Transcript Document

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Understanding Computer
Understanding Input Devices
Understanding Output Devices
Understanding How Data is Processed and Stored
Computer Software
Storage Devices
Computer Safety
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Computer
A computer is an electronic machine that takes in data, stores
and processes the data, and then produces information.
Computers work because they are controlled by instructions
stored in memory. They process the data according to these
instructions.
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software
Computer
Hardware
data
When people talk about computers, they refer to hardware
and software. The parts of the computer you can see and
touch are called hardware. The instructions are called
computer programs or software. Data is the raw facts in the
form of words, sounds, numbers, or pictures.
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Computer
Information
Memory
Input
Input is the data you enter into a computer. A computer uses
memory and storage to store data. A computer processes data
to produce information. Information is data that has been
processed so that it is organized, useful, and meaningful.
Output is what the computer produces. Output can be words,
sounds, numbers, or pictures.
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Computer
Computers are divided into three general categories:
supercomputers, mainframes, and personal computers.
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Computer
Supercomputer are the fastest, most powerful, most
expensive, and largest computers. Supercomputers are
used by governments, scientists, and businesses, when
complicated jobs need to be done.
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Computer
Mainframe computers also are large computers that do large
jobs. The amount of data processed and the speed at which
the data is processed is not as great as for supercomputers.
A hospital might use a mainframe computer to schedule the
staff, keep track of the patients, and make sure people get
the right medications.
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Computer
Personal computers are computers that people use in
their daily lives. Personal computers are smaller and
process less data at slower speeds that mainframe
computers.
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Computer
The two main types of personal computers are PC
compatibles (PC’s) and Macintosh computers (Macs)
made by Apple computer company. The two biggest
differences between Apple computers and PCs are the
operating systems and the basic processor.
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Computer
A notebook computer, also called
laptop, is a personal computer that
is small enough to fit in a backpack.
A handheld computer, also called PDA, is an even smaller
personal compute that you can hold in your hand.
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Input Device
Each piece of hardware is called a device. Different
devices have different jobs. You use an input device to
enter data into the computer. The keyboard and the
mouse are input devices. The microphone, camera, and
scanner also are input devices
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Input Device
Function keys
Numeric keypad
Standard keyboard
You use the keyboard to type characters into the computer.
Characters are letters, numbers, and symbols. A typical
keyboard has between 101 and 105 keys. The three areas of
the keyboard are the standard typing area, numeric keypad,
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and function keys.
Input Device
The mouse is a pointing device that is designed to fit in
the palm of your hand. You press and release the mouse
button to input data. The press and release is called a
click. You drag, point, click, and double-click the mouse to
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give commands to the computer.
Input Device
A scanner, a digital camera, a touch screen, a digital video
camera, a graphic tablet, and a microphone are examples
of other input devices. The input device depends on the
data you have to enter.
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Output Device
You use an output device to get information out of the
computer. A printer prints the information on paper.
Speakers or headphones play sound as the output. The
monitor, speakers, and printer are the output devices you will
use the most.
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Output Device
A monitor shows you information on a screen like a
television set. When you turn on a computer, you will
see icons, pictures, and words on the screen. The
screen you see when you start the computer is called
the desktop.
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Output Device
A printer prints the information on paper. Your computer
is connected to a printer. You print when you need the
output on paper. One printer might be connected through
a network to many computers. Computers that are on a
network can share one printer.
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Output Device
Printers are categorized in several ways, including
the technology they use to print, the number of
pages they can print in a minute, and whether they
can print using colored inks.
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Output Device
The fastest, but most expensive printers, are called laser
printers. Laser printers use a beam of light to transfer toner
onto paper to create the images. Toner is a fine powder that
works like ink. Printing speeds are measured as ppm, which
stands for pages per minute. Laser printers can print at
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speeds of up to 40 ppm.
Output Device
Ink-jet printers, although slower than laser printers,
print at speeds of one to eight pages per minute. In-jet
printers use a special nozzle to spray small drops of
colored ink on paper to create the image.
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Output Device
Sound Card
Speakers are an output device for words, music or sounds.
Computers have two or more speakers because of the way
sound is distributed. A sound card is hardware inside the
system unit that processes the sounds. Headphones rest on
your head and cover your ears so that only you hear the
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sounds.
How Data is Processed
and Stored
The system unit has hardware inside that processes the
data. The system unit is closed to protect the
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processing hardware.
How Data is Processed
and Stored
If you opened the computer, you would see chips. A chip
is a small, electronic device. A chip is manufactured from
a silicon wafer, which is cut to a small size and imprinted
with circuits and electronic devices.
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How Data is Processed
and Stored
The motherboard is the main circuit board in the system unit.
It also is called the system board. All the chips and other
electronic components of the system unit are connected to the
motherboard.
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How Data is Processed
and Stored
The Processor is one type of chip. The brains of every
computer is the processor. The processor also is called
the CPU. CPU stands for Central Processing Unit – it
does all the processing.
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How Data is Processed
and Stored
Computers also have memory chips. Some memory chips in
computer are called RAM. RAM, which stands for random
access memory, temporarily stores data and programs
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while you work on the computer.
How Data is Processed
and Stored
Digital computers use special codes to understand data.
Digital uses 0’s and 1’s to represent a choice of one of two
states – on or off, yes or no, one or zero.
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How Data is Processed
and Stored
8 bits equals 1 byte
Each 0 or 1 is called a bit; these bits are organized into
groups of eight, which are called bytes. A byte represents
one character.
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How Data is Processed
and Stored
Kilobyte means one thousand bytes 1,000
Megabyte means one million bytes 1,000,000
Gigabyte means one billion bytes 1,000,000,000
Memory is measured in kilobytes or megabytes. Storage,
where data and programs are kept after the computer is
turned off, is measured in gigabytes.
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How Data is Processed
and Stored
Input devices are connected to the computer by using cables
that plug into ports. A port is what you plug the connector
into so data can be transmitted to the computer. Circuit
boards that connect to the motherboard have ports that are
visible on the back of the system unit. Different types of port
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connects peripherals.
How Data is Processed
and Stored
A USB port connects devices such as digital
cameras.
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How Data is Processed
and Stored
A serial port connects devices such as a
joystick or modem.
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How Data is Processed
and Stored
A parallel port connects printers.
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Computer Software
Hardware and Software work together in a computer to
process data and create information. You have learned
that software, or a program, contains the instructions
that tell the computer what to do. The two main types
of software are system software and application
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software.
Computer Software
System software is the operating system. The
operating system runs the computer. It is like the boss
of all the software in the computer.
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Computer Software
If you have a PC, you probably have a
version of the Windows operating
system running your computer.
If you have a Mac computer, you have a
version of the Mac OS running your
computer.
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Computer Software
Application software is a program that does a
specific job. You can install different applications
depending on the jobs you want the computer to do.
Many different types of software are available.
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Storage Devices
Computers use files to store data. Files can have
instructions, words, pictures, sounds or numbers.
Software is stored in files. Each file has a file
name that identifies the file. Storage devices read
the data from the storage media and write data to
the storage media.
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Storage Devices
A floppy disk is removable storage; you can take it
with you. Floppy disks are magnetic media, which
means they use magnetic technology to create
patterns of 0s and 1s to store data.
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Storage Devices
A hard disk is a storage device that is inside the
system unit of your computer. The hard disk also uses
magnetic technology to record the data.
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Storage Devices
A CD is a compact disc. CDs use optical
technology to create the pattern of 0s and 1s to
store data. Optical technology is laser, or light,
technology. A CD-ROM stores software. It also
can store music files and data files. ROM stands
for Read Only Memory.
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Storage Devices
A CD-ROM drive is the hardware a computer uses
to read data, music and software form a CD. A CDR can read from a CD and also can write data,
music, and software on a CD-R.
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Storage Devices
DVD-ROM (digital video disc-ROM) is another type of
optical storage technology. DVDs can store much more
data than CDs. DVD-ROMs are used to store large
software programs or full-length films.
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Computer Safety
Ethics are rules to help you know whether something is
right or wrong. Etiquette is how you behave. Netiquette
is etiquette on the Internet. You will learn about rules
that you must follow when you are on the Internet.
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Computer Safety
Computers are expensive; you must treat a computer
as you would any valuable machine. You cannot eat or
drink while you work on a computer. Be sure your
hands are clean before you type on a keyboard. Hold
floppy disk, CD-ROM, and DVD-ROMs properly. If
you have a problem with a computer, ask your teacher
or the person in charge for help. Do not put heavy
objects on the computer. Do not bang or hit the
hardware.
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Computer Safety
Sometimes programs contain errors that cause the
computer to do things that you do not expect. A
crash is when the computer stops working, and you
have to restart the computer. These errors or
mistakes in programming are called bugs.
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Computer Safety
A computer virus is a program design by a person on
purpose to harm other peoples’ computers. A
computer virus can cause your computer to crash in
such a way that you cannot restart it easily.
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Computer Safety
You can protect your computer from viruses by using
antivirus software. You install antivirus software on
your computer to detect and remove viruses before
they can do harm.
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Computer Safety
Make sure an adult knows when you are working on a
computer. If you see something on the screen that
scares you or makes you sad, quit the program and
then tell your teacher.
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Computer Safety
You always should be considerate of others’ work. You
should get permission to use things that are not yours.
You never should comply somebody’s work or software
without asking for permission. A copyright means the
person who created the work also owns the work.
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Computer Safety
Any information about you, your family, and your
friends is personal. Do not give out names, addresses,
or telephone numbers to anyone unless you have
permission from them, a family member, or a teacher.
You know which files are yours because you named
them. Never open other people’s files unless you get
permission. You should never delete any files that you
did not create.
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