Throughout the history of computers, one aspect has plagued and restricted its growth more than any other: permanent storage. From the very first computers that used punched cards and tape for input and storage to the refrigerator-sized hard drive (pictured right), the tale of non-volatile memory lays the foundations for today’s ubiquitously digital world. At the same time, however, computer storage is strangely disassociated from the breakneck advances in silicon transistor fabrication, and so it offers an interesting counterpoint to the Megahertz War, Moore’s Law, and today’s surge towards low-power system-on-chip computing.

This diametric split stems from the fact that computer storage must be permanent, while almost every silicon-based, lithographic process is focused on making circuits that are incredibly fast and volatile. This gap has obviously lessened in recent years with the wholescale adoption of transistor-based NAND flash memory used by every digital gadget under the sun, but the gulf is still clearly visible when you look at hard drives, optical discs (CD, DVD, Blu-ray), and tapes.

To understand the difference between computer storage (non-volatile: hard drives) and computer memory (volatile: DRAM) we must head back into the mists of time, to the emergence of IBM and its infatuation with punched cards.