Technology
How does a hard drive work?
A hard drive works by storing data as microscopic magnetized spots on spinning platters. A tiny arm with a read/write head flies just above the surface, flipping and reading the magnetic direction of each spot to write and retrieve 1s and 0s.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how a hard drive works.
Step by step
- 1Data lives as magnetic patterns on rapidly spinning disks (platters).
- 2A read/write head on a moving arm hovers nanometers above the surface.
- 3Magnetizing a spot one way stores a 1, the other way a 0.
- 4To read, the head detects each spot's magnetic direction as the platter spins beneath it.
- 5Mechanical parts make it slower and more fragile than an SSD, but cheaper per gigabyte.
Frequently asked questions
- Why are hard drives slower than SSDs?
- The head must physically move and the platter must spin to the right spot, adding mechanical delay an all-electronic SSD avoids.
- What happens if you drop a hard drive?
- A shock can make the head strike the platter (a 'head crash'), scratching the surface and destroying data — SSDs have no such risk.
- Why are hard drives still used?
- They cost much less per gigabyte than SSDs, so they remain popular for bulk storage and backups.