Operating Systems, Software, and Applications
Scope
This domain tests how operating systems manage hardware, users, files, and applications, and how software is installed, updated, and removed. Expect questions on Windows, macOS, Linux, and mobile OS concepts.
Concepts to master
Understand the kernel, file systems (NTFS, APFS, ext4, FAT32/exFAT for removable media), user accounts and permissions (administrator vs standard, UAC, sudo), services/daemons, startup items, registry (Windows) and plists (macOS), package management (apt, dnf, MSI, DMG, app stores), and compatibility (32-bit vs 64-bit). Know virtual machines and containers at a conceptual level, and licensing basics (perpetual vs subscription).
Traps
- Assuming an administrator account removes the need for elevation prompts (UAC still applies).
- Confusing file permissions with encryption.
- Ignoring file-system limits: FAT32 caps single files at 4 GB - a common cause of failed large copies to USB drives.
- Installing software from untrusted sources; questions reward vendor-signed installers and app stores.
- Not rebooting after driver or kernel updates.
Rule of thumb
When an application fails, isolate the layer: does the OS run? Does the dependency exist? Is the user permitted? Is the file intact? Reinstall is the last step, not the first.
Worked example
A user cannot copy a 6 GB video to a USB stick formatted FAT32. The copy fails because FAT32's maximum file size is 4 GB. Back up the data, reformat to exFAT (or NTFS), and copy again.