Hardware Reference
In-Depth Information
Mobile computers have the added requirement that they use as little energy as
possible to perform their tasks. The less energy they use the longer their battery
will last. This is a challenging design task because mobile platforms such as tablets
and smartphones must be frugal in their energy use, but at the same time, users of
these devices expect high-performance capabilities, such as 3D graphics, high-defi-
nition multimedia processing, and gaming.
Next, we come to the personal computers that most people think of when they
hear the term ''computer.'' These include desktop and notebook models. They
usually come with a few gigabytes of memory, a hard disk holding up to terabytes
of data, a CD-ROM/DVD/Blu-ray drive, sound card, network interface,
high-resolution monitor, and other peripherals. They have elaborate operating sys-
tems, many expansion options, and a huge range of available software.
The heart of every personal computer is a printed circuit board at the bottom or
side of the case. It usually contains the CPU, memory, various I/O devices (such as
a sound chip and possibly a modem), as well as interfaces to the keyboard, mouse,
disk, network, etc., and some expansion slots. A photo of one of these circuit
boards is given in Fig. 1-10.
Notebook computers are basically PCs in a smaller package. They use the
same hardware components, but manufactured in smaller sizes. They also run the
same software as desktop PCs. Since most readers are probably quite familiar with
notebook and personal computers, additional introductory material is hardly need-
ed.
Yet another variant on this theme is the tablet computer, such as the popular
iPad. These devices are just normal PCs in a smaller package, with a solid-state
disk instead of a rotating hard disk, a touch screen, and a different CPU than the
x86. But from an architectural perspective, tablets are just notebooks with a dif-
ferent form factor.
Beefed-up personal computers or workstations are often used as network ser-
vers, both for local area networks (typically within a single company), and for the
Internet. These come in single-processor and multiple-processor configurations,
and have gigabytes of memory, terabytes of hard disk space, and high-speed net-
working capability. Some of them can handle thousands of transactions per sec-
ond.
Architecturally, however, a single-processor server is not really very different
from a single-processor personal computer. It is just faster, bigger, and has more
disk space and possibly a faster network connection. Servers run the same operat-
ing systems as personal computers, typically some flavor of
UNIX
or Windows.
