Operating Systems

What is the primary role of an operating system (OS)?

The first program loaded onto a system; manages other application programs and controls access to hardware resources (memory, processing, storage, networking).

List the four general types of operating systems you may support as an A+ technician.

• Home client OS

• Business client OS

• Network Operating System (NOS)

• Smartphone/Tablet OS

What is a home client operating system designed for? Give examples.

Designed for standalone machines or small workgroup networks (SOHO).
Examples: Windows (desktop/laptop), macOS.

What is a business client operating system designed for? Give an example of how it works.

Designed for systems connected to a centrally-managed business domain network (e.g., Active Directory).
Users log in with domain credentials; server validates and grants access to shared resources (file shares, printers, etc.).

What does NOS stand for? What is its purpose?

Network Operating System.
Designed to run on servers in a business network (always-on, 24/7). Serves resources to clients.
Example: Windows Server 2019 or 2022 running Active Directory.

What is a smartphone/tablet operating system? Give examples.

OS designed for handheld mobile devices with a streamlined touch interface (instead of keyboard/mouse).
Examples: Android, iOS, iPadOS.

Compare open-source vs. proprietary (closed-source) operating systems.
Back:

Open-source: Source code is publicly available; anyone can download, modify, and redistribute.
Examples: Linux, Android.
Proprietary (closed-source): Code is owned by a company; only they can modify/distribute.
Examples: Windows (Microsoft), macOS (Apple), ChromeOS (Google).

What is the typical support lifecycle for Windows client OS vs. Windows Server (NOS)?

• Windows home/business client versions: ~5 years of support.

• Windows Server (NOS) versions: up to ~10 years of support.

Define EOL (End of Life) in the context of operating systems. Why is it important?

When manufacturer support ends (no more updates, security patches, or bug fixes).
Systems become permanently vulnerable to new threats. Organizations must plan upgrades before EOL.

What is extended support? Give a historical Windows example.

Additional paid support period after mainstream support ends.
Example: Windows XP mainstream support ended April 2009; extended support (extra cost) continued until April 2014 (total ~12+ years).

What should organizations do when an OS approaches EOL? (Exam scenario tip)

Create a plan to upgrade/replace aging systems with a currently supported OS (e.g., upgrade Windows 10 to Windows 11 before October 14, 2025).

Which operating systems are covered under Objective 1.1 for the A+ Core 2 exam?

Workstation/client OS: Windows, Linux, macOS, Chrome OS.
Mobile OS: iOS, iPadOS, Android.

Name the major file systems you need to know for Objective 1.1 and match them to their primary OS.

• NTFS / ReFS → Windows

• FAT32 / exFAT → Cross-platform (Windows, others)

• ext4 / XFS → Linux

• APFS → Apple (macOS, iOS, iPadOS)

Why are compatibility concerns important when supporting multiple OS types?

Different OS use different file systems, drivers, applications, and networking features. Technicians must understand cross-OS compatibility issues when troubleshooting or deploying in mixed environments.

Give one real-world exam-relevant example of planning for OS lifecycle.

If a company is still using Windows 10, they must plan to upgrade to Windows 11 by October 14, 2025 (Windows 10 EOL date) to continue receiving security updates.

What is Microsoft Windows?

A graphical operating system developed and published by Microsoft. It is one of the most popular OSes in the world for desktops, laptops, and workstations. First version (Windows 1.01) released in 1985.

List the main Windows naming conventions used over time.

• Early: Version numbers (e.g., Windows 1.01, 2.01, 3.1)

• Then: Year-based (e.g., Windows 95, 98, 2000, ME)

• Then: Titles (e.g., Windows XP, Vista)

• Now: Numbers again (Windows 7, 8, 8.1, 10, 11)

Which Windows desktop versions are the primary focus for the A+ Core 2 exam?

Windows 10 and Windows 11.
Exam objectives include content for both (Windows 10 remains supported until October 2025; Windows 11 is the current modern version).

What does the CompTIA A+ Core 2 exam objectives note say about Windows 10/11 content?

Versions of Windows not at end of mainstream support (up to and including Windows 11) are in scope. Objectives without a specific version can include Windows 10 and Windows 11 content as it relates to the job role.

What is Windows Server? How is it named?

The server-based version of Windows.
Named with a year (e.g., Windows Server 2012, 2016, 2019, 2022). Released roughly every 3–4 years.

Which Windows Server versions share a common codebase with desktop Windows?

Windows Server 2012 → shares codebase with Windows 8.1

Windows Server 2016, 2019, and 2022 → share codebase with Windows 10

Compare the support lifecycle for Windows desktop vs. Windows Server OSes.

• Desktop OS (e.g., Windows 10/11): ~5 years of support

• Server OS: ~10 years of support Reason: Servers run critical business production environments → harder to update/upgrade (downtime, data migration). Desktops are easier to replace/upgrade.

List the support end dates for the main Windows Server versions (as covered in the lesson).

• Windows Server 2012: End of life October 2023

• Windows Server 2016: Supported until January 2027

• Windows Server 2019: Supported until January 2029

• Windows Server 2022: Supported until October 2031

For the A+ Core 2 exam, should you focus more on Windows desktop or Windows Server?

Primarily Windows desktop/laptop (Windows 10 and 11) for end-user support.
The exam is focused on IT support roles, not deep server administration (that is covered in Server+ or Microsoft certifications).

Why does the CompTIA A+ exam emphasize Windows so heavily compared to Linux or macOS?

Windows has dominant market share (~75% as of 2022, previously ~90%) in home, enterprise, and government desktop/laptop environments. Most organizations use Windows, so the exam heavily tests Windows troubleshooting, configuration, and command-line skills.

Recommendation if you primarily use Linux or macOS while preparing for A+ Core 2.

Install Windows in a virtual machine to gain hands-on experience with the GUI, command-line environment, configurations, and settings that will be tested.

Why do servers receive longer support lifecycles than desktop OSes?

Servers support entire business operations. Updates/upgrades require downtime and data migration, making them more complex. Desktops are easier and faster to upgrade or replace (typical user hardware lifespan is 3–5 years).

What are the three main Linux distribution families?

Red Hat-based, Debian-based, SUSE-based. All other distributions are forks of these three.

Give examples of distributions for each main Linux family.

• Red Hat-based: Fedora, CentOS

• Debian-based: Ubuntu

• SUSE-based: openSUSE

What does "open-source" mean for Linux?

The entire OS (kernel, drivers, utilities) source code is publicly available. Anyone can view, modify, and create their own distributions.

Who created Linux and in what time period? Why?

Linus Torvalds in the early 1990s. He wanted a free, Unix-like OS for personal computers.

What is the relationship between Unix and Linux?

Linux was built as a free, open-source Unix-like OS. Unix (1960s, Bell Labs) was proprietary and expensive for servers/mainframes.

How do different Linux distributions make money?

• Subscription model (Red Hat, SUSE)

• Free software + paid enterprise support (Ubuntu)

• Fully community-supported (Fedora, Debian, Mint, Arch, CentOS)

What is the Standard Release Model in Linux?

Uses version numbers (e.g., Ubuntu 22.04.1 LTS). Even versions = Long-Term Support (5 years). Odd versions = 9 months support.

What does LTS mean in Linux distributions?

Long-Term Support — receives updates and security patches for 5 years (recommended for production use).

What is the Rolling Release Model?

No version numbers. Updates are continuously released as soon as they are stable. Example: Arch Linux. More secure but complicates change management.

Where is Linux commonly used besides desktops/servers?

Embedded devices, IoT devices, Android (mobile), Chrome OS.

What percentage of internet servers run Linux?

80% (vs. ~20% Windows). Lower resource requirements make it ideal for servers.

Why is Linux popular in server environments?

Lower resource (memory/CPU) requirements, free/open-source, highly customizable, stable for web hosting and cloud infrastructure.

Should you install Linux for hands-on practice for the A+ exam?

Yes — install in a virtual machine to practice command-line tools and utilities.

Compare Linux and Windows in terms of development and licensing.

• Windows: Single company (Microsoft), proprietary, paid

• Linux: Developed by many companies/individuals, open-source, mostly free

What are two common ways to run Linux on a client machine?

With a full graphical user interface (GUI) similar to Windows, or command-line only (requires less resources).

Why is Linux command-line knowledge important for the A+ exam?

Many Linux systems (especially servers and IoT) run without a GUI. You need basic comfort with tools/utilities for troubleshooting.

What is a "fork" in Linux distributions?

A new distribution created by taking existing source code (e.g., from Red Hat) and modifying it (Fedora and CentOS are forks of Red Hat).

When choosing a Linux distribution for long-term use, what should you prioritize?

An LTS (Long-Term Support) version from the Standard Release Model to ensure 5 years of security updates.

What is the primary purpose of the Android operating system?

Designed specifically to support smartphones and tablets. It is open-source and based on Linux.

Why can hardware vendors create their own customized versions of Android?

Android is open-source with publicly available code, so any manufacturer can download, modify, and customize it at no cost.

Which devices use Android versus iOS?

Android runs on all non-Apple smartphones and tablets. iOS is exclusive to Apple hardware. Android holds approximately 72% market share.

Who originally released Android and when?

Released by the Open Handset Alliance (primarily backed by Google) in September 2008.

How are Android version names chosen?

All versions are named after desserts (e.g., Vanilla Ice Cream = Android 15, Red Velvet Cake, Pistachio Ice Cream).

What is the typical support lifecycle for Android versions compared to desktop/server OS?

Much shorter — average support period is only about 3 years (vs. 5–10 years for Windows/Linux).

What limits the ability to upgrade older Android devices?

Hardware constraints (processing power and storage). Backward support from manufacturers typically lasts only 3–5 years.

Why does the end of Android support create a security risk?

Once support ends, no more security patches or updates are provided for vulnerabilities, even if the hardware still works.

Do all devices running the same Android version (e.g., version 12) behave identically?

No — each manufacturer (Samsung, Google, Sony, etc.) creates its own customized implementation, so features and operation can differ.

What is ChromeOS? Who developed it and what is its underlying technology?

Proprietary operating system developed by Google; based on open-source Chromium OS, which was originally derived from Linux.

What hardware is ChromeOS specifically designed to run on

Chromebooks (laptops) and Chromeboxes (desktops) created by Google and its manufacturing partners; designed as very low-cost devices typically selling between $100 and $300.

What is the primary purpose and design philosophy of ChromeOS?

Web-centered experience built around accessing online/web applications (such as Google Docs and Google Sheets); created as an inexpensive, easy-to-use “computer for everyone” that focuses on getting users online quickly rather than running powerful local software.

What types of applications can be used on a ChromeOS device?

Primarily web-based/cloud applications; also supports direct installation of Android applications (APK files) for offline use.

Why is ChromeOS considered extremely secure? List the built-in security features.

Stripped-down OS with built-in virus protection, firewalls, data encryption, support for multiple users, and automatic background updates; every application and web app runs in its own isolated sandbox.

What is sandboxing in ChromeOS and why is it important?

Each app or web app runs inside its own isolated sandbox; if malicious code appears, it is contained and cannot infect the rest of the system.

How does the boot time of ChromeOS compare to Windows?

ChromeOS boots in 1–5 seconds from the power button (almost instant) because it is a lightweight, stripped-down, web-browser-like operating system; Windows typically takes 30–60 seconds or more.

Why has ChromeOS become especially popular in the education market?

Low cost, high security, fast boot times, and web-based access to textbooks/online learning tools; market share doubled from ~5 % to ~10 % of global laptop OS usage after the 2020 COVID pandemic.

For CompTIA A+ Core 2 Objective 1.1, what are the four key exam points about ChromeOS?

1. Proprietary OS created by Google.
2. Runs on specific Chromebook/Chromebox hardware.
3. Stripped-down design provides high security and fast boot.
4. Primarily uses web applications but also supports Android APKs.

On what hardware can macOS be legally installed according to Apple's EULA?

Only on Apple-built hardware (iMacs, Mac desktops, and MacBooks). It cannot be installed on non-Apple PCs.

Why is macOS generally more stable than Windows or Linux?

Apple only supports a limited number of its own hardware configurations, unlike Windows/Linux which must support any combination of PC parts.

What was macOS previously called, and what does the "X" refer to?

Previously called OS X (Version 10 of the Mac operating system). It is now simply called macOS.

What kernel is macOS built on, and how does it relate to Unix?

Darwin kernel, which is based on Unix (just like Linux).

How does Apple name macOS versions, and what does the exam expect you to know?

Early versions used big cat names; current versions use California locations (e.g., Ventura). Exam does NOT require memorizing specific names — only recognize macOS/OS X as the Apple desktop OS.

For the CompTIA A+ exam, what should you know about macOS/OS X?

It is a desktop operating system that only runs on Apple devices (iMacs, Mac desktops, MacBooks).

Is there an additional cost for macOS or its updates when you buy Apple hardware?

No — macOS and all updates to newer versions are provided at no extra cost.

Is macOS open-source or proprietary software? How does it compare to Linux and Windows

Proprietary (closed-source). You cannot access the underlying code — same category as Windows and Chrome OS; unlike open-source Linux.

Why does Apple not charge separately for macOS?

Because it is the only operating system that works on their hardware, and they control both the OS and the devices.

In the context of Objective 1.1 and 1.8, what key distinction should you remember about macOS versus other workstation OSes?

Hardware exclusivity + Unix-based kernel (Darwin) + proprietary nature + free updates with hardware purchase = very stable desktop OS limited to Apple devices.

What mobile operating systems does Apple develop for its smartphones and tablets?

iOS (iPhones) and iPadOS (iPads)

Are iOS and iPadOS open-source or closed-source?

Closed-source (proprietary technology owned by Apple)

What is the underlying foundation of both iOS and iPadOS?

Derived from Unix

On what hardware can iOS run?

Only Apple iPhone devices

On what hardware can iPadOS run?

Only Apple iPad tablets

What is the relationship between iOS and iPadOS?

iPadOS is a fork of iOS; they share a common codebase but iPadOS adds tablet-specific features

What two major features does iPadOS support that the original smartphone-focused iOS does not?

Multitasking (two apps side-by-side) and Apple Pencil (stylus support)

Why does iPadOS include multitasking while iOS does not?

Larger screen real estate on iPads (10–12 inch) vs. smartphones (5–7 inch)

How does Apple handle version releases and updates for iOS/iPadOS?

New version released each year; free unlimited updates for the life of the device

How long does Apple typically support older iOS/iPadOS devices?

Very long support — at the time of recording, devices over 6 years old still receive the latest OS updates

What is the purpose of a file system?

The way to organize and structure data on any storage device (HDD, SSD, flash drive, etc.) so files can be easily stored and retrieved. It defines where each file begins and ends. A file system must be created/formatted before you install the OS on that device.

Which file systems are recommended for Windows, Linux, and macOS?

Windows: NTFS (default for clients), ReFS (servers), FAT32/exFAT (external/removable). Linux: ext4 (most common default) or XFS (high-performance). macOS: APFS (default), exFAT/FAT32 (external/cross-platform).

What is NTFS (full name and key details)?

New Technology File System. Proprietary 64-bit file system developed by Microsoft. Default for all modern Windows (10/11 and Server). Supports large volumes (~8 PB theoretical, ~256 TB practical in most cases)

Key features and limitations of NTFS?

Features: journaling (ensures data integrity on crash/power loss), EFS encryption, file/folder permissions & ownership, auditing, quota management, Volume Shadow Copy Service (snapshots/previous versions). Limitation: Primarily Windows-only; Linux/macOS need third-party tools for full read/write support.

What is ReFS and its main advantages?

Resilient File System. Microsoft’s modern file system for servers and large-scale data storage. Up to 35 PB volumes. Designed for resiliency against corruption (uses checksums and auto-repair). Works seamlessly with Storage Spaces for advanced storage management

ReFS limitations compared to NTFS?

Lacks legacy features such as file compression, disk quotas, and Encrypting File System (EFS). Trades those features for better scalability, fault tolerance, and performance in enterprise/virtualization/backup workloads.

What is FAT32? Include its limits and best use case.

File Allocation Table 32. Older file system with near-universal compatibility (Windows, macOS, Linux). Max file size 4 GB, max volume 2 TB. Still popular for small USB flash drives and removable media, but rarely used as a primary OS file system today.

What is exFAT? How does it improve on FAT32?

Extensible File Allocation Table. 64-bit modern replacement for FAT32. Supports massive files (16 EB) and volumes (128 PB). Native cross-platform compatibility (Windows, macOS, Linux). Ideal for flash drives, SD cards, and external HDDs with large media files.

What is ext4? Primary OS and key features?

Fourth Extended File System. Default for most modern Linux distributions. 64-bit with journaling for data integrity. Supports huge volumes (1 EB) and files (16 TB). Offers excellent reliability and performance on Linux systems.

What is XFS? When is it preferred?

Extended File System. High-performance 64-bit journaling file system (originally from Silicon Graphics, now popular in Linux). Excellent for large files and high-speed data throughput (media production, scientific computing, enterprise storage). Up to 8 EB; fast recovery after crashes.

What is APFS? For which devices/OS?

Apple File System. Default file system for macOS, iOS, and iPadOS (since ~2018). Optimized for SSDs. Features: built-in encryption, snapshots, and space sharing. Supports up to 8 EB files. Not natively compatible with Windows or Linux

Best file system for cross-platform external/removable storage? Why?

exFAT. It provides large file/volume support and native read/write compatibility across Windows, macOS, and Linux without FAT32’s 4 GB file-size limit. Lacks advanced security/journaling features of NTFS/ext4/XFS.