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216 Part Two Information Technology Infrastructure

for cloud services is usually based on a per-hour or other per-use charge. Even
if a company can approximate the hardware and software costs to run a specific
computing task on premises, it still needs to figure in how much of the firm’s
network management, storage management, system administration, electric-
ity, and real estate costs should be allocated to a single on-premises IT service.
An information systems department may not have the right information to ana-
lyze those factors on a service-by-service basis.
Large firms are most likely to adopt a hybrid cloud computing model where
they use their own infrastructure for their most essential core activities and
adopt public cloud computing for less-critical systems or for additional process-
ing capacity during peak business periods. Cloud computing will gradually shift
firms from having a fixed infrastructure capacity toward a more flexible infra-
structure, some of it owned by the firm, and some of it rented from giant com-
puter centers owned by computer hardware vendors. You can find out more
about cloud computing in the Learning Tracks for this chapter.

GREEN COMPUTING

By curbing hardware proliferation and power consumption, virtualization
has become one of the principal technologies for promoting green comput-
ing. Green computing or green IT, refers to practices and technologies for
designing, manufacturing, using, and disposing of computers, servers, and
associated devices such as monitors, printers, storage devices, and networking
and communications systems to minimize the impact on the environment.
Reducing computer power consumption has been a very high “green”
priority. Information technology is responsible for about 2 percent of total
U.S. power demand and is believed to contribute about 2 percent of the
world’s greenhouse gases. Cutting power consumption in data centers has
become both a serious business and environmental challenge. The Interactive
Session on Organizations examines this problem.

HIGH-PERFORMANCE AND POWER-SAVING
PROCESSORS

Another way to reduce power requirements and hardware sprawl is to use
more efficient and power-saving processors. Contemporary microproces-
sors now feature multiple processor cores (which perform the reading and
execution of computer instructions) on a single chip. A multicore proces-
sor is an integrated circuit to which two or more processor cores have been
attached for enhanced performance, reduced power consumption, and more
efficient simultaneous processing of multiple tasks. This technology enables
two or more processing engines with reduced power requirements and heat
dissipation to perform tasks faster than a resource-hungry chip with a single
processing core. Today you’ll find PCs with dual-core, quad-core, six-core, and
eight core processors.
Intel and other chip manufacturers have developed microprocessors that
minimize power consumption, which is essential for prolonging battery life
in small mobile digital devices. Highly power-efficient microprocessors, such
as ARM, Apple’s A4 and A5 processors, and Intel’s Atom are in netbooks, digi-
tal media players, and smartphones. The dual-core A5 processor used in the
iPhone 4S and the iPad2 has about 1/50 to 1/30 the power consumption of a
laptop dual-core processor.

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