أساسيات نظام التشغيل وتوزيعات لينكس

Introduction to Operating Systems

• Operating Systems (OS) are software that manage hardware and software components on a computing device.
• OSs schedule programs to run and provide services (e.g., printing).
• OS is commonly abbreviated as OS.

Exam Objectives

• 1.1 Linux Evolution and Popular Operating Systems: Focuses on the development of Linux and its major distributions.
• 4.1 Choosing an Operating System: Involves knowledge of major operating systems and Linux distributions.

Operating Systems Overview

• Modern users have three major OS choices: Microsoft Windows, Apple macOS, and Linux.
• Only Microsoft Windows is based on proprietary code not related to Unix or Linux.

Decision Points for Choosing an OS

• Role: Consider whether the system will be used by a single user (desktop) or multiple users remotely (server).
• Function: Determine if it needs to run specific software and what user skills are needed.
• Life Cycle: Understand the OS's service lifetime, release cycles, and maintenance cycles for support and updates.
• Stability: Assess if the OS releases are beta (not tested) or stable (tested).
• Compatibility: Check if the OS is backward compatible with earlier versions of software.
• Cost: Annual fees are often needed for Windows, while Apple macOS works only with Apple hardware, and Linux distributions vary greatly in support costs.

Microsoft Windows

• Offers desktop and server versions.
• Has a slow release cycle (3-5 years) with a long maintenance cycle.
• Emphasizes backward compatibility.
• Its GUI (Graphical User Interface) is used.
• Improved scripting and management abilities are being developed to compete with Linux.

Apple macOS

• Runs only on Apple hardware.
• The Server version adds packages to the desktop version for management and sharing.
• UNIX certified.
• Has new major releases every 18-24 months.

Linux

• Users need to choose a distribution after choosing Linux.
• Different distributions are focused on distinct uses (e.g., desktop, server, scientific, network).
• While some offer commercial support, many rely on volunteers.

Linux Distributions (Examples)

Red Hat

• Focuses on server applications (e.g., web serving, file serving).
• Releases Red Hat Enterprise Linux (RHEL), a stable distribution.
• Sponsors the Fedora Project (desktop with latest software).
• CentOS is a free version of RHEL but doesn't offer support.
• Scientific Linux is a specific-use distribution.

SUSE

• An early Linux distribution.
• Primarily a server product, although a workstation version exists.
• Originally derived from Slackware.
• Contains proprietary code (some modules/addons).
• OpenSUSE is a completely open-source, free version with multiple desktop packages.

Debian

• Founded by a community effort to promote open-source software.
• Created an internal package management system based on the .deb file format.
• Ubuntu is a very popular derivative with desktop, server, and app variants and LTS (Long-Term Support) versions.
• Linux Mint is a derivative of Ubuntu with various free versions, some having license restrictions.

Android

• Provides a mobile platform.
• Lacks traditional GNU/Linux packages to be fully compatible with desktop use.
• Sponsored by Google.

Other Linux Distributions

• Raspbian: A Linux distribution for Raspberry Pi hardware.
• Linux From Scratch (LFS): An online book and source code for building a custom Linux distribution.