| Scenarios |
Buying Computer Systems, continued
Which Models
Today
consumer computer systems are generally distinguished into
several categories based on scale and performance factors.
These include
- hand-held computers
- laptop, notebook, or otherwise portable computer systems
- desktop computer systems
- workstations
- servers
Hand-held computers (such as the Palm Pilot series) are intended for more specialized, limited applications such as managing a calendar, inventory control, remote communications, and the like.
The
next three categories denote general-purpose computing
devices that may be used for a variety of computing tasks.
They differ primarily in size, performance, features, and
(naturally) cost.
Desktop
computer systems are designed for both flexibility and
economy. Workstations, on the other hand, are usually
desktop systems with higher performance, added features, and
a larger price tag. Laptops, of course, are portable systems
that offer convenience for a premium price as well.
Servers
are computer systems which support Web communications, file
sharing, print services, and other services available to
local computers over a network.
The
choice of category will largely depend on how the computer
will be used and what sort of budget you have.
Understanding Hardware Specs
Most
hardware vendors give specific information about the
specifications of the models that they sell. In most cases,
you may purchase models that have established specs or you
may customize some of these to suit your individual needs.
In general, though, it is useful to understand what some of
these specifications really mean. Here are some basic
guidelines on what these hardware specs are about.
- Processor and Clock Speed
- The choice of processor is very important. It must be
compatible with the software that you intend to use. Some
operating systems, for example, run on only one type or
class of processors. The clock speed (which is usually
expressed in Megahertz--MHz--or
GigaHertz--GHz--denotes the top speed for the
processor when performing instruction cycles. A higher
clock speed means a faster processor. But clock speed is
a lot like how fast you automobile can accelerate from 0
- 60 m.p.h. or what is the engine's maximum rating for
RPMs. These tell you about what your car can do, but it
is very rarely that you would get to exploit them. For
practical purposes, small differences in clock speed may
not translate to real differences in how responsive your
system is doing ordinary tasks.
- RAM or Main Memory
- Random access memory (RAM) is described mainly
by the amount or quantity available in the system. Today
most systems have RAM that measures in Megabytes
(MB). As mentioned earlier, the amount that you
need depends on what your software (OS and applications)
require. You should be careful to distinguish the
capacity for RAM in your system versus how much actual
memory is configured. Many systems, for example, permit
far more memory than they actually have installed. This
means that you can expand the total amount of memory by
purchasing RAM chips and installing them at a later time.
There are a number of technologies for RAM which are
denoted by ominous acronyms such as SIMMs, DIMMs, DRAM,
SDRAM, and RDRAM.
- Hard Drive
- Like RAM, your main interest is how much storage and
what is the cost? Capacity is typically expressed in
Gigabytes (GB). Drive speeds may also vary.
- Video Monitor
- There are several technologies available today. The
standard CRT technology is similar to that used for
televisions. On the other hand, laptaps employ LCDs for
flatter, low-energy displays. The size of the monitor is
usually expressed in inches measured diagonally across
the screen. The actual viewable area may be smaller. In
CRTs, the refresh rate tells you how often the system
rescans its horizontal lines. Higher rates mean sharper
images with less eye fatigue. Dot pitch refers to how
finely the image is formed; smaller numbers mean better
details. LCD screens employ different technologies to
produce their images. Today, the TFT ("thin film
transistor") is a popular choice. While TFT is more
expensive, it outperforms older LCD technologies.
Finally, whether CRT or LCD, the maximum resolution
informs you how many pixels horizontally and vertically
can be displayed on your monitor. Higher resolutions
usually mean more viewable area with less scrolling.
- Video Card (Graphics Adapter)
- The video monitor requires specific hardware to
support the processing of video images for your monitor.
These cards also contain special memory or storage used
in transferrring data to the screen. Better (more
expensive) video cards are useful for larger, higher
resolution monitors and graphic-intensive
applications.
- Sound Card
- The sound card combines hardware and software for
both the digital recording and playback of digital sound.
The choice of sound card depends again on how you plan to
use your system. Most standard sound cards are suitable
for basic sound recording, video games, and the like.
However, if you have special needs for sound recording or
playback, a higher performance sound card should be
selected.
- DVD, CD-ROM, CD-RW
- The choice of optical disc depends a variety of factors. A CD-ROM
is suitable for installing software and using data stored on this medium.
If you wish to view DVD discs, a DVD drive would be needed. (However,
currently, there are not very many applications available that exploit
the capabilities of DVD.) DVD drives also read CD formats. If you plan
to record music or large amounts of data, a CD-RW drive is a good choice.
Some manufacturers have models that combine all of these functions into
a single drive unit.
- Other Secondary Memory Storage
- Besides optical drives, you may need a floppy drive
or a removable magnetic disk drive to load data into and
archive data from your system. Removable hard drives
(such as Zip disks) come in several sizes or capacities.
Floppy disks are useful for transporting only small
amounts of data; larger quantities will require a
removable hard disk.
- Modem
- A modem is needed if you intend to connect to the
Internet using standard telephone service from your home.
The speed of today's modems is measured in both how fast
it transmits (usually slower) and receives (faster)
digital messages. A modem can also be configured to send
and receive facsimile or fax messages from your
computer.
- Network Card
- If the computer system is intended to connect to a LAN, you will need a network interface card that is compatible with that network. For wireless networking, a wireless card (for example, Wi-Fi) is needed. (You usually do not need both a network card and a modem unless you plan to connect to a network at both home and office.)
The
choice of features and specfiications can be a daunting
task. For help with the technical terminology, consult the
references at the end of this
section.
In
the next section, you can consult some of the leading
manufacturers of software and hardware for more information
about purchasing computer products.
This page last updated 4/05
Maintained by Tom Allen.
Furman University
© 2001