OS Organization Chapter 2 William Stallings book

The flashcards below were created by user geschw66 on FreezingBlue Flashcards.

  1. What is an Operating System?
    A program that controls the execution of application programs

    An interface between applications and hardware
  2. Main objectives of an OS:
    • Convenience
    • Efficiency
    • Ability to evolve
  3. Key Interfaces of an OS:
    • Instruction set architecture (ISA)
    • Application binary interface (ABI)
    • Application programming interface (API)
  4. What is the role of an OS?
    OS is responsible for managing a computer's resources.
  5. A computer is a set of _?_ resources for the ____, _____ and _____ of data.
    A computer is a set of  shared resources, for the movement, storage,and processing of data.
  6. Computer as a Resource Manager. What is the section with the question mark known as:
    Image Upload 1
    Operating System.
  7. Identify the areays of this computer system:
    Image Upload 2
    • 1 Operating System Software
    • 2 Programs and Data
    • 3 Processors
    • 4 I/O Controllers
    • 5 I/O Devices: Printers, keyboards, cameras etc.
    • 6 Memory
  8. A major OS will evolve over time for anumber of reasons:
    • Hardware upgrades
    • New types of hardware
    • New services
    • Fixes
  9. Evolution of Operating Systems Stages include:
    • SerialProcessing
    • Simple Batch Systems
    • Multiprogrammed Batch Systems
    • TimeSharing Systems
  10. Describe Serial Processing:
    • No operating system
    • programmers interacted directly with the computer hardware...
    • Computers ran from a console with display lights, toggle switches, some form of input device, and a printer...
    • Users have access to the computer in “series”...
  11. Serial Processing; Problems of:
    Scheduling and Set up Time.
  12. Serial Processing Problem: Scheduling:
    • most installations used a hardcopy sign-up sheet to reserve computer time
    • time allocations could run short or long, resulting in wasted computer time.
  13. Serial Processing Problem: Setup time
    A considerable amount of time was spent just on setting up the program to run
  14. Describe Simple Batch Systems:
    • Because early computers were very expensive, it was important to maximize processor utilization via the concept of a Monitor.
    • User no longer has direct access to processor as in Serial Processing
    • Jobs are submitted to computer operator who batches them together and places them on an input device.
    • Program branches back to the monitor when finished
  15. Monitor (Simple Batch System)
    • Monitor controls the sequenceof events
    • Resident Monitor is software always in memory
    • Monitor reads in job and gives control
    • Job returns control to monitor
  16. Simple Batch System: Processor Point of View:
    • Processor executes instruction from the memory containing the monitor
    • Executes the instructions in the user program until it encounters an ending or error condition
    • “Control is passed to a job” means processor is fetching and executing instructions in a user program
    • “Control is returned to the monitor” means that the processor is fetching and executing instructions from the monitor program
  17. Simple Batch System: “Control is passed to a job” means?
    In a simple batch system, “Control is passed to a job”  means that the means processor is fetching and executing instructions in a user program
  18. Simple Batch System: “Control is passed to the monitor” means
    In a simple batch system it means that the processor is fetching and executing instructions from the monitor program
  19. Job Control Language (JBL):
    Special type of programming language used to provide instructions to the monitor
  20. Simple Batch Systems: Desirable Hardware Features: Memory protection for monitor:
    While the user program is executing, it must not alter the memory area containing the monitor
  21. Simple Batch Systems: Desirable Hardware Features: Timer:
    Prevents a job from monopolizing the system
  22. Simple Batch Systems: Desirable Hardware Features: Privileged instructions:
    can only be executed by the monitor
  23. Simple Batch Systems: Desirable Hardware Features: Interupts:
    gives OS more flexibility in controlling user programs
  24. Modes of Operation: User Mode:
    • user program executes in user mode
    • certain areas of memory are protected from user access.
    • certain instructions may not be executed.
  25. Modes of Operation: Kernel Mode:
    • monitor executes in kernel mode
    • privileged instructions may be executed
    • protected areas of memory may be accessed

  26. Simple Batch System: Overhead: Processor time
    • Processor time alternates between execution of user programs and execution of the monitor

  27. Simple Batch System: Overhead: Sacrifices
    • Sacrifices:
    • -->some main memory is now given over to the monitor...
    • -->some processor time is consumed by the monitor...
  28. Despite overhead, the simple batch system improves utilization of the computer T/F ?
  29. MultiProgramming or Multitasking
    • Central theme of modern OS
    • Multiple programs in main memory at the same time
    • Needs additional H/W that supports I/O interrupts and DMA (independent I/O processor, I/O channel)
  30. Characteristics of Multiprogramming:
    • There must be enough memory to hold the OS (resident monitor) and one user program.
    • When one job needs to wait for I/O, the processor can switch to the other job, which is likely not waiting for I/O.
  31. Define Multiprogramming:
    In multiprogramming,also known as multitasking memory is expanded to hold three, four, or more programs and switch among all of them.
  32. Paging:
    • Allows processes to be comprised of a number of fixed-size blocks, called pages.
    • Program references a word by means of a virtual address
    • Provides for a dynamic mapping between the virtual address used in the program and a real (or physical) address in main memory
  33. Paging: Program references a word by means of a virtual address...
    • consists of a page number and an offset within the page
    • each page may be located anywhere in main memory
  34. Uniprogramming:
    The processor spends a certain amount oftime executing, until it reaches an I/O instruction; it must then wait until that I/O instruction concludes before proceeding
  35. Time Sharing Systems:
    • Can be used to handle multiple interactive jobs.
    • Processor time is shared among multiple users.
    • Multiple users simultaneously access the system through terminals, with the OS interleaving the execution of each user program in a short burst or quantum of computation.
  36. A Process contains three components:
    • executable program
    • the associated data needed by the program (variables, work space, buffers, etc.)
    • the execution context (or “process state”) of the program
  37. Process Management: The entire state of the process at any instant is contained in its __?__
  38. The entire state of the process at any instant is contained in its context
Card Set:
OS Organization Chapter 2 William Stallings book
2016-02-12 04:55:10
OS OperatingSystems Computer

Show Answers: