🛡️ File Formats for Backups
Question is: Will you be able to open today’s files in your data backups in 20 years?
For example the original proposal for the World Wide Web (WWW), written by Tim Berners-Lee in 1989, is an important piece of internet history. However, this Word document can’t be opened on modern computers.
Solution is: Use standard file systems/partitions/file formats/file suffixes and avoid non-standard/proprietary/exotic ones!
✅ Recommended File Formats
| File Suffix | File Format | Reason for Recommendation |
|---|---|---|
.csv |
Spreadsheet table | ASCII based (RFC 4180) |
.dng |
Digital Negative | open source, lossless standard (ISO 12234-4:2026) |
.html |
Web page | open standard by World Wide Web Consortium (W3C) |
.ini |
Program settings | ASCII based |
.jpg/.png/.tif |
Single image | standard (not lossless! keep generation loss in mind) |
.m3u |
Playlist | simple ASCII/Unicode lines |
.md |
Markdown | ASCII/Unicode based (RFC 7763) |
.mp3 |
Audio recording | ISO/IEC 11172-3, ISO/IEC 13818-3 (not lossless) |
.od* |
Open Document Format | ISO/IEC 26300 standard |
.pdf |
Portable Document Format | open standard, includes everything |
.txt |
Pure Text | ASCII/Unicode based |
.xml |
Extensible Markup Language | open standard derived from SGML (ISO 8879) |
❌ File Formats to Avoid
| File Suffix | File Format | Reason |
|---|---|---|
.dll |
Dynamic linked library | proprietary (Windows x86 only) |
.doc |
Microsoft Word text | proprietary |
.exe |
Program executable | proprietary (Windows x86 only) |
.xls |
Microsoft Excel table | proprietary |
.raw |
Raw image format | highly proprietary per camera |