In an ideal world, computers would only have one type of data storage, but thanks to the laws of physics and businesses, we have two main types (three if you count CPU L caches). There's DRAM or RAM, which is fast, expensive, and doesn't retain its data without power. And then there's regular storage, today represented by NAND flash, which has more capacity, retains its data longer, but is slower in comparison. Combining all those benefits, without the drawbacks, has been one of the holy grails of computing. And IBM might have found its version of the answer in its 3-bit phase-change memory.