This year will see the end of the iPod Classic and with it the 1.8-inch disk drive, 90 percent of which are sold by Toshiba. This is a testament to the rise of flash memory and Solid State Disk (SSD) drives, but that’s not the only cause or the only result, because I predict that late in the year the venerable 3.5-inch disk form factor will hit end-of-life, too.

Apple is by far the largest consumer of 1.8-inch disk drives with most of the rest going into competing media players and netbooks. Toshiba might be able to keep its 1.8-inch disk business going to serve those alternate markets but I don’t think Apple will allow it, applying pressure primarily to keep those little drives out of tablets.

So far this prediction is a no-brainer, but the end of 3.5-inch drives is where I’m taking some risk. Margins are so low in the drive business that I think the surviving companies will be forced to sacrifice their extremities to survive. That means concentrating on the heart of the market, which is 2.5-inch drives. We used to think of these as strictly notebook drives, but today they come in all speeds, all interfaces, and with multiple platters into the terabyte range. They fit better, too, in data center racks and use less power.

Freed from having to support two form factors the disk drive makers will not only regain a little margin, they’ll spur a new generation of enterprise-class storage products using the new drives.

Understand that this NOT me declaring the supremacy of the SSD, because those drives are still way too expensive. There will still be 800+ million disk drives manufactured worldwide in 2011 and most of those will be 2.5-inch.