Operating Systems Overview

The Operating System (OS) serves as the conductor of your computer, overseeing all resources and creating a foundation for other programs to operate efficiently. It is the central software that connects the hardware components with the user.

Primary duties of an Operating System

Resource Management: The operating system effectively distributes and regulates hardware resources such as CPU, memory, storage space, and peripherals.
Process Management involves supervising the running of applications, making sure they are adequately resourced and operate smoothly.
User Interface (UI): The operating system offers a user interface (UI), like a graphical desktop or command line, for users to engage with the computer and its applications.
Security measures in operating systems safeguard computers from malware, unauthorized access, and various security threats.
Networking involves features that enable connection to networks, enabling internet access, resource sharing, and communication with other devices.
Device Drivers: The OS controls device drivers, necessary programs that allow the operating system to interact with specific hardware components.

Many contemporary operating systems are equipped with a range of extra functions, like:

Management of files and folders: Tools for arranging, generating, and handling them.
Multitasking allows for the simultaneous running of multiple programs.
Memory Management: Enhances the utilization of accessible memory to ensure efficient system functionality.
Software Updates: Offers processes for adding updates and patches to enhance security and performance.

Parts of an Operating System

Core components include:

Kernel: Frequently known as the central component of the operating system, the kernel serves as the connector between the hardware and software. It manages basic functions such as memory handling, task scheduling, communication with device drivers, and ensuring security. It directly manages hardware resources.
Shell: The shell serves as the interface for users to interact with the kernel. It allows users to communicate with the operating system and utilize its different features through text commands or a graphical interface. Examples of commonly used shells are the command prompt in Windows and bash in Linux/macOS.

Shell and command line are commonly interchanged terms, but they do have a slight distinction in meaning.

Command Line: This pertains to the user interface itself. It is the written interface where commands are typed in response to the prompt. It refers to any text-based interface where you communicate with a computer by entering commands.
Shell: The shell, a program, interprets commands typed into the command line. It serves as a middleman between you and the kernel of the operating system. The shell interprets your commands, converts them into instructions the kernel can process, and then shows the output or error messages.

Additional Essential Components

Although not directly part of the core, other significant components play a role in the overall operation of an operating system:

Device Drivers: These are particular software applications that function as mediators between the operating system and particular hardware devices. They enable the operating system to comprehend and interact with various components such as printers, GPUs, or network adapters.
System Utilities: These tools are already built-in and assist with duties such as system administration, disk management, file management, and additional tasks.
Libraries: Consist of pre-existing code that applications can use for carrying out particular tasks. This decreases repetition and streamlines the process of creating software.

Libraries offer several benefits:

Reduced Code Redundancy: Libraries offer a centralized place for common tasks, such as printing to the console, instead of each program having to write the same code for these functionalities.
Simplified Development: Programmers can use pre-existing library functions to reduce the time and effort required to create new software.
Consistency: Libraries assist in maintaining uniformity in the execution of tasks across various programs.

Applications: Separate But Essential

Software programs such as web browsers, word processors, or games are individual applications that operate on top of the operating system. They depend on the operating system for managing resources, communicating with hardware, and accessing different services. Consider them as the tools in the operating system, each fulfilling its own role under the guidance of the kernel.

Firmware

The OS depends on firmware stored in non-volatile memory (e.g. flash ROM) in each hardware component for operation. It serves as a middleman, offering fundamental guidance for the device to operate and interact with the OS. Firmware guarantees:

Hardware Management: It starts and manages basic operations of the hardware part it’s placed in, like a hard drive, network adapter, or graphics card.
OS Interaction: Firmware gets the hardware ready for the operating system by conducting fundamental tests and setting up a line of communication.
Limited Functionality: Firmware provides a specialized set of instructions designed for the particular device, unlike a comprehensive operating system.

BIOS/UEFI: Initiating the System

BIOS (Basic Input/Output System) and its successor, UEFI (Unified Extensible Firmware Interface), are vital firmware programs located on the motherboard. When you turn on your computer, these programs are the first to execute, serving as a go-between for the hardware and the operating system. Primary functions of BIOS/UEFI consist of:

POST (Power-On Self-Test): At startup, BIOS/UEFI conducts a self-assessment to confirm the operation of important hardware elements such as memory and storage. Error codes or beeps are commonly used to indicate any problems that may arise.
Basic Configuration: BIOS/UEFI allows users to adjust system settings such as boot order, hardware priority, and date/time through a simple interface.
Boot Process Initiation: BIOS/UEFI initiates the bootloader, a compact program that subsequently finds and starts the operating system.

UEFI (introduced in 2005) offers several advantages over BIOS, including:

Improved User Interface: UEFI often provides a visual interface for simpler browsing in contrast to the text-heavy BIOS interface.
Enhanced Security Features: UEFI offers enhanced security features to defend against attacks at the boot level.
Scalability: UEFI enables the use of bigger storage devices and enables the creation of more intricate boot setups.