1. Introduction to Computers

2. 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

3. 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

4. Why is a computer so powerful?
Power is derived from the computer’s capability to perform the information processing cycle with speed, reliability, and accuracy
The computer’s capacity to store huge amounts of data and information
The computer’s ability to communicate with other computers

5. 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

6. 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

7. 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

8. Input Devices con’t… The Keyboard The Mouse
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

9. 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

10. 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

11. 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

12. Output Devices con’t… 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

13. Output Devices con’t…
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

14. 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

15. Storage Devices con’t…
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

16. Storage Devices con’t…
Floppy disks con’t…
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

17. Storage Devices con’t…
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

18. Storage Devices con’t…
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)

19. Storage Devices con’t…
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, DVD+RW

20. Storage Devices con’t…
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

21. Storage Devices con’t…
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

22. Storage Devices con’t…
DVD+RW 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 DVD+RW 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

23. Storage Devices con’t…
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

24. 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

25. 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 computer’s memory from auxiliary storage
graphical user interface (GUI) – visual cues or icon symbols

26. Computer Software con’t…
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

27. Computer Software con’t…
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

28. Computer Software con’t…
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

29. 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

30. Networks and the Internet con’t…
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 ( ), accessing information, shopping, meeting and conversing with people, and accessing sources of entertainment and leisure

31. Networks and the Internet con’t…
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

32. Networks and the Internet con’t…
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

33. Networks and the Internet con’t…
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 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

34. Networks and the Internet con’t…
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