CSCI 5828 — Spring 2010

The Grades page has been updated with a "scores" table that displays your projected grade in the class. The projected grade is calculated using the tables I posted just after the midterm and assigning a 40% weight to the project grades and a 20% weight to all other assignment categories (as described on the Evaluation page).

Note: there are no opportunities for extra credit in this class. We've got one more assignment, Project 5, to include into these calculations before the projected grades become final.

The grades for Homework 4 are now available on the Grades page.

Please plan on coming to lecture this Thursday, April 22nd. A guest lecturer, Tom Smallwood, will be there to talk about the issues encountered by real companies as they shift from a traditional approach to software development to an agile approach. In addition, after Tom's lecture, it will be time to fill out FCQs for this class. Aaron Schram will be administering the FCQs during the last 10 minutes of lecture. So, please attend the lecture to hear Tom's presentation and to submit your FCQs. Thanks! Note: I will post Tom's slides as soon as he sends them to me.

The grades for P3 and P4 are now available on the Grades page.

The grades for the SE Presentations are now available on the Grades page. For the most part, the class did very well on this assignment and a nice set of presentations on a diverse set of SE-related topics. I will be able to answer questions about the grades when I return from my business trip on Monday, April 19th.

I have now graded all of the SE Presentations. I will post the grades later tonight. All of the presentations, save one, have been posted on the Presentations page. A homework related to these presentations will appear on the website later tonight.

REMINDER: There will be no lectures this week as I will be in Edinburgh, Scotland presenting a paper at the 2010 Visions of Computer Science conference.

The slides for Lecture 21 and Lecture 22 are now available.

The grades for part 2 of the semester project are now available on the Grades page.

If your SE Presentation is too large to send via e-mail, you can give CU's web files service a try:

<http://www.colorado.edu/its/webfiles/index.html>

All you need is your identikey and password and you gain access to 100 MB of storage. Upload your presentation there and then set the permissions on the file such that I can download it. (Test it out yourself before sending me the link. Remember, you need to be able to download the file WITHOUT logging in.)

Details of Project 3 are now available.

The slides for Lecture 18 are now available.

Lecture 18 is going to cover additional topics related to FSP. I'm moving the lecture on Scala's agent model and chapter 5 of Breshears to next week. FYI.

Part 2 of the Semester Project is now available on the Assignments page.

The grades for the midterm are now posted on the Grades page (to see them, be sure to scroll down past the Homeworks table).

Project Proposals are due at the end of this week. SE presentation are due at the end of week 10. The assignment for the first iteration of the semester will be going up later today.

I have finished grading the exams of the 30 students who took the midterm on Tuesday (25 in-class, 5 CAETE). Midterms will be handed back today at the start of lecture and we'll spend today's lecture discussing the exam.

The average score on the exam was an 85.1. The minimum score was 50. The maximum score was 102 (perfect score + 2 extra credit). The median score was 90 while the most common score (the mode) was a 91. The standard deviation was 12. Finally, here is a histogram of the scores achieved on this exam:

Since there is no class in the CAETE studio ahead of us, I'm going to hand out exams starting at 9:10 AM and will let students start on the exam at 9:15 AM. The test will end at 10:45 AM sharp because we DO have a class in the CAETE studio directly after our class session.

Finally, if you are a CAETE student who plans to take the test using a test proctor, please let me know. I think all of my CAETE students plan on attending the exam in person tomorrow. I just wanted to confirm: so if you are a CAETE student and you are NOT attending the exam in person, please send me a message. Thanks.

The video for Lecture 14 is located here:

<http://engineeringonline.colorado.edu/tegrity/kena/CSCI5828101/CSCI5828L14.wmv>

Note: there are no new slides for that Lecture, so I will not be posting slides for Lecture 14 on the Lectures page.

The slides for Lecture 11, Lecture 12 and Lecture 13 are now available.

Grades for Homework 3 are now available on the Grades page. The grader said that everyone who submitted an assignment did a good job meeting the basic requirements. He did say that a few people made calculation errors when constructing their iteration plans... be careful, as you will lose points on the midterm if you make such mistakes on the exam.

A student wrote me with questions on concurrency. On the assumption that there are other students with these same questions, I've decided to share my answers with the rest of the class.

1. When there is single processor, multiple threads, then its simulated parallelism.

   Yes, there is concurrency but there is not true parallelism.

2. When we have multiple processors, multithreads, then there is a potential for true parallelism to occur.

   Yes, if we have multiple processors and a program using multiple threads then there is a potential for true parallelism to occur. As we've seen, it is up to the scheduler of the programming language's run-time. When I wrote a multi-threaded script in Ruby 1.9, I only received concurrency. Ruby's scheduler was not able to take advantage of the multiple processors on my laptop. However, when I wrote a multi-threaded program in Java, I received true parallelism. Java's scheduler was able to create the threads such that they ran on multiple processors at the same time.

3. For sequential programming, we have single thread, single processor.

   Better to say: for sequential programming, we have only a single thread of control. A sequential program can be run on a computer that has multiple processors but it will only ever make use of a single processor.

4. Whats multitasking and timesharing? Is that common for all three, I mean, multitasking and time sharing is seen in all the three cases.?  Why always the chapter starts from multitasking and proceeds to multithreading?

   I'm not quite sure I understand your question but here goes.

   Time sharing in computer systems is what I typically call simulated parallelism. The scheduler knows that it has three threads to run, so it runs thread 1 for a little bit, then runs thread 2 and then runs thread 3. Each thread makes progress over time, but only one is running at any one time.

   A task is something that a concurrent program needs to perform. In one of my example programs, the task was to read an XML file and count the number of tags within it. In that program, I created six threads to process files, one thread to read the files into memory, and one thread to send output to System.out (8 threads total). Each time the producer thread read in a file and stuck its contents on the queue, a task was created. Each time a consumer thread, pulled a file off the queue and processed it, a task was completed.

   I pointed that program at a directory that contained 40,000 XML files to process. So, when the program was running, it processed 40,000 tasks using 8 threads.

5. How does the accuracy and performance in true parallelism differ from simulated parallelism? Can you elaborate this taking a scenario?

   This is difficult to answer. You will get better performance with true parallelism if you have lots of independent tasks being processed by multiple threads, since all of the threads can run at the same time. If you have simulated parallelism, then you can still have lots of tasks and threads but the overall program will take longer to run because only one thread can run at a time.

   The accuracy should be the same in both cases. The same code is executing, the only difference is how many threads are active at once.

6. Last but not the least, now a days , there is dual/quad core processor with multithreading , in which case true parallelism occurs, which is also called concurrency. Right? The author refers concurrency to case 1 and 2. am I right?

   Yes, if you have a quad-core processor on your laptop, you have essentially four cpus that can be active at the same time. If you then right a program with multiple threads and those threads are assigned to the four cpus at the same time by the program's scheduler, then you get true parallelism. If the scheduler isn't set-up to handle parallelism (as is the case with ruby's scheduler) then you get simulated parallelism. Both programs would be considered a concurrent application.

Details for the first assignment of the semester project are now available.

The slides and example source code for Lecture 9 are now available.

Slides for Lecture 7 and Lecture 8 are now available.

Grades for Homework 2 are now available on the Grades page.

I originally planned to cover Chapter 3 of the Breshears textbook tomorrow during Lecture 8 but I've discovered that I need more time to prepare. As such, I've decided to cover the material from Chapter 4 of the Head First Software Development textbook instead. I will present Chapter 3 of the Breshears textbook next week. My apologies for the last minute change.

I've updated the Grades page to contain "submitted/not submitted" info for HW 2. I'm sending HW 2 to the grader today and I hope he'll have it graded by early next week. FYI.

I had a bug in the code I used to generate student ids. That bug has been fixed and the Grades page refreshed to contain the correct ids. Sorry for the confusion.

The grades for homework 1 are now posted on the Grades page. Stay tuned for instructions on how to calculate your id.

The slides for Lecture 3 and Lecture 4 are now available on the Lectures page, along with the example source code discussed during Lecture 4.

Homework 1 is now available.

The slides for Lecture 1 are now available. Don't forget to read No Silver Bullet before Lecture 2 tomorrow.

A placeholder page for Class Assignments has now been added.

Information about the textbooks for this semester is now available.

I have added the syllabus statements that the University recommends all students see at least once a semester to the class website.