SSD2: Introduction to Computer Systems

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SSD2 Introduction to Computer Systems

• ISS,WHU

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Unit 1. Computer Systems

• 1.1 Overview of Computer Systems
• 1.2 Evolution of Computer Systems
• 1.3 Data Representation in a Computer System

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Subsystems of a Computer

• Network System
• Internet services (email)
• Network connections (modems, network cards)

• Software System
• Operating System (Unix, Mac OS, Microsoft
• Windows)
• Web browser (Netscape, Internet Explorer)
• Office productivity applications (Microsoft
• Office, Star Office)

• Hardware System
• Keyboard
• Monitor
• System unit

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Hardware System
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Hardware Components Peripheral Devices

• Equipment added to computer to enhance its
  functionality
• Modify and expand the basic computer system
• Examples of peripheral devices
• Keyboard
• Monitor
• Mouse
• Printer
• Scanner
• Digital Video Camera
• Graphic Tablet
• Joy Stick

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Hardware Components Storage Devices

• Optical Disks
• CD-ROM
• CD-RW
• DVD-ROM
• Magnetic Disks
• Floppy disk
• Hard disk (removable fixed)

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What is Software?

• Software is a set of computer instructions or
  data.
• Software receives input from the user and
  processes this input through the computer to
  produce output.
• Software directs how the computer interacts with
  the user.
• Software specifies how to process the user's data

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Software System

• Two categories
• Operating system software,
• Application software

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Software System

• Operating system software, also called system
  software, is the master controller for all
  activities that take place within a computer
• Examples of OS software
• Microsoft Windows
• Unix
• Mac OS
• Application software is a set of one or more
  computer programs that helps a person carry out a
  task
• Examples of application software
• Microsoft Word
• Internet Explorer
• Macromedia Dreamweaver
• Adobe Acrobat Reader

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Network System

• A network provides connections among computers to
  enable computers on a network to share data (e.g.
  documents), hardware (e.g. printers), and
  software resources (e.g. application programs).
• Network users can also send messages to each
  other.
• A network must be secured to protect data from
  unauthorized usage (e.g. using login name and
  password to gain access to a network).

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Basic Computer Model

• All computers perform four basic operations
• Input Data
• Process Data
• Store Data
• Output Data

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Basic Operations

• Input data is to feed information which can be
  supplied by any person, environment or other
  computer.
• Processing data is manipulating data by
  performing calculations, sorting lists of words
  or numbers, drawing pictures.
• Storing data is for future retrieval and
  processing. Memory holds data that is waiting to
  be processed, and storage areas hold data
  permanently until the data is deleted.
• Output data is the result produced by a computer,
  which includes reports, documents, music, graphs
  and pictures.

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Categories of Computers

• Computers are classified based on their
  technology, function, physical size, performance
  and cost. The categories of computers include
• Personal computers
• Handheld computers
• Mainframes
• Supercomputers

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Personal Computer (PC)

• Designed to meet the computing needs of an
  individual
• Desktop computers
• Notebook computers

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Handheld Computer

• Designed to fit into a pocket, run on batteries,
  and be used while you are holding it
• Also called a PDA (Personal Digital Assistant)
• Send and receive e-mail
• Use maps and global positioning
• Maintain expense account, contacts, to-do lists,
  memos, etc.
• Make voice calls using cellular service

A personal digital assistant (PDA) accepts
infoon a touch-sensitivescreen
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Mainframe Computer

• It is a large and expensive computer that is
  capable of handling requests and passing data
  simultaneously to many users.
• Used by governments and large corporations to
  provide centralized storage and control
• Processes billions of data per second and
  includes many units where one directs overall
  operations, a second one handles communication
  between users, and third searches for requests
  given by user.

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Supercomputer

• It is the fastest type of computer.
• Supercomputers are very expensive and are
  employed for specialized applications that
  require immense amounts of mathematical
  calculations.
• It is often used for
• Breaking codes
• Modeling weather systems
• Simulating nuclear explosions
• Research simulations
• Capable of performing over 600 billion
  floating-point operations per second.
• Examples Deep Blue, PARAM 1000, Hitachi's SR2201

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Evolution of Computers

• Needed calculation devices to keep track of
  accounting for commerce
• 1200sManual Calculating Devices the abacus

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Evolution of Computers (continued)

• 1600sMechanical Calculators
• Used wheels, gears, and counters
• To work a mechanical calculator, the operator
  enters the numbers for a calculation, and then
  pulls a lever or turns a wheel to carry out the
  calculation
• Example the Pascaline invented by Blaise Pascal.
  It used some principles of the abacus, but used
  wheels to move counters.

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Evolution of Computers (continued)

• 1800sPunched Cards(punched card )
• Used holes following a specific pattern to
  represent the instructions given to the machine
  or stored data
• Different program instructions can be stored on
  separate punched cards, which can be fed through
  the computing machine repeatedly.
• Once punched, the cards were fed into a card
  reader that used an array of metal rods to
  electronically read the data from the cards and
  tabulate the results. This is called the
  Hollerith Tabulating Machine
• Hollerith incorporated The Tabulating Machine
  better known today as IBM.

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Evolution of Computers (continued)

• Charles Babbage designed a new general-purpose
  calculating device, the Analytical Engine, which
  is the ancestor of modern computers.
• It included the essential components of
  present-day computers, which are input, process,
  storage, and output of data.

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Evolution of Computers (continued)

• 1940sVacuum Tubes
• Used to control the flow of electrons. Since
  vacuum tubes responded faster than mechanical
  components, faster computations were possible.
  But, the tubes consumed a lot of power and burned
  out quickly.
• The first computer prototype using vacuum tubes
  was ENIAC (Electronic Numerical Integrator and
  Computer). It was designed to calculate
  trajectory tables for the U.S. Army during World
  War II, but it was not completed until three
  months after the war.

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Evolution of Computers (continued)

• 1950sTransistors
• Smaller, cheaper, more reliable, and consumed
  less power than vacuum tubes.
• Could perform 200,000 to 250,000 calculations per
  second.

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Evolution of Computers (continued)

• 1960sIntegrated Circuits
• Thin slice of silicon packed with microscopic
  circuit elements such as wire, transistors,
  capacitors, and resistors.
• Enabled the equivalent of thousands of vacuum
  tubes or transistors to be packed onto a single
  miniature chip about the size of your fingernail
• Reduces the physical size, weight, and power
  requirements for devices such as computers

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Evolution of Computers (continued)

• 1970s to PresentMicroprocessor
• Combined components of a computer on a microchip
• Can be manufactured and then programmed for
  various purposes

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Evolution of Computers (continued)

• Pace of Processor Advancement

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Applications of Computer Systems

• In Education
• Multimedia-Facilitated Learning
• Simulation-Based Education
• Intelligent Machine-Based Training
• Interactive Learning
• In Business
• Supply Chain Management
• Project Management
• Customer Relationship Management
• Sales and Marketing Using Electronic Commerce
• Manufacturing Research

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Applications of Computer Systems

• In Entertainment
• Movies
• Video Games
• Music
• Digital Photography
• Travel
• Wearable Computer Systems
• Developing new applications of computer systems
• Research at Carnegie Mellon University
• http//www.cs.cmu.edu/research/projects/
• Research at Massachusetts Institute of Technology
  Media Lab http//www.media.mit.edu/

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Computer Industry

• Computer industry encompasses those companies
  that manufacture handheld computers, personal
  computers, high-end workstations, servers,
  mainframes, and supercomputers
• Information technology industry (or IT industry),
  is typically used to refer to the companies that
  develop, produce, sell, or support computers,
  software, and computer-related products
• IT companies include
• Equipment manufacturers
• Chipmakers
• Software publishers
• Service companies
• Retailers

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Computer Industry (continued)

• The 1990s spawned a group of Internet-based
  companies that came to be called dot coms, from
  the companies domain names, which inevitably
  ended with .com and many of the companies even
  incorporated .com into their official company
  names
• Amazon.com was one of the first Internet-based
  companies

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Computer Industry (continued)

• Governments and private businesses have
  discovered that they can become much more
  efficient with a liberal application of computers
  and other information technologies
• As businesses globalize, they encounter new
  competitors with technological advantages
• Bottom line if your business competitors turn
  to technology, so must you

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Careers in Computing

• A systems analyst investigates the requirements
  of a business or organization, its employees, and
  its customers in order to plan and implement new
  or improved computer services
• A security specialist analyzes a computer
  systems vulnerability to threats from viruses,
  worms, unauthorized access, and physical damage
• A computer programmer designs, codes, and tests
  computer programs
• A quality assurance specialist participates in
  alpha and beta test cycles of software
• A database administrator analyzes a companys
  data to determine the most effective way to
  collect and store it

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Careers in Computing (continued)

• A network specialist/administrator plans,
  installs, and maintains one or more local area
  networks
• A computer operator typically works with
  minicomputers, mainframes, and supercomputers
• A computer engineer designs and tests new
  hardware products, such as computer chips,
  circuit boards, computers, and peripheral devices
• A technical support specialist provides phone or
  online help to customers of computer companies
  and software publishers

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Careers in Computing (continued)

• A technical writer creates documentation for
  large programming projects, and writes the online
  or printed user manuals that accompany computers,
  peripheral devices, and software
• A computer salesperson, or sales rep, sells
  computers
• A Web site designer creates, tests, posts, and
  modifies Web pages
• A manufacturing technician participates in the
  fabrication of computer chips, circuit boards,
  system units, or peripheral devices

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Careers in Computing (continued)

• The U.S. Bureau of Labor Statistics (BLS)
  projects that the number of jobs in the computer
  industry will substantially increase between now
  and 2008
• According to the BLS, the largest increases in
  available jobs will be for database
  administrators, computer support specialists, and
  computer engineers
• Over the next few years, economic trends may
  cause significant changes in the job market
• A daily look at in-demand tech skills can be
  viewed at http//mshiltonj.com/sm/

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IT Salaries in the U.S.
Source http//www.bls.gov
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1.3 Data Representation in a Computer System

• 1.3.1 Bits and Bytes
• 1.3.2 Number Systems

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1.3.1 Bits and Bytes

• Recall computers are made up of electrical
  components
• Data can be represented electronically with
  electrical components being on or off.
• On and off states can be represented using digits
  0s and 1s. For example
• 0 Off state
• 1 On state
• Thus, data can be represented digitally using
  digits 0 and 1.
• 0 and 1 are called binary digits.
• Each binary digit is called a bit(????,??).
• Eight Bits equal to one byte (??).

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Data Representation Using Binary Digits

• A piece of data, such as an alphabet letter, may
  be represented using a sequence of binary digits-
  0's and 1's.
• There are several types of codes used to
  represent character data.
• Extended ASCII (America Standard Code for
  Information Interchange) code,
• the alphabet letter "a" can be represented using
  a series of eight binary digits, "01100001."

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Extended ASCII code

• uses eight bits (or one byte) to represent input
  characters.

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data representing

• All data, including audio, visual, and program
  instruction data can be represented and stored
  using a sequence of binary digits, or a sequence
  of bytes.

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A file is a collection of data.

• In some files, the bits of data directly encode
  individual letters, numbers, and punctuation
  symbols that make up words and sentences.
• In other files such as an image file, the bits of
  data need to be computed in order for them to
  transform to images that we can interpret.

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A file is a collection of data.

• Most applications encode information in
  specialized ways that are not readable by humans.
  such as Microsoft Word or PowerPoint
• even though Microsoft Word is often used to edit
  text, a Word document cannot be properly
  displayed by a simple text editor like Notepad
  because the document includes information in a
  format specific to Microsoft Word.
• Therefore, it must be opened by Microsoft Word to
  be read.
• Some files have a header section that indicates
  which format was used to encode the data in order
  to allow the computer to reassemble the binary
  data back into the human-readable form of the
  document.

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Increasing Need for Bytes
Decade 1970s 1980s 1990s 2000s
Order of magnitude in Storage capacity Thousands Millions Billions Trillions
Prefix Kilo (103) Mega (106) Giga (109) Tera (1012)
Abbreviation K M G T
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In terms of storage, more is betterwhich

• more information in the form of both data and
  programs that act on that data can be stored.
• Corresponding to the growth in storage capacity,
  memory capacity is also increasing.
• Moreover, memory technologies are getting
  smaller, lighter, and faster, for about the same
  price.

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1.3.2 Number Systems

• Decimal base 10 (digits 0-9)
• Binary base 2 (digits 0-1)
• Hexadecimal base16 (digits 0-9 and A-F)
• Each hexadecimal digit represents four binary
  places.
• Hex digit can be used as shorthand for binary
  notation
• One Hex digit four bits
• One byte 8 bits two Hex digits