Martin Geisler Online

It’s time for the exams — I’ll be working at problems in dADS for four hours this Monday… So things will probably be somewhat quiet here at gimpster.com the next month or so. Bye for now!

It seems that the Windows community is suffering from yet another virus-attack. I’ve received 53 — no make that 54 — mails from all over the world with an attachment of type audio/x-wav and various subjects.

I believe that this is the W32/Klez.h@mm virus that is to blame, so please get yourself some good antivirus software (and keep it updated) if you’re using Windows or any other operating system for that matter — you can also get antivirus software for Linux these days. It’s just that the vast majority of viruses target Windows based machines because there are so many more machines to infect by doing so instead of going after Linux or Macs.

It’s also much harder for a virus to infect a machine like mine because I don’t use a mailreader that will execute each and every script it sees… It does happen from time to time that I receive a HTML-email. Gnus will then invokes the W3 webbrowser in Emacs to display the mail. This browser doesn’t support any of the scripting languages used by viruses — it just displays the page. It’s this kind of simplicity that keeps systems secure — I’ve never heard that all those scripting capabilities were used for something useful, instead we hear again and again that a virus has been allowed to executed malicious code on the client machine. So if you’ve never used those scripting capabilities, then please turn them off — if you can…

I discovered yesterday, that the extended addresses I’m using with TMDA had stopped working. I guess that NETsite must have changed the configuration on the mailserver. So I had to deactivate TMDA until I found a solution to the problem — I wrote them an email and they suggested that I made [email protected] the catch-all address for the domain.

So, that solved the problem, but I was still unprotected a couple of hours The result: four spam mails in by inbox! I’m glad that TMDA is on guard once again.

I’ve been a big fan of the package management system in Debian ever since began using it. It’s the most complete and carefully maintained system I’ve seen for this.

But apart from their package management system, Debian is also famous (or should we say infamous :-) for their strict demands on the licensees of the programs in the distribution: They will only distribute programs that are truly free. I was reminded of this today when I tried to compile the dADS report with LaTeX — it complained about missing files. I discovered that they had removed several LaTeX packages because the files weren’t licensed properly!

They have removed these files: algorithm.sty, algorithmic.sty, beton.sty, booktabs.sty, caption.sty, euler.sty, footbib.sty, fvrb-ex.sty, picinpar.sty.

I’m actually using 6 of these packages/files at the moment, so that was kind of bad for the document :-) But it only took a couple of minutes to download them again from CTAN. I’ve now placed the packages in my own texmf-tree in my home directory so that they’ll be preserved next time the good guys at Debian decides to change something.

Well, I’ve done various stuff — Jérémy and I have made the first third of the mandatory assignment in dADS. It’s actually an interesting assignment: we have to design an algorithm that will find the maximum matching in a bipartite graph. The first thing we had to do, was to prove that an algorithm written in pseudo code was valid and correct. The algorithm uses a transition system to color the nodes in the graph, so we had to prove a couple of things about that too.

This week we have to design efficient datastructures that will allow us to color the graph using the transition system in time O(m+n) where m is the number of edges in the graph and n in the total number of vertexes. We will use these datastructures in the final third of the assignment where we have to implement the algorithm in Java. Exciting stuff…

I plan to publish the report here at gimpster.com when we’re finished, so stay tuned. (It’s in Danish, so don’t be too excited if you cannot read that :-)