Toshiba announced last week that they are producing a 1.8" hard drive using perpendicular recording to allow hard drive storage capabilities to 40 GB on a single platter. These types of drives are found in small hand-held devices such as Apple's iPod MP3 player. Computers typically use 2.5" hard drives.
These drives are special because they feature perpendicular recording technology. Typically, data is stored on a hard drive in using small magnetic charges on a metal disk that record the data. These charges are typically stored in a horizontal pattern along the disk. To compare, if you were building a house, this house would be a single story, ranch house design.
Toshiba's technology differs using techniques to store data perpendicular to the disk, or "vertically". To compare, think of this as a 2 story home, or a 3 story apartment building. Magnetic charges, representing the data, are stacked vertically.
This is a very interesting concept, something that I am having trouble visualizing in my mind on how it would work. It certainly makes sense -- having the data stored above the disk greatly increases the data density, and the capabilities of the drive. I am curious on how the heads read and write the data, and if the drives will still be able to hold their data in the event of a physical shock, such as dropping it. The equivalent of a cyber-earthquake, if you extend my analogy above.