Operating Systems - Deadlock and Race Conditions
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Questions and Answers

If the File Size is 256 bytes, how many blocks are needed for File 3?

  • 3 (correct)
  • 4
  • 1
  • 2

    • What is the address of the next block assigned to File 3 in noncontiguous file storage with linking at the directory level?

  • 20
  • 4
  • 19 (correct)
  • 7

    • How many blocks are allocated for File 1, File 2, and File 3 in indexed storage allocation using a one-level index?

  • 1 (correct)
  • 2
  • 5
  • 3

    • What type of access is granted to USER2014 for File 2?

    <p>execute only (A)</p> Signup and view all the answers

    Which user has the highest level of access to File221 in the access control list?

    <p>USER2017 (A)</p> Signup and view all the answers

    Which of the following is NOT a responsibility of the File Manager?

    <p>Determine when data should be moved to secondary storage (C)</p> Signup and view all the answers

    What is the main advantage of using fixed-length records?

    <p>They are easier to access directly. (A)</p> Signup and view all the answers

    Which of the following file organization methods is best suited for accessing records directly?

    <p>Direct (D)</p> Signup and view all the answers

    Which of these is NOT a common command that a user might use to interact with the File Manager?

    <p>FORMAT (C)</p> Signup and view all the answers

    What file organization method would be most suitable for a file that is frequently updated with new records?

    <p>Indexed Sequential (C)</p> Signup and view all the answers

    What is the main purpose of buffering?

    <p>To group individual records into blocks for more efficient storage and retrieval (C)</p> Signup and view all the answers

    What is the main difference between primary storage and secondary storage?

    <p>All of the above (D)</p> Signup and view all the answers

    Which of the following file access methods is characterized by storing records in a way that allows for easy access to individual records based on their address?

    <p>Direct (B)</p> Signup and view all the answers

    Which of the following scenarios describes a race condition?

    <p>A thread reads a global variable and modifies it based on a value written by another thread, leading to unexpected behavior. (C)</p> Signup and view all the answers

    What is the status of the system after reducing the resource graph by P1, as described in the content?

    <p>The system is stable with no blocked processes. (B)</p> Signup and view all the answers

    What is the primary difference between deadlock and starvation?

    <p>Deadlock involves multiple threads blocking each other, while starvation involves a single thread being repeatedly denied access to a resource. (A)</p> Signup and view all the answers

    Which of these is NOT a primary storage medium?

    <p>HDD (B)</p> Signup and view all the answers

    In the resource graph provided, if P2's request for R2 is granted before P1's, what impact does this have on the system?

    <p>The system will become unstable, as P1's progress is dependent on R2 remaining available. (C)</p> Signup and view all the answers

    Which of the following is a potential outcome of a race condition?

    <p>A program crashing or producing incorrect results. (D)</p> Signup and view all the answers

    Which of these is NOT an example of secondary storage media?

    <p>RAM (A)</p> Signup and view all the answers

    Which of the following is considered a relative filename?

    <p>Tutorial9 (B), myfile (D)</p> Signup and view all the answers

    What type of storage allows files to use any available storage space on the disk?

    <p>Non-contiguous storage (D)</p> Signup and view all the answers

    What type of storage does not necessarily improve storage space utilization?

    <p>Indexed storage (A)</p> Signup and view all the answers

    Which type of storage allows direct access to records?

    <p>Indexed storage (D)</p> Signup and view all the answers

    What is the primary disadvantage of contiguous storage?

    <p>Limited storage space (C)</p> Signup and view all the answers

    How many extents are required to store File 1, given its size is 768 bytes and the physical size of each extent is 256 bytes?

    <p>3 (B)</p> Signup and view all the answers

    Which of the following files in the diagram of non-contiguous file storage use 3 extents?

    <p>File 1 (C)</p> Signup and view all the answers

    What is the primary purpose of linking extents in non-contiguous storage?

    <p>To provide a mechanism for file expansion (D)</p> Signup and view all the answers

    Study Notes

    Tutorial 6

    • Deadlock, Starvation, and Race Conditions:
      • Deadlock: Occurs when two or more threads are blocked indefinitely, waiting for each other to release resources.
      • Starvation: Occurs when a low priority thread is constantly denied resources by higher priority threads.
      • Race Condition: Occurs when multiple threads interact negatively, resulting in unpredictable outcomes due to the order of their instructions.

    Tutorial 6 - Resource Graph

    • Deadlock Identification: A directed graph can reveal if a system is currently deadlocked or not. It shows resources and processes.
    • Blocked Processes: Check for any process that is waiting for a resource that is unavailable.
    • Process Reduction: Removing a process from the graph and updating it to reveal other states of the system.
    • System Stability: A system is stable if a process' request can be granted without leading to further instability.

    Tutorial 7

    • Parallel Processing (Multiprocessing): Two or more processors working simultaneously.

    • Multiprocessing Benefits:

      • Higher throughput (faster completion of tasks)
      • Increased computing power

    • Multiprocessing Levels:

      • Job Level: Synchronization not needed.
      • Process Level: Moderate synchronization required.
      • Thread Level: High synchronization required

    • Master/Slave Configuration Disadvantages:

      • Master failure means the entire system fails.
      • Inefficient resource utilization.
      • High interrupt frequency

    • Symmetric Configuration Advantages:

      • Increased reliability
      • Efficient resource usage
      • Load balancing
      • Graceful degradation in case of failures

    • Test and Set Locking Drawbacks:

      • Starvation: Processes can get stuck waiting for the critical section.
      • Resource Consumption: Waiting processes consume resources if they remain endlessly waiting.

    Tutorial 7 - Semaphores

    • Semaphores: Flag that tracks the availability of a resource (ON/OFF).

    • Wait Operation: Testing a resource (blocking process if unavailable).

    • Signal Operation: Indicating a resource is available (unblocking a process).

    • Synchronization Role: Manages CPU/memory/IO device access to prevent simultaneous access causing issues.

    Tutorial 8

    • Secondary Storage: Permanent memory - examples include punch cards, Blu-ray discs, floppy disks, magnetic tapes, USB drives, CDs, cloud storage.
    • Primary Storage (Main Memory): Temporary memory; data lost when power off; used for CPU processing.
    • Buffering: Storing data temporarily before sending to a slower device (monitor, hard drive).
    • Blocking: Grouping data records into blocks for efficient access/storage.

    Tutorial 8 - Disk Capacity Calculations

    • Calculations : Using formulas for calculating waste in space, number of tracks, rotational speed and total time to transfer data

    Tutorial 9

    • File Management Criteria:

      • File organization (sequential, direct, indexed).
      • Record structure (fixed-length, variable-length).
      • Access control (matrix, lists, capabilities).
      • Storage method (contiguous, non-contiguous, indexed).

    • File Manager Responsibilities:

      • Tracking file locations.
      • Managing storage allocation and access.
      • Assigning files.
      • Deallocating files.

    • User-File Manager Communication: Commands such as OPEN, COPY, DELETE, RENAME.

    • Fixed vs. Variable Length Records:

      • Fixed Length: Easier direct access, sequential access speedier.
      • Variable Length: Adaptable to varying record sizes, but more complex to address.

    • Absolute vs. Relative File Names:

      • Absolute: Full path (e.g., c:/documents/filename.txt).
      • Relative: Path relative to the current directory (e.g., filename.txt).

    Tutorial 9 - Other Topics

    • File Organization Types: Sequential, direct, indexed sequential storage (contiguous, noncontiguous, indexed).

    Tutorial 10

    • Noncontiguous File Storage: Diagrammed examples of non-contiguous storage: showing how different files take up different parts of the storage space, with links between different areas. This shows where files are located in memory and how to find them when needed.
    • Index Tables: Tables showing how to refer to different storage locations and how different parts of a file are stored across the storage space using pointers that link to where the file begins, or how long it is.

    Tutorial 10 - Access Control for Files

    • Access Control Matrix: Describes what type of access (read, write, delete, execute) different users have to different files.

    • Access Control List (ACL): Lists what access each user has to a specific file. (e.g. User 2010 can only read and execute (R-E-) on File 1)

    • WORLD category: All users that are not included in other groups.

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    Related Documents

    Tuto 6-9 (OS) PDF

    Description

    This quiz covers key concepts of deadlock, starvation, and race conditions in operating systems. It explores the implications of these issues on resource management and system stability using resource graphs. Test your understanding of how multiple threads can affect performance and reliability.

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