Several key technologies are coming to market in the next three years that will ensure data storage will not only keep up with but exceed demand. Heat-assisted magnetic recording and bit-patterned media promise to increase hard drive capacity initially by 40% and later by 10-fold, or as Seagate's marketing proclaims: 20TB hard drives by 2020. At the same time, resistive RAM technologies, such as Intel/Micron's 3D XPoint, promise storage-class memory that's 1,000 times faster and more resilient than today's NAND flash, but it will be expensive — at first. Meanwhile, NAND flash makers have created roadmaps for 3D NAND technology that will grow to more than 100 layers in the next two to three generations, increasing performance and capacity while ultimately lowering costs to that of hard drives."Very soon flash will be cheaper than rotating media," said Siva Sivaram, executive vice president of memory at SanDisk.