IT Fundamentals220-1102

CompTIA A+ OS and Software: Windows, macOS, Linux, and Security Essentials

Core 2 (220-1102) shifts from physical hardware to software, operating systems, and security. You need to know Windows deeply enough to troubleshoot it with command-line tools, understand macOS and Linux well enough to support users on those platforms, apply basic security controls, and handle operational procedures. This is where being a help desk technician stops feeling abstract and starts feeling like real work.

12 min
5 sections · 10 exam key points

Windows Operating Systems: Editions, Features, and Upgrade Paths

The A+ exam tests Windows 10 and Windows 11 features. Key editions: Home (consumer, no Group Policy, no BitLocker management, no Remote Desktop host), Pro (adds Group Policy, BitLocker, Remote Desktop host, Hyper-V, joining Azure AD and local domain), Enterprise (adds BranchCache, AppLocker, DirectAccess, long-term servicing options). Windows 11 hardware requirements: 64-bit CPU, 4 GB RAM, 64 GB storage, UEFI firmware with Secure Boot, TPM 2.0, and DirectX 12 graphics. The A+ exam focuses on practical administration: Task Manager (CPU, memory, disk, network usage, startup tab for disabling startup programs), Resource Monitor (per-process detail), Event Viewer (Application, Security, System logs), Disk Management (initialise disks, create partitions, extend/shrink volumes), Device Manager (driver management, hardware conflicts shown with yellow exclamation marks).

Command-Line Tools Every Technician Must Know

The A+ exam presents many scenario questions where you must choose the correct command-line tool. Critical ones: ipconfig /all (shows full IP configuration including MAC and DNS), ping (tests layer 3 connectivity), tracert / traceroute (shows each hop to destination, identifies routing failures), nslookup / dig (DNS query testing), netstat -an (active connections and listening ports), sfc /scannow (System File Checker — repairs corrupted Windows system files), DISM /Online /Cleanup-Image /RestoreHealth (repairs the Windows image before running SFC), chkdsk C: /f /r (checks drive for errors and repairs bad sectors — requires restart on the active drive), diskpart (partition management at command line), gpupdate /force (reapplies Group Policy), gpresult /r (shows applied policies for current user and computer).

macOS and Linux for A+ Technicians

macOS basics: Finder is the file manager, Spotlight (Cmd+Space) searches the system, System Preferences/Settings manages configuration, Activity Monitor is the Task Manager equivalent, Disk Utility manages partitions and repairs file systems, Terminal provides bash/zsh shell access. macOS-specific features: Time Machine (automated local and network backups), AirDrop (peer-to-peer file transfer over Wi-Fi/Bluetooth), FileVault (full-disk encryption), iCloud (synchronises documents, photos, settings). Linux basics for A+: the file system hierarchy (/ is root, /home for user files, /etc for configuration, /var for logs, /tmp for temporary files), essential commands (ls, cd, pwd, cp, mv, rm, mkdir, cat, grep, chmod, chown, ps, top, df -h, sudo), package managers (apt for Debian/Ubuntu, yum/dnf for Red Hat/CentOS). File permissions: read (4), write (2), execute (1) — chmod 755 gives owner full access, group and others read/execute.

Security Controls and Best Practices

The Core 2 exam dedicates about 25% of questions to security. Essential controls: least privilege (users get only the permissions they need), multifactor authentication (something you know + something you have + something you are), strong passwords (length beats complexity — 16+ character passphrases are stronger than 8-character passwords with symbols), account lockout policies (lock after N failed attempts to prevent brute force), disable default accounts (guest, administrator accounts that ship enabled by default). Malware types: virus (attaches to files, requires user to run), worm (self-replicates across networks without user action), ransomware (encrypts files, demands payment), spyware (silently monitors activity), adware (unwanted ads), rootkit (hides deep in OS to conceal other malware). Malware removal: identify and quarantine, disable System Restore (prevents re-infection from restore points), boot to safe mode or external media, run multiple scanner tools, restore from clean backup.

Operational Procedures: Documentation, Safety, and Professionalism

About 22% of Core 2 is operational procedures. Documentation types: network diagrams (logical and physical topology), incident reports (what happened, when, impact, resolution), change management documentation (request, approval, test plan, rollback plan, implementation), asset tags and inventory logs. Safety procedures: ESD (electrostatic discharge) protection — wear an anti-static wrist strap when handling components, work on anti-static mats, keep components in ESD bags, never touch chip contacts. MSDS/SDS (Safety Data Sheet) for chemicals used in cleaning and maintenance. Environmental concerns: proper disposal of batteries (do not landfill), CRTs (contain lead — hazardous waste), toner cartridges (recycle programmes). Professionalism: maintain user privacy (do not look at personal files without permission), set and meet expectations, follow up after service, avoid personal calls or distractions during service, respect confidentiality.

Key exam facts — 220-1102

  • Windows Pro adds Group Policy, BitLocker, Remote Desktop host, and Hyper-V over Home edition
  • sfc /scannow repairs Windows system files; run DISM /RestoreHealth first if SFC fails
  • chkdsk /f /r repairs file system errors and bad sectors — requires restart on active drive
  • chmod 755 = owner rwx, group r-x, others r-x in Linux
  • Worms self-replicate; viruses require a host file; ransomware encrypts and demands payment
  • Malware removal: quarantine, disable System Restore, safe mode, multiple scanners, restore from backup
  • Windows 11 requires TPM 2.0, Secure Boot, and UEFI firmware
  • Least privilege principle: grant only the minimum access required for the job function
  • ESD wrist strap must be grounded to chassis to be effective
  • ipconfig /all shows full network configuration including MAC address and DNS servers

Common exam traps

Running antivirus in Windows is sufficient malware protection

Antivirus is one layer. Defence in depth requires: updated OS and applications, user training, email filtering, web filtering, network segmentation, backups, and least-privilege accounts.

Formatting a drive removes all data permanently

A standard format only removes the file allocation table entries; data remains on the platters/cells and can be recovered. Secure erase, DoD wipe, or physical destruction is needed for sensitive data.

Linux is immune to malware

Linux has fewer malware threats than Windows due to lower market share and default security posture, but it is not immune. Linux servers are actively targeted, and rootkits, ransomware, and cryptominers all have Linux variants.

Longer passwords with special characters are always more secure

Length is the dominant factor in password strength. A 16-character passphrase of random words is stronger than an 8-character password with symbols because it has more entropy.

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