Operating Systems and Software Support
Platforms and editions
Windows editions differ mainly by management and security features: Home lacks domain join and full BitLocker management, Pro adds them, Enterprise adds volume licensing and advanced management. macOS and Linux have equivalent concepts - users, file permissions, update and package mechanisms. Mobile operating systems sandbox apps and depend on the vendor store and OS updates for patching.
Accounts and permissions
Least privilege is the default stance. On Windows, NTFS permissions apply locally and across the network, while share permissions apply only over the network; when both are in play, the most restrictive result wins. UAC prompts for elevation but does not mean the logged-in user is an administrator.
Tools to recognize
Task Manager (processes, startup impact), Device Manager (drivers), Event Viewer (logs), msconfig, System Restore, Safe Mode, Windows Update. Command line: ipconfig for network settings, ping for reachability, sfc /scannow for system file integrity, chkdsk for disk errors, diskpart for partitions, gpupdate for policy refresh. Know which tool maps to which symptom.
Installation and software support
Confirm compatibility (32- versus 64-bit), licensing, and free disk space before installing. Application failures are usually compatibility, a corrupt user profile, a missing dependency, or permissions - not a broken operating system. Back up before making changes.
Rule of thumb
Match the tool to the layer. App crashes at launch point to compatibility or Event Viewer; corrupt system files point to sfc; disk errors point to chkdsk; a boot failure points to Safe Mode or System Restore. Worked example: an application works for one user but not another on the same PC - suspect the profile or permissions, not the installation.