and electronic devices. It enables access to vast amounts of information, facilitates communication with people worldwide, and provides numerous other functionalities.

### **Intranet**

An **Intranet** is a private network used within an organisation or group to share information and resources securely.