Threads and Processes in Operating Systems

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Questions and Answers

What is the concept of parallelism in computing?

Executing tasks in a sequential manner

Executing multiple tasks simultaneously (correct)

Executing a single task on multiple cores

Executing tasks in a random order

Which type of parallelism involves distributing subsets of the same data across multiple cores and performing the same operation on each subset?

Multi-threading

Task parallelism

Implicit threading

Data parallelism (correct)

Which thread library provides an API for thread creation and synchronization, commonly used in UNIX OSs?

OpenMP

Thread pools

Fork-join

Pthreads (correct)

What is the method of threading where the creation and management of threads is done by compilers and run-time libraries rather than programmers?

Implicit threading Signup and view all the answers

What are the two general approaches to thread cancellation?

Asynchronous cancellation and deferred cancellation Signup and view all the answers

What is a thread?

A basic unit of CPU utilization Signup and view all the answers

What do threads in a process share?

OS resources, such as open files Signup and view all the answers

Which of the following is a benefit of using threads?

Easier resource sharing within a process Signup and view all the answers

What is the main advantage of multi-threaded programming in multi-core systems?

Improved concurrency and more efficient use of multiple cores Signup and view all the answers

What is the difference between concurrency and parallelism?

Parallelism allows tasks to make progress simultaneously Signup and view all the answers

How does multi-threading benefit the scalability of a process?

It allows a process to take advantage of multiprocessor architectures Signup and view all the answers

What is the purpose of the 'pthread_cancel' function in the given code?

To terminate the specified thread Signup and view all the answers

What is the role of the 'pthread_exit' function in the given code?

To terminate the calling thread Signup and view all the answers

What does the 'pthread_join' function do in the 'main' function?

It waits for the specified thread to finish Signup and view all the answers

What does the 'pthread_self' function return?

The ID of the current thread Signup and view all the answers

What is the purpose of the 'pthread_create' function?

To create a new thread Signup and view all the answers

What does the 'pthread_cancel' function do if there are multiple instances of the specified thread?

Terminates one instance of the specified thread randomly Signup and view all the answers

'pthread_cancel' and 'pthread_exit' are functions provided by which multi-thread library?

pthreads Signup and view all the answers

'pthread_join' is used for which purpose in multi-threading?

Waiting for a specific thread to finish execution Signup and view all the answers

Study Notes

Parallelism is a computing concept where more than one task is executed simultaneously.
Parallelism can be achieved on a multi-core system.
Types of parallelism include data parallelism and task parallelism.
Data parallelism distributes subsets of the same data across multiple cores and performs the same operation on each.
Task parallelism distributes threads across cores, each thread performing a unique operation.
Multi-threading is one way to achieve parallelism.
User threads are managed by user-level threads libraries, while kernel threads are supported by the kernel.
Multi-threading models include Many-to-One, One-to-One, and Many-to-Many.
In the Many-to-One model, many user-level threads are mapped to a single kernel thread. This can result in reduced concurrency and poor performance on multi-core systems.
In the One-to-One model, each user-level thread maps to a single kernel thread. This allows for more concurrency and better performance but comes with more overhead.
In the Many-to-Many model, many user-level threads are mapped to many kernel threads. This allows for optimal utilization of resources and good performance.
Thread libraries provide an API for creating and managing threads.
Pthreads is a POSIX API for thread creation and synchronization, and is commonly used in UNIX OSs.
Thread ID is the thread analogue to the process ID and is assigned by the Pthread library.
Creating a thread involves defining and launching a new thread using the pthread_create() function.
Terminating a thread involves either calling pthread_exit() from within the thread or using pthread_cancel() to terminate another thread.
Joining and detaching threads are used to manage the execution of threads. Joining allows one thread to wait for the termination of another, while detaching allows a thread to terminate immediately and automatically release its resources.
Implicit threading is a method of threading where the creation and management of threads is done by compilers and run-time libraries rather than programmers.
Methods of implicit threading include thread pools, fork-join, and OpenMP.
Thread pools create a pool of threads that await work, allowing for efficient processing of tasks.
Fork-join involves forking multiple threads and joining them together to process a task, allowing for parallelism in a tree-like structure.
OpenMP is a set of compiler directives and APIs for C, C++, and FORTRAN that identifies parallel regions of code.
Thread cancellation allows for a thread to be terminated before it has finished, allowing for better performance in some cases.
There are two general approaches to thread cancellation: asynchronous cancellation and deferred cancellation.
In asynchronous cancellation, the thread is terminated immediately.
In deferred cancellation, the thread is allowed to periodically check if it should be cancelled, allowing for a more graceful termination.

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Description

Test your knowledge of threads and processes in operating systems with this quiz. Learn about the basic unit of CPU utilization, the characteristics of traditional processes, and the implementation of multiple tasks by separate threads.