IBM introduced the 650 RAMAC (Random Access Method of Accounting and Control) disk-storage system— a memory device based on rotating disks.
This was the first hard drive. It permitted random access to any of the million characters distributed over both sides of 50 two-foot-diameter disks. It stored about 2,000 bits of data per square inch and had a purchase price of about $10,000 per megabyte. By 1997 the cost of storing a megabyte on a hard drive dropped to around ten cents.
Filed under: Memory / Mnemonics / Data Storage