Transcript How Computers Work

CIT 1100
In this chapter you will learn how to  Describe the workings of keyboards
 Explain how to connect and use mice and
other pointing devices
 Describe how to work with monitors
The standard computer uses two types of input
devices and one output device
 Keyboard
 Mouse
 Monitor enables the computer to show you the
results of those commands
 Less common I/O devices include:
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Printers
Speakers
Touch-screen
Microphones
The keyboard enables you to communicate with the processing
parts of the computer
 You can enter commands that the computer understands even if
you don't have an operating system
 Applications including the OS, supports specific keyboard
commands
 Keyboard is the primary input device for all personal computers
and many computing devices
 Manufacturers have added extra keys to the standard keyboard,
but most still have the same basic keys
 Keyboards in English-speaking countries all have the same
layout, called QWERTY
 Function keys can change a lot depending on the program, but
Fl is almost always Help
Keyboards use two basic connectors to plug into a
computer
 The old style is called a mini-DIN or PS/2
connector. It is round, with six pins and a small
tab so that you can only insert it one way
 PS/2 connectors are still very common. Some
motherboards color the keyboard PS/2 socket
purple
 MOST newer keyboards use a rectangular USB
connector USB connectors are keyed so that you
can't plug them in incorrectly
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Most operating systems come with a utility
that allows the user to make adjustments to
the keyboard
Mice and other pointing devices enable you to move a
cursor around the screen and select things
 Mice designed for Windows computers traditionally
have two buttons
 You can left-click to select something on the screen
 Right-clicking gets you information about whatever
you click
 Double-left click to tell Windows to do something with
whatever you select
Many current mice have a scroll wheel in the center
that enables you to move up and down in a window
 When you're on a Web page, for example, you can
scroll up and down by clicking the arrows on the
right side of the page or by rotating the wheel
 Mice use one of two connectors to plug into a
computer just like the keyboard
 Older mice use a mini-DIN or PS/2 connector, the
mouse port is green
 Most mice today connect via USB
Mice originally came with a ceramic ball that tracked
the movement and translated that to the computer
 Older ball mice collected dust and grime on the
sensors and have to be cleaned periodically
 Newer optical mice use a red light to track
movement, they don't have to be cleaned
 Trackballs have buttons and wheels, just like mice.
Trackballs are great when you don't have a normal
table on which to work or when you have wrist
difficulties
The primary output device for the computer
 It displays results of input and the computer's
processing
 Advanced much since the first monochrome
display devices
 Two varieties CRT and LCD, Cathode Ray Tube
(CRT) monitors use the same technology as old
televisions, LCD is the newest
 CRTs require extremely high voltage > 30,000
Volts
 LCDs consume considerably less power
CRTs contain an assortment of hazardous
materials, including lead, phosphorus, and
mercury, they cannot be disposed of in landfill
 Contact a computer recycling company to
dispose of old computer components
The video card also knows as the GPU (graphics
processing unit) helps the CPU and operating
system change the image on the display
 The GPU is a processor that can rapidly access
video memory which is used to create images on
the CRT
 Specifically designed to handle computer
graphics, much more efficiently than the CPU
 Most newer desktop and notebook computers
have integrated GPUs
 Integrated video is not as powerful as a dedicated
video card
 Most gamers will not use embedded video chips
The oldest connector type is the Video Graphics Array (VGA)
connector It has 15 pins, laid out in three rows of five
 The VGA connector is used primarily by CRT monitors still used
on many LCD monitors
 Today's most commonly used connector is the Digital Visual
Interface (DVI) connector. Depending on the monitor, it can
have up to 29 pins
 The High-Definition Multimedia Interface (HDMI) connector is
unique because it is used for both video and audio signals,
whereas VGA and DVl only carry video signals
 HDMI is found on more HD televisions than monitors, but it is
becoming more popular with computers, the connector looks
somewhat like USB but only fits in HDMI ports.
In addition to the physical buttons on the monitor, the
Display applet in Windows also controls the appearance of
the display
The resolution determines the number of pixels used to
As the resolution changes so does the size of the Icons
create the image on the monitor, its the number of pixels
across by the number of pixels down 1440 X 900
Monitors can be rotated to display in Portrait view for full page text editing