A. Computer
A. Computer
Basics
Basics
A. Computer
A. Computer
Basics
Basics
Unit Objectives:
Unit Objectives:
1.01-1.04
1.01-1.04
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 closed).
– These two states of the circuit are represented by two digits, 0 and 1.
• Called the binary system
Benefits of Using
Computers
• Error-free calculations
• Speed
• Flexibility
• Storage
What Is A
Computer System?
• Hardware: the
tangible, physical
equipment that can
be seen and touched
such as:
– Computer Case
– Monitor
– Keyboard and Mouse
– Disk Drive
– Speakers
• Software: the intangible set of instructions that tells the computer what to do; know as programs or software programs.
– Two types: application and system software programs • Data: information entered
into the computer to be
processed, which consists of the following:
– Text, numbers, sounds, and images
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
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.
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.
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)
Data Communications
• Network: when computers are connected to
other computers
– They can share information and sometimes
hardware (printers)
– 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,
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 division.
– Logical operations involve comparisons.
• Control Unit: is the “boss” and coordinates all of the CPU’s activities.
– 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.
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.
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.
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.
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.
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.
Input, Output, &
Storage Devices
• Input device:
hardware that
allows you to
communicate
with your
computer.
• Output device:
hardware that allows
your computer to
communicate with
the user
• Storage device:
allows you to store
or retrieve
Computer Input
Devices
• Keyboard
• Mouse/Trackball
• Joystick
• Light pen
• Pointing Stick
• Touchpad
• Touch screen
• Bar code reader
• Scanner
• Microphone
Computer Output
Devices
• Monitor: screen that
display information
such as text, numbers,
and pictures.
– softcopy
• Printer: gives you
information from the
computer in printed
form.
– Hardcopy
• Speakers: allow you
to hear voice,
music, and other
sounds from your
computer.
• Modem: allows you
to use your
computer to
Three Types of Printers
•
Dot Matrix
– Gives a printed image in a pattern (matrix) of
tiny ink dots.
• Less expensive and not as clear
•
Inkjet Printer
– Better quality of printed document
• 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.
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.
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
understand.
• Accessing data is faster
• Amount of data that can be stored is much more than what can be stored on a floppy disk.
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
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 drive
– look similar to audio
tapes.
– Holds more than
Floppy
• Optical discs: use laser
technology to read and write data on silver platters.
– CD-ROM (Compact Disk Read-Only Memory) can store up to 800MB of information/data.
– 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 CD-ROM)
Systems Software
• A group of programs that coordinate and control the resources and operations of a computer system.
– Enables all components of the computer system to communicate.
• 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,
Application Software
• Programs that work with the OS software to
help you use your computer to do specific
types of work.
• Categories:
–
Business
–
Communications
–
Graphics and Multimedia
–
Education and Reference
–
Entertainment and Leisure
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
= cell
• Grade book, financial info
• Database
– Lets you set up an
electronic filing
systems
– Enter text and
numbers
• Find, search, and
printer info in
different ways
Software
• Communications
– Works with your modems or network hardware and allows your computer to communicate with other computers.
• Exchange computer files and email
• Graphics Software
– Uses pictures or images to help communicate messages.
• 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
Software
• Education &
Reference
– Available on many
topics
– Help
– Easier
– Quicker
• Examples: AR,
Encyclopedia, etc.
• Entertainment &
Leisure
– Fun
– Games and
simulations
Integrated Software
• Combine several
software
applications into
one program.
– Include:
– Work Processing
– Spreadsheet
– Database
– Communication
• Examples:
– MS Works
– MS OFFICE
Proper Computer Care
• Keep food and drinks away from the computer
and keyboard.
• 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.
Proper Diskette Care
• Do not remove from drives while drive in
running or light is on.
• Avoid contact with magnets and
electromagnetic fields.
• 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.
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
scratches.
• Avoid hot and cold locations.
• Make a back-up copy of your programs and files.
• Insert into CD ROM Drive properly; label facing
up.
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
printer.
How to Maintain your
Computer System
• Start a notebook of information on your system.
– Serial numbers
– Vendor support telephone numbers – User IDs
– Date and vendor for each equipment and software purchase. – Trouble log
• 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.
Ergonomics
• 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.
