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Components
Seagate Technology created the first hard disk drive for microcomputers. The
disk held 5 megabytes of data, five times as much as a standard floppy disk,
and fit in the space of a floppy disk drive. The hard disk drive itself is a
rigid metallic platter coated on both sides with a thin layer of magnetic
material that stores digital data. Along with the benefit of increased
storage, hard disks have one major drawback: Permanent installation into the
computer decreases their portability.
Seagate Technology grew out of a 1979 conversation between Alan Shugart and
Finis Conner, who had worked together at IBM. The two men decided to found the
company after developing the idea of scaling down a hard disk drive to the same
size as the then-standard 5 1/4-inch floppies. Upon releasing its first
product, Seagate quickly drew such big-name customers as Apple Computer and
IBM. Within a few years, it had sold 4 million units.
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Components
The first optical data storage disk had 60 times the capacity of a 5 1/4-inch
floppy disk. Developed by Philips, the disk stored data as indelible marks
burned by a laser that could not be overwritten -- making it useful primarily
for storing large quantities of information that would never need revision.
Two years later, Philips created an erasable optical disk using special
material, a laser, and magnetism to combine the capacity of an optical disk
with the convenience of an option to erase and rewrite.
A laser beam recording a spiral of information on a photosensitive surface
produces an optical disk. Two layers of clear plastic protect the metal
surface on which the information is recorded. On erasable optical disks, also
called magneto-optic disks, the entire metal surface is magnetized in one
direction. Instead of recording information permanently by melting holes in
the metal, the laser heats a spot to just below its melting point so a magnet
can reverse the direction of the metal's magnetic flux. Reheating the disk to
restore its original orientation erases it.
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Networks
John Shoch at the Xerox Palo Alto Research Center invented the computer
"worm," a short program that searched a network for idle processors.
Initially designed to provide more efficient use of computers, the worm had the
unintended effect of invading networked computers, creating a security threat.
Shoch took the term "worm" from the book "The Shockwave
Rider," by John Brunner, in which an omnipotent "tapeworm"
program runs loose through a network of computers. Brunner wrote:
"No, Mr. Sullivan, we can't stop it! There's never been a worm with
that tough a head or that long a tail! It's building itself, don't you
understand? Already it's passed a billion bits and it's still growing. It's
the exact inverse of a phage -- whatever it takes in, it adds to itself instead
of wiping... Yes, sir! I'm quite aware that a worm of that type is
theoretically impossible! But the fact stands, he's done it, and now it's so
goddamn comprehensive that it can't be killed. Not short of demolishing the
net!" (247, Ballantine Books, 1975).
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