Developments in TDK's hard drive technology could lead to another boost in the capacity of hard drives within a few months, a roadmap presented this week shows. The storage firm is currently going through qualification tests of 640GB drive platters that would fit into a typical 3.5-inch drive and so would allow significantly more storage than existing 2TB drives from Hitachi, Seagate and Western Digital. A premium but commonplace four-platter drive could hold just over 2.5TB of data.

Mass production of the drives would start slowly in November, according to an eyewitness to the presentation from the Register, and ramp up to full speed by January, most likely leading to 2.5TB drives from one or more companies shortly afterwards.

Additionally, TDK is poised to produce 320GB platters destined for 2.5-inch drives and as a consequence make producing thin 640GB notebook hard disks more feasible. These are already starting production and should reach full production by December, hinting that they may ship either at the end of 2009 or in very early 2010. Seagate already has a 640GB external drive using early technology but still hasn't set a definitive launch date.

If the manufacturer can squeeze in an extra platter then it hits 3TB from a single HDD.