Here is some news from IBM. What do you make of it?
SAN JOSE, Calif.--(BUSINESS WIRE)--Dec. 30, 1996--IBM researchers today announced
the first demonstration of product-level components working together to write and read data on a
computer hard disk at a density of 5 billion bits per square inch (775 million bits per square
centimeter).
Five billion bits (5 gigabits) of data equals the text on 312,500 double-spaced typewritten pages: a
104-foot-tall stack of paper, about as tall as a nine-story building. Put another way, at 5 gigabit
density, the text of 625 novels could be stored in a single square inch of disk surface. It is nearly
three times the density of the most advanced disk drive available today.
"With this achievement, IBM continues its 40-year-old tradition of industry leadership in data
storage," said Currie Munce, who directs the data-storage research and advanced technology
development efforts for IBM's Research and Storage Systems Divisions here.(a) "We are
committed to developing and extending those data-storage technologies required to meet our
customers' ever-increasing needs to store vast amounts of digital information -- which now
including images, video and large data bases -- in higher-capacity or more-portable devices."
The test data was read at both product-level speed (10 million bytes per second; 80 million bits
per second; 1 byte equals eight bits) with accuracy (one error in a billion bits, a figure that would
be further improved in products to essentially flawless performance by using standard
error-correction procedures).
Also notable is that this demonstration used only extensions of proven technologies:
-- an advanced version of the innovative magnetoresistive (MR) recording heads that IBM has
been making by the tens of millions,
-- an ultra-low-noise magnetic alloy disk coating on which the bits are written, and
-- improved electronics employing state-of-the-art equalization techniques that enable all the
components to work together to achieve the desired high-speed and accuracy.
This demonstration also indicates how fast IBM is now incorporating its research results into its
disk-drive products. One-gigabit-per-square-inch data-storage density was first demonstrated in
1989 and achieved in a product earlier this year (1996). IBM expects to deliver products with
3-gigabit-per-square inch density within only a few years of its 1995 laboratory announcement.
Products at 5-gigabit-per-square-inch densities should arrive in products even faster after this
announcement.
The 5-gigabit-per-square-inch record was set by a team of scientists and engineers from IBM's
Almaden Research Center and Storage Systems Division who work together at Almaden as part
of a joint program aimed at helping incorporate new scientific achievements into IBM's disk-drive
products.
Called the Advanced Magnetic Recording Laboratory, this is the same IBM organization that was
the first to demonstrate 1-gigabit (1989) and 3-gigabit (1995) per-square-inch data recording and
reading on magnetic hard disks. In 1994, the group also announced the world's most sensitive
magnetic recording head -- the spin valve -- which employs the "giant magnetoresistive" effect and
is expected to be used to extend magnetic data storage densities to 10 gigabits per square inch
around the turn of the century.
After IBM introduced the industry's first hard-disk drive with an MR head in 1991, the annual
increase in areal density (the number of bits stored in a given area of disk surface) doubled from
30 percent to a staggering 60 percent a year.
Today, 5-gigabit density is nearly three times the density of the industry's highest-density disk drive
-- IBM's Travelstar VP, a 2.5-inch-format drive for portable subnotebook computers. With an
areal density of 1.44 billion bits (gigabits) per square inch, the two-disk Travelstar VP holds up to
1.6 billion bytes (gigabytes, or GB) in a slim package only 9.5mm (slightly more than one-third of
an inch) thick. At 5-gigabit density, this disk drive could hold more than 6 gigabytes of data --
greater than the text of 6,000 average novels -- and nine-disk, 3.5-inch disk drives used as
network servers could hold nearly 55 GB each.
TECHNICAL INFORMATION
In the 5-gigabit demonstration, bits were stored at a linear density of 240,000 bits per inch along
concentric tracks packed at 21,000 per radial inch. At this density, each bit measures only about
47 by 4 millionths of an inch (1.2 by 0.1 millionths of a meter) in size -- so small that nearly 1,000
bits could fit across the diameter of a human hair.
The data bits themselves are recorded onto a thin film of a ultra-low-noise, four-component
magnetic alloy that coats the aluminum disk. The alloy's composition and fabrication conditions are
designed for very high bit density and very low magnetic noise -- critical advantages in reading the
tiny bits. Another thin coating of a hard material protects the alloy film from contact with the
recording head.
The measured error rates during IBM's 5-gigabit tests were very low -- one in 1 billion, which
would decrease by a factor of a million to one in one quadrillion after applying standard
error-correction codes -- and meet the stringent data-integrity requirements of the computer
industry. The latter figure is equivalent to transcribing more than 300,000 years of The Wall Street
Journal before making a single typographical error. This level of accuracy takes into account the
fact that the head will not always be perfectly positioned over the data tracks, indicating that the
system is capable of essentially flawless performance under realistic operating conditions and not
just in a carefully controlled laboratory environment.
MR recording heads have an inductive "write" element and an MR "read" element. The electrical
resistance of materials inside the head that exhibit the MR effect changes according to the strength
of any magnetic field present. The MR head reads data by monitoring the rapid changes in
resistance that occur as it flies over the disk at a height of less than 2 millionths of an inch -- so
narrow a gap that even visible light can't pass through.
IBM is the world's largest supplier of computer data-storage products. Through its Storage
Systems Division (SSD), the corporation provides a full line of data-storage solutions for IBM
systems, for original equipment manufacturers (OEMs) and for commercial distribution. Its
offerings include disk drives, disk arrays and subsystems, magnetic tape subsystems, automated
tape libraries, optical drives and libraries, controllers and related data-storage management
software. In 1996, IBM announced a $380 million investment in SSD to start a new business
selling MR heads. |
