Dicky Almoedir
Pitra (1701316292)
Student
Assignments 6: Pages 290-291 of textbook Discovering Computers
Lecturer: Tri Djoko Wahjono, Ir, M.Sc
1. What is input,
and what are the differences among a program, a command, and a user response?
Input is any data or
instructions entered into the memory of a computer, to provide or give
something to the computer, in other words the state or act of a computer or a
component of computer or relevant device being accepting something from the
user or from a device or from a software either automatically or manually.
Programs respond
to commands that a user issues. A command is an instruction that causes
a program to perform a specific action. Users issue commands by pressing keys
on the keyboard, clicking a mouse button, speaking into a microphone, or
touching an area on a screen.
A program
is a series of related instructions that tells a computer what tasks to perform
and how to perform them. It is a sequence of instructions, written to perform a
specified task with a computer.
A user response
is an instruction a user issues by replying to a question displayed by a
program. A response to the question instructs the program to perform certain
actions.
A keyboard is an
input device that contains keys users press to enter data and instructions into
a computer. Desktop computer keyboards typically have from 101 to 105
keys. All desktop computer keyboards have a typing area that includes the
letters of the alphabet, numbers, punctuation marks, and other basic keys. Many
desktop computer keyboards also have a numeric keypad on the right side of the
keyboard. A keyboard also contains other keys that allow users to enter data
and instructions into the computer.
Keyboards for
mobile computers and devices are built in the top of the system unit. To fit in
these mobile computers and devices, the keyboards usually are smaller and have
fewer keys than desktop computer keyboards.
3. What are
different mouse types, and how do you use a mouse?
A mouse is a
pointing device that fits under the palm of your hand comfortably. Most desktop
computer users have some type of optical mouse, which uses
devices that emit and sense light to detect the mouse’s movement. Some use
optical sensors, and others use a laser. The latter, often referred to as a laser
mouse, usually is more expensive than the former. You can place an
optical mouse on nearly all types of flat surfaces. A newer type of
mouse, called an air mouse, is a motion-sensing mouse that, in
addition to the typical buttons, allows you to control objects, media players,
and slide shows by moving the mouse in predetermined directions through the
air.
Windows users work
with a mouse that has at least two buttons. For a right-handed user, the left
button usually is the primary mouse button, and the right mouse button is the
secondary mouse button. Left-handed people, however, can reverse the function
of these buttons.
4. What are the
various types of touch screens, and how does a touch-sensitive pad work?
A touch screen is a touch-sensitive display
device. Touch screens that recognize multiple points of contact at the same
time are known as multi-touch. Users interact with touch screens by touching
areas of the screen such as pictures, numbers, letters, or locations identified
on the screen. A kiosk is a freestanding computer that usually includes a touch
screen. Microsoft Surface is a 30-inch tabletop dis- play that allows one or
more people to interact with the screen using their fingers or hands. A
touch-sensitive pad is an input device that enables users to scroll through and
play music, view pictures, watch videos or movies, adjust volume, and/or
customize settings on a portable media player or other mobile device.
5. What are the
various types of pen input, and what are other types of input for smart phones?
With pen input,
you touch a stylus or digital pen on a flat surface to write, draw, or make
selections. A stylus is a small metal or plastic device that looks like
a tiny ink pen but uses pressure instead of ink. A digital pen, which is
slightly larger than a stylus, typically provides more functionality than a
stylus, featuring electronic erasers and programmable buttons. Most digital
pens, often simply called pens, are pressure-sensitive.
Computers and
mobile devices often use handwriting recognition software, which is a
program that translates the handwritten letters and symbols created on the
screen with the stylus or pen into characters that the computer or device can
process.
To capture a
handwritten signature, a user writes his or her name on a signature capture
pad with a stylus or pen that is attached to the device. Software then
transmits the signature via a cable connected to a port on the computer.
Signature capture pads often include a magnetic stripe card reader and work
with POS terminals. Some smart phones have digital cameras that have
touch-sensitive pads. Others have a portable keyboard or optical
keyboard built in.
6. What are the
purposes of gamepads, joysticks and wheels, light guns, dance pads, and
motion-sensing game controllers?
A gamepad,
which is held with both hands, controls the movement and actions of players or
objects in video games or computer games. On the gamepad, users press buttons
with their thumbs or move sticks in various directions to trigger events. Gamepads
communicate with a game console or a personal computer via wired or wireless
technology.
A joystick is
a handheld vertical lever mounted on a base. You move the lever in different
directions to control the actions of the simulated vehicle or player. The lever
usually includes buttons, called triggers, that you press to initiate certain
events. Some joysticks also have additional buttons you press to perform other
actions.
A wheel is
a steering-wheel-type input device. Users turn the wheel to simulate driving a
car, truck, or other vehicle. Most wheels also include foot pedals for
acceleration and braking actions. Joysticks and wheels typically attach via a
cable to a personal computer or game console.
A light gun is
used to shoot targets and moving objects after you pull the trigger on the
weapon. Instead of emitting light, most light guns work by detecting light.
When the user pulls the trigger, the screen uses one of several techniques to
send light, which is received by a receptor in the barrel of the gun. Light
guns typically attach via a cable to a game console or personal computer.
A dance pad is
a flat electronic device divided into panels that users press with their feet
in response to instructions from a music video game. These games test the user’s
ability to step on the correct panel at the correct time, following a pattern
that is synchronized with the rhythm or beat of a song. Dance pads communicate
with a game console or a personal computer via wired or wireless technology.
Motion-sensing game
controllers allow the user to guide on-screen elements by moving a handheld input
device in predetermined directions through the air. Some are sold with a
particular type of game; others are general purpose. Sports games, for example,
use motion-sensing game controllers, such as baseball bats and golf clubs, as
their input device. These types of controllers communicate with a game console
or a personal computer via wired or wireless technology.
7. How does
resolution affect the quality of a picture captured on a digital camera?
One factor that
affects the quality of digital camera photos is its resolution. Resolution is
the number of horizontal and vertical pixels in a display device. A pixel (short
for picture element) is the smallest element in an electronic image. The
greater the number of pixels the camera uses to capture a picture, the better
the quality of the picture. Thus, the higher is the resolution, the better is
the picture quality, but the more expensive is the camera.
Digital camera
resolutions range from approximately 4 million to more than 16 million pixels (MP).
A camera with a 7.1 MP (7,100,000 pixels) resolution will provide a better
quality than one with a 4 MP resolution. As a general rule, a 4 MP camera is
fine for photos sent via e-mail or posted on the Web.
8. How are voice
recognition, web cams, and video conferencing used?
Voice recognition, also called speech
recognition, is the computer’s capability of distinguishing spoken words.
Voice recognition programs recognize a vocabulary of preprogrammed words, which
can range from two words to millions of words.
A Web cam,
also called a PC video camera, is a type of digital video camera that
enables a home or small business user to capture video and still images, send
e-mail messages with video attachments, add live images to instant messages,
broadcast live images over the Internet, and make video telephone calls.
A video
conference is a meeting between two or more geographically separated people
who use a network or the Internet to transmit audio and video data. To
participate in a video conference using a computer, you need video conferencing
software or use a video conferencing Web application, along with a microphone,
speakers, and a video camera attached to or built in to a computer.
9. How do the
various types of scanners and reading devices work?
An optical
scanner, usually called a scanner, is a light-sensing input device
that reads printed text and graphics and then translates the results into a
form the computer can process. Four types of scanners are flatbed, pen,
sheet-fed, and drum. A flatbed scanner works in a manner similar to a
copy machine except it creates a file of the document in memory instead of a
paper copy. Once you scan a document or picture, you can display the scanned
object on the screen, modify its appearance, store it on a storage medium,
print it, fax it, attach it to an e-mail message, include it in another
document, or post it on a Web site or photo community for everyone to see.
Many scanners
include OCR (optical character recognition) software, which can
read and convert text documents into electronic files. OCR software is useful
if you need to modify a document but do not have the original word processing
file.
Businesses often
use scanners for image processing, which consists of capturing,
storing, analyzing, displaying, printing, and manipulating images. Image
processing allows users to convert paper documents such as reports, memos, and
procedure manuals into electronic images. Users distribute and publish these
electronic documents on networks and the Internet.
RFID (radio
frequency identification) is a technology that uses radio signals to
communicate with a tag placed in or attached to an object, an animal, or a
person. RFID tags, which contain a memory chip and an antenna, are available in
many shapes and sizes and sometimes are embedded in glass, labels, or cards.
Some RFID tags are as small as a grain of sand; others are the size of a
luggage tag. An RFID reader reads information on the tag via radio
waves. RFID readers can be handheld devices or mounted in a stationary object
such as a doorway.
Bar Code Reader, also called a bar
code scanner, is an optical reader that uses laser beams to read bar codes
by using light patterns that pass through the bar code lines. A bar code is
an identification code that consists either of a set of vertical lines and
spaces of different widths or a two-dimensional pattern of dots, squares, and
other images. The bar code represents data that identifies the manufacturer and
the item. A newer type of bar code, called a 2-D bar code, can store much more
data than the traditional linear bar code.
Optical mark
recognition (OMR) is a technology that reads hand-drawn marks such as small
circles or rectangles. A person places these marks on a form, such as a test,
survey, or questionnaire answer sheet. With a test, the OMR device first scans
the answer key sheet to record correct answers based on patterns of light. The
OMR device then scans the remaining documents and matches their patterns of
light against the answer key sheet.
10. What are
various biometric devices?
A biometric
device translates a personal characteristic into digital code that is
compared with a digital code stored in the computer to identify an individual.
A fingerprint reader captures curves and indentations of a fingerprint.
A face recognition system captures a live face image and compares it
with a stored image. A hand geometry system measures the shape sand size
of a hand. A voice verification system compares live speech with a
stored voice pattern. A signature verification system recognizes the
shape of a signature. An iris recognition system reads patterns in the
iris of the eye. Retinal scanners scan patterns of blood vessels in the
back of the retina.
11. How do POS
terminals, automated teller machines, and DVD Kiosks work?
A terminal is
a computer, usually with limited processing power, that enables users to send
data to and/or receive information from a host computer. The host computer
processes the data and then, if necessary, sends information (output) back to
the terminal. The host computer usually is a server or mainframe.
The location in a
retail or grocery store where a consumer pays for goods or services is the
point of sale (POS). Most retail stores use a POS terminal to record
purchases, process credit or debit cards, and update inventory. Many POS
terminals handle credit card or debit card payments and thus also include a
magstripe reader. Some have a fingerprint reader that is linked to a payment
method such as a checking account or credit card. After swiping your card
through the reader or reading your fingerprint, the POS terminal connects to a
system that authenticates the purchase. Once the transaction is approved, the
terminal prints a receipt for the customer.
A DVD kiosk is
a self-service DVD rental machine that connects to a host computer through a
network. The DVD kiosks, some of which can hold more than 600 DVDs, are located
nationwide at retail stores, fast-food restaurants, grocery stores, airports,
and other convenient public locations.
An automated
teller machine (ATM) is a self-service banking machine that connects
to a host computer through a network. Banks place ATMs in convenient locations,
including grocery stores, convenience stores, retail outlets, shopping malls,
sports and concert venues, and gas stations, so that customers conveniently can
access their bank accounts.
12. What are
alternative input devices for physically challenged users?
A keyguard
is a metal or plastic plate placed over the keyboard that allows users to
rest their hands on the keyboard without accidentally pressing any keys. A
keyguard also guides a finger or pointing device so that a user presses only
one key at a time. Keyboards with larger keys also are available. Still another
option is the on-screen keyboard, in which a graphic of a
standard keyboard is displayed on the user’s screen. Another option for people
with limited hand movement is a head-mounted pointer to
control the pointer or insertion point. To simulate the functions of a mouse
button, a user works with switches that control the pointer. The switch might
be a hand pad, a foot pedal, a receptor that detects facial motions, or a
pneumatic instrument controlled by puffs of air.
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