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All articles A–Z

Every article in this language, sorted alphabetically.

/

  • /etc/fstab LinuxWhat each field of /etc/fstab means, why UUIDs are used, and how to test a new entry before rebooting.
  • /tmp and temporary files LinuxWhat /tmp and /var/tmp are for, when Linux cleans them, and how systemd-tmpfiles controls their age limits.

A

  • Android recovery mode AndroidWhat Android recovery mode is, how to open it with buttons, and what its options such as wipe and update do.
  • Android System WebView AndroidWhat Android System WebView is, why it is updated through Google Play, and what to do when apps that show web pages crash.
  • Android version and security patch level AndroidHow to see which Android version and security patch your phone has, how to update, and why the patch date matters.
  • App cache vs app data on Android AndroidThe difference between Clear cache and Clear storage (data) on Android, what each removes and when to use which.
  • App hibernation (unused apps) AndroidHow Android puts unused apps into hibernation, removes their permissions and frees space, and how to exempt an app.
  • App permissions on Android AndroidHow Android runtime permissions work, how to review them per app or per permission, and what 'only while using the app' means.
  • apt autoremove LinuxWhat apt autoremove removes, why packages become 'no longer required', and how to check the list before removing anything.
  • APT package cache (apt clean and autoclean) LinuxWhere APT keeps downloaded .deb files, how apt clean, autoclean and autoremove differ, and what is safe to remove on Debian and Ubuntu.

B

C

  • cron and crontab LinuxHow cron runs scheduled jobs, the five crontab time fields, where system cron files live and how systemd timers compare.

D

  • Developer options and USB debugging AndroidHow to turn on Android developer options, what USB debugging allows, and why to switch it off when you do not need it.
  • Device Manager WindowsHow to use Device Manager to find devices without drivers, read error codes, update, roll back or uninstall a driver.
  • df (disk free) LinuxHow to read df output, why Use% can reach 100% before Avail is zero for normal users, and how to check inodes with df -i.
  • Digital Wellbeing AndroidWhat Android's Digital Wellbeing shows, how app timers, Bedtime mode and Focus mode work, and how to use the dashboard.
  • Disk Cleanup (cleanmgr) WindowsWhat the classic Disk Cleanup tool removes, what 'Clean up system files' adds, and how to run cleanmgr from the command line.
  • Disk usage with du and ncdu LinuxHow to find what fills a Linux disk with du and the interactive ncdu, with options that stay on one file system.
  • DISM (Deployment Image Servicing and Management) WindowsWhat DISM is, the /CheckHealth, /ScanHealth and /RestoreHealth commands, and how DISM and SFC work together to repair Windows.
  • Driver Store (DriverStore\FileRepository) WindowsWhat the Windows Driver Store is, why it grows, and how to list and remove old driver packages safely with pnputil.

E

  • Event Viewer WindowsHow to read Windows event logs in Event Viewer, which logs matter for crashes and errors, and how to export or clear them.

F

G

  • Google Play Protect AndroidWhat Google Play Protect scans, what its warnings mean, and how to check that it is on.
  • Google Play services AndroidWhat Google Play services does on an Android phone, why it uses battery and storage, and how to update or reset it safely.

H

I

J

L

  • Load average LinuxWhat the three load average numbers mean, how they relate to CPU cores, and when a high load is a problem.
  • logrotate LinuxWhat logrotate does, how its configuration in /etc/logrotate.conf and /etc/logrotate.d works, and how to test a rule safely.
  • lsblk and block devices LinuxHow to list disks and partitions with lsblk, read sizes, file systems and mount points, and identify a new disk safely.

M

  • Microsoft Defender Antivirus WindowsWhat the antivirus built into Windows does, how to run quick, full and offline scans, and how it works with other antivirus programs.
  • Microsoft Defender SmartScreen WindowsWhat SmartScreen is, why it shows 'Windows protected your PC' for new downloads, and how to check a file before running it.

O

  • OOM killer LinuxWhat the Linux out-of-memory killer does, how to find out which process it killed, and how to make it less likely.

P

  • pagefile.sys (page file) WindowsWhat the Windows page file does, why it should not be removed, and how its size is managed.
  • Private DNS AndroidWhat the Private DNS setting in Android does, the difference between Automatic and a provider hostname, and how to set it up.

Q

  • Quick Share AndroidHow Quick Share sends files between Android phones, tablets and Windows PCs nearby, its visibility settings and common problems.

R

  • rsync LinuxHow rsync copies and synchronises files, what the trailing slash changes, and how to test with --dry-run before --delete.

S

  • Safe mode on Android AndroidWhat Android safe mode is, how to start it on Pixel, Samsung and other phones, and how to use it to find a problem app.
  • SFC (System File Checker) WindowsWhat sfc /scannow does, how to read its results, where the CBS.log is and when to run DISM first.
  • SSH keys LinuxHow SSH key authentication works, how to create a key with ssh-keygen, install it on a server and protect it.
  • Startup apps WindowsWhere Windows lists the programs that start with it, what the startup impact means, and how to turn startup apps off safely.
  • Storage Sense WindowsWhat Storage Sense does in Windows 10 and 11, which files it removes, and how to configure it safely.
  • Swap space on Linux LinuxWhat swap is, how to see it with free and swapon, how to add a swap file, and what vm.swappiness changes.
  • System Restore WindowsWhat System Restore and restore points do, what they do not touch, and how to create a restore point or go back to one.
  • systemd units and systemctl LinuxWhat a systemd unit is, the common unit types, and how to start, stop, enable and inspect services with systemctl.

T

  • Task Scheduler WindowsWhat Windows Task Scheduler does, where tasks live, and how to view, disable or remove a task safely.
  • Temporary files in Windows WindowsWhere Windows keeps temporary files (%TEMP%, C:\Windows\Temp), what is safe to delete and the supported ways to clean them.

U

  • UFW (Uncomplicated Firewall) LinuxHow UFW manages the Linux firewall on Ubuntu, how to allow SSH before enabling it, and how to list and delete rules.
  • USB tethering on Android AndroidHow to share an Android phone's mobile data with a computer over a USB cable, with the menu paths on Pixel, Samsung, Xiaomi and Huawei.

W