IBM Introduces Billion-Bit Hard Disk

Imagine a stack of 100,000 double-spaced, typewritten pages--enough paper to make a stack 33 feet tall--shrunk to one square inch.

International Business Machines Corp. said Wednesday that it has achieved that condensing job by storing, for the first time, a billion bits of information on a square inch of a magnetic hard disk.

The record data density is 15 to 30 times greater than that of current hard-disk magnetic devices, IBM said.

It will be several years before billion-bit, or “gigabit,” disks, will be available commercially.

IBM invented the first commercial magnetic hard-disk drives in the mid-1950s, and they have since become the most popular devices for storing computer data.

In the gigabit demonstration at IBM’s Almaden Research Center in San Jose, an aluminum disk was coated with a thin film of a magnetic cobalt alloy, which held the recorded bits.

Experimental equipment recorded and read at a data rate of 3.5 million bytes per second. The measured error rates were sufficiently low--one in a billion, decreasing to one in 10 trillion when error correction codes were used--to meet the requirements of the computer industry.

That latter accuracy level, IBM said, was the equivalent of transcribing more than 10,000 years of a newspaper before making a mistake.