Using Management Information Systems

1
Using Management Information Systems

• David Kroenke
• Hardware and Software
• Chapter 3

2
Learning Objectives

• Learn the terminology necessary to be an
  intelligent consumer of hardware products.
• Know the functions and basic features of common
  hardware devices.
• Understand the essentials of the representation
  of computer instructions and data.
• Know the purpose of the CPU and main memory, and
  understand their interaction.

3
Learning Objectives (Continued)

• Understand the key factors that affect computer
  performance.
• Learn basic characteristics of the four most
  popular operating systems.
• Know the sources and types of application
  software.
• Learn about viruses, Trojan horses, and worms and
  how to prevent them.

4
Essential Hardware Terminology

• Computing devices consists of computer hardware
  and software.
• Hardware is electronic components and related
  gadgetry that input, process, output, and store
  data according to instructions encoded in
  computer programs or software.
• Your personal computer and other computers like
  it are general-purpose computers.
• They can run different programs to perform
  different functions.

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Essential Hardware Terminology (Continued)

• Some computers are special-purpose computers.
• The programs they run are fixed permanently in
  memory.
• The computer in your cell phone is a
  special-purpose computer, and so is the computer
  in your car that meters fuel to your cars
  engine.
• The principles and fundamental components of
  general-purpose and special-purpose computers are
  the same
• The sole difference is the computer can process a
  variety of different programs

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Input, Processing, Output, and Storage Hardware

• One easy way to categorize hardware is by its
  primary function
• Input hardware
• Processing hardware
• Output hardware
• Storage hardware
• Communication hardware

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Figure 3-1 Input, Process, Output, and Storage
Hardware
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Processing Hardware

• Processing devices include the central processing
  unit (CPU), which is sometimes called the brain
  of the computer.
• The CPU selects instructions, processes them,
  performs arithmetic and logical comparisons, and
  stores results of operations in memory
• The CPU works in conjunction with main memory.
• The CPU reads data and instructions from memory,
  and it stores results of computations in main
  memory (RAM).
• Computers also can have special function cards
  that can be added to the computer to augment the
  computers basic capabilities.
• A common example is a card that provides enhanced
  clarity and refresh speed for the computers
  video display.

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Storage Hardware

• Storage hardware saves data and programs.
• A magnetic disk is by far the most common storage
  device, although optical disks, such as CDs and
  DVDs are popular.
• In large corporate data centers, data are
  sometimes stored on magnetic tape.

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Binary Digits

• Computers represent data using binary digits,
  called bits.
• A bit is either a zero or a one.
• Bits are used for computer data because they are
  easy to represent physically.
• A computer can be designed so an open switch
  represents zero and a closed switch represents a
  one.
• Or, the orientation of a magnetic field can
  represent a bit
• Magnetism in one direction represents a zero
• Magnetism in the opposite direction represents a
  one
• Or, for optical media, small pits are burned onto
  the surface of the disk so that they will reflect
  light
• In a given spot, a reflection means a one
• No reflection means a zero

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Figure 3-4 Bits Are Easy to Represent Physically
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Computer Instructions

• Computers use bits for two purposes
  Instructions and Data
• Instructions Add two numbers together
• The collection of instructions that a computer
  can process is called the computers instruction
  set.
• Microsoft Intel instruction set.
• Macintosh - PowerPC instruction set
• In 2006, Apple began offering Macintosh
  computers with a choice of either Intel or
  PowerPC processors.
• Currently, you cannot run a program designed for
  one instruction set on a computer having a
  different instruction set.

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Computer Data

• 2. Data.
• All computer data are represented by bits.
• The data can be numbers, characters, currency
  amounts, photos, recordings, or whatever.
• Bits are grouped into 8-bit chunks called bytes.
• For character data, such as letters in a persons
  name, one character will fit into one byte.
• Thus, when you read a specification that a
  computing device has 100 million bytes of memory,
  you know that the device can hold 100 million
  characters.

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Figure 3-5 Important Storage-Capacity Terminology
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Ambiguity of Binary Data

• It is not possible to determine the type of
  computer data just by looking at the data.
• The bit string 01000001 can be interpreted as the
  decimal number 65, as the character A, or as part
  of a picture or a sound file.
• Further, it could be part of a computer
  instruction.
• The CPU determines how to interpret a bit string
  from the context in which it encounters it.
• If the string occurs in the context of reading
  instructions, it will be interpreted as a
  computer instruction.
• If it occurs during arithmetic operations, it
  will be interpreted as the number 65.

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Knowledge for the Informed Professional

• Suppose that your IS department states that you
  can buy three different computer configurations
  for three different prices.
• The computers are described by expressions like
  the following
• Intel Pentium 4 Processor at 2.8 GHz with 533MHz
  Data Bus and 512K cache, 256MB RAM
• Intel Pentium 4 Processor at 2.8 GHz with 533MHz
  Data Bus and 512K cache, 512 MB RAM
• Intel Pentium 4 Processor at 3.6 GHz with 533MHz
  Data Bus and 1MB cache, 256 MB RAM

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Knowledge for the Informed Professional
(Continued)

• Now, you, have two choices
• You can tell the people in the IS department to
  specify what they think is best
• Or, with a little bit of knowledge on your part,
  you can work with the IS department to ask
  intelligent questions about the relationship of
  these computers to the kind of work your
  department does

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Figure 3-6 Computer with Applications Loaded
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CPU and Memory Usage

• The motherboard is a circuit board upon which the
  processing components are mounted and/or
  connected.
• The central processing unit (CPU) reads
  instructions and data from main memory, and it
  writes data to main memory via a data channel, or
  bus.
• Main memory consists of a set of cells, each of
  which holds a byte of data or instruction.
• Each cell has an address, and the CPU uses the
  addresses to identify particular data items.
• Main memory is also called RAM memory, or just
  RAM.
• RAM stands for random access memory.
• The term random is used to indicate that the
  computer does not need to access memory cells in
  sequence rather, they can be referenced in any
  order.

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CPU and Memory Usage (Continued)

• To store data or instructions, main memory or RAM
  must have electrical power. When power is shut
  off, the contents of main memory are lost.
• The term volatile is used to indicate that data
  will be lost when the computer is not powered.
• Main memory is volatile.
• Magnetic and optical disks maintain their
  contents without power and serve as storage
  devices.
• You can turn the computer off and back on, and
  the contents of both magnetic and optical disks
  will be unchanged.
• Magnetic and optical disk are nonvolatile.

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The Contents of Memory

• Memory is used for three purposes
• It holds instructions of the operating system
• It holds instructions for application programs
  such as Excel or Acrobat.
• It holds data.
• The operating system (OS) is a computer program
  that controls all of the computers resources
• It manages main memory.
• It processes key strokes and mouse movements.
• It sends signals to the display monitor.
• It reads and writes disk files.
• It controls the processing of other programs.

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Memory Swapping

• Memory swapping occurs when there is a request to
  the operating system to store data in memory and
  the data will not fit because there is not enough
  free memory to store the requested data.
• For this case, the operating system will have to
  remove or swap something to make space.
• Smaller degrees of swapping occurs when
• Your computer has a very large main memory.
• You use only one or a few programs at a time.
• You use small files.
• You may have a serious problem if
• Your computer has a small memory capacity.
• You need to use many programs or process many
  large data files.
• Solution - add more main memory!

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Work at the CPU

• The CPU reads instructions and data from memory
  via the data bus.
• The maximum speed at which it transfers data is
  determined by the speed of main memory and the
  speed and width of the data bus.
• A bus that is 16 bits wide can carry 16 bits at a
  time one that is 64 bits wide can carry 64 bits
  at a time.
• The wider the bus, the more data it can carry in
  a given interval of time.
• ,

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Work at the CPU (Continued)

• Because the data transfer rate depends on both
  the width of the data bus and the speed of main
  memory, another way to speed up the computer is
  to obtain faster memory.
• Some data are accessed more frequently than other
  data.
• Because of this, computer engineers found they
  could speed up the overall throughput of the CPU
  by creating a small amount of very fast memory,
  called cache memory.
• The most frequently used data are placed in the
  cache.
• Typically, the CPU stores intermediate results
  and the most frequently used computer
  instructions in the cache.
• ,

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Figure 3-7 Picture File Overlays Memory
Previously Used by Excel
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Work at the CPU (Continued)

• Each CPU has a clock speed that is measured in
  cycles per second, or hertz.
• A fast modern computer has a clock speed of 3.0
  gigahertz (abbreviated GHz), or 3 billion cycles
  per second.
• In general, the faster the clock speed, the
  faster work will get done.
• ,

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Figure 3-8 Hardware Components and Computer
Performance
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CPU and Data Bus

• A fast CPU and data bus are most useful when
  processing data that already reside in main
  memory.
• Once you have downloaded a large spreadsheet, a
  fast CPU will rapidly perform complicated,
  formula-based what-if analyses.
• A fast CPU also is useful for processing large
  graphics files.
• Example, manipulating the brightness of the
  elements of a large picture
• If the applications that you or your employees
  use do not involve millions of calculations or
  manipulations on data in main memory, then buying
  the fastest CPU is probably not worthwhile.
• ,

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Main Memory

• Two key performance factors for main memory are
  speed and size.
• Normally, a particular computer make and model is
  designed to use a given memory type, and the
  speed for that type is fixed.
• There is nothing you can do to increase memory
  speed.
• You can, however, increase the amount of main
  memory, up to the maximum size of memory that
  your computer brand and model can hold.
• If your computer is constantly swapping files,
  installing more memory will dramatically improve
  performance.
• Memory is cheap and is often the best way to get
  better performance

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Magnetic Disks

• Magnetic and optical disks provide long-term,
  nonvolatile data storage.
• The types and sizes of such storage devices will
  affect computer performance.
• Data are recorded on magnetic disks in concentric
  circles.
• The disks spin inside the disk unit, and as they
  spin magnetic spots on the disks are read or
  written by the read/write head.
• The time required to read data from a disk
  depends on two measures
• Rotational delay the time it takes the data to
  rotate to the data point
• Seek time - time it takes the read/write head arm
  to position the head over the correct circle

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Figure 3-9 Magnetic Disk Components
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Optical Disks

• There are two kinds of optical disks CDs
  (compact disks) and DVD (digital versatile
  disks).
• Both are made of plastic and coated with a
  photosensitive material.
• Bits are recorded by burning a pit into the
  photosensitive material using a low-power laser.
• The presence of a pit causes light to reflect and
  signifies a one the absence of reflection
  signifies a zero.
• Nonvolatile
• The practical differences between CDs and DVDs
  are capacity and speed.
• A typical CD has a maximum capacity of 700 MB,
  whereas a DVD disk can store up to 4.7GB.
• DVD transfer rates about 10 times faster than
  those for CDs.

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Video Displays

• There are two types of video display monitors
  CRTs and LCDs.
• CRT monitors use cathode ray tubes, the same
  devices used in traditional TV screens.
• dot pitch - the distance between pixels on the
  screen.
• The smaller the dot pitch, the sharper and
  brighter the screen image will be.
• LCD monitors use a different technology called
  liquid crystal display.
• With LCD monitors, no tube is required, so they
  are much slimmer, around 2 inches or so deep.
• pixel pitch - distance between pixels on the
  screen.
• The smaller the pixel pitch, the sharper and
  brighter the image will be.

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Figure 3-10 Contemporary Operating Systems
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Application Software

• Application software consists of programs that
  perform a business function.
• Some application programs are general purpose,
  such as Excel or Word.
• Other application programs are specific
• QuickBooks, for example, is an application
  program that provides general ledger, and other
  accounting functions.
• You can buy computer software several ways
• Off-the-shelf
• Off-the-shelf with alterations
• Tailor made

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Application Software (Continued)

• Horizontal-market application software provides
  capabilities common across all organizations and
  industries.
• Word processor, graphics programs, spreadsheets,
  and all presentation programs are all
  horizontal-market application software.
• Vertical-market application software serves the
  needs of a specific industry.
• Examples of such programs are
• Those used by dental offices to schedule
  appointments and bill patients
• Those used by auto mechanics to keep track of
  customer data and customers automobile repairs
• Those used by parts warehouses to track
  inventory, purchases, and sales

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Application Software (Continued)

• Sometimes organizations develop custom
  application software.
• They develop such programs themselves or hire a
  development vendor.
• Custom development is difficult and risky.
• Every application program needs to be adapted to
  changing needs and changing technologies .

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Figure 3-11 Software Sources and Types
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Firmware

• Firmware is computer software that is installed
  into devices like printers, print servers, and
  various types of communication devices.
• The software is coded just like other software,
  but it is installed into special, read-only
  memory of the printer or other device.
• Users do not need to load firmware into devices
  memory.
• Firmware can be changed or upgraded, but this is
  normally a task for IS professionals.

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Summary

• Computing devices consists of hardware and
  software.
• General-purpose computers can run multiple
  programs special-purpose computers, like those
  in cell phones, run only one program that is
  fixed in memory.
• Hardware can be categorized according to its
  primary functions input, processing, output, and
  storage.
• Input hardware includes devices such as keyboards
  and mice.

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Summary (Continued)

• Processing hardware includes the CPU and main
  memory.
• Output devices are video displays, printers, and
  the like.
• Storage devices include magnetic and optical
  disks.
• Computers use bits to represent data.
• A bit, or binary digit, has a value of zero or
  one.
• Bits are used to represent computer instructions
  and data.

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Summary (Continued)

• Four popular operating systems are Windows, Mac,
  OS, Unix, and Linux.
• Computer software consists of the operating
  system and application software.
• Software can be purchased off-the-shelf,
  purchased off-the-shelf and then altered, or
  tailor-made.
• Types of software include horizontal, vertical,
  and custom.
• Firmware is program code installed in read-only
  memory of printers or communications devices.

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Security GuideViruses, Trojan Horses, and Worms

• A virus is a computer program that replicates
  itself and consumes the computers resources.
• The program code that causes unwanted activity is
  called the payload.
• There are many different virus types
• Viruses
• Trojan horses
• Worm

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Virus

• A computer virus attaches itself to a program or
  file so it can spread from one computer to
  another, leaving infections as it travels. Much
  like human viruses, computer viruses can range in
  severity Some viruses cause only mildly annoying
  effects while others can damage your hardware,
  software or files. Almost all viruses are
  attached to an executable file, which means the
  virus may exist on your computer but it cannot
  infect your computer unless you run or open the
  malicious program. It is important to note that a
  virus cannot be spread without a human action,
  (such as running an infected program) to keep it
  going.  People continue the spread of a computer
  virus, mostly unknowingly, by sharing infecting
  files or sending e-mails with viruses as
  attachments in the e-mail.

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Worm

• A worm is similar to a virus by its design, and
  is considered to be a sub-class of a virus. Worms
  spread from computer to computer, but unlike a
  virus, it has the capability to travel without
  any help from a person. A worm takes advantage of
  file or information transport features on your
  system, which allows it to travel unaided. The
  biggest danger with a worm is its capability to
  replicate itself on your system, so rather than
  your computer sending out a single worm, it could
  send out hundreds or thousands of copies of
  itself, creating a huge devastating effect. One
  example would be for a worm to send a copy of
  itself to everyone listed in your e-mail address
  book. Then, the worm replicates and sends itself
  out to everyone listed in each of the receiver's
  address book, and the manifest continues on down
  the line. Due to the copying nature of a worm and
  its capability to travel across networks the end
  result in most cases is that the worm consumes
  too much system memory (or network bandwidth),
  causing Web servers, network servers and
  individual computers to stop responding. In more
  recent worm attacks such as the much-talked-about
  .Blaster Worm., the worm has been designed to
  tunnel into your system and allow malicious users
  to control your computer remotely

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Trojan horses

• A Trojan Horse is full of as much trickery as the
  mythological Trojan Horse it was named after. The
  Trojan Horse, at first glance will appear to be
  useful software but will actually do damage once
  installed or run on your computer.  Those on the
  receiving end of a Trojan Horse are usually
  tricked into opening them because they appear to
  be receiving legitimate software or files from a
  legitimate source.  When a Trojan is activated on
  your computer, the results can vary. Some Trojans
  are designed to be more annoying than malicious
  (like changing your desktop, adding silly active
  desktop icons) or they can cause serious damage
  by deleting files and destroying information on
  your system. Trojans are also known to create a
  backdoor on your computer that gives malicious
  users access to your system, possibly allowing
  confidential or personal information to be
  compromised. Unlike viruses and worms, Trojans do
  not reproduce by infecting other files nor do
  they self-replicate.

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Security GuideViruses, Trojan Horses, and Worms
(Continued)

• Prevention steps are
• Find and apply patches to the operating system
  and to applications.
• Never download files, programs, or attachments
  from unknown Web sites.
• Do not open attachments to emails from strangers.
• Do not open unexpected attachments to emails,
  even from known sources.
• Run a retroactive antivirus program at regular
  intervals, at least once per week.

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Key Terms and Concepts

• Antivirus programs
• Application software
• Binary digit
• Bus
• Byte
• Cache memory
• CD-R
• CD-ROM
• CD-RW
• CRT monitor

Central processing unit (CPU) Clock speed Custom
software Data channel Dot pitch DVD-R DVD-ROM DVD-
RW Firmware General-purpose computer Gigabyte
(GB) Hardware




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Key Terms and Concepts (Continued)
Horizontal-market application Input
hardware Intel instruction set Kilobyte (K) LCD
monitor License agreement Linux Mac OS Macro
virus Main memory Megabyte (MB) Memory swapping

Motherboard Nonvolatile OEM (original equipment
manufacturer) Off-the-self software Open-source
community Operating system (OS) Optimal
resolution Output hardware Patch Payload Pixel

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Key Terms and Concepts (Continued)

Pixel pitch Power PC instruction set RAM
memory Seek time Software piracy Special function
cards Special-purpose computer Storage
hardware Terabyte (TB) Trojan horse Unix
Vertical-market application Virus Volatile Windows
Worm