Page 620 - Introduction to Business

594 PART 6 Managing Business Operations, Management Information Systems, and the Digital Enterprise

measured in gigabytes and a faster access rate, but they are much more expensive
than floppy disks and not as portable.
Optical disks can be compact disks (CDs) or digital video disks (DVDs). CDs store
up to 660 megabytes and can be compact disk–read-only memory (CD-ROM), which
is read-only storage, compact disk–recordable (CD-R), which can record data only
once, and compact disk–rewritable (CD-RW), which can record data many times.
DVDs are the same size as CDs but have a much higher storage capacity. DVDs can
store a minimum of 4.7 gigabytes. DVDs are used to store multimedia applications
and movies, and like CDs, they can also be read-only, recordable, and rewritable.
In 1999 the amount of information created and stored was
• 240 terabytes on paper
• 427 petabytes on film
• 83 terabytes on optical disks (music and data CDs/DVDs)
• 1.693 exabytes on magnetic disks (camcorder and data tapes)
for a total of 2.1 exabytes. We have clearly gone from an era with little information
to an era with “too much” information.
input devices Computer system devices People interact with computers via the input and output devices. Input devices
such as the keyboard or mouse that are are used to collect and transform data into an electronic form that the computer
used to collect and transform data into can use. The two most common input devices are the keyboard and the computer
an electronic form that the computer
can use mouse. Other input devices are pen-based input such as in PDAs, audio input such
as voice recognition, and optical scanning such as desktop scanners and bar-
output devices Computer system coding scanners. Output devices display the information processed by the com-
devices such as video monitors or puter to the user. The principal output devices are video monitors and printers.
printers that are used to display the
information processed by the computer The last element of modern computer systems is communications devices,
for users which provide connections between the computer and other computers via
communications devices Computer telecommunications networks.
system devices that provide Modern computers can be classified as mainframe computers, midrange com-
connections between the computer and puters, microcomputers, and supercomputers. Mainframe computers are large, fast,
other computers via
telecommunications networks and powerful computers. They can process millions of instructions per second and
mainframe computers Large, fast, and have large primary storage capacity. They are used for very large business applica-
powerful computers that are used for tions such as those at international banks, airlines, and major corporations.
very large business applications
Midrange computers are medium-sized computers capable of serving the
midrange computers Computers that needs of many business organizations. Midrange computers can be used as mini-
are medium-sized and capable of
serving the needs of many business computers in systems at factories, universities, and research laboratories, or they
organizations can be used as servers providing software and related resources for other comput-
ers over a network.
microcomputers Computers that satisfy Microcomputers are computers that satisfy the needs of individual users.
the needs of individual users Microcomputers can be used as personal computers (PCs) in the laptop or desktop
versions or as workstations, which have more powerful mathematic and graphical
capabilities than personal computers. For example, workstations are used for com-
puter-aided design by engineers and for portfolio analysis by investment bankers.
supercomputers Extremely powerful Supercomputers are extremely powerful computers specifically designed for
computers specifically designed for applications requiring complex calculations at a very high speed. They have been
applications requiring complex traditionally used for scientific work such as global weather forecasting and com-
calculations at a very high speed
putational cosmology and astronomy, and for military research on defense systems
and classified weapons. Supercomputers are now starting to be used in business for
massive manipulations of data such as those required by data mining, described
later in the Databases section of this chapter. Deep Blue, the computer that
defeated world chess champion Garry Kasparov in 1997, was a supercomputer
manufactured by IBM.
The speed at which computers operate has been increasing at an unprece-
dented rate. The speed has evolved from milliseconds, thousandths of a second, to

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