30 Part I • Information Technology
(Japan). As noted earlier, over 80 percent of new PCs now
employ Intel processor chips, with most of the remainder
using AMD chips; in addition, most of these new PCs use
the Microsoft Windows operating system (usually
Windows 7).
The only microcomputer vendor that is not produc-
ing an IBM-compatible PC—and doesn’t use the Windows
operating system—is Apple. Initially, the Apple
Macintosh found tough going in the business world against
the entrenched PCs, but its easy-to-use graphical interface
won it many converts in the late 1980s and early 1990s.
Then Macintosh sales hit a plateau, and Apple struggled
until it introduced the iMac in 1998. The colorful iMac
added a spark to the Apple product line and made Apple
profitable again, and Apple continues to innovate with
other computers such as the MacBook, MacBook Pro, and
MacBook Air notebooks and the Mac Pro and Mac Mini
desktops. The Macs use Apple’s own Mac OS X Snow
Leopard operating system (not Windows) and micro-
processor chips manufactured by Intel. Apple’s market
share is still small—less than 10 percent of the U.S. micro-
computer market and perhaps 5 percent of the worldwide
market (Burroughs, 2008; Gonsalves, 2009a). However,
with its computers and other products such as the very suc-
cessful iPod music player, the iTunes music distribution
service, and the widely popular iPhone smartphone, Apple
has built a profitable and growing niche for itself. Between
Apple and the various PC vendors, the microcomputer
market is extremely competitive and should remain so for
the foreseeable future.
Microcomputers have been put to a myriad of uses in
the home, schools, and colleges. In the business world,
they are used for word processing, spreadsheets, presenta-
tions, and small database applications; as terminals into
larger computers; as clients in client/server applications;
and as the point of entry into the Internet and the World
Wide Web. Stand-alone microcomputers in a large organi-
zational setting are a thing of the past: For managers to do
their jobs, they need microcomputers linked into the cor-
porate computer network so that they can access data and
applications wherever they exist. Microcomputers are also
important for small businesses, where they do operate as
stand-alone machines or on small local area networks
(LANs)—but even in these cases microcomputers usually
have access to the Internet.
Midrange Systems
Midrange systemsconstitute the broadest category of
computer systems, stretching all the way from microcom-
puters to the much larger mainframes and supercomput-
ers. Somewhat arbitrarily we have defined this type of
computer system as costing from $4,000 (the top of the
microcomputers category) to $1,000,000 (near the bottom
of the mainframes category), with power ranging from
2,500 to 250,000 MFLOPS.
Today’s midrange systems have evolved from two
earlier computer categories that have now disappeared—
workstations and minicomputers. The term workstation,
as used here, describes a powerful machine that is run by a
microprocessor (just as a PC is run by a microprocessor),
which may or may not be used by a single individual
(whereas a PC is used by a single individual).
Workstations are based on the microprocessor chip, but
the chips tend to be more powerful than those used in mi-
crocomputers. Workstations are, in fact, grown-up, more
powerful microcomputers. Workstations were originally
deployed for specific applications demanding a great deal
of computing power, high-resolution graphics, or both,
but they more recently have been used as Web servers, in
network management, and as servers in client/server
applications. (Chapter 5 will discuss client/server sys-
tems.) Furthermore, because of their very strong
price–performance characteristics compared to other
types of computers, workstations made inroads into the
domains of traditional midrange systems (such as depart-
mental computing and midsized business general process-
ing) and mainframes (large business general processing).
These inroads made by workstations into the midrange
systems domain have been so significant that we have
chosen to combine these categories for our discussion.
The development of the reduced instruction set
computing (RISC)chip is largely responsible for the suc-
cess of this class of machines, at least at its upper end. You
will recall from our earlier discussion that some computers
have a large instruction set (mainframes), while others
have a considerably smaller instruction set (microcomput-
ers). The designers of the RISC chips based their work on
a reduced instruction set, not the complete instruction set
used on mainframe chips. By working with a reduced
instruction set, they were able to create a smaller, faster
chip than had been possible previously. Variations of these
RISC chips power most of the machines at the upper end
of the midrange systems category today.
Let us turn to the second set of roots for the
midrange systems category. Until the 1990s, these middle-
of-the-road systems were called minicomputers.
Originally, these machines were just like the larger main-
frame machines, except that they were less powerful and
less expensive. For a while the larger minicomputers were
even called superminicomputers,which is a strange
name, using both superandminias prefixes. These tradi-
tional midrange systems were very important, serving as
departmental computers, handling specific tasks such as