Operating System Concepts Chapter 3: Processes
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What happens to a child process if its parent terminates?

  • All child processes are terminated due to cascading termination. (correct)
  • Only the child process terminates if it has completed its task.
  • The child continues execution independently.
  • The child is allowed to run but cannot communicate with the parent.

    • Which system call can a parent use to terminate a child process?

  • abort() (correct)
  • exit()
  • wait()
  • kill()

    • What is a possible reason for a parent process to abort a child process?

  • The child has completed its tasks successfully.
  • The child has exceeded its allocated resources. (correct)
  • The parent process has received an external request.
  • The child process is performing optimally.

    • What is indicated if a child process cannot continue after its parent terminates?

    <p>Cascading termination is enforced by the operating system.</p> Signup and view all the answers

    How does a parent process wait for the termination of its child processes?

    <p>By utilizing the wait() system call.</p> Signup and view all the answers

    Which statement about child processes is NOT true?

    <p>Child processes can run independently of their parent.</p> Signup and view all the answers

    What are the two primary operations provided by the interprocess communication facility?

    <p>send(message) and receive(message)</p> Signup and view all the answers

    Which of the following is NOT a consideration when implementing communication links between processes?

    <p>What programming language should be used?</p> Signup and view all the answers

    When two processes want to communicate, what must they first establish?

    <p>A communication link</p> Signup and view all the answers

    In a message passing system, what determines if processes can effectively communicate?

    <p>The existence of a communication link</p> Signup and view all the answers

    Which aspect of message passing defines how many processes can share a communication link?

    <p>Link association</p> Signup and view all the answers

    What is a possible characteristic of links in message passing systems?

    <p>Links can be either unidirectional or bidirectional</p> Signup and view all the answers

    What describes a process in an operating system?

    <p>A program in execution that can include multiple execution threads.</p> Signup and view all the answers

    Which of the following is NOT a state of a process?

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

    What is included in the Process Control Block (PCB)?

    <p>Information about process state and scheduling.</p> Signup and view all the answers

    What role does the short-term scheduler play in process management?

    <p>Selects which process should be executed next on the CPU.</p> Signup and view all the answers

    What happens during a context switch?

    <p>The current process state is saved and the new process state is loaded.</p> Signup and view all the answers

    What is the main function of process creation in an operating system?

    <p>To create a hierarchy of processes managed by a main process.</p> Signup and view all the answers

    In UNIX systems, which system call is used to create a new process?

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

    How do I/O-bound processes generally operate compared to CPU-bound processes?

    <p>They perform many short CPU bursts and spend more time doing I/O.</p> Signup and view all the answers

    What is a characteristic of a long-term scheduler?

    <p>Controls the degree of multiprogramming.</p> Signup and view all the answers

    What is one of the functions of interprocess communication (IPC)?

    <p>To enable processes to share memory directly.</p> Signup and view all the answers

    What happens to a process if its parent terminates without invoking wait()?

    <p>It becomes an orphan process.</p> Signup and view all the answers

    Which of the following is NOT a type of process in the Google Chrome multiprocess architecture?

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

    Which is a reason for using cooperating processes?

    <p>Increasing computation speedup</p> Signup and view all the answers

    What is the primary purpose of the renderer process in Chrome?

    <p>Render web pages and handle HTML.</p> Signup and view all the answers

    What status information does the call wait() return?

    <p>Pid of the terminated process and status information.</p> Signup and view all the answers

    Which interprocess communication model involves sharing a common memory area?

    <p>Shared memory</p> Signup and view all the answers

    What is the function of the browser process in Google Chrome?

    <p>Manage the user interface and I/O operations.</p> Signup and view all the answers

    What occurs if no parent process invokes wait() for a terminated process?

    <p>The process becomes a zombie.</p> Signup and view all the answers

    What is the purpose of the handle that the server returns to the client?

    <p>To facilitate message exchange through a specific port</p> Signup and view all the answers

    Which of the following statements about sockets is true?

    <p>A socket is a combination of IP address and port number</p> Signup and view all the answers

    What type of socket allows data to be sent to multiple recipients in Java?

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

    What is the primary function of stubs in Remote Procedure Calls?

    <p>To act as proxies for procedures on the server</p> Signup and view all the answers

    What does External Data Representation (XDL) account for in remote communication?

    <p>Data format between different architectures</p> Signup and view all the answers

    What is the primary issue with communication via pipes?

    <p>The direction of communication can vary</p> Signup and view all the answers

    Which of the following best describes the connection between two sockets?

    <p>It consists of a one-to-one communication channel</p> Signup and view all the answers

    What is the significance of ports below 1024?

    <p>They are well-known ports used for standard services</p> Signup and view all the answers

    What enhances the reliability of remote communication in RPC?

    <p>Messages can be delivered exactly once</p> Signup and view all the answers

    What role does the rendezvous service play in remote communication?

    <p>It connects clients and servers</p> Signup and view all the answers

    Study Notes

    Process Concept

    • A process is a program in execution, consisting of program code, current activity (including the program counter and processor registers), stack (temporary data), data section (global variables), and heap (dynamically allocated memory).
    • Execution begins when an executable file is loaded into memory, distinguishing a process from a passive program stored on disk.
    • Multiple processes can derive from the same program, especially with multiple users executing the same application.

    Process States

    • Processes can be in various states:
      • New: Creating process.
      • Running: Executing instructions.
      • Waiting: Awaiting an event.
      • Ready: Prepared to execute when assigned to a processor.
      • Terminated: Finished execution.

    Process Control Block (PCB)

    • PCB stores essential information for each process, including:
      • Process state (e.g., running or waiting).
      • Program counter location.
      • Contents of CPU registers.
      • CPU scheduling information (e.g., priorities).
      • Memory management data (allocated memory).
      • Accounting info (CPU usage, elapsed time).
      • I/O status information (allocated devices, open files).

    Process Scheduling

    • Objective: Maximize CPU utilization and facilitate quick process switching for time-sharing.
    • Scheduling queues include:
      • Job queue: All processes in the system.
      • Ready queue: Processes in memory, ready to execute.
      • Device queues: Processes waiting for I/O devices.
    • Processes can migrate among these queues.

    Types of Schedulers

    • Short-term scheduler (CPU scheduler): Selects the next process for execution; called frequently and must operate quickly.
    • Long-term scheduler (job scheduler): Determines which processes to bring into the ready queue; invoked infrequently and may operate slowly.
    • Processes are either I/O-bound (frequent short CPU bursts) or CPU-bound (few long CPU bursts).

    Context Switching

    • A context switch occurs when the CPU switches processes, saving the state of the old process and loading the new one's state.
    • Context-switch time is an overhead, reducing efficiency, particularly in complex systems.
    • Hardware support affects speed; some CPUs provide multiple register sets for faster context switches.

    Process Operations

    • Operating systems must manage process creation, termination, and other aspects for effective resource handling.
    • Processes are identified and managed through a unique process identifier (pid).

    Process Creation

    • Parent processes create child processes, forming a hierarchical structure.
    • Child processes can share resources with the parent or operate independently, either concurrently or waiting for termination.
    • System calls like fork() create new processes, while exec() replaces the current process’s memory space.

    Process Termination

    • A process terminates using the exit() system call, which also passes status data to the parent.
    • The parent can terminate child processes using abort(), especially if resources are exceeded or tasks are no longer necessary.
    • Cascading termination occurs when a parent process exits, leading to the termination of all its children.

    Interprocess Communication (IPC)

    • IPC allows processes to share data and synchronize activities.
    • Cooperating processes require IPC to share information, speed up computation, and enhance modularity.
    • Two IPC models are:
      • Shared memory: Processes communicate through shared variables.
      • Message passing: Processes communicate without shared variables using send/receive operations.

    Message Passing Mechanism

    • Processes establish communication links and exchange messages to synchronize actions.
    • The IPC facility provides operations for sending and receiving messages, which can vary in size.
    • Key implementation issues include link establishment, capacity, unidirectionality vs. bidirectionality, and message size limits.### Client-Server Communication
    • A client initiates a connection by sending a request to a server.
    • The server responds by creating two private communication ports and provides the client with the handle to one.
    • Client and server use the port handle for message exchange and listening for replies.

    Communication Mechanisms in Client-Server Systems

    • Various methods include:
      • Sockets
      • Remote Procedure Calls (RPC)
      • Pipes
      • Remote Method Invocation (Java)

    Understanding Sockets

    • A socket serves as an endpoint for communication, represented by a combination of an IP address and port number.
    • Example: Socket 161.25.19.8:1625 indicates using port 1625 on a host with IP address 161.25.19.8.
    • Communication occurs between a pair of sockets; ports below 1024 are designated as "well-known" for standard services.
    • The loopback address 127.0.0.1 is used to refer to the local system.

    Socket Types in Java

    • Java supports three socket types:
      • Connection-oriented (TCP): Establishes a reliable connection.
      • Connectionless (UDP): Does not establish a connection prior to sending data.
      • MulticastSocket: Allows data to be sent to multiple recipients simultaneously.

    Remote Procedure Calls (RPC)

    • RPC simplifies the process of invoking procedures across networked systems.
    • Uses port numbers to differentiate services.
    • Stubs function as client-side proxies to the actual server procedure.
    • The client-side stub finds the server, marshals parameters, while the server-side stub unpacks them for execution.

    Data Representation in RPC

    • External Data Representation (XDL) is utilized to manage data across different architectures (big-endian and little-endian).
    • RPC entails more complex failure scenarios than local calls, ensuring messages can be delivered exactly once rather than potentially being lost.

    Additional Features of RPC

    • Operating systems often provide a rendezvous (matchmaker) service to facilitate client-server connections.

    Pipes

    • Pipes function as conduits for communication between processes.
    • Important considerations include whether the communication is unidirectional or bidirectional.

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    Chapter 3: Processes PDF

    Description

    Explore the fundamental concepts of processes in operating systems through this quiz based on Chapter 3 of 'Operating System Concepts'. Understand process scheduling, interprocess communication, and IPC systems, including client-server communication examples. Test your knowledge and grasp of these critical topics!

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