IT Support, Networking and Infrastructure
Operating systems: Windows, macOS, Linux
Most support tickets end up inside an operating system, whatever the user blamed first. Deep knowledge of Windows is still the baseline in most offices, but a technician who cannot find their way around macOS settings or a Linux shell now runs into that gap every week. This page covers installing, configuring and repairing desktop systems, the area A+ Core 2 examines more than any other.
Why this topic exists: Installing, configuring and securing desktop operating systems is A+ Core 2's largest domain (Operating Systems 28 %) and the daily ground of support work.
Operating-system work is the everyday core of desktop support: installing Windows, macOS or Linux on new machines, keeping them patched, setting up accounts and file permissions, and working out why a laptop that ran fine yesterday now takes four minutes to reach the login screen. Much of it is invisible when done well. The user notices only the update that broke the printer driver or the upgrade that removed a setting they relied on. The same work now extends to the phones and tablets that carry company email and files, which A+ treats as operating systems in their own right rather than as accessories.
A+ Core 2 makes this its largest area. Operating Systems carries 28 % of the exam and covers installation across Windows, macOS, Linux and mobile platforms, the built-in Windows administration tools, file systems, updates and upgrades. Security carries another 28 % and brings in encryption and access control on the same machines. SFIA files the professional version of the work under system software administration, which spans operating systems and the utility software around them in every kind of environment.
Three systems, the same questions
| Question | Windows | macOS | Linux desktop |
|---|---|---|---|
| Where settings live | The Settings app, with Control Panel still behind it for older options | System Settings, often locked down by device-management profiles | The desktop environment's tools, with plain configuration files underneath |
| How software arrives | Installers, the Microsoft Store, winget | The App Store, disk images, Homebrew for many technical users | The distribution's package manager, plus Flatpak or Snap |
| Whole-disk encryption | BitLocker | FileVault | LUKS, usually chosen at installation |
| First look at a slow machine | Task Manager and Event Viewer | Activity Monitor and Console | top or a graphical monitor, then the system journal |
The fix that creates the next ticket
- Granting a user local administrator rights to make an error disappear. It works today and undermines least privilege for the life of the machine.
- Reinstalling before diagnosing. A fresh install hides the cause, and the same driver or policy brings the fault straight back.
- Switching on disk encryption without storing the recovery key where the organisation keeps them. The first failed update then turns into lost data.
- Pushing an update to every machine at once instead of a small test group first.
Windows remains the operating system most office technicians meet first, but the gap that costs time now is usually the other two. A technician who cannot find a setting on a Mac or read a log on a Linux machine ends up escalating tickets that were never difficult. A+ certifies the breadth, and Linux+ takes the Linux side to administrator depth. From here the silo branches toward servers, in Windows Server and Active Directory or Linux administration, and toward the people using the machines, in IT support and the service desk.
Next to this topic
- IT fundamentalsWhat computers, networks, operating systems and data are for, before fixing any of them: the scope of Tech+ and of the first weeks of every support course (SFIA Delivery and operation; A+ Core 1).
- Hardware, mobile devices and troubleshootingComponents, peripherals, mobile devices and the troubleshooting method are the largest part of A+ Core 1 (Hardware 25 %, Hardware and Network Troubleshooting 28 %, Mobile Devices 13 %, read 2026-09-26).
- Linux administrationThe command line, package management, filesystems, users, services, scripting and networking as LPIC-1 objectives v5.0 lay them out (topics 101–110); Linux+ and RHCSA test the same ground.
- Windows Server and Active DirectoryDomains, group policy, file and print, identity for the desktop estate: the server side of most business IT (SFIA System software administration; Microsoft's Windows Server hybrid administrator track).
- Networking fundamentalsThe OSI and TCP/IP models, addressing, subnetting, DHCP and DNS are the first domains of Network+ (Networking concepts 23 %) and CCNA (Network Fundamentals 20 %).
- IT support and the service deskTickets, incidents, requests, remote support and the operational procedures of A+ Core 2 (21 %): the job most people enter IT through (Google IT Support; ITIL's service desk and incident practices).
- IT service management (ITIL)The practices that run IT as a service: incident, problem, change enablement, service level, continual improvement (ITIL's practice model, Version 5 since February 2026 with ITIL 4 in parallel; ITIL Foundation; ServiceNow CSA).
- Virtualisation and server infrastructureHypervisors, virtual machines and server hardware sit between the desktop and the cloud (A+ Core 1 Virtualization and Cloud Computing 11 %; SFIA Infrastructure operations; VMware and Server+).
- Scripting and automation for administratorsPowerShell, Bash and Python are how administrators stop doing the same thing twice (LPIC-1 topic 105; CCNA Automation and Programmability 10 %; SFIA System software administration).
Concepts to know
Glossary entries with the reason each one matters here.
- Least Privilege
User accounts and permissions are where operating-system security begins.
- Encryption
Disk encryption is a desktop-support task now.
Certifications that test it
Vendor exams and free certificates; facts, cost and the preparation path are on each page, and the certifications hub has them all.
Tools of the trade
- Linux
One of the three desktop and server operating systems.
Frequently asked
- Does A+ expect me to know macOS and Linux?
- Yes. The Core 2 installation objectives name Windows, macOS, Linux and mobile platforms. Windows still gets the most detailed treatment, but someone preparing who has never opened a Mac terminal or a Linux shell will meet questions they cannot reason through.
- Which Linux distribution should I practise on?
- Whichever your target workplace uses, if you know it. Otherwise pick one mainstream desktop distribution and stay with it long enough to learn its package manager and its logs; the skills carry across distributions far more than the menus do.
- Should I dual-boot or use virtual machines to learn?
- Virtual machines, at least at first. You can install, break and restore each system in minutes without risking the computer you rely on, and snapshots let you rehearse an upgrade before trying it for real.
Courses in the directory
99 courses are filed here; the top 6 by our ranking, details and the provider link on each course page.
Advanced Operating Systems
Udacity
Last reviewed 26 September 2026 · Getting Digital