CompTIA A+: Operating Systems Concepts
Importance ★★★★★ · 28% (estimate)
Overview
This chapter is the largest part of Core 2 along with security. It covers Windows editions and installs, the built-in Windows tools, command-line commands, file systems, and the basics of macOS and Linux. Expect questions that ask which tool or command fits a task.
Windows Home and Pro differ in business features. Pro can join a domain, use Group Policy Editor, host Remote Desktop sessions, and use BitLocker drive encryption, while Home cannot. Useful tools include Task Manager for running apps and startup items, Event Viewer for logs, Device Manager for drivers, Disk Management for partitions, and Services for background services.
At the command line, ipconfig shows network settings, ping tests reachability, tracert shows the path to a host, chkdsk checks a disk, sfc /scannow repairs system files, and gpupdate /force applies Group Policy right away. NTFS is the main Windows file system and supports permissions and large files. FAT32 is widely compatible but cannot hold one file over 4 GB, and exFAT is a good choice for large files on flash drives.
On macOS, Time Machine makes backups, FileVault encrypts the disk, and Keychain stores passwords. On Linux, ls lists files, cd changes folders, chmod changes permissions, sudo runs a command with administrator rights, and apt or dnf installs software, depending on the distribution.
Key concepts
Home vs. Pro
Windows Pro adds business features that Home lacks, such as joining a domain, BitLocker, Group Policy Editor, and hosting Remote Desktop.
Memory tipNeeds a domain or BitLocker = Pro or higher.
Event Viewer
Windows tool that shows system, application, and security logs with errors and warnings.
Memory tipWhat happened and when = Event Viewer.
sfc /scannow
System File Checker scans protected Windows system files and replaces damaged ones.
Memory tipCorrupt system files = sfc.
NTFS, FAT32, exFAT
NTFS: Windows default with permissions and large files. FAT32: very compatible but 4 GB maximum file size. exFAT: for flash drives with large files.
Memory tipBig file will not copy to a USB drive = FAT32 limit.
chmod and sudo
On Linux and macOS, chmod changes file permissions and sudo runs a single command with administrator (root) rights.
Memory tipPermission denied for an admin task = sudo.
Time Machine
The built-in macOS backup tool that keeps hourly, daily, and weekly copies on an external drive.
Memory tipMac backup = Time Machine.
Often tested
- ipconfig /release and /renew get a new DHCP address; ipconfig /flushdns clears the DNS cache.
- Windows 11 requires TPM 2.0 and a UEFI system that supports Secure Boot.
- Use Task Manager's Startup tab to stop apps from launching at sign-in.
- gpupdate /force applies Group Policy changes now; gpresult shows which policies apply.
- Disk Management creates, deletes, and formats partitions in Windows.
3 sample questions
Verified practice questions from this unit.
Question 1. Which Windows command shows a computer's IP address, subnet mask, and default gateway?
- ① nslookup
- ② tracert
- ③ ping
- ④ ipconfig
▼ Show answer and explanation▲ Hide answer and explanation
Answer: ④ ipconfig
Key point: ipconfig shows IP settings
ipconfig lists the network settings of each adapter, including IP address, subnet mask, and default gateway. ipconfig /all adds more detail, such as DNS servers and the MAC address.
Wrong choices
- nslookup: nslookup asks a DNS server about a name. It does not show the PC's IP settings.
- tracert: tracert shows the path to a remote host, not the PC's own IP settings.
- ping: ping tests whether another device can be reached. It does not list the PC's own settings.
Question 2. Which Windows tool shows logs of system errors, warnings, and security events?
- ① Disk Management
- ② Event Viewer
- ③ Task Scheduler
- ④ Device Manager
▼ Show answer and explanation▲ Hide answer and explanation
Answer: ② Event Viewer
Key point: Event Viewer = Windows logs
Event Viewer keeps logs of what happens in Windows, such as application errors, system warnings, and security events like sign-ins. It is a good place to look when you need to know what went wrong and when.
Wrong choices
- Disk Management: Disk Management manages drives and partitions, not logs.
- Task Scheduler: Task Scheduler runs tasks at set times. It does not show the system's error logs.
- Device Manager: Device Manager lists hardware and drivers. It does not keep the system's event logs.
Question 3. A user cannot copy a 6 GB video file to a USB flash drive that has 32 GB of free space. The drive is formatted with FAT32. Why does the copy fail?
- ① The flash drive is full
- ② Video files must be compressed before copying
- ③ Only administrators can copy video files
- ④ FAT32 cannot store a single file larger than 4 GB
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Answer: ④ FAT32 cannot store a single file larger than 4 GB
Key point: FAT32 maximum file size = 4 GB
FAT32 is an older file system that works with almost any device, but one file on it cannot be bigger than 4 GB. Reformatting the drive as exFAT or NTFS removes that limit. Formatting erases the drive, so copy off any files first.
Wrong choices
- The flash drive is full: The drive has 32 GB free, which is plenty of space for a 6 GB file.
- Video files must be compressed before copying: Video files do not need to be compressed to copy. The file size limit is the issue.
- Only administrators can copy video files: Copying a video file to a flash drive does not require administrator rights.
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