Operating Systems: Multiprogramming and Scheduling Concepts Quiz
16 Questions
7 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the purpose of a Process Control Block (PCB)?

  • To store only the Process ID (PID) for each process
  • To manage the CPU scheduling of processes
  • To maintain information on user interactions with processes
  • To hold information necessary for the operating system to manage a process (correct)
  • Which component of the PCB helps determine which instruction a process should execute next?

  • Program counter (correct)
  • Process state
  • Pointers to child processes
  • Memory-management information
  • In the context of a PCB, what does CPU Scheduling information include?

  • Details about memory management for the process
  • Data related to parent processes
  • Information on I/O devices allocated to the process
  • Process priority and scheduling parameters (correct)
  • What triggers the creation of a new process according to the text?

    <p>A user request for a new process</p> Signup and view all the answers

    Which type of process is associated with specific functions rather than user interaction?

    <p>Background process</p> Signup and view all the answers

    What does the Process ID (PID) represent in the context of process management?

    <p>An identifier assigned to uniquely distinguish each process</p> Signup and view all the answers

    In a multiprogramming environment, processes never compete for resources.

    <p>False</p> Signup and view all the answers

    If a process requests a resource that is not available, it immediately exits the system.

    <p>False</p> Signup and view all the answers

    A deadlock situation can only occur if the Request condition is met.

    <p>False</p> Signup and view all the answers

    In a deadlock, at least one resource must be held in a shareable mode.

    <p>False</p> Signup and view all the answers

    Circular wait is one of the necessary conditions for a deadlock to occur.

    <p>True</p> Signup and view all the answers

    A process can use a resource without requesting it first.

    <p>False</p> Signup and view all the answers

    Under normal operation, a process may utilize resources in any arbitrary sequence.

    <p>False</p> Signup and view all the answers

    Round-Robin Algorithm guarantees the shortest average waiting time for processes.

    <p>False</p> Signup and view all the answers

    Multilevel Queue Scheduling assigns each process to a single queue.

    <p>True</p> Signup and view all the answers

    CPU bursts are continuous and do not have any idle time during execution.

    <p>False</p> Signup and view all the answers

    Study Notes

    Job and Processes

    • A job is a set of program instructions corresponding to a particular computational task, such as payroll or inventory.
    • In multiprocessor systems, a job is a group of collaborating processes forming a unit.
    • The terminology "job" developed during the time when the major activity of the Operating System (OS) was job processing.
    • Jobs are typically executed without user input for minutes, hours, or days.
    • The term "job" is often used interchangeably with "process".

    Processes

    • A process is a program in execution, requiring certain resources such as CPU time, memory, files, and I/O devices to accomplish its task.
    • A process is an asynchronous activity and is referred to as the "animated spirit" of a procedure.
    • A process moves through a series of discrete states, including:
      • Newborn: process creation
      • Running: process is executing instructions
      • Waiting: process is waiting for I/O or event completion
      • Ready: process is waiting for CPU
      • Terminated: process has finished execution
    • A process has an address space consisting of:
      • Text region: stores the code that the processor executes
      • Data region: stores variables and dynamically allocated memory
      • Stack region: stores instructions and local variables for active procedure calls

    Process Control Block (PCB)

    • A Process Control Block (PCB) is a data structure that maintains information about a process.
    • A PCB is created by the OS and includes information such as:
      • Process ID (PID)
      • Process state (running, ready, or waiting)
      • Program counter
      • Credentials
      • Pointer to the process's parent process
      • CPU scheduling information
      • Pointers to the process's child processes
      • Memory-management information
      • I/O status information

    Resource Allocation

    • Resources vary from system to system, but a typical OS has to allocate the following items to a process:
      • CPU
      • Memory
      • Registers
      • I/O devices
      • Files
    • Scheduling queues include:
      • Job queue: processes that enter the system are put in this queue
      • Ready queue: keeps all processes that are residing in main memory and are ready and waiting to execute
      • Device queues: keep all processes waiting for a particular I/O device

    Schedulers

    • Long-term scheduler (job scheduler): selects a process from a pool of processes and loads it into memory for execution.
    • Short-term scheduler (CPU scheduler): selects from among the processes that are ready to execute and allocates the CPU to one of them.
    • Medium-term scheduler: an additional level of scheduling that supports the idea of swapping processes in and out of memory.

    CPU Scheduling

    • CPU scheduling is the basis of multiprogrammed OS.
    • CPU scheduling is a fundamental OS function that allows the OS to make the computer system more productive.

    Scheduling Policies

    • Scheduling policies include:
      • First-Come-First-Served (FCFS): allocates the CPU to the process that requests the CPU first.
      • Shortest-Job-First (SJF): allocates the CPU to the process with the shortest next CPU burst.
      • Priority Scheduling: allocates the CPU to the process with the highest priority.
      • Round-Robin (RR) Algorithm: designed especially for time-sharing systems, uses a small unit of time called a quantum or time slice.
      • Multilevel Queue Scheduling: partitions the ready queue into several separate queues, each with its own scheduling algorithm.
      • Multilevel Feedback Queue Scheduling: allows a process to move between queues.

    Algorithm Evaluation

    • Algorithm evaluation methods include:
      • Analytic evaluation: uses the given algorithm and the system workload to produce a formula or number that evaluates the performance of the algorithm for that workload.
      • Deterministic modeling: uses a particular workload and defines the performance of each algorithm for the workload.### Process Management
    • Process Management deals with the allocation and management of system resources
    • Process Control Block (PCB) is a data structure that contains information about a process
    • Process Termination occurs due to:
      • Normal exit (voluntary)
      • Error exits (voluntary)
      • Fatal error (involuntary)
      • Killed by another process (involuntary)

    Resource Allocation

    • Resources vary from system to system, but a typical OS has to allocate:
      • CPU
      • Memory
      • Registers
      • I/O devices
      • Files
    • Resource Allocation involves:
      • Long-term scheduling (job scheduling)
      • Short-term scheduling (CPU scheduling)
    • Job queue: processes that enter the system are put in this queue
    • Ready queue: keeps all processes that are residing in main memory and are ready to execute
    • Device queues: keep all processes waiting for a particular I/O device

    Scheduling

    • Scheduling involves selecting a process from the ready queue and allocating the CPU to that process
    • Schedulers:
      • Long-term scheduler (job scheduler): selects a process from a pool of processes and loads it into memory for execution
      • Short-term scheduler (CPU scheduler): selects from among the processes that are ready to execute and allocates the CPU to one of them
    • Medium-term scheduler (optional): supports the idea of adding and removing processes from main memory
    • Context Switch: the task of switching the CPU to another process, which requires saving the state of the old process and loading the saved state for the new process

    Scheduling Policies

    • Scheduling policies include:
      • First-Come, First-Served (FCFS)
      • Shortest-Job-First (SJF)
      • Priority Scheduling
      • Round-Robin Algorithm (RR)
      • Multilevel Queue Scheduling
      • Multilevel Feedback Queue Scheduling
    • Each policy has its own criteria, such as:
      • CPU utilization
      • Throughput
      • Turnaround time
      • Response time
      • Waiting time
      • Priority

    Algorithm Evaluation

    • Algorithm evaluation involves:
      • Analytic evaluation: uses a formula or number to evaluate the performance of an algorithm for a given workload
      • Deterministic modeling: evaluates the performance of an algorithm for a given workload
    • Evaluation methods include:
      • FCFS
      • SJF
      • RR (quantum = 10)

    Deadlocks

    • Deadlocks occur when:
      • A process requests a resource that is not available
      • The process waits for the resource to become available
      • The waiting process holds resources that are requested by other waiting processes
    • Necessary conditions for a deadlock to occur:
      • Mutual exclusion: at least one resource must be held in a non-sharable mode
      • Hold and wait: a process must be holding one resource and waiting for another resource
      • No preemption: a process cannot be forced to release a resource
      • Circular wait: a set of waiting processes must exist, each waiting for a resource held by the next process in the set

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Test your knowledge on multiprogramming, process management, resource allocation, scheduling policies, and deadlock in operating systems. This quiz covers topics like jobs, processes, and the collaboration among them in a multiprocessor system.

    More Like This

    Use Quizgecko on...
    Browser
    Browser