So averaging 7 and 10 years together into 8.5, I think the first GB hard drives were in 1996, and saw the "LaCie" Terabyte Hard Drive premiere sometime in the summer of 2004 (see http://www.lacie.com/products/product.htm?pid=10462 ). That way, there are 8.5 years between new orders of magnitude in Hard drive space after all. This way, we may expect to see: 1-Petabyte Hard Drives around the beginning of 2013 1-Exabyte Hard Drives in the summer of 2021 1-Zettabyte Hard Drives around the beginning of 2030 1-Yottabyte Hard Drives in the summer of 2038 1-(Brontobyte?) Hard Drives around the beginning of 2047! We are unsure what 1000 (or 1024) Yottabytes will be named. There are scattered reports that Brontobyte will be the next level above Yottabyte, or the Nonabyte will be the one above Yottabyte instead. I think it'll be the "Xennabyte" because if you go here: http://www.geocities.com/jl152dogs/Big_Number_List.html and use the Find feature (Ctrl+F) and type in "Yottillion", you'll see the familiar prefixes right above it. Since Gigillion is to Gigabyte, Petillion is to Petabyte, etc..., then look down the list some more. See the trend? There is Xennillion right below Yottillion so "Xennabyte" HAS TO be the level after Yottabyte. And as you see beyond even that, there is "Vekillion" so "Vekabyte" would be after Xennabyte. This way, 1-Xennabyte Hard Drives will be seen around the beginning of 2047, then 1-Vekabyte Hard Drives will premiere in the summer of 2055. That way, I'll enjoy my retirement years at the ripe old age of 70 with one of the many thousands of holodeck programs in the holo-room of my humble interstellar colony pod, exponentially more than retirees are enjoying their lives right now! (Yes, I turn 70 in 2055.)

Projecting an answer based on current trends is not reliable. We are unlike to see the capacity of individual hard drives increase in the future at the same rate they have in the past. Large-scale drive arrays already can produce storage systems well into terabyte territory. There is a finite limit to what can be done with any one technology. There are physical and electrical limitations imposed by the current hard drive design and technology, factors such as the density in which data can be packed, stable and reliable operation of the drive motors at higher speeds, the precision of the electro-mechanial systems used to move the heads, and the size of the head itself. We are already quite close to a number of limits imposed by existing computer technology. You can only fabricate chips up to a particular density, beyond which they cannot be made using existing technology. You cannot lay down ever smaller and ever narrower tracks on a PCB before problems develop with signal integrity. It is far more efficient and reliable to build large-capacity storage systems from multiple drives using a protocol such as RAID, even as the drives continue to grow in capacity. A single drive is fragile, unless you use a second to shadow the first. And data striping allows for a drive failure with no loss of data.