CGS 3763 Operating Systems Concepts Spring 2013

Dan C. Marinescu

Office: HEC 304

Office hours: M-Wd 11:30 - 12:30 AM

Last time: Examples of client-server systems: Web Heterogeneous systems Remote Procedure call

Today: Answers to student questions from last week’s lectures Threads

Next time Reading assignments

Chapter 4 of the textbook Chapters 4 textbook slides

Lecture 17 – Friday, February 15, 2013

2Lecture 17

Questions from February 4th lecture

1. Which process is faster message passing or shared memory?

2. What are the advantages and disadvantages between message passing and shared memory?

3. More explanation on the Operating System Shell and C Shell.

4. What is the difference between child processes and threads?

5. More concepts on asynchronicity would help me better to analysis this topic.

6. How does interprocess communication come into play with the processes?

7. Are the fork and exec commands only in UNIX?

Lecture 17 3

Questions from February 6 lecture

More explanations of blocking and non-blocking messages. How does non-blocking increase optimization?

More explanations of Hourglass Architecture. More on the idea of multiplexing and de-multiplexing. Does

multiplexing and de-multiplexing compress data, or do something else?

Is peer-to-peer different that point-to-point communication? If so, what are advantages of each?

Are Sockets used in all network/internet communications or just some?

What are the benefits of using asynchronous communication instead of synchronous?And the opposite?

Lecture 17 4

Questions from February 8 lecture

Message buffering Is IPV6 better than IPV4? If so, what makes it better? What does the Data Link Layer consist of? More example of how RPC’s differ from other procedure calls. Are there any benefits to using encapsulation versus decapsulation

methods?

Lecture 17 5

Threads

Thread the smallest sequence of programmed instructions that can be

managed independently by an operating system scheduler a light-weight process multiple threads can share the same address space

On a single processor, multithreading generally occurs by time-division multiplexing, the processor switches between different threads. This context switching generally happens frequently enough that the user perceives the threads or tasks as running at the same time.

On a multiprocessor or a multi-core system the threads actually run at the same time, with each processor or core running a particular thread or task

Lecture 17 6

Single- and multi-threaded processes

Lecture 17 7