The Mainframe Era
1956
IBM Model 350 Disk File — World's first HDD. 50 platters, 24-inch diameter, size of a refrigerator. 3.75 MB
1961
IBM 1301 — Introduced self-flying read/write heads on air bearings, dramatically improving reliability.
1973
IBM 3340 "Winchester" — Established sealed drive architecture still used in all HDDs today.
The PC Era
1980
Seagate ST-506 — First 5.25-inch drive. Brought HDD into personal computers. 5 MB
1983
IBM PC XT — Shipped with a 10 MB internal HDD, making hard drives standard in personal computers.
1992
Seagate Barracuda — First 7,200 RPM consumer hard drive. Set the performance standard for two decades.
2002
First Serial ATA (SATA) drives — Replaced parallel ATA with a faster, thinner interface standard still in use today.
Capacity Milestones
2007
First 1 TB hard drive — Took 51 years from the 3.75 MB original. Just 2 years later, the first 2 TB drive arrived. 1 TB
2013
First helium-filled HDD (HGST) — Helium reduces drag, enabling more platters and higher capacity in the same chassis.
2019
First commercial HAMR drives (Seagate) — Heat-assisted recording breaks the density barrier. 16 TB
The SSD Revolution
~2005
Flash-based SSDs enter market — Samsung, SanDisk bring NAND SSDs as drop-in HDD replacements. Early cost: ~$50/MB.
2010
HDD unit production peaks — From this point forward, SSD adoption steadily erodes HDD shipment volumes.
2020+
SSDs reach price parity — Consumer SSDs become competitive with HDDs at common capacities. NVMe SSDs hit mainstream. SSD revenue exceeds HDD revenue.
Cost per Gigabyte — Then vs Now
* HDD cost per GB. SSD cost has followed a similar curve with a ~10 year lag. Values are approximate based on historical market data.