-The magnetic HDD is 50 years old. In 1956 IBM introduced 305 RAMAC (random access method of accounting and control), which is like the great-great-great grandfather of today’s disks. It was the size of a refrigerator, and stored a total of 4.4 megabytes on 50 doubled-sided, two-foot-diameter disks. The disk had a density of 2,000 bits of data per square inch and had a purchase price of $10,000,000 per Gbyte. -Today’s laptop drives are typically 2.5 inches and are a size of a deck of cards, and can store upto 160 gigabytes - or 131 billion bits per square inch. Price is less than $1 per gigabyte. -Consumers bought 739.7 million gigabytes of hard-drive storage space last year. That is 11 times what they bought in 2003. (NYT) -In the U.S. alone, $600 million worth of external hard drives were sold in 2006, up 53% from 2005, The NPD Group, a market research firm, says. (NYT) More here