Lucas123 writes: New numbers show hybrid drives, which combine NAND flash with spinning disk, will double in sales from 1 million to 2 million units this year. Unfortunately for Seagate — the only manufacturer of hybrids — solid-state drive sales are expected to hit 18 million units this year and 69 million by 2016. Low-capacity, cache SSDs, which typically have 20GB to 40GB of capacity and run along side hard drives in notebooks and desktops, will see their shipments rise even more this year to 23.9 million units, up by an astounding 2,660% from just 864,000 units in 2011. Shipments will then jump to 67.7 million units next year, cross the hundred-million-unit mark in 2015, and hit 163 million units by 2016, according to IHS iSuppli. If hybrid drives are to have a chance at surviving, more manufacturers will need to produce them, and they'll need to come in thinner form factors to fit today's ultrabook laptops.