1990s · RETRO HISTORY
Floppy Disks Explained: 5.25-inch vs 3.5-inch
A practical history of the removable disks that moved files between computers.
Editor's note: This is an original introductory guide. Hardware revisions, software compatibility and preservation conditions can vary by model.
Two familiar formats
Floppy disks were removable magnetic storage media used for software, documents and backups. The flexible disk inside the protective jacket is the reason for the name.
How disks stored data
The larger 5.25-inch disk was common on earlier personal computers, while the more rigid 3.5-inch disk became familiar in later machines. Capacity varied by format and density; not every disk was interchangeable.
Preserving old disks
Magnetic media can deteriorate over time. Keep disks away from heat, moisture and magnetic fields, and make verified copies of important data when possible.