Lesson 4: Drives
and Peripherals
Time Estimate
30 minutes
Case
The case, or chassis, provides several important attributes to the PC,
including: structural integrity for the system's elements, air inlets
and outlets to define the air flow pattern and keep your system cool,
"hard" mounting points for drives, and the system's cosmetic look.
Recent power requirements and cooling needs of many current CPUs make your
computer case selection a critical choice. For example, the AMD Athlon
has particular case requirements, listed at the AMD Web site.
Baby Case
The baby case is a small desktop case that holds a small number of
items. It holds a maximum of two drives because the 130 to 175W power
supply usually goes right behind them, leaving no space for an internal
hard drive. You must also use a small motherboard with a minimum of
features, or ports, and you have very few expansion slots to work with.
Because of these issues, a baby desktop case limits your options and
future expansions, so you should choose one only if you need a minimum
system, and where desktop space is a premium.
Desktop Case
Desktop cases come in a variety of shapes and sizes, and offer more
versatility than baby cases. With a regular desktop case, you can usually
expect two external drive bays and two internal drive bays, which are
great for one floppy drive, CD-ROM, and one or two hard drives. If you
find a desktop case with three external drive bays, you can add a tape
drive. Additional advantages to regular desktop cases include support
of larger power supplies (usually 200 to 250W), and space for larger
motherboards and more expansion boards.
Tower Case
This is a large, vertically mounted case designed to hold the maximum
number of drives. There are often four or more external drive bays, and
at least four internal drive bays. The extra space also allows for the
largest power supplies (300W and higher), which are necessary to
support an array of different drives. Tower cases can hold the largest
motherboards, although motherboards are rarely larger than those found in
regular desktops. Tower cases also provide the best air ventilation by
supporting three or more fans and air filters. This ventilation also
allows for more effective cooling of high-end CPUs (even multiprocessor
motherboards). On the down side, tower cases are expensive and usually
only serious system builders need them. Also, their placement on the
floor can cause strains on mouse cabling, keyboard, monitor, and other
equipment.
If a desktop case is too small, and a full tower case is too large, you
can get a mini tower, which offers a little more space than a desktop
case. You can also put this smaller vertical case on a desktop, making
short cables easier to work with.
Case Manufacturers
Power Supply
A power supply provides all of the energy a computer needs. There must
be ample power to serve everything in the system. Otherwise, the
system will not work properly, if at all. A 250W (Watt) to 300W supply
provides enough power for most users, but servers or other "high-end"
systems may demand more power.
From a practical standpoint, power supply upgrades are more common, and
important, than you might think. A new supply will have no impact on
system performance, but if you plan to add many new devices to the
system (i.e., new drives), you may need a bigger power supply to handle the
increased demand. You may also need to match a new power supply and
motherboard if the new motherboard requires advanced "power conservation"
signals from the power supply.
Power Connectors
Power connectors are two different sets of cables connected to the
power supply. One set plugs into the motherboard; the other set provides
power to each drive. There must be enough drive power cables to run
each drive in your system, otherwise, you'll need "Y cables" to split
power. In practice, avoid using "Y cables," you are better off with more
drive power cables. As a the power supply offers more wattage, more
drive cables become available.
Note: AT and ATX style motherboards use different power
connections. Make sure that you use a power supply style that matches your
motherboard. There are no adapters to convert AT to ATX power signals (or
vice versa).
Power Supply Manufacturers
Drive System
The drive system is a form of permanent storage. While motherboard
memory holds files and programs when the system is on, the drive system
stores them when the system is off. A variety of drives are available
for today's PC, including the ones listed below:
| 1.44MB Floppy drives |
| 100/250MB Zip drives |
| 120MB LS-120 drives |
| 2GB Jaz drives |
| Hard drives |
| CD-ROM drives |
| CD-R (recordable) drives |
| CD-RW (rewritable) drives |
| DVD-ROM drives |
| DVD-RAM drives |
| Tape drives |
Most contemporary systems use three drives:
- 3.5" floppy drive
- hard drive
- CD-ROM drive
While the venerable 3.5" floppy drive still comes with almost all
computers, drives with larger capacities are gradually fulfilling its
purpose to provide removable storage and the ability to transfer files from
one computer to another. You should plan to add a large capacity
"floppy" drive, such as a Zip or LS-120, to your system. Many builders and
upgraders select a CD-ReWritable (CD-RW) drive in place of a CD-ROM
drive to meet their data transfer needs. They then use 3.5" drives for
smaller data.
You will also need a drive controller circuit either in the
motherboard, or as separate expansion board plugged into one of the motherboard's
expansion slots.
Drive upgrades are some of the most interesting because computer users
always seem to need more storage. Upgrade options range from adding a
second hard drive or CD-RW drive, to installing SCSI hard drives, tape
drives, and other removable media drives, such as CD recorders or Zip
drives. The choice of upgrade depends on your particular needs. If you
just need local storage, a new hard drive works fine. If you want to
protect your work, add a backup tape drive. If you transfer work
between systems, add an Iomega Jaz or Zip drive. If you create your own
multimedia presentations, add a CD recorder. DVD and DVD-RAM drives are
now a popular upgrade replacing CD-ROM and CD-RW drives.
Floppy Drive Manufacturers
Hard Drive Manufacturers
CD Drive Manufacturers
Video System
A video system displays text and graphics, and most computers require
one. The video system requires both a video adapter and a monitor. The
video adapter circuit (also referred to as a 3D accelerator, graphics
card, or graphics accelerator) sometimes comes with the motherboard, but
more frequently as an expansion board that plugs into one of the
motherboard's expansion slots. Walk through your favorite computer store to
see an assortment of powerful video cards. The monitor connects to the
video adapter through a single 15-pin video cable. Monitors provide a
view into the PC, and come in a variety of styles, sizes, and features.
Video has always been a data-intensive operation, traditionally
presenting a processing bottleneck for most computers. Even with the advanced
motherboard busses available today, and new technologies like video
acceleration, MMX and 3DNow instruction sets, and the accelerated graphics
port (AGP), video remains challenged by the constant demand for
ever-increasing screen resolution and color depth. As a result, upgrading the
video board almost always yields a noticeable improvement in video
performance (and system performance as the video processing bottleneck is
relieved). Competition among video chip manufacturers is intense. With
constantly falling prices and increasing performance, a new video card
should always be considered when upgrading a system.
You should consider video support a necessity when deciding what
components to purchase for your system. Make sure your selections include 2D
and 3D support, along with as much video memory as your budget allows.
Integrated video support on your motherboard lowers the total cost of
your system, but this also means that your video will require a certain
amount of RAM. Also, make sure you can disable the video support from
the motherboard if you plan to upgrade the system with a separate video
card.
Video Board Manufacturers
Monitors
The video board drives the monitor, which displays the video image.
Select a 15 to 21 inch SVGA monitor with a dot spacing, or pitch, of .28
or less. Also, make sure the monitor is non-interlaced. Interlaced
monitors tend to show more flicker, causing eye fatigue. Notice that the
monitor's signal cable has a 15-pin high-density connector on the end,
which fits with your video board's connector.
Monitor Manufacturers
I/O, Parallel, Serial, and USB Ports
I/O means "Input/Output," the connections a computer uses to
communicate with devices in the real world. In virtually all cases, I/O come
with the motherboard (accessible through the PC back panel). If the
motherboard does not come with I/O ports, you can always add some an I/O
expansion board plugged into a motherboard expansion slot.
Your system also needs parallel and serial ports. Parallel ports
operate printers and other devices, such as Iomega or SyQuest drives.
Serial ports can also operate printers, but more commonly support mice and
external modems.
Modern motherboards have two small round PS/2 ports, one for the mouse
and one for the keyboard. They are usually labeled, and are not
interchangeable.
You probably also have one or two Universal Serial Bus (USB) ports.
Since the release of Windows 98/SE, USB has become a major asset for
external peripheral devices, and you can find printers, scanners, modems,
mice, keyboards, joysticks, and other devices available for USB. You
can also attach a large number of devices to the same USB port,
eliminating the type of contention problems multiple parallel port devices
have.
Sound System
Virtually all PCs today use a high-quality Sound Blaster-compatible
stereo sound board with full-range powered speakers. With the rapid
evolution of sound technology, few motherboards incorporate sound hardware.
You'll need to add a sound board to a motherboard expansion slot.
Sound boards also offer other features, such as joystick/ musical
instrument digital interface (MIDI) ports that can further enhance the system's
capabilities.
A few current motherboards include some type of integrated audio
support, usually through the chipset and the addition of "industry-standard"
support (i.e., Audio Codec '97 support). These motherboards might also
include an audio/modem riser (AMR) slot, which allows you to implement
inexpensive and standardized modems. Note that the design of these
features lower system costs, but do not provide high performance. Each of
these devices are "software dependent," and require CPU resources for
sound and a modem.
Motherboards with AC '97 support include plug-in connections for
speakers, microphone, line input, and joystick/MIDI devices. An ATX-type
motherboard places the connectors in a group after the parallel port
connector. You will need to purchase and install an AMR Modem (currently
$10 to $15) if you decide to use the motherboard's AMR slot features.
Sound boards are not typical upgrade candidates. Sound cards are
generally low-bandwidth devices (many still use the motherboard's ISA bus),
and system performance normally does not improve with a sound card
upgrade. Unless you're a true audiophile, chances are you won't even notice
a difference between sound cards. In most cases, sound cards are
upgraded when an older defective sound card gets replaced, or when hardware
incompatibilities force you to change to a different model.
Sound Board Manufacturers
Game Port
If you plan to play games, such as a flight simulator or racing game,
you need a game port and a joystick. Motherboards rarely provide a
stand-alone game port, but sound boards usually do. However, if the
motherboard does provide a built-in sound circuit, it often includes a game
port as well. You could also add a stand-alone game port card in a
motherboard expansion slot, or add a multi-I/O board that includes a game
port.
Mouse and Keyboard
Your system needs a keyboard, which comes in about as many different
sizes, shapes, and features as a mouse. Make sure the keyboard connector
is compatible with the keyboard connector on the motherboard. Today,
most keyboards use the small PS/2 type barrel connector, but you may
also select a USB keyboard.
Select a good pointing device, a mouse or trackball depending on your
personal taste. You generally have the choice between a serial, PS/2,
or USB mouse. Serial and PS/2 mice are basically the same thing, with
slightly different port connectors. A USB mouse uses a USB port from a
hub or USB port on the back of the PC.
Manufacturers
Conclusion Points
To conclude, review these main points from this lesson:
- The motherboard is the central part of every PC, containing the
CPU, RAM, chipset, I/O ports, and drive adapter(s), which form the
foundation of your system
- The case provides a physical foundation for the system
- A power supply operates the motherboard, expansion devices, and
drives
- The case requires a keyboard and mouse to interact with the system
- A working system also requires a video adapter and monitor, along
with one or more drives to boot the operating system and store files
- A sound card and speakers can add sound
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