Files, backups and recovery

Learn where your files actually live, how to keep copies that survive a dead disk or a bad click, and what to do in the first minutes after something is lost. Five short lessons, a quiz after each, and a lab where you recover deleted photos and test a restore yourself.

What you will be able to do

By the end of this track you can:

• tell an HDD from an SSD from a memory card, and explain what a partition and a filesystem are;
• say what "delete" really does, and why deleted files on an SSD rarely come back;
• spot the signs of a failing drive and read its health with a tool;
• plan a 3-2-1 backup, explain why sync is not a backup, and test a restore;
• handle a lost-file emergency without making it worse, and recover photos to a different drive;
• move to a new computer without leaving keys or settings behind, and prove a copy is complete with a folder comparison or checksums;
• choose formats and media for files you want to open in twenty years.

Who it is for

Anyone who has ever lost a file, or would rather not: students, home users with a phone full of photos, testers and new developers. You need a computer and, for the lab, a spare USB stick or SD card you own and do not need. No command-line experience is required; the few commands shown are explained line by line.

The lessons

Lesson 1How storage worksDrives, partitions, filesystems, what deleting does, TRIM and failing drives.→Lesson 2Backups that workThe 3-2-1 rule, backup vs sync vs archive, versions, encryption and test restores.→Lesson 3Recovering lost filesThe first rule, imaging a failing disk, recovering and repairing photos and videos.→Lesson 4Moving and sharing filesMoving to a new computer, sending files between devices, and proving a copy is complete.→Lesson 5Archives and discsLong-term storage, optical discs, ISO images, verifying a burn and formats that last.→LabPractise a recovery and a restoreDelete photos from a spare stick, get them back, then back up and test a restore.→

Apps that use this knowledge

App	What it does
CloudDrop	Uploads one folder to your own cloud and never deletes anything there
DiskRescue	Recovers photos and videos from failing, reformatted or emptied drives, and repairs damaged media files
Clone Studio	Moves your files, app list and settings from an old Linux computer to a new one
Disc Writer	Burns data discs and disc images on Linux, and checks the burn
Delta View	Compares and synchronizes folders, so you can check a copy before you trust it
NearShare	Sends files between a Linux computer and nearby phones and PCs over Wi-Fi
lmdb-lws-backup	Takes encrypted, verified backups of an LMDB database on a Linux server
SysVitals	Shows the health of your drives in a terminal

How long it takes

Each lesson takes 15 to 25 minutes to read, plus a five-minute quiz. The lab takes 30 to 60 minutes. You can do the whole track in an afternoon, or one lesson a day.

Next steps

• Start with How storage works
• Lost something right now? Go straight to Recovering lost files and stop using the drive