One of the reasons as to why I haven’t update GimpsterDotCom for a while is, that I suddenly cannot resolve any DNS names?! There’s nothing wrong with my connection to the Internet, I just cannot resolve DNS names to IP addresses. So I haven’t checked my mail for the last five days, and I haven’t looked after GimpsterDotCom until now.

Although I can’t use the Internet, or at least not use any part of it for which I don’t know an IP address, I’ve still been able to utilize my fine broadband LAN connection through the use of FreeNet. Fortunately my FreeNet node knows most of it’s peers through an IP address, so it still works even though the rest of the system doesn’t. That’s pretty cool! I’ve been trying to upload all the eight CDs that make up the latest stable release of [Debian][]. So far I’ve uploaded two CDs, it’s awfully slow and takes an insane amount of RAM. But it’s doable, it just takes time.

So, please bear over with me until I get this DNS thing sorted out.

Update

I’ve now sorted things out again — there’s now two DNS servers for our LAN, 10.2.2.10 and 10.2.2.12, the first of which doesn’t work at the moment. My machine has a permanent IP address, so I’m not using DHCP and therefore I didn’t discover the change automatically, which left my computer without a working DNS server.

I’ve just emptied my mgeisler@mgeisler.net mailbox and I’ll come back to you as soon as possible. There were 400 mails waiting for me, but the vast majority of these are either SPAM (which TMDA “reads” for me) or traffic from the various mailinglists I follow.

But it’s good to be back on the Internet! :-)

I haven’t updated GimpsterDotCom lately, sorry about that :-(

Let me just give you a quick recap of the last few weeks… I had my Easter Holidays, and it was great. I spend a couple of days visiting my family in Aalborg, and I spend the rest of the time here at [Skejbygård][], enjoying the sun and the wonderful people you find here.It really made me long for the summertime which is just around the corner…

When I got back to [Skejbygård][], I discovered that Kristian Kristensen was going to Århus for a MicroSoft seminar on DotNet. So we met afterwards his seminar and I gave him a tour of DAIMI at the University of Aarhus and Århus itself before I showed him [Skejbygård][] so that he finally could see how and where I lived. It was really great to get together and talk about “old days”.

We’ve also had a “Decade Party” here at [Skejbygård][]. The name “Decade Party” means that the music that was played was grouped into music from different decades along the evening. We started with dinner for all of [Skejbygård][] at 19:00 and then the party was held afterwards. At 21 to 22 the music was from the 1930s: swing with the bartenders were dressed up like people from an old gangster movie. Then there was music from the 1950s, 1970s where Martin Justesen made a great performance as John Travolta from Saturday Night Fever, 1980s, 1990s and then just comtemporary music. It was a really great idea and the party was a huge success!

I’ve just found this super plugin for Mozilla called Electrix. This makes it possible to edit text areas in an outside editor, such as the great [GNU][] [Emacs][]. This is very handy for editing a site like this where big text areas are abundant…

Ahh, there’s just a single day left until the Easter holidays start, and I’m only having three hours tomorrow accourding to my schedule!

Not that I’ve been studying all that much the last couple of days… I sat down yesterday and tried to make the Turing Machine that would take an input tape with “aaaaaa#aaaaaaaaa” and turn it into “aaa“.

In other words: calculate the greatest common divisor of m and n represented by the input a^m#a^n. In the above case, the greatest common divisor of 6 and 9 is 3 if I’m not mistaken.

It turned out that Turing Machines are extremely annoying to program! Even the simplest operation gets enormously complicated. Somehow I managed to sit up all night trying to get things to work — I just kept tweeking and changing my program, hoping to catch that finaly special case that ruined the result. Amazingly I didn’t get that tired, it’s as if you reach a point and from then on you can carry on. But I still have a bad feeling that I’m going to get really tired soon…

I used a rather nice program called gturing to test my program, which you can find here. The comments are in Danish, sorry about that, but I used the program in a Danish hand-in exercise and when I rewrote things this morning I changed the English comments into Danish ones so that they would be easier to use in the report. I believe that the program now handles all correct input correctly. Correct input is input that matches the RegularExpression “a^m#a^n”.

The program also handles cases like “#“, “aaa#“, and “#aaa“. With the first input the machine calculates gcd(0, 0) = 0, the two other inputs represent gcd(3, 0) = gcd(0, 3) = 3. The reason why gcd(0, 0) = 0 is, that gcd(m, n) is defined as the unique whole number d that satisfies

Div(d) = Div(m) intersect Div(n)

where Div(n) = { d in N | d divides n }. Here we have that Div(0) = N, that is, all natural numbers divide 0 — take a natural number and multiply it with 0 to see for your self. So we look for a number d that satisfies that Div(d) = N. The only number that has this property is 0 itself, so this means that gcd(0, 0) = 0.

Mikkel Krøigård and I finished the assignment for DAIMI:dDist Thursday evening as we had predicted. After that I just relaxed, I don’t know what Mikkel did, but I suspect he did the same :-) It was really finally to get way from the project which we’ve coded quite a lot on all last week. We don’t even get a grade for it, we just have to have it approved before we’re allowed to attend the aural exam that will be held all too soon now.