Welcome to PGSS 2008!

You probably want to look at the Syllabus and Resources items in the menu on the left, as well as the Lecture notes there.
(I could have linked them to this text, but you might as well start using the menu now.)

Also, be sure to look at the Textbook link, for any mistakes discovered in the textbook!

If anyone wants to talk with me one-on-one, send me email.

(As the course progresses, I'll put up more announcements on this page.)

Tues Jul 1: The course web servers are up.
I believe the whole PGSS CS website is up-to-date. Let me know if anything is out of date or doesn't seem to be working.

Tues Jul 1: I mentioned in class today that checkers has been solved just last year by a computer program, after 18 years of computing; it will never lose. There is a Wikipedia entry about this (under the name "Draughts, English (i.e. checkers)"). The scientific article is also on the web.

Mon Jul 14: In class on Friday, someone asked how you prove that an algorithm is optimal, that is, the best algorithm that can be written for a particular problem. This sort of thing is basically a math proof, except that you also have to establish the correspondance between the algorithm and the mathematical objects that the proof concerns. So there are a lot of different methods, just as there are various approaches to math proofs.
Here is an example of a proof that sorting (putting a list of things into order) must require n log n time in the most general case.
We'll see some really different kinds of proofs later in class, such as proving that some problems cannot be solved by any computer!

Tue Jul 15: IMPORTANT: Some of you received notes on your homework about consulting a TA, and have not done so.
Please see a TA by tomorrow night (Wednesday) or they will have to give you a violation.
In the future, all "redo"s will be due one week after the homework is due (i.e. the following Sunday night at midnight), and failure to redo by this time will be treated as a late homework assignment.

Tue Jul 15: For the next homework (Assignment 2), the written part will be due at midnight Sunday (the first nanosecond of Monday).

Wed Jul 16: Someone asked in class about what happens if you run out of IP addresses. Since it's 32 bits, there are at most 4.29 billion addresses. We are actually running out, but it's not an emergency, contrary to this news report that was even carried on KDKA TV news the other day. We'll see why tomorrow.

Wed Jul 16: The FishNet server that your Assignment 2 program will talk to over the net is up and ready.
(Don't wait until the last moment to start working on Assignment 2.)
Contact me (by email) or the TAs if it's ever down. The TAs are easier to find outside of normal business hours.

Thu Jul 17: Someone asked about the whole list of well-known port numbers. It's available from IANA here.
The ports we've talked about are "tcp" ports. "udp" ports are for another protocol that is used for applications that need real-time, and don't need to recover lost packets (like Skype phonecalls probably).
You can see that port 80 is indeed HTTP.
Servers using the secure (encrypted) version of the protocol (HTTPS) listen on port 443.

Thu Jul 17: The solution for Assignment 0 is now available under "solutions" in the left-hand menu.

Thu Jul 17: By the way, this New Years Day was the 25th anniversary of the Internet going live. Google celebrated it with a special logo image.
(If you look closely at the logo, you can see "ACK" in the confetti. There's also "SYN", which is used to open a TCP connection.)

Sun Jul 20: There was a report of web trouble.
As of 3:50pm, the class webservers and the FishNet server all seem to be up. Please let the TAs know (or email Dr. Bob) if there's any further trouble, and please be as specific as possible as to what seems to be wrong. Thanks.

Mon Jul 21: I mentioned last week, when talking about the Internet, how bad people might have legions of machines that they've taken over, and use them to attack somebody. This sort of thing is called a botnet.
As I thought, it was Estonia that seems to have been attacked in such a way last year. Right after they had made the Russians really angry...
One cool (evil) thing about the Storm botnet from the article: if you try to look at it too much, it attacks you!

Tue Jul 22: The TAs have agreed to (try to) run the FishNet Tournament. So, if you're up for it, keep improving your Assignment 2 programs. Good luck!

Wed Jul 23: FishNet tournament info: You will have until Monday Jul 28 to improve your FishNet program. If you want to enter the tournament, you should modify your code in the way specified here.

Wed Jul 23: Noam Chomsky has been busier than I thought. This is the movie that I was thinking of. But he has been in lots of others since.

Thu Jul 24: The solution for Assignment 1 is now available.

Thu Jul 31: The 2008 FishNet Tournament: We have a winning team, which will be announced at the PGSS Banquet Friday evening. We will then post the results here.

Sat Aug 2:
The 2008 FishNet tournament Grand Prize winner is:
FishMan, by Aman Sinha, William Gamber, and John Subosits. Congratulations!
The Grand Prize (a bag of Goldfish!) was awarded to each of them at the PGSS Banquet.
They also receive eternal fame for one year on this webpage!
Due to their close second-place finish, an Honorable Mention is awarded to
The_Goveyz, by Deepthi Shashidhar, Angela Hsieh, and Lavanya Sivakumar. Good work!
Click on the fish for more details.