Chapter 2 Introduction to Systems Architecture

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Chapter 2Introduction to Systems Architecture
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Chapter Goals
Chapter 2
Systems Architecture

• Discuss the development of automated computing
• Describe the general capabilities of a computer
• Describe computer system components and their
  functions
• List computer system classes and their
  distinguishing characteristics

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Chapter Goals
Chapter 2
Systems Architecture

• Define the role and function of application and
  system software
• Describe the economic role of system and
  application development software
• Describe the components and function of computer
  networks

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Introduction to Systems Architecture
Chapter 2
Systems Architecture

• The term systems architecture describes a
  computer systems components and the interaction
  between them.

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Automated Computation
Chapter 2
Systems Architecture

• A definition of a computer is any device that
  can
• Accept numeric inputs
• Perform computational functions, such as addition
  and subtraction
• Communicate results

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Automated Computation
Chapter 2
Systems Architecture

• Modern computer systems may implement the
  basic functions using many methods and/or
  devices
• Implement computation electronically
• Implement storage optically
• Implement communication using a combination of
  electronics and mechanics

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Mechanical Implementation
Chapter 2
Systems Architecture

• The difference engine is an early mechanical
  computation device that was designed to perform
  repetitive mathematical computations.
• The mechanical implementation of computers used
  gears and wheels and other mechanical movements.

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Mechanical Implementation
Chapter 2
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Mechanical Implementation
Chapter 2
Systems Architecture

• There are inherent limitations and
  shortcomings of mechanical computation including
• Complex design and construction
• Wear, breakdown, and maintenance and mechanical
  parts
• Limits on operating speed

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Electrical Implementation
Chapter 2
Systems Architecture

• The design of the mechanical computer devices
  gave way to the construction of electrical
  devices during World War II.
• Electrical devices were used to replace
  mechanical devices within the computer system,
  and input/output devices.

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Electrical Implementation
Chapter 2
Systems Architecture

• Electrical computers addressed most of the
  shortcomings of mechanical computation.
• The use of the electrical components made it
  possible to increase the speed of the computer
  system, which made it possible to solve larger
  more complex problems.

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Optical Implementation
Chapter 2
Systems Architecture

• Data can be represented as pulses of light and
  stored either directly or indirectly by materials
  that reflect or dont reflect light.
• Optical devices are currently used for storing
  and retrieving large amounts of data.

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Quantum Computing
Chapter 2
Systems Architecture

• Some scientists and engineers have been
  experimenting with quantum computing devices
  during the last decade.
• These experiments are still in their infancy and
  a commercially viable quantum computer is
  estimated to be more than a decade away.

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Quantum Computing
Chapter 2
Systems Architecture
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Computer Capabilities
Chapter 2
Systems Architecture

• Primary characteristics of a computer
• General-purpose processor capable of performing
  computation, data movement, comparison, and
  branching functions
• Storage capacity sufficient to hold large numbers
  of program instructions and data
• Flexible communication capability through the use
  of multiple media and devices

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Computer Capabilities
Chapter 2
Systems Architecture

• A processor is a device that performs data
  manipulation and/or transformation functions
  including
• Computation
• Comparison
• Data movement

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Computer Capabilities
Chapter 2
Systems Architecture

• A processor executes a sequence of instructions
  stored in a program.
• An instruction is a signal or command to a
  processor to perform one of its functions.

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Computer Capabilities
Chapter 2
Systems Architecture

• A processor executes a function is response to an
  instruction.
• A long sequence of instructions is called a
  program.

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Computer Capabilities
Chapter 2
Systems Architecture

• A processor can be classified as
• General-purpose
• Special-purpose

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Computer Capabilities
Chapter 2
Systems Architecture

• A general-purpose processor is capable of
  executing many different instructions in many
  different sequences or combinations.
• Their function can be changed by altering the
  program that directs its actions.

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Computer Capabilities
Chapter 2
Systems Architecture

• A special-purpose processor is designed to
  perform only one specific task.
• Used by devices such as microwave ovens, compact
  disc players and computer printers.

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Computer Capabilities
Chapter 2
Systems Architecture

• Formulas and Algorithms
• If processing tasks require more than a
  processors computation instructions, a formula
  and/or algorithm is needed.

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Computer Capabilities
Chapter 2
Systems Architecture

• Formulas
• A processor executes a sequence of computation
  and data movement instructions to solve a formula.

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Computer Capabilities
Chapter 2
Systems Architecture

• Formulas
• Gross_Profit Quantity_Sold x Selling_Price
  Selling_Expenses

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Computer Capabilities
Chapter 2
Systems Architecture

• Algorithms
• Computer processors also can perform a more
  complex class of processing tasks called
  algorithms.

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Computer Capabilities
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Computer Capabilities
Chapter 2
Systems Architecture

• The procedure for computing United States income
  tax is an example of an algorithm.
• The program examines the income value and decides
  which set of instructions to execute to compute
  the tax.

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Computer Capabilities
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Computer Capabilities
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• If decisions need to be made within the
  processing tasks, then comparisons and branching
  is needed.
• Comparisons are called conditions and the result
  of evaluating the condition is true or false.

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Computer Capabilities
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Systems Architecture

• When a comparison condition is true, the
  program jumps or branches to the first
  instruction that implements the corresponding
  formula.

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Computer Capabilities
Chapter 2
Systems Architecture
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Computer Capabilities
Chapter 2
Systems Architecture

• Storage Capacity
• A computer stores immediate processing
  results, data and programs.

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Computer Capabilities
Chapter 2
Systems Architecture

• Input/Output Capability
• A computers input/output devices must be
  flexible and encompass a variety of communication
  modes.

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Computer Capabilities
Chapter 2
Systems Architecture

• Input/Output Capability
• The communication modes are
• Sound
• Text
• Graphics

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Computer Capabilities
Chapter 2
Systems Architecture

• Input/Output Devices
• Video display
• Keyboard
• Mouse
• Printer
• Modem
• Network Interface

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Computer Hardware
Chapter 2
Systems Architecture

• Computer Hardware Functions
• Processing
• Storage
• External communication
• Internal communication

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Computer Hardware
Chapter 2
Systems Architecture
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Computer Hardware
Chapter 2
Systems Architecture

• Computer System Components
• Central Processing Unit (CPU)
• Primary Storage
• Secondary Storage
• Input/Output Units
• System Bus

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Computer Hardware
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Systems Architecture
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Computer Hardware
Chapter 2
Systems Architecture

• Central Processing Unit (CPU)
• Arithmetic and Logic Unit
• Registers
• Control Unit

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Computer Hardware
Chapter 2
Systems Architecture
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Computer Hardware
Chapter 2
Systems Architecture

• The Arithmetic and Logic Unit contains
  electrical circuits that implement each
  instruction.
• The Registers are small internal storage
  locations that hold a single instruction or data
  item.

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Computer Hardware
Chapter 2
Systems Architecture

• The Control Unit has two primary functions
• Control movement of data to and from CPU
  registers and other hardware components
• Access program instructions and issue appropriate
  commands to the ALU

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Computer Hardware
Chapter 2
Systems Architecture

• The system bus is the primary pathway for data
  transmission among hardware components.

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Computer Hardware
Chapter 2
Systems Architecture

• Storage Devices
• Primary Storage
• Secondary Storage

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Computer Hardware
Chapter 2
Systems Architecture

• Primary Storage
• Primary storage is referred to as memory or
  main memory.
• Primary storage holds program instructions
  that are currently being executed and data being
  processed by those instructions.

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Computer Hardware
Chapter 2
Systems Architecture

• Primary Storage
• Primary storage is referred to as Random
  Access Memory (RAM).
• The data stored in RAM is volatile. Volatile
  data is lost when the computer system is turned
  off.

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Computer Hardware
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• Secondary Storage
• Secondary storage refers to nonvolatile
  storage devices.

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Computer Hardware
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Systems Architecture

• Secondary storage devices hold
• Program not currently being executed
• Data not needed by currently executing programs
• Data needed by currently executing programs that
  does not fit within available primary storage

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Computer Hardware
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Computer Hardware
Chapter 2
Systems Architecture

• Input/Output Devices
• Each input/output device is a separate hardware
  component attached to the system bus.

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Computer Hardware
Chapter 2
Systems Architecture

• Input devices accept input from a human and
  convert that input into something the computer
  can understand.
• Output devices display information to the user
  and implement communication among computer
  systems.

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Computer Hardware
Chapter 2
Systems Architecture

• Input devices include
• Keyboards
• Pointing devices
• Voice recognition

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Computer Hardware
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Systems Architecture

• Output devices include
• Video displays
• Printers
• Plotters
• Devices for speech and sound output
• Modem
• Network Interface Units

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Computer System Classes
Chapter 2
Systems Architecture

• Computer systems can be loosely classified
  into the following categories
• Microcomputer/Network Computer
• Minicomputer
• Mainframe
• Supercomputer

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Computer System Classes
Chapter 2
Systems Architecture

• Microcomputer
• A microcomputer (personal computer or
  workstation) is a computer system designed to
  meet the information-processing needs of a single
  user.

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Computer System Classes
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Systems Architecture

• Network Computer
• A network computer is a microcomputer with
  minimal secondary storage capacity and little or
  no installed software.

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Computer System Classes
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• Minicomputer
• A minicomputer is designed to provide
  information processing for multiple users and to
  execute many application programs simultaneously.

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Computer System Classes
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Systems Architecture

• Mainframe
• A mainframe computer system is designed to
  handle the information processing needs of a
  large number of users and applications.

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Computer System Classes
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• Supercomputer
• A supercomputer is designed for one purpose,
  to quickly perform many mathematical
  computations.

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Computer System Classes
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The Role of Software
Chapter 2
Systems Architecture

• Definition of Software
• Software Types
• System Software Layers
• Operating Systems
• Application Development Software

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The Role of Software
Chapter 2
Systems Architecture

• Definition of Software
• Software translates user needs and requests
  into computer instructions that, when executed,
  will produce a result that satisfies the need or
  request.

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The Role of Software
Chapter 2
Systems Architecture
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The Role of Software
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Systems Architecture

• Software Types
• Application software
• System software

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The Role of Software
Chapter 2
Systems Architecture

• Application software is a stored set of
  instructions for responding to a very specific
  request.

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The Role of Software
Chapter 2
Systems Architecture

• System software is a collection of programs
  that are used to
• Implement utility functions needed by many
  application programs
• Allocate computer resources to application
  programs
• Manage computer resources

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The Role of Software
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Systems Architecture
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The Role of Software
Chapter 2
Systems Architecture

• System Software Layer Functions
• System management
• System services
• Resource allocation
• Hardware interface

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The Role of Software
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Systems Architecture
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The Role of Software
Chapter 2
Systems Architecture

• Operating Systems
• An operating system is a collection of
  programs that
• Provides utility functions needed by users and
  application programs.
• Allocates computer resources among multiple users
  and application programs
• Controls access to computer hardware

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The Role of Software
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Systems Architecture

• Operating system functions
• Program storage, loading and execution
• File manipulation and access
• Secondary storage management
• Network and interactive user interfaces

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The Role of Software
Chapter 2
Systems Architecture

• Application Development Software
• Application development software describes
  programs used to develop other programs.

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The Role of Software
Chapter 2
Systems Architecture

• Application Development Software
• Program translator
• Program editors
• Debugging tools
• System development tools

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Economics of System and Applications Development
Software
Chapter 2
Systems Architecture

• Three economic facts of computer hardware
  and software
• System software requires hardware resources.
• The cost per unit of computing power has
  decreased at nearly an exponential rate.
• Software is more cost effective when it is reused
  many times.

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Economics of System and Applications Development
Software
Chapter 2
Systems Architecture
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Technology Focus Intel CPUs and Microsoft
Operating Systems
Chapter 2
Systems Architecture
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Computer Networks
Chapter 2
Systems Architecture

• A computer network is a set of hardware and
  software components that allows information,
  software and hardware resources to be shared
  among multiple users and computer systems.

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Computer Networks
Chapter 2
Systems Architecture
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Computer Networks
Chapter 2
Systems Architecture

• Computer network functions
• External Resources
• Network Software
• Network Communication and the Physical Network

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Computer Networks
Chapter 2
Systems Architecture

• External Resources
• Much of the complexity of modern networks
  arise from the huge quantity of distributed
  resources and the difficulties inherent in
  finding, accessing and managing those resources.

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Computer Networks
Chapter 2
Systems Architecture

• Network Software
• System Software must
• Find the requested resources on the network
• Negotiate resource access with distant resources
  allocation software
• Receive and deliver the resources to the
  requesting user or program

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Computer Networks
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Systems Architecture

• Network Software
• System software must (cont.)
• Listen for resource requests
• Validate resource requests
• Deliver resources via the network

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Computer Networks
Chapter 2
Systems Architecture

• Network Communication and the Physical
  Network
• A computer system requires at least one hardware
  device to implement its connection to a network.

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Computer Networks
Chapter 2
Systems Architecture

• Network Communication and the Physical
  Network
• The physical network is a complex combination of
  communication protocols, methods of data
  transmission and network hardware devices.

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Summary
Chapter 2
Systems Architecture

• A computer is an automated device for performing
  computational tasks.
• Computer capabilities include processing,
  storage, and communication.
• A computer system consists of a central
  processing unit, primary storage, secondary
  storage and input/output devices.

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Summary
Chapter 2
Systems Architecture

• A computer system can be classified as a
  microcomputer, minicomputer, mainframe and
  supercomputer.
• The role of software is to translate user
  processing requests into machine instructions.
• An operating system is the most important type of
  system software on most computer systems.

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Summary
Chapter 2
Systems Architecture

• A computer network is a set of hardware and
  software components that permits information,
  software, and hardware resources to be shared
  among multiple users and computer systems.

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Summary
Chapter 2
Systems Architecture