Welcome to the Wiki page of the course Search Engines, WS 2009 / 2010. Lecturer: Hannah Bast. Tutorials: Marjan Celikik. Course web page: click here.
Here are PDFs of the slides of the lectures so far: Lecture 1, Lecture 2.
Here are PDFs of the exercise sheets so far: Exercise Sheet 1, Exercise Sheet 2.
Here are your solutions and comments on the previous exercise sheets: Exercise Sheet 1.
Here are the rules for the exercises as explained in Lecture 2.
Exercise Sheet 2
Here are the details about the three servers (UDP, TCP, HTTP) for Exercise 4:
All three servers are running on our machine vulcano.informatik.uni-freiburg.de
The UDP server is running on port 8888 of that machine. You can send it a number and it will then send you back that number of bytes, in packets of 1000 bytes. (That means you also have to read packets of 1000 bytes.) The first ten bytes of each packet contain the packet id. That is interesting for checking which packets get lost and in which order packets arrive.
The TCP server is running on port 9999 of that machine. You can send it a request of the form GET /<number of bytes> HTTP/1.1, or you can just a downloading problem like wget or curl and time it.
The HTTP server is running on port 80, as web servers normally do. Just download the file http://vulcano.informatik.uni-freiburg.de/file_100M ans measure the time.
For measuring your transfer and error rates, as requested by the exercise, repeat your experiments several times and also at different times, and form the average of these measurements (or report several numbers if you get very different results). You should ask for large amounts of data, like 10 MB or 100 MB.
Here you can upload your solutions for Exercise Sheet 2.
Questions or comments below this line, most recent on top please
Hi, I have some question about my exercise Sheet 1, I saw in my exercise page that my name, my upload solution and code in gray color and other persons in blue color. I try to click my attachment file in my exercise page, and I have some message that there are no attachment. any body know about this issue?because my exercise uploaded on Monday 26octTriatmoko 30 Oct09 22.18
Hi Björn + all: For Exercise 4 from Exercise Sheet 1 you had to write code that is at least able to process 2-word queries. If your code can indeed only handle 2-word queries and not an arbitrary number of query words, that is also fine for this exercise, you won't get less points because of that. Your second question is also very valid. You should put the various functionalities into modules / classes of their own, so that you can easily combine them for the three different binaries required for Exercises 1 - 3. Each of your three programs will then be quite short, just putting together the right things. I should have added it to my list of evil coding NoNos: never ever duplicate code, but instead put it in a class / module of its own. I hope this answers your questions, if not please ask again. Sorry for the late answer, but I was super busy until now, hardly had time to breathe. Hannah 30Oct09 19:08
I have a question concerning exercise 2. There was no concrete task to produce "query processing code" on ex sheet 1. Are there any requirements that have to be fulfilled? Should it be able to handle two word queries? n-word queries? Additionally there is something else I want to ask: I think it surely isn't bad practice to write a more generic webserver and use it for exercises 1-3. Apart from that it says "change your code" some times in the exercises. How should your submission behave w.r.t. the exercises? Different src files / executables for each exercise? One program that solve each exercises depending on startup parameters? Anything else? Björn 30ct09 2:25pm
I now reorganized the page. Old stuff went to separate pages (links above). The idea is that the front page is always for the current lecture / exercises. The problem with your exercise page should be solved now, Ivo. Hannah 30ct09 00:05am
Having problems to access my exercise page after loging in - IvoChichkovExercises, Ivo 29Oct 22:56pm
Sorry to bother you. I added the Link to exercise sheet 2 with the linked pdf. Needed this to find the sheet as fast as possible. Marius 29Oct 10:04 p.m.
Is there a webpage for exercise sheet 2 somewhere? Johannes 29Oct 07:45 pm