CHAPTER 1
Installing and Supporting
I/O Devices
Suraya Alias
Basic Principles
I/O Device
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Internal – h/disk, cd drives, dvd drives
External – keyboard, monitor, scanner
Can be connected using ports (USB), motherboard
(serial) or ports from expansion card
When supporting I/O devices, fundamental principles to
remember;
1. Every I/O device is controlled by software
2. Refer to documentation when installing
3. Some devices need application software in order to
function
4. Problems with device sometimes can be solved using
driver’s update
5. Learning hardware I/O is like a moving target
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Ergonomic keyboard
Designed for safe and comfortable interactions between human
beings and machine
4 methods to connect a keyboard
2) PS/2 connector
(mini din)
1) DIN connector
3) USB
4) Wireless connection
Working with keyboard
Mouse and pointing devices
1) Mouse
◦ Wireless
◦ With keypad
2) Trackball
Methods of connecting
a mouse
1) PS/2 mouse port
2) Mouse bus card
3) Serial port
4) USB port
5) Y connection
6) cordless
3) Touchpad
Mouse technologies
• Wheel mouse
• Optical mouse
1) Barcode reader
2) Fingerprint reader
3) Iris recognition reader
Biometric device – input device that inputs
biological data about a person.
Which can be used to identify a person’s
Fingerprint, eyes, voice, face and handwriting.
Special Input devices
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Resolution = the number of individual dots of color, known as pixels,
contained on a display.
◦ Images are formed by series of dots and pixels
◦ Resolution is expressed by identifying the number of pixels on the
horizontal axis (rows) and the number on the vertical axis
(columns), such as 800x600.
◦ Resolution is affected by a number of factors, including the size of the
screen.
Dot pitch = diagonal distance between two closest dots of the same color
Refresh rate = how often an image is updated or redrawn on the
monitor
◦ Low refresh rate will cause the image to flicker and lead to eye strain
Screen size / viewable size = diagonal length of a monitor’s viewing
area (the smaller the better quality)
Interlaced = refresh the monitor by painting alternate rows (odd and
even) on the screen
Contrast ratio = the contrast between true black and true white color on
the screen (the higher the better)
Terms & definition
Characteristics
CRT
Screen size
Y
Refresh rate
Interlaced
LCD
CRT
LCD
Contrast ratio
Y
Y
Viewing Angle
Y
Y
Display type
Response Time
Y
Characteristics
Y
Dot pitch
Y
Resolution
Y
Pixel Pitch
Backlighting
Y
Y
Y
Y
Y
Color Quality
Y
Multiscan
Y
Connectors
Y
Y
Y
Choosing Monitors
1) CRT
2) LCD
CRT
CRT (Cathode Ray tube) is a
large sealed glass tube inside
the monitor.
 Tiny dots of phosphor material
in Red, Green and Blue (RGB)
combines to make up each pixel
(dots of color).
 Inside the CRT, an electron
beam moves back and forth
across the back of the screen.
 This causes the dots to glow,
producing an image
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LCD
Also known as Flat panel
displays (FPDs).
 Liquid crystal display technology
works by blocking light.
Specifically, an LCD is made of
two pieces of polarized glass
(also called substrate) that
contain a liquid crystal material
between them.
 A backlight creates light that
passes through the first
substrate. At the same time,
electrical currents cause the
liquid crystal molecules to align
to allow varying levels of light to
pass through to the second
substrate and create the colors
and images that you see.
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How Monitor Works
Video cards
A video card is rated by the bus it uses
and the amount of video RAM on the card.
 Both features affects the overall speed
and performance of the card
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Buses used by video cards
1) VESA bus – (Video Electronics Standard Association), internal bus
that was developed for faster connection between the devices and
processor
2) PCI bus – (Peripheral Component Interconnect) is a local bus that was
developed by Intel for better integration between of data such audio
and video
3) AGP bus – (Accelerated Graphic Port) is a bus that directly access the
RAM that will improve the graphic display
4) New PCI Express bus – newer bus and faster bus to replace the old
AGP and PCI, used in faster CPU
Video Memory
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Types of video memory
1)
2)
3)
4)
5)
6)
7)
VRAM (Video RAM)
SGRAM (Synchronous Graphic RAM)
WRAM (Window RAM)
3-D RAM (3D)
MDRAM (Multibank DRAM)
G-DDR (Graphic Double data rate )
DRDRAM (Direct Rambus DRAM)
• Most computers provide one or more USB ports, one parallel
port, IEEE 1394 (Firewire) port or serial port to be used for a
variety of devices
Using Ports, Expansion Slots
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Three types of parallel ports are ;
1. Standard Parallel Port (SPP) – old printer port (data flow in one
direction
2. EPP – Enhanced Parallel Port, data flow in two direction
3. ECP – Extended Capabilities Port (uses DMA – direct memory
access channel)
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USB ports (Universal serial ports) is the easiest port to configure
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Serial ports are sometimes configures as COM1, COM2,COM3 or COM4
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Parallel ports are configures as LPT1, LPT2 or LPT3
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The IEEE 1394 bus provides, 4, 6 or 9 pin connectors
Using Ports, Expansion Slots