Backup

A backup is a copy of digital information intended to allow recovery from loss, corruption, or damage. In Audio/Video, Maker and Web contexts this includes saving media and session files, design files and firmware, bills of materials, and server data such as databases and configuration. For servers and similar infrastructure this usually involves snapshots, incremental backups, offsite replication, versioning, encryption and regular restore testing so you can recover from hardware failure, accidental deletion or ransomware.

Example: during editing of a long video project an internal drive fails. Because you had automated incremental backups to a NAS plus offsite cloud copies, you can restore the latest project files and proxies without losing hours of work. In a maker project you keep source code (Arduino/ESP), PCB Gerbers and 3D STLs both in a Git repo and in separate backups (e.g. encrypted copies to an external drive and S3) so hardware loss or a firmware mistake can be recovered quickly. For web/servers you take daily database dumps, periodic server snapshots, and keep at least one offsite copy; if a database becomes corrupt you can restore a dump and apply binary logs to roll forward to a recent point in time.