Week 7 Threads

Question 1

What are some benefits of Threads

Answer 1

Responsiveness, Resource Sharing, Economy, Scalability

Question 2

What is Parallelism?

Answer 2

It implies a system can perform more than one task simultaneously

Question 3

There are two types of parallelism. What is Data parallelism?

Answer 3

Distributes subsets of the same data across multiple cores, same operation on each

Question 4

There are two types of parallelism. What is Task Parallelism?

Answer 4

Distributing threads across cores, each thread performing a unique operation

Question 5

What is Concurrency?

Answer 5

It supports more than one task making progress.

Single processor/core, scheduler providing concurrency

Question 6

What are user threads?

Answer 6

Management done by user-level threads library.
There are three primary thread libraries:
- POSIX Pthreads
- Windows Threads
- Java Threads

Question 7

What are Kernel threads?

Answer 7

Supported by the Kernel
Examples include virtually all OS's 
- Windows
- Max OS X
- Linux etc.

Question 8

There are three Multithreading models.

Describe Many - to - One

Answer 8

Multiple user threads mapped to a single kernel
Examples include
- Solaris Green Threads
- GNU Portable Threads

Question 9

There are three Multithreading models.

Describe One - to - One

Answer 9

One user thread to one kernel
Ex:
- Windows
- Linux

Question 10

There are three Multithreading models.

Describe Many - to - Many

Answer 10

Multiple kernels to multiple user threads
Ex:
- Solaris pre version 9
- Windows with thread fiber package

Question 11

What’s a Thread Library?

Answer 11

• It provides the programmer with APU for creating and managing threads