Not long ago Seagate launched their 10 Terabyte hard drives into different market segments. In front of analysts the CEO of Seagate also announced that 12 Terabyte models are almost ready for evaluation and their soon being shipped to customers for testing.
Like the recently introduced 10 Terabyte drives, the internals of the 12 Terabyte models will also be filled with Helium and not with normal air. The lower density of Helium helps in reducing friction between the platters and the air and therefore more platters can be put into the 3.5 inch enclosure, increasing storage density.
It's rahter likely that the first 12 Terabyte drives will only be available in the enterprise segment. This is actually standard procedure, while in a second step the drives are being fed into mainstream channels.
On another note we're curious to see how many years it is going to take until SSDs will overtake HDDs in terms of storage density, while also keeping the cost a reasonable level. The fact that Western Digital and Seagate are investing more and more in SSDs are in my opinion a solid hint, that we're closing in on such an event.
Source: Seagate