According to this Asia Times Online news report, Toshiba Corp. has succeeding in developing a hard disk drive (HDD) that measures just 0.85 inches (22 mm) in diameter. You can take a look at the drive itself in this Impress PC Watch article here in Japanese. More on Toshiba's tiny HDD:
"The drive, which is small enough to be used in mobile phones, can store up to two hours of high-definition moving images and just under 60 hours of music. Its tiny size will likely lead to the development of extremely small video cameras.
Toshiba aims to start shipping samples if its HDD to makers of cellular phones next summer and begin full-fledged production in early 2005 at its Ome, Tokyo, plant. After order volume rises, production will be moved to its HDD plant in the Philippines."
The drive itself currently features a 2-3 GB (gigabyte) storage capacity. It'll be interesting to see what Japanese products will be the first to utilize this.