Learning Objectives

• Explain why it's essential to learn about computers today.
• Describe several uses for computers in business or personal life.
• Identify some of the major components of a computer system and explain their relationships to one another.
• Define terms that commonly arise in reading about or discussing computers.
• Describe the purpose of a network and what the Internet is.
• List the five major categories of computers, giving at least one example of what the computers in each category might be used for.
• Discuss the social impact of computers and some issues that arise from their prominence in our society.

• Most skill based jobs now heavily depend on the creation, collection, and dissemination of information.
• Computers are also prevalent in the home, as well as in our society in general.
  

• Having experience with, and a basic level of comfort with, computers is important for everyone.
• Being and becoming
• "computer literate"
• "computer science literate"

• A computer is a machine that accepts data as input, processes it into information, and presents the information as output or stores it.

• Input—what is supplied to a computer to process
• Processing—the conversion of input to output
• Output—the results of computer processing
• Storage—saving data, results, or programs for future use

• This is the VonNeumann model of the computer, after John VonNeumann
  
• "A general purpose machine that is adapted to specific purposes by programs."

• (The stereo system analogy, and why a stereo is not a computer: it lacks programmability)
  

• Pre-Computers and Early Computers
• The Babbage difference engine
  
• Abacus, Slide Rule, mechanical calculator
• Punch card Tabulating Machine
• Jaquard loom
  
• First Generation (~1946-57)
• Electromechanical & vacuum tube
• Eniac and Univac
• Second Generation (~1958-63)
• Transistor based
• Programming Languages
  
• Third Generation (~1964-1970)
• Integrated circuits
• Operating systems
• Fourth Generation (~1971-present)
• Microprocessors
• Apple II, Mac & IBM PC
  
• Computer Networks
• Fifth Generation (now and the future)
• Artificial intelligence
• Voice Recognition
• Optical computing

• Hardware is all of the physical parts of in a computer system.
• A computer system consists of the computer itself and its peripheral devices.
• The "computer itself" is the CPU and RAM (+ system board support chips)
• "Peripheral devices" or "peripherals"
• Are all other attached devices: keyboard, monitor, printer hard disk, floppy disk, CD & DVD drive, ports, modem, etc., together with their various adapter boards and chips.
• whether external, or located in the "system unit", or even on the system board (motherboard)
• Peripherals be thought of as all devices except the CPU and memory (i.e., that's a good test answer.)
• Peripheral Device Classifications:
• Input: Keyboard, mouse
• Output: printer, monitor
• Input/Output: disk drive, sound card

• The CPU (Central Processing Unit or microprocessor chip) is at the heart of any computer system.
• The CPU performs all of the arithmetic, logical, data movement and other digestive operations of the computer.
• The CPU carries out program instructions
• Peripheral devices may contain microprocessor chips (usually specialized) and/or RAM, but are not "computers"

• Two kinds of storage
  
• Volatile memory (RAM, or Random Access Memory, or Primary Storage)
• All data in RAM are lost when power is turned off or lost
• Secondary Storage: disk, cd, dvd, flask memory, etc
  

• The programs or instructions that are used to tell the computer hardware what to do.
• Two basic kinds of software:
• Application software: performs specific tasks or applications for an end user.
  
• Word Processor
• Spreadsheet
• Accounting
• File Manager
• Game
• Checkbook organizer
• email

• Systems software: allows a computer to operate and run application software.
• Also called the Operating System (OS)
• Microcomputer OS's: Windows, MAC OS, Linux
• Larger Computer OS's: Linux, Unix, AIX, Solaris, OS400
• OS Versions: e.g., Windows 95, Windows ME, Windows 2000, Windows XP
  

• Some Features of the Windows OS user interface:

• Which type is a Browser: system or application software?

• included inside products like cars: fuel injection control, automatig braking system, climate control
• adapted to specific tasks-- not general purpose conputers

Mobile Devices

• Very small, portable computing devices
• Based on a wireless phone or pager
• May have limited Internet access
• Smart phone
• iPhone, Palm Pre, Blackberry, HTC Android
• a mobile phone offering advanced capabilities, often with PC-like functionality.
• Handheld computers (PIMs <Personal Information Managers>, PDAs <Personal Digital Assistants>)
• SmartBook: a low cost, possibly ARM based NetBook (below)
  
• Intended primarily for email and web browsing
• A step up from the SmartPhone
  

Personal Computers
 
• Microprocessors allow for the creation of computers small enough to fit on a desk or lap.
• Also called Microcomputers
  
• Microcomputers are single user computers.

• Desktop units, towers and minitowers
• Portable units: laptops, notebooks, tablets
  

• Network computers or thin clients:
• designed for just network use, usually local area network use
• no local storage: boots from nbetwork, all programs and data stred on a server
• vs. the dumb terminal, which has a keyboard and display but no CPU/processing power
  
• NetBook: a small portable laptop computer designed for wireless communication and access to the Internet
  
• Internet appliance: a PC or device designed just for Internet access
• Ultra Mobile PC's: UMPC's  (compare SmartBook, above)
  

• Synchronization of data and information among computers via:
  
• Wireless network
  
• Bluetooth
• docking station
  
• Two main microcomputer "platforms":
• "PC compatible"—a personal computer based on Intel microcomputer or compatible CPU chips, from the "IBM PC" introduced in 1980
• "Macintosh"—a type of personal computer manufactured by Apple, formerly based on the PowerPC microprocessor chip, now Intel based too.
  

Midrange Computers
 
• Also called midrange servers, minicomputers
• Multiple user, a few to 100's of of users
• Medium sized computers
• Fall between microcomputers and mainframes in processing power
• e.g., IBM iSeries, pSeries

 

Mainframes 

• Also called high-end servers or enterprise class servers
  
• Used in organizations that have extraordinary demands for processing power for business applications
  
• Multi user: 100's-1000's of users (overlapping mini's)
• (A) mainstay of almost all large organizations
• Specialize in high volume processing of business transactions
• Teleprocessing

• Offer very fast speeds and extreme degrees of accuracy
• Most often are used for scientific and mathematical applications
• weather forecasting
• aeronautical design
• nuclear research
• missile defense system control
• Massively Parallel Computing: many CPU's working on a problem simultaneously
• Speeds measured in megaflops and teraflops, soon petaflops
  

A network is two or more intelligent devices connected by a communication link.

• Two or more computers in a home, now typically connected wirelessly, are also a network
  

Network Servers

• Network servers manage resources (data and devices) on a network.
• Web servers are servers connected to the Internet to store and "serve" Web pages to browsers.
• "Online" meanings and examples:
• Ready to send and receive data to and from the network
• Ready to function, as a printer
• Business transactions over the Internet
• Web surfing, chatting, instant messaging
• "Standalone" = a computer not connected to a network

The Internet

• The Internet is the largest and most well known computer network in the world.
• E-mail and accessing the Web are two of the most common Internet activities.
• Internet is made up of
  
• ISP's
• Regional networks
• Backbone networks
• Web servers
• The World Wide Web refers to all of the web pages available on all the HTTP web servers on the Internet
• Web pages are accessed with a browser program like Internet Explorer, Safari, Firefox or Opera
• Also by your web enabled cellphone
• Internet is not the same thing as the World Wide Web
  
• The Internet is the infrastructure for the World Wide Web
• The Internet is also the infrastructure for email and file sharing, for instance

• Modem or other network adapter
• dialup via the public telephone network
  
• broadband: cable, DSL, satellite
  
• Appropriate software program: browser, usually
  
• ISP: a service that connects you to the Internet
• User ID and password to log on
• Web browser: MS Internet Explorer, Mozilla Firefox, Apple Safari
  

• Protocol
  
• http = Hypertext Transport Protocol, a protocol used for communication on the World eide Web
  
• ftp   = File Transfer Protocol
• .org is a Top Level Domain:
  
• Generic TLD's: .com, .org, .net, .gov, .mil, and the newer .biz, .info, etc.
• Country TLD's: .de = Germany, .sc = Seychelles Island, etc.
• www.pbskids.org is a domain name (everything after the protocol up to the next slash, if any)
  
• A domain name is an alias for an IP (Internet Protocol) address:
  
• 149.48.228.139 for www.pbskids.org
• www.deltacollege.edu = 72.3.225.60
• Your browser's address bar will recognize IP addresses just as well as domain names.
  
• Every domain name and IP address is unique on the Internet
• Every web server on the Internet has an IP address, and your computer has one too.
• Domain Name Servers (DNSs) translate domain names to IP addresses for routing across the Internet
  
• Domain Name Registrars administer Domain names and IP addresses
  
• ICANN (Internet Corporation for Assigned Names and Numbers)  oversees Domain Name Registrars  worldwide
• www. is not required as a prefix, e.g., http://slashdot.org/
  
• folder=an area on the domain where web pages and other folders can be stored
• index.html is the name of the page itself
• .html (Hypertext Markup Language) indicates this page  was written in HTML
  
• .php, .asp, .jsp and others indicate the page was generated dynamically by a program running on the Web Server.
  
• URL (Uniform Resource Locater) The combination of  protocol, domain name (or IP address), folder and page (file) name all taken together.
  
• eMail addresses uniquely identify a mail user and a mail server, separated by an @
• No blank spaces are allowed
• (blank spaces are allowed in a web page name, but your browser will replace them with "%20")
• Pronouncing Domain Names
• I'll leave this to you

Surfing the Web

• Your browser
• Address Bar: where you can type a URL of a page you want to see. contains the URL of  the page you are currently viewing
  
• Home Page: the page you see when you start your browser (to change: Tools | Internet Options | General |Use Current)
• Hyperlinks: take you to a different page when you click on them
• can be text or graphics
• Your mouse cursor changes to a hand when hovering on a hyperlink
  
• Tabbed Browsing: multiple pages tabbed in a single browser window.
• Right click on a hyperlink and select Open in new tab to keep the new page from replacing the old
  
• Favorites
  
• Called bookmarks in some browsers
• Allows you to return easily to a domain or page
• Click Favorites | Add to Favorites
• Managing Favorites: folders, etc.
• History list: tracks the url's you've visited in the past x weeks
• Under the little turn back the clock glyph on the IE tool bar

• Search sites:Google, Yahoo, Ask

• Keyword and directory searches
• Reference sites: www.wikipedia.org, http://en.wiktionary.org/ for example
• eMail

• "billions of messages daily"
• Two ways to access email
• Mail Clients
  
• Examples: MS Outlook, Mozilla Firefox
• Morley calls this "conventional email"
  
• Webmail
  
• Examples hotmail, gmail, Delta student and faculty email
  
• Webmail is also offered by POP3 ("conventional mail") servers
  

• The information age = the prominence of information technology.
• Benefits of a computer oriented society include the fact that day-to-day operations of many individuals are positively affected by computers.
• Problems include health, security and privacy concerns.
• We will cover these as we go along and in detail in later Chapters.