A. Computer Basics
1.00 Examine the role of hardware
and software.
Unit Objectives:
What Is A Computer?
• An electronic device that receives
data, processes data, stores data, and
produces a result (output).
• A collection of electronic circuits,
which can be on or off (open or
– These two states of the circuit are
represented by two digits, 0 and 1.
• Called the binary system
• Combining bits (0 and 1), you can represent
any character or number.
Benefits of Using
Error-free calculations
Consistency and repetition
What Is A
Computer System?
• Software: the intangible
• Hardware: the
set of instructions that
tangible, physical
tells the computer what to
equipment that can be
do; know as programs or
software programs.
seen and touched such
– Two types: application
Computer Case
Keyboard and Mouse
Disk Drive
and system software
• Data: information entered
into the computer to be
processed, which consists
of the following:
– Text, numbers, sounds,
and images
• People: the users of the
computers who enter the
data and use the output.
Types of Computers
• Supercomputer: most powerful
– Used to do things like predict hurricanes and
navigate satellites
• Mainframes and minicomputers: used by
business and government to process large
amounts of information
• Personal computers: smaller and less
powerful than the other types of
Personal Computers
• Desktop computer: designed to be used on
a desktop.
• Notebook/Tablet computer: designed to
be used on a desktop but still small enough
to be portable.
• Laptop computer: designed to be small
enough and light enough to be used on your
Additional Types
of Computers
• PDAs (Personal Digital Assistants): a handheld
device that is often used in conjunction with a
desktop or other PC.
– May have a special keyboard, some use
a pen or stylus for entering data
- Data can be transferred to a desktop or laptop computer
• Web TV: provides easy access to the Internet
without having to have a traditional computer.
– Enables you to connect to the Internet and usually
includes a keyboard or other device for entering and
selecting data.
Data Communications
• The technology that enables computers to communicate
• The transmission of text, numeric, voice or video data from
one machine to another.
• Popular examples:
– Internet, electronic messages (e-mail), faxes, and electronic or
online banking
• Four components:
– Sender: the computer that is sending the message.
– Receiver: the computer receiving the message.
– Channel: the media that carries or transports the message.
(telephone wire, coaxial cable, microwave signal, or fiber optic)
– Protocol: the rules that govern the orderly transfer of the
data sent.
Data Communications
• Network: when computers are connected to other
– They can share information and sometimes hardware
– Local Area Networks (LAN): computers connected
together in a relatively close location such as in the
same building or department.
• The data and software for these computers are stored on
a central computer called the file server.
– Wide Area Networks (WAN): when local area networks
are expanded to include several local area networks
within a city, state, region, territory, country, continent,
or the world.
System Components
Central Processing Unit (CPU): the microprocessor, the brains of
the computer.
– Housed on a tiny silicon chip
– Chip contains millions of switches and pathways that help your computer
make important decisions.
• CPU knows which switches to turn on and which to turn off because it
receives its instructions from computer programs (software).
– CPU has two primary sections:
• Arithmetic/logic unit
• Control unit
Arithmetic/logic unit (ALU): performs arithmetic computations
and logical operations; by combining these two operations the ALU
can execute complex tasks.
– Arithmetic operations include addition, subtractions, multiplication, and
– Logical operations involve comparisons.
Control Unit: is the “boss” and coordinates all of the CPU’s
– Uses programming instructions, it controls the flow of information
through the processor by controlling what happens inside the processor.
• We communicate with the computer through programming languages.
COBOL, C++, or VisualBasic.net, HTML, Java Script for example.
System Components
Memory: found on the motherboard; short term and long term.
– Random Access Memory (RAM): memory on the motherboard
that is short term; where data, information, and program
instructions are stored temporarily on a RAM chip or a set of
RAM chips.
• When the computer is turned off or if there is loss of power, what
ever is stored in RAM disappears.
• This memory know as the main memory and is considered volatile.
• The computer can read from and write to RAM.
– Read-Only Memory (ROM): memory on the motherboard that
is long term; where the specific instructions that are needed
for the computer to operate are stored.
• This memory is nonvolatile and your computer can only read from a
ROM chip.
• The instructions remain on the chip regardless if the power is
turned on or off.
• Most common is the BIOS ROM; where the computer uses
instructions contained on this chip to boot or start the system
when you turn on your computer.
System Components
• Basic Controllers: on the motherboard, a
device that controls the transfer of data
from the computer to a peripheral device
and vice versa.
• Examples: keyboards, mouse, monitors, and printers.
• Generally stored on one single chip.
• Serial and Parallel Ports: used to connect
our peripheral devices to the computer;
usually one serial and one parallel port on
a computer.
• Serial devices transmit data one bit at a time.
– A modem may be connected to this port.
• Parallel devices transfer several bits at a time.
– A printer may be connected to this port.
System Components
• Universal Serial Bus (USB): a new
standard that supports data transfer
rates of up to 12 million bits per second.
– A single USB port can be used to connect up to
127 peripheral devices
– Expected to replace serial and parallel ports in
the near future.
• Expansion Slots: an opening on the
motherboard where a circuit board or
expansion board can be inserted.
– Examples: Additional Memory, video cards,
modem cards, and sound cards.
How Does A Computer
Process Data?
• PC system case – the metal and plastic
case that houses the main system
components of the computer.
• Central to all of this is the motherboard
or system board that mounts into the case.
– Motherboard: is a circuit board (a thin plate
or board that contains electronic components)
that contains many integral components.
Data Representation
• ASCII (American Standard Code for
Information Interchange): the most
popular and widely used standardized
coding system
• Byte: eight bits or combinations of ones
and zeros represent a character.
– MB-Megabyte or roughly 1 million bytes
– GB-Gigabyte or roughly one billion bytes
Input, Output, & Storage
• Input device:
hardware that
allows you to
communicate with
your computer.
• Output device:
hardware that allows
your computer to
communicate with the
• Storage device:
allows you to store or
retrieve information
Computer Input Devices
Light pen
Pointing Stick
Touch screen
Bar code reader
Graphics Tablet
Digital Cameras
Computer Output Devices
• Speakers: allow
• Monitor: screen
you to hear voice,
that display
music, and other
information such as
text, numbers, and
• Modem: allows you
– softcopy
to use your
• Printer: gives you
computer to
information from
communicate with
other computers.
the computer in
printed form.
– Hardcopy
Three Types of Printers
• Dot Matrix
– Gives a printed image in a
pattern (matrix) of tiny
ink dots.
• Less expensive and not as
• Inkjet Printer
– Better quality of printed
• Machine uses an ink
cartridge and a printing
element to print a finer
image on the paper.
• Laser
– Best quality of
printed documents
• Laser beam and an
ink toner cartridge
are used to produce
the images.
• More expensive
• Quick
Storage Devices
• Magnetic storage devices use oxide-coated
plastic storage media called mylar.
– As the disk rotates in the computer, an
electromagnetic read/write head stores or
retrieves data in circles called tracks.
• Tracks are numbered from the outside to the inside
and as data is stored on the disk it is stored on one
of these numbered track.
• Each track is labeled and the location is stored in a
log on the disk known as a file allocation table (FAT).
Types of Storage Devices
• Hard Disk Drive: used to store data inside
of the computer.
– Magnetic platter that holds a large amount of
information in a form the computer can
• Accessing data is faster
• Amount of data that can be stored is much more than
what can be stored on a floppy disk.
• Size of Hard drive is measured in megabytes or
Types of Storage Devices
• Floppy Disk: flat circles of iron oxide-coated
plastic enclosed in a hard plastic case.
– Most are 3 ½ inches and have a capacity to hold
1.44 MB or more of data.
• Zip Disk: capable of storing tremendous
amounts of information
- They are only the size of a 3 inch disk but can
hold as much as 1 gigabyte of data
Types of Storage Devices
• Magnetic Tape Drives:
used for making
backup copies of large
volumes of data.
– Very slow
– Can be used to replace
data that may have
been lost on the hard
– look similar to audio
– Holds more than Floppy
• Optical discs: use laser
technology to read and
write data on silver
– CD-ROM (Compact Disk
Read-Only Memory) can
store up to 800MB of
– You can only read data
from a CD
– You can store data on a CD
only if you have a CD
Burner and writable CDs
(CD-R or recordable CDROM)
– DVD (Digital Versatile
Disk) is the size of a
regular CD and can be
played in a regular CD or in
a DVD movie player.
Systems Software
• A group of programs that coordinate and control
the resources and operations of a computer
– Enables all components of the computer system to
• Operating System (OS): provide an interface
between the user or application program and the
computer hardware.
– Win 95/98/2000
– Mac System 6/7
• Utility programs: help you perform housekeeping
chores; complete specialized tasks related to
managing the computer’s resources, file
management, and so on.
• GUI (graphical user interface): graphical symbols
(icons) represent files, disks,
programs, and other objects.
Application Software
• Programs that work with the OS software
to help you use your computer to do
specific types of work.
• Categories:
Graphics and Multimedia
Education and Reference
Entertainment and Leisure
Integrated Programs
Business Software
• Word Processing
– program that allows you
to create, edit, and
print text documents
• Report, flyer, memo
• Spreadsheet
– Numbered Rows and
Lettered Columns
– Intersection of them =
• Grade book, financial
• Database
– Lets you set up an
electronic filing
– Enter text and
• Find, search, and
printer info in
different ways
– Address book,
Card Catalog
• Communications
– Works with your
modems or network
hardware and allows
your computer to
communicate with other
• Exchange computer
files and email
• Graphics Software
– Uses pictures or images
to help communicate
• Multimedia:
combines text,
graphics, animation,
video, and audio.
• Clip art: graphical
images to be added
to documents
• Desktop Publishing:
uses both pictures
and words to give
you the ability to
create documents
– Newsletters and
• Education &
– Available on many
– Help
– Easier
– Quicker
• Examples: AR,
Encyclopedia, etc.
• Entertainment &
– Fun
– Games and
– Tests your skills
– interactive
Integrated Software
• Combine several
applications into
one program.
Work Processing
• Examples:
– MS Works
– Lotus SmartSuite
Proper Computer Care
• Keep food and drinks away from the computer and
• Avoid dusty locations.
• Use a surge protector.
• Keep magnets Away.
• Do not block vents on the CPU.
• Avoid bright sunny locations.
• Do not move the computer while it is in use.
• Always exit programs properly.
• Use a virus check program on a regular basis.
Proper Diskette Care
• Do not remove from drives while drive in running
or light is on.
• Avoid contact with magnets and electromagnetic
• Keep disks stored in a clean, cool and dry place
with a protective cover.
• Keep protective metal slider in place.
• Use a virus check program on a regular basis.
• Avoid hot and cold locations.
• Make a back-up copy of your programs and files.
Proper CD ROM Care
• Keep CDs stored in a clean, cool and dry place
with a protective cover.
• Avoid touching the back side of the CD; to avoid
• Avoid hot and cold locations.
• Make a back-up copy of your programs and files.
• Insert into CD ROM Drive properly; label facing
• Only write on CD’s with a CD Marking Pen on a
label or the correct side of the CD.
Proper Care of Printers
• Avoid cold, hot, and dusty locations.
• Always use the correct ink or toner replacement.
• Always have the proper printer cable connected
to your computer.
• Never pull paper out of a printer in motion.
• Do not turn off the printer while printing.
• Read the instruction manual before operating a
• Always use the proper type of paper in your
How to Maintain your
Computer System
Start a notebook of information on your system.
Periodically review disk directories and delete unneeded files.
Make sure all plug-ins are secure at all times.
Turn off the power and disconnect the equipment form the power
source before you open the inside of you computer.
Keep surrounding area dirt and dust free.
Back up files and data regularly.
Periodically defragment your hard disk.
Protect your system from computer viruses
Learn to use system diagnostic programs
Serial numbers
Vendor support telephone numbers
User IDs
Date and vendor for each equipment and software purchase.
Trouble log
• The science of designing equipment for a
comfortable and safe working environment.
• Proper Computer Ergonomics
– Sit up straight and lean forward slightly from the waist.
– Keep your feet flat on the floor.
– Your body should be about a hand’s length from the front of
the keyboard and centered with the keyboard.
– Keep your fingers on the home row keys and curved.
– Keep your wrists up, not touching the keyboard or desk.
– Focus your eyes on the book, copy or screen.
– Place all materials you will type on the right side of the
computer and supplies on the left side.
– Keep any items you are not using off your desk.
– Occasionally rest your eyes and take short breaks.
– Avoid lights that cause glare on the monitor.

Unit I: Computer Basics