Magnetic-disk areal density grew extraordinarily rapidly for decades, faster than the semiconductor-density trend during important periods.
The 2005 article projected continued rapid gains, and growth slowed sharply after about 2010 as magnetic recording hit physical limits. Its earlier run is why cheap bulk storage arrived before anyone had planned what to do with it.
In practice
- A photo library that filled a hard drive in 2004 fits in a corner of one in 2014, which is why nobody deletes anything any more.
- Growth slowed after about 2010, which is why cloud storage prices stopped falling as fast as customers had come to expect.
- Possible explanations
- The explanation is engineering: successive recording technologies each raised density until they hit a physical limit, and the trend line is the envelope of those jumps rather than a single mechanism.
- In its favour
- The historical run was real and fast, and it is why cheap bulk storage arrived when it did, which reshaped everything from photography to data retention.
- Against it
- Growth slowed sharply after about 2010 as magnetic recording approached physical limits, so the projection failed, which is the usual fate of extrapolated technology curves.
- Standing
- Growth slowed markedly after about 2010.
- Subject
- Technology & Software
- Essay
- The curves, the limits and the laws of software