A. Computer Basics

Unit Objectives:1.01-1.04

1.00 Examine the role of hardware and software.

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• Combining bits (0 and 1), you can

represent any character or number.

Benefits of Using Computers

• Error-free calculations• Speed• Flexibility• Storage• Consistency and repetition

What Is AComputer 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• 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 computers

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 lap.

Additional Typesof 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 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, 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 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.– COBOL, C++, or VisualBasic.net, HTML, Java Script for example.

System ComponentsMemory: 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 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 information

Computer Input Devices

• Keyboard• Mouse/

Trackball• Joystick• Light pen• Pointing Stick• Touchpad

• Touch screen• Bar code

reader• Scanner• Microphone• Graphics Tablet• Digital

Cameras

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 communicate with other computers.

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.

• 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 understand.• 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

gigabytes.

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 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)

– 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 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, XP, Windows 7

• Utility programs: help you perform housekeeping chores; complete specialized tasks related to managing the computer’s resources, file management, and so on.

• – Disk Cleanup, Defragmenter, Anti Virus• 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:– Business– Communications– 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• MS Word

• Spreadsheet– Numbered Rows and

Lettered Columns– Intersection of them

= cell• Grade book, financial

info• MS Excel

• Database– Lets you set up

an electronic filing systems

– Enter text and numbers• Find, search,

and printer info in different ways

– Address book, Card Catalog

– MS Access

Software• Communications

– Works with your modems or network hardware and allows your computer to communicate with other computers.

• Exchange computer files, chat, email

• Graphics Software– Uses pictures or

images to help communicate messages.

-editing, Photo Shop

• Multimedia: combines text, graphics, animation, video, and audio.– PowerPoint

• Desktop Publishing: uses both pictures and words to give you the ability to create documents– Newsletters and

brochures– MS Publisher

Software• Education &

Reference– Available on

many topics– Help– Easier– Quicker

• Example: Encyclopedia, Wikipedia etc.

• Entertainment & Leisure– Fun– Games and

simulations– Tests your skills– interactive

Integrated Software• Combine

several software applications into one program.– Include:– Word

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.• 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 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.• 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 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.• 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 printer.• Always use the proper type of paper in your

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.• Protect your system from computer viruses• Learn to use system diagnostic programs

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.– 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.