I've been watching disk storage advances since the 80's and I'm constantly amazed at what they're doing with this technology.
This year, for the first time, Western Digital has announced a 10TB drive, the He10.
In order to achieve this density of storage, they use multiple platters, each platter storing more than a TB of data. They fill the drives with helium in order to fly the heads closer to the surface than on traditional air-filled drives.
You probably won't be getting one for the Holidays: the He10 drive is designed for datacenter rack use – high performance, low power usage, high reliability (2.5M hours MTBF.) It runs at 7200 RPM and the SAS version has a 12Gb per second transfer rate.
This kind of high density storage means lower power, less rack space and better performance for very large datacenters.
As SSD drives increase in capacity, the competition between these technologies will continue for the foreseeable future – this is important in our increasingly data-centric world.