Computer Systems Lab

Grades

Matteo Corti (ID/BD/WAI) — Tue, 07 Aug 2007 10:49:46 +0000

I just submitted the grades to the Studiensekretariat. If you want to know your grade just ask me or Mathias.

Lecture evaluation results

Matteo Corti (ID/BD/WAI) — Tue, 12 Jun 2007 11:40:04 +0000

The results of the course evaluation are available (PDF):

and will be discussed during the last lecture.

Sample solution to the proxy lab

Matteo Corti (ID/BD/WAI) — Mon, 11 Jun 2007 17:01:07 +0000

On the lab page you can find a sample solution to the filesystem lab.

OpenMP parallel lab is online

payerm — Fri, 08 Jun 2007 12:52:35 +0000

The last (optional) lab is finally online. You can get all the details at the parallel lab webpage.

As usual, if there are any questions, comments or bugs, file them to Mathias.

So long, and have fun with the last optimization lab.

Possible problem with parse_uri if the URL is malformed

payerm — Wed, 06 Jun 2007 15:10:15 +0000

If the URL that is passed to parse_uri just contains a hostname withouy any path (e.g. http://www.foo.bar) then the function might cause a core dump because there is a small bug in the parse_uri function…

The diff for the parse_uri function looks as follows:

/* Extract the host name */
hostbegin = uri + 7;
- hostend = strpbrk(hostbegin, ” :/\r\n\0″);
+ /* does not work because it maps to the end-of-string and strpbrk
+ * will return NULL
+ */
+ //hostend = strpbrk(hostbegin, ” :/\r\n\0″);
+ hostend = strpbrk(hostbegin, ” :/\r\n”);
+ if (hostend == NULL) hostend = hostbegin+strlen(hostbegin);
len = hostend – hostbegin;
strncpy(hostname, hostbegin, len);
hostname[len] = ‘\0′;

Of course you can download the corrected handout at http://www.lst.inf.ethz.ch/teaching/lectures/ss07/2100/proxy_lab/proxylab-handout.tar

Semesterapéro

Matteo Corti (ID/BD/WAI) — Wed, 06 Jun 2007 12:31:34 +0000

The traditional D-INFK Semesterapéro with teachers and students will take place on July, 19 at 5:30pm in the Dozentenfoyer (HG J floor).

Programming language of choice for proxy-lab

payerm — Mon, 04 Jun 2007 18:28:11 +0000

As Matteo said in the lecture you can choose your programming language for this lab. But keep in mind that the exercise should not be made simpler than it is in C. So you should not use any high-level functions to program sockets and use high-level objects for String manipulation or URL-handling.

Also dont use any uncommon or unusual languages. If you are in doubt, check back with Mathias.

Deadline extension for proxy lab & information for HTTP/1.1

payerm — Thu, 31 May 2007 10:02:54 +0000

Some of you told me that you don’t have enough time to complete the proxy lab, so the deadline is postponed to June, 10.

Also you have to take care for some special hickups if you use HTTP/1.1 because the connection is not closed when all data is transfered.

You can use the following procedure to avaid a (forever) blocking read:

Read the header line based and parse the content-length field (if present)
If the content-length is present, then read the given bytes and pass them to the client
Otherwise continue reading until you read

Also keep in mind that you might need to reformat “GET http://server/path/ HTTP/1.1″ to “GET path/ HTTP/1.1\nHost: server” depending on the server implementation of HTTP/1.1.

Last lab: optional

Matteo Corti (ID/BD/WAI) — Wed, 30 May 2007 13:46:29 +0000

The last lab about parallelization with OpenMP will be optional and will provide the possibility to raise the grade of a student or a group (but not to lower it).

I will present the details during monday’s lecture.

New exercise sheet for the proxy_lab available

payerm — Tue, 29 May 2007 09:32:18 +0000

I was told that there was a mistake in the proxy_lab and filesystem_lab exercise sheets. They stated that groups up to three people could be formed, but the course homepage itself says that only groups up to two people are allowed.

So I wanted to clarify that only groups up to TWO people are allowed to work together.

I hope that this does not cause any inconveniences to you. If there are any problems, step by at my office and we’ll try to solve them!