Introduction to Computers

1
Introduction to Computers

• And How to Purchase, Install, and Maintain a
  Personal Computer

2
Objectives

• Define the term computer and discuss the four
  basic computer operations input, processing,
  output, and storage
• Define data and information
• Explain the principal components of the computer
  and their use
• Describe the use of floppy disks, hard disks, and
  other storage media
• Discuss computer software and explain the
  difference between system software and
  application software

3
Objectives cont

• Identify several types of personal computer
  application software
• Discuss computer communications channels and
  equipment and the Internet and World Wide Web
• Explain how to purchase, install, and maintain a
  personal computer
• Define e-commerce

4
What is a computer?

• Computer
• an electronic device, operating under the control
  of instructions stored in its own memory unit
• this memory unit can
• accept data input
• manipulate data process
• produce information output
• store results for future use - storage

5
What does a computer do?

• Computers perform four general operations
• input, process, output, and storage
• Information processing cycle
• inputting, processing, outputting, and storing
  make-up this cycle
• Processing requires data
• data collection of raw facts, figures, and
  symbols given to a computer during the input
  operation
• Manipulate data to create information
• information data that is organized, meaningful,
  and useful

6
Why is a computer so powerful?

• Power is derived from the computers capability
  to perform the information processing cycle with
  speed, reliability, and accuracy
• The computers capacity to store huge amounts of
  data and information
• The computers ability to communicate with other
  computers

7
How does a computer know what to do?

• It must be given a detailed set of instructions
• These instructions are called a computer program
  or software
• Executes one program instruction after another
  until the job is complete

8
What are the components of a computer?

• Six primary components
• input devices
• the processor
• memory
• output devices
• storage devices
• communications devices
• the processor, memory, and storage device are
  housed in a box-like case called the system unit

9
Input Devices

• Input device any hardware component the allows
  you to enter data, programs, commands, and user
  responses into a computer
• primary input devices
• keyboard
• mouse
• other input devices
• digital camera
• scanner
• microphone

10
Input Devices cont

• The Keyboard
• desktop computer keyboard typically has 101 to
  105 keys
• handheld computers use an onscreen keyboard and
  use a stylus to select keys
• The Mouse
• a pointing device that fits under the palm of
  your hand
• control the movement of the pointer on the screen
  and make selections from the screen
• one to five buttons
• bottom is flat and contains a mechanism or ball
  that detects movement
• notebooks have a pointing device built into the
  keyboard

11
Processor

• Processor or central processing unit (CPU)
  interprets and carries out the basic instructions
  that operate a computer
• made up of the control unit and arithmetic/logic
  unit
• control unit interprets the instructions
• arithmetic/logic unit performs the logical and
  arithmetic processes
• 42 million transistors and performs operations 10
  million times in a tenth of a second

12
Memory

• Memory or random access memory (RAM) electronic
  components that store instructions waiting to be
  executed by the processor, data needed by those
  instructions, and the results of processed data
• consists of one or more chips on the motherboard
• motherboard or system board main circuit board
  to which electronic components are attached
• memory is measured in kilobytes or megabytes
• 1 kilobyte (K or KB) 1,000 memory locations
• 1 megabyte (M or MB) 1,000,000 memory locations
• memory location or byte stores one character

13
Output Devices

• Output devices make information from processing
  available for use
• can be presented in many forms
• printed report or displayed on a screen
• printers and display devices are common output
  devices for word processing, spreadsheets, and
  database management

14
Output Devices cont

• Printers
• two kinds of printers
• impact printers strikes an inked ribbon against
  the paper (dot matrix printer)
• Nonimpact printers form characters by means
  other than striking a ribbon against paper
  (ink-jet printers or laser printers)
• advantage print higher-quality text and
  graphics, better job printing different fonts,
  quieter, can print in color

15
Output Devices cont

• Display devices an output device that visually
  conveys text, graphics, and video information
• monitor plastic or metal case that houses a
  display device
• two types of monitors CRT and LCD
• cathode ray tube (CRT) television- like, most
  common
• LCD or flat panel monitor uses a liquid display
  crystal, similar to a digital watch
• surface of screen is composed of individual
  picture elements called pixels
• resolution of 800 x 600 480,000 pixels
• each pixel can be illuminated to form parts of a
  character or grpahic shape on the screen

16
Storage Devices

• Storage devices used to store instructions,
  data, and information not being used in memory
• six types of storage devices
• floppy disks
• zip disks
• optical discs
• tape
• miniature storage media

17
Storage Devices cont

• Floppy disks or diskette
• portable, inexpensive storage medium that
  consists of a thin, circular, flexible plastic
  disk with a magnetic coating enclosed in a
  square-shaped plastic shell
• typically can store up to 1.44 megabytes of data
  or 1,474,560 characters
• a portable storage medium
• portable means you can remove the medium from one
  computer and carry it to another computer
• floppy disk drive device that can read from and
  write to a floppy disk

18
Storage Devices cont

• Floppy disks cont
• a type of magnetic disk, which uses magnetic
  patterns to store items on its surface
• read/write storage media
• can access (read) data from and place (write)
  data on a magnetic disk
• must be formatted
• formatting process of preparing a disk for
  reading and writing by organizing the disk into
  storage locations called tracks and sectors
• track a narrow recording band that forms a full
  circle on the surface of the disk
• sector capable of holding 512 bytes of data
• 80 track per side and 18 sectors per track
• access time time required to access and
  retrieve data

19
Storage Devices cont

• Zip Disk portable magnetic media
• can store up to 750 MB
• can be built-in or external
• make it easier to transport many files or large
  items
• graphics, audio, or video files
• back up important data and information
• backup a duplicate of a file, program, or disk
  that you can use in case the original is lost,
  damaged, or destroyed

20
Storage Devices cont

• Hard disks consists of one or more rigid metal
  platters coated with a metal oxide material that
  allows data to be recorded magnetically
• data is recorded on a series of tracks
• spin 5,400 to 7,200 revolutions/minute
• number of platters vary
• storage capacity one billion characters to more
  than 200 billion characters
• 1 billion bytes 1 gigabyte (GB)

21
Storage Devices cont

• Optical discs storage medium that consists of a
  flat, round, portable, metal storage medium
• 4.75 inches in diameter
• less than 1/20 of an inch thick
• Two types of optical discs
• CD
• DVD
• Variety of formats
• CD-ROM, CD-R, CD-RW, DVD-ROM, DVDRW

22
Storage Devices cont

• CD-ROMs or compact disc read-only memory- type of
  optical disc that uses laser technology for
  recording
• can contain audio, text, graphics, and video
• can only read, cannot erase or modify the content
• holds 650 MB 1 GB of data
• CD-R or compact disc-recordable multisession
  optical disc that you can record your own items
  on
• can read from many times
• can write on each part only one time
• cannot erase

23
Storage Devices cont

• CD-RW or compact disc-rewritable an erasable
  disc you can write on multiple times
• write and rewrite data, instructions, and
  information multiple times
• DVDs technology that can be used to store large
  amounts of text and even cinema-like videos
• DVD-ROM or digital video disc-ROM high capacity
  optical disc
• store 4.7 GB to 17 GB
• read-only

24
Storage Devices cont

• DVDRW or DVD-rewriteable can erase and record
  multiple times
• major use
• edit videos from a video camera or VCR, stored
  and edited on your computer, and then written to
  a DVDRW disc
• Tape magnetically coated ribbon of plastic
  housed in a tape cartridge capable of storing
  large amounts of data and information at a low
  cost
• primarily used for long-term storage and backup

25
Storage Devices cont

• Miniature Storage Media rewritable media in the
  form of a flash memory card
• solid-state device that consists entirely of
  electronics and contain no moving parts
• used with PDAs, digital cameras, music players,
  and smart phones
• used to store digital images, music, and documents

26
Communications Devices

• Communications device hardware component that
  enables a computer to send (transmit) and receive
  data, instructions, and information to and from
  one or more computers
• widely used communication device is the modem
• communications occur over transmission media
• cables, telephone lines, cellular radio networks,
  and satellites
• some are wireless

27
Computer Software

• two types of software
• system software
• application software
• System software programs to control the
  operations of computer equipment
• operating system set of programs that tell the
  computer how to perform the functions of loading,
  storing, and executing an application program and
  how to transfer data
• booting when a computer is turned on, the
  operating system is loaded into the computers
  memory from auxiliary storage
• graphical user interface (GUI) visual cues or
  icon symbols

28
Computer Software cont

• Application Software programs that tell a
  computer how to produce information
• examples personal information manager,
  accounting, computer-aided design, desktop
  publishing, picture and video editing, and
  educational
• commonly used applications word processing,
  electronic spreadsheet, and presentation graphics
• software package Microsoft Office

29
Computer Software cont

• Word processing software used to create, edit,
  format, and print documents
• advantage users can easily make changes to the
  document
• Electronic spreadsheet software user can add,
  subtract, and perform user-defined calculations
  on rows and columns of numbers
• eliminates tedious recalculations, easily
  converted into a graphic form

30
Computer Software cont

• Database software user can enter, retrieve, and
  update data in an organized and efficient manner
• Can access data in different ways and create
  custom reports
• Presentation graphics software allows users to
  create documents called slides to be used in
  presentations

31
Networks and the Internet

• Network collection of computers and devices
  connected via communications media and devices
  such as cables, telephone lines, modems
• users can share resources, such as hardware
  devices, software programs, data, and information
• saves time and money
• LAN or local area network network that connects
  computers in a limited geographic area
• computer lab, offices, groups of buildings
• WAN or wide area network network that covers a
  large geographical area
• districts offices of a national corporation

32
Networks and the Internet cont

• The Internet worldwide collection of networks
  that links together millions of computers by
  means of modems, telephone lines, cables, and
  other communications devices and media
• world largest network
• use the Internet for a variety of reasons
• Sending messages (e-mail), accessing information,
  shopping, meeting and conversing with people, and
  accessing sources of entertainment and leisure

33
Networks and the Internet cont

• Connect to the Internet in one of two ways
• through an Internet service provider
• through an online service provider
• Internet service provider (ISP) organization
  that supplies connections to the Internet for a
  monthly fee
• Online service provider (OSP) provides access
  to the Internet, but it also provides a variety
  of other specialized content and services

34
Networks and the Internet cont

• The World Wide Web or the Web contains billions
  of documents called Web pages
• most popular segment of the Internet
• Web page document that contains text, graphics,
  sound, and/or video and has built-in connections,
  or hyper-links, to other Web documents
• Web site related collection of Web pages
• Web browser software program used to access and
  view Web pages

35
Networks and the Internet cont

• Uniform Resource Locator or URL unique Web page
  address
• consists of a protocol, domain name, and
  sometimes the path to a specific Web page or
  location in a Web page
• URLs begin with http//
• http stands for hypertext transfer protocol
• domain name identifies the Web site, which is
  stored on a Web server
• Web server computer that delivers (serves)
  requested Web pages

36
Networks and the Internet cont

• Electronic Commerce or e-commerce conducting
  business activities online
• Three types of e-commerce
• Business to consumer (B2C) sale of goods to the
  general public
• Consumer to consumer (C2C) one consumer selling
  directly to another
• Business to business (B2B) goods and services
  to other businesses