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.

The 1956 RAMAC was the size of a refrigerator, and stored a total of 4.4 megabytes on 50 doubled-sided, two-foot-diameter disks.

In the late 50's, disk density was 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.

External hard drive prices declined 28.4% from $197 in 2003 to $141 in 2006 and the amount of storage space on the drives doubled.

Per Gigabyte retail price of hard disk drive storage in 2003 was $2.04, but in 2006 it was 77 cents, according to The NPD Group.

The recording density for data — aka capacity — has increased 60,000,000-fold in 50 years.

The amount of worldwide information is projected to grow from 161 exabytes in 2006 to 988 exabytes in 2010. An Exabyte is a million terabytes.

By 2013, the total amount of data will overwhelm the total amount of digital storage by a factor of nearly 2 to 1. 2007 is the year that our ability to stuff bits into the digital universe will outstrip our ability to store them.

Research shows that in large-scale IT installations, the annual disk replacement rates typically exceed 1%, with 2-4% common and up to 13% observed on some systems.