EDPS015 LECTURE NO' 3

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EDPS015LECTURE NO. 3

• The Computer HW/SW in Detail

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Processing Characteristics

• Machine Cycle Time is the time it takes to
  execute an instruction. It is a measure of
  processing speed.
• Clock Speed is the rate at which the electronic
  pulses that synchronize computer operations are
  produced measured in Hertz.

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Processing Characteristics

• Wordlength is the number of bits the CPU can
  process at one time.
• Physical Characteristics of the CPU likewise
  affect processing, such as the distance between
  points.

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Multiprocessing

• It is the simultaneous execution of two or more
  instructions at the same time.
• Coprocessor speeds processing by executing
  specific types of instructions while the CPU
  works on another processing activity.

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Multiprocessing

• Parallel Processing is a form of multiprocessing
  that speeds processing by linking several
  processors to operate at the same time or in
  parallel.
• Grid Computing is the use of a collection of
  computers, often owned by multiple individuals,
  to work in a coordated manner.

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Memory Characteristics

• Storage Capacity is the amount of information
  that a memory device can store, measured in
  Bytes.
• Access Time is the time it takes to read a block
  of memory.

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Memory Hierarchy

• Primary Memory generally employs semiconductor
  technology, and is either on-chip or on-board it
  is very fast and expensive.
• Secondary Memory generally employs magnetic or
  optical technology, and is usually removable or
  mobile it comes in large capacity and is cheap.

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Types of Memory

• Volatile or non-volatile, depending on whether
  stored information is lost or not when the device
  is powered off.
• Static or dynamic, depending on whether stored
  information erodes in time.

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Memory Access Methods

• RAM or random access memory.
• Sequential or serial access memory.
• ROM or read only memory.
• Direct or memory access without having to pass
  by other data in sequence.

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Performance Indicators

• Computer Performance is characterized by the
  amount of useful work accomplished by a computer
  system compared to time and resources used.
• Short response time for a given piece of work
• High throughput or rate of processing work

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Performance Indicators

• Low utilization of computing resources
• High availability of the computing system

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Performance Metrics

• Traditionally described in terms of clock speed.
• Availability or the fraction of time that a
  resource is available for use.
• Bottleneck or the resource with the lowest
  maximum throughput in a system with more than one
  component.

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Performance Metrics

• Latency or the delay between start and end of an
  operation, or between request and response.
• Pathlength or processing time per unit of work,
  calculated as utilization divided by throughput.
• Throughput or work completed per unit time.
• Utilization or fraction of time a resource is
  busy

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The Computer Hardware

• Computer Memory and I/O Devices

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Secondary Storage Devices

• Magnetic Tape
• Magnetic Disk
• Floppy Disk
• Hard Disk, Removable HDD, Portable HDD
• Compact Disk CD ROM / R / RW
• Digital Versatile Disk DVD ROM / R / RW

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Secondary Storage Devices

• Memory Cards (MMC, SD, Micro SD, Duo)
• Flash Disk / USB Drive

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Input Devices

• PC Input Devices (Mouse Keyboard)
• Voice-Recognition Devices
• Terminals
• Touch Screens
• Bar-Code Scanners
• Optical Data Readers (OMR OCR)

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Input Devices

• Point-of-Sale (POS) Devices
• Automatic Teller Machines (ATM)
• Magnetic Ink Character Recognition (MICR)
  a.Devices
• Radio Frequency Identification (RFID) Devices

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Output Devices

• Cathode Ray Tube (CRT) Display Monitors
• Liquid Crystal Displays (LCD)
• Organic Light Emitting Diodes (OLED)
• Printers and Plotters

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Types of Computer Systems

• Handheld
• Portable
• Thin Client
• Desktop
• Workstations

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Types of Computer Systems

• Servers
• Mainframe
• Supercomputer

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The Computer Software

• Types, Classifications, and Samples

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Definition of Terms

• A computer program is a set of instructions for
  the computer.
• Documentation is text that describes the program
  functions to help the user operate the computer
  system.

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Definition of Terms

• A computer system platform is the combination of
  a particular hardware configuration and systems
  software package.
• Sphere of influence is the scope of problems and
  opportunities addressed by a particular
  organization.

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Classification by Sphere of Influence

• Personal Productivity Software
• Groupware or Workgroup Software
• Enterprise Software

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Classification by Type

• Systems software is the set of programs designed
  to coordinate the activities and functions of the
  hardware and various programs throughout the
  computer system.
• Application software is the program that helps
  users solve particular computing problems.

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Kinds of System Software

• System Support Programs include utility programs,
  security and performance monitors.
• System Development Programs provide an
  environment for the development of programs.

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Kinds of System Software

• System Management Programs include operating
  systems and operating environments.
• An Operating System (OS) is a set of computer
  programs that control the computer hardware and
  act as an interface with application programs.

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OSComputerUser Combo

• Single computer, single user typical in handheld
  and personal computers.
• Single computer, multiple user typical in server
  and mainframe computing environments.
• Multiple computers typical in networks.
• Special purpose computers.

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6 Basic OS Functions

• Determine sequence in which jobs or processes are
  executed.
• Cause application programs to be executed and
  likewise cause the various system resources to
  perform or to be available as specified by the
  application.

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6 Basic OS Functions

• Maintain security by requiring user
  authentication.
• Support multiprogramming where multiple users can
  run multiple programs at the same time.

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6 Basic OS Functions

• Handle interrupts or events that cause the
  suspension of programs currently running to allow
  another program to be executed in response to the
  interrupt or event.
• Keep track of resource usage.

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Specific OS Functions

• Common Hardware Functions, acting as intermediary
  between application programs and the hardware.
• User Interface, which could be CLI or GUI.
• Hardware Independence, providing an application
  program interface (API).

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Specific OS Functions

• Memory Management, converting a users request
  for data in logical view to physical view.
• Processing tasks, providing multitasking and
  time-sharing capabilities.
• Networking capability, enabling interconnection
  with other computers.

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Specific OS Functions

• Access to system resources, providing user
  authentication and access verification.
• File management, ensures that files in secondary
  storage are available when needed and protected
  from unauthorized access.

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Types of Application Software

• Custom-programmed
• Pre-written

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Pre-written Software Packages

• General Business
• Industry-Specific
• Organizational Productivity
• Games Entertainment
• Personal Productivity

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Personal Productivity Packages

• Word processors
• Desktop publishers
• Electronic spreadsheets
• Database Management Systems
• Graphics

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SHORT HOME VIDEO

• An Introduction to Computer Hardware