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Pros:

• Getting to see DefCon

Cons:

• Having my photo and personal information permanently added to some US database (and considering the nature of such a visit, I'm quite sure that would not be the good guys column)
• Having to trade in my normal paper passport for an evil biometric RFID steal-my-data-from-a-distance one
• Getting to see only DefCon. Why spend a fortune on transatlantic airline tickets and stay there just a couple of days?
• Considering this offer (and the fact that it is cheaper for people from US to come to Europe), there will probably be some people from DefCon at CCCamp. So even CCCamp will probably be more interesting than usual.

Here are some pictures from 13th MFRU (or IFCA in English, International Festival of Computer Arts) in Maribor.

I've been there yesterday evening to do a short presentation of my redesigned Galaksija. It felt a bit strange to present my work at an art festival, since I didn't thought of Galaksija as a work of art. In the end I think that my talk about Galaksija didn't quite reach the audience (although I tried to leave out as many boring technicalities as possible).

On the other hand I saw a number of interesting projects, but I think posting by blurry photos wouldn't do them justice.

This little figure made out a RJ-45 connector and a piece of UTP cable was the first exhibit I saw.

Amazon noir exhibit was one of the more interesting ones. Authors managed to copy a number of complete books using some feature of the amazon.com web site that allows you to read small parts of some books in the shop. The details of how they managed to do that are pretty well hidden on their web page.

Galaksija's corner.

Looking back, the best exhibit of the festival I saw was the "My name is Urška" project. A photo of it would really be pointless here since the whole point of the exhibit was to see a photo of a girl smoothly morphing from a healthy look to how she would look if she had one of genetic disorders while a display showed a statistical frequency of this disorder.

Someone dug through a telecom cable for my neighborhood or so my ISP tells me. It cut my server off the net (together with all telephones and ADSL lines in sight) for nearly a day and a half.

In semi-related news, secondary DNS for tablix.org is also currently down (so much for redundancy).

And since bad things tend to happen together, a glitch in my dovecot IMAP server deleted half my mailbox. As expected, I was just going to make a backup for this month, meaning I lost a lot of mail I received since April. If I don't answer, you now know the reason.

I'm still investigating this by the way. It seems to be related to this issue. "nobody sane has that many messages in one mailbox" they say? Uhm...

Update: I've been told that I can expect more down time the following week as they will be repairing the damaged cable.

I'm going to VCFE, München tommorow.

I was going to write something here about Galaksija's shiny new Acrylic glass case and new Galaksija tools, but I still have too many things to prepare so it'll have to wait.

So, I if you want to see my redesigned Galaksija in real life and you'll be near München this weekend, drop by. Look for Cyberpipe's computer museum.

While I use a terminal to do most of my work I do often use Nautilus to move files around and sort things into directories. It's quite annoying when I get just a lot of default "foot" icons when I'm working with files made with gEDA (which is a lot these days).

So, here's my second try at making icons:

(These icons are derived from the text-x-generic icon of the Tango base icon theme and are licensed under the Creative Commons Attribution Share-Alike license)

Update: Added icons for PCB layouts and Gerber files. SVG versions.

On Saturday I went to see Sunshine. I've read the review in the NewScientist last week and didn't expect much from it. Now, I'm surprised NewScientist even bothered to review a movie like this.

The science part of this science-fiction story is just unbelievably bad. I don't have a problem with the fact that the basic plot was impossible (there isn't nearly enough mass on the whole earth to make a device that could produce any kind of power output comparable to the sun, stars don't stop just like that, etc, etc), that is also true for many good sci-fi stories. It's the little details that really annoy me:

• They equate vacuum and weightlessness. As soon as air pressure is restored in the airlock, things fall down (I would think that anyone who passed elementary school physics should get this right).
• Mariner 10 flew by Mercury in 1973 (without any futuristic heat shielding) and didn't vaporize in an instant.
• Low temperature is the least of your problems when you are going to explosively decompress an airlock without a wearing a space suit.
• Come on, you have immersive three-dimensional displays for therapy, but the astronauts must peek through a narrow slit in their helmet?

Interestingly the basic theme of the movie (people getting obsessed with exposing themselves to the light and stuff like that) strongly reminded me of a short sci-fi story Flying toward the light by Herbert W. Franke (I only have Slovenian translation here, so the title may be a bit off). It talks about a fleet of ships from Pluto that are going toward the inner solar system in search of planets that are warmer (and trying to figure out what happened to the previous expedition). It turns out that they get so addicted to the light and warmth that they can't get enough of it and they get closer and closer to the sun until everyone looses perception and is too late to avoid crashing into the sun.

I found this two pages long story much more enjoyable and thought provoking than the whole Sunshine movie - and in the end it also doesn't turn into a cheap horror movie with rotating scalpels (??) and other sickening stuff.

This a picture of the packaging of a Manhattan USB-to-parallel port adapter...

...and this is from their website:

At least they acknowledge that the information on the packaging is incorrect.

A couple of people pointed me to this "amusing" web page about Mac users. Now while I usually ignore individuals using language like this, I am guilty of answering "it just works" when people ask me why I use an Apple laptop. So I feel like I ought to explain this a bit.

My Powerbook certainly doesn't always "just work". As any other software I know Mac OS X has its share of bugs and I can even say that when something does go wrong, OS X is the worst of all operating systems at giving you a clue about what went wrong (to give a recent example I encountered: Connection error: -5. See also my previous post about iPod problems). In that case your only hope of finding out the cause of the problem is a Google search turning up some insider information that was leaked by an Apple developer.

However from my experience if any system deserves the label "it just works" it is definitely a Mac. To give some examples why I think so:

• My mobile phone connected via Bluetooth to my Powerbook and synchronized contacts, shared GPRS connection and sent SMSes without needing one bit of tweaking configuration or installing drivers. On a windows computer a similar trick involves spending several hours installing gigabytes of software, setting up network connections, "My Bluetooth places" and I don't know what else, including reinstalling everything once every three months because the installation mysteriously broke.
• I have connected and printed to numerous printers from HP to Xerox again without installing drivers or configuring anything. A lot of times it was far easier to connect a printer to my laptop to print something than to convert a document to a format that can be read by some other computer that was already connected to a printer.
• OS X is the only operating system with a usable sleep mode I saw. You close the lid, and the computer goes to sleep. You open the lid, computer is ready almost instantly. Compare this to you usual (Windows-running) laptop for example where a) suspend-to-disk takes longer to restore than a fresh boot (I can quote a number of examples of this, mostly from Compaq/HP) or b) suspend-to-RAM drains the battery in a couple of days. I have also not yet seen it crash when you connect or disconnect some device while it is in sleep.
• Installation of native OS X applications doesn't require clicking through wizards or similar nonsense. If you no longer need an application just drag it to the trash can and its gone. Of course this one-file-per-application principle has its (not-so-short) list technical problems, but so far I haven't come across a single one. Majority of apps will work correctly 10 seconds after you drag them to the Applications folder. A lot of free software will also work without problems.
• Another thing about software installation is that (again, from my perspective) I needed so little extra applications beyond what OS X provided by default. My Powerbook was useful from the moment I unpacked it from the box. I'm perfectly happy with the built-in address book, mail reader, web browser, calendar and music player. With vanilla OS X I access files on Windows shares, NFS exports, SSH servers, etc. and I can give others access to my files via a Windows share or a HTTP server.

Again, I don't want to give the impression that I'm making a commercial for Macs. In most cases I prefer to use free software. For example all my desktop computers have Debian GNU/Linux installed. Debian usually requires me to spend more time to set up a specific feature (for example a new piece of hardware, a new network configuration, etc.) but the flexibility provided by free software far outweighs this problem. Desktop computers also don't move much and their software and hardware configuration is quite stable and time I spend on maintaining them is minimal. On the other hand, when I'm traveling I usually don't have time to tinker with some configuration until the feature I need at that moment works correctly. I just want my laptop to be always ready.

Microsoft's web page that promotes Slovenian version of Vista says that it requires Internet Explorer or Firefox to display "advanced dynamic graphic content". They even link to getfirefox.com!

On the other hand they seem to ignore Mac users, since the site misidentifies Safari as Netscape 5.

Perhaps they meant Microsoft Firefox?

Today I saw this advertisement for Microsoft in the newspaper:

It says that the high school I used to attend switched completely from a "heterogeneous system" that used Linux and OpenOffice to a "rich and stable environment" of Windows Vista.

That's sad. When I left that school five years ago things looked like they were slowly moving away from a Microsoft monoculture (at that time that meant Windows95 and friends). School's mail and web servers were already running on some flavor of Unix and publicly accessible computers in the library had Red Hat installed on them. In fact I had my first experience with Free software while attending that school.

Thanks to everybody who sent me advice on how to solve the flipped-character problem. I was pleasantly surprised at how many of you are following my Galaksija project - especially people from outside former Yugoslavia.

It turned out that flipped characters were the least of my problems. I figured out the cause after some 15 minutes and I only had to reprogram the character generator EPROM with the bit order reversed.

Poor video quality, power supply overheating and audio interface insensitivity were a bit harder to solve. I'll post some details (and hopefully a screencast) tomorrow.

Because I feel like ranting today, here's a list of technical things that have recently been bothering me:

• Noisy operational amplifiers and the faculty not teaching us enough about how to deal with (or even accurately calculate) amplifier noise in real-life cases.
• An analog electronic circuit (involving said opamps) which works on the protoboard and for which I'm not able to show analytically why it works (anyone who knows his or her way around trigonometric functions and Fourier analysis wants to help? It all boils down to a simple looking mathematical problem I don't know how to solve)
• iTunes suddenly forcing me to delete 1/4 of my music collection because there is not enough space on my ipod even though this same collection was stored on this same ipod for a year or so with 100 MB to spare.
• Ugly Iceweasel thing replacing Firefox in Debian Testing. Suddenly I have three icons in my applications menu that all look like a green blob - one for a mail client, one for a web browser and one for some kind of a profile manager I never bothered to start. Now that kills usability.
• Having to fix a mail loop on Friday evening at half-past midnight to prevent millions of email messages from being automatically sent across the net by stupid software that was chasing its own tail.

Somebody obviously did the hard work of porting Tablix and G-Tablix to Windows Vista instead of Boštjan and me :)

This is from nixbit.com, one of the hundreds of "free software directories" that popped up recently on the net and that are disgustingly full of adds. The funny thing is that the download link doesn't even point to the Windows port of Tablix...

This is printed circuit board for Galaksija's motherboard. I've made it this weekend out of a Bungard presensitized board (the black areas on the photo below are parts where I tried to fix damaged photoresist with a marker).

Unfortunately this material had different properties than the board I used for the keyboard. I should have figured out something was wrong when I saw that the photoresist was brown, not purple and smelled differently.

It seems that 4 minutes exposure under my 500W halogen lamp wasn't enough and after developing there was still some photoresist on the exposed parts of the board. I tried to compensate for this by leaving the board in the etching solution for some more time.

The results aren't encouraging. While the quality of the exposure (sharpness of lines and alignment of solder and component masks) is pretty good there are a lot of holes in the copper that shouldn't be there. It looks like the photoresist got scratched.

This pretty much makes this board useless. I can't make a prototype with a PCB for which I can't be reasonably sure that it is flawless.

I guess it's time for plan B.

Note: I was writing this in very early morning on 30 December.

I'm currently on train to Munchen. Unfortunately I haven't been able to stay in Berlin for the whole duration of the Congress (this year it's also one day longer - the closing talk will be later today). So far I've mostly posted photographs and didn't write much about my general impressions of 23C3. Now I have several hours to waste on the train and I intend correct that.

Comparing with 21C3 I can say that there were fewer really interesting talks. From the titles and abstracts in the Fahrplan I must say that I expected more. However this may be just because 21C3 was my first visit of such an event and I was mostly amazed at everything I saw then. Anyway, here are some of the most interesting talks I've attended:

Detecting temperature through clock skew by Tobias Gruetzmach was a quite impressive demonstration of how the minute effect of the temperature on the resonant frequency of quartz oscillators can be exploited to track machines on the internet, detect honeypots and even communicate between machines in a rack (defeating the so-called air-gap security).

In the talk How to build a complete FPGA-based DVB-T transmitter Tobias Gruetzmach and Thomas Kleffel also presented a DVB-T (terrestrial digital video broadcasting) system they designed. It was a very interesting introduction into how DVB works and they also showed how relatively simple transmitting equipment can be made for much less money than the cost of professional equipment.

I've already mentioned the Sputnik project in one of my previous posts.

In Console Hacking 2006 Thomas Kleffel presented the state of the art in game console hacking. It's an interesting topic because consoles like XBox are systems that are designed specifically to prevent any tampering and employ a number of intriguing hardware features to achieve that. The talk unfortunately left an impression that the manufacturers are beginning to get more successful - none of the last generation of consoles can currently be modified in a convenient way to run home-brew code.

Finally, Functional body modification by Quinn Norton also deserves to be mentioned. Although not exactly my field of interest, it was impressive to listen about her first-hand experience with a magnet implanted in a tip of one of her fingers. Although I'm a bit skeptical whether this will become a normal thing for people working with electronic circuits in the near future I can certainly agree that it would be quite useful if you could sense electromagnetic fields with your bare hands.

Some notes on the hardware I saw around the conference: two years ago I was surprised at how many people had Apple laptops. This year I believe other brands of (x86) laptops were again more common, however I would estimate that approximately one quarter were still Macs. On the other hand I was surprised at how often I saw Nokias 770. Obviously all that excitement of Gnome developers over this little Linux-running computer had some results.

The theme of the Conference was Who can you trust? remember? Well, at least one participant had some advice to share on that topic. He had the following text written on the back of his T-shirt: Who can you trust? Trust us!

Here are some interesting signs that can be seen in Congress Center:

NOC (our Network Operations Center) had some problems yesterday with the uplink. This is the picture of their whiteboard when they were trying to get the link back up. Just left of the board and not on the picture was a sign "NOC needs more beer".

This is the announcement of the German Government Initiative for keyboard use. Translated to English it says: Over 70 million Germans do not use a console. Do not click yourself away.

Today I received a mail with a very interesting subject: Hi, pancake plant.

Unfortunately the body of the message was a fairly standard advertisement for questionable medicines. Well, at least they tried to be innovative .

Yesterday I saw the prototype made by the One Laptop Per Child Project. It on displayed at the Wikipedia booth (I've heard that it was brought there by Samuel Klein, a veteran wikipedian who joined the OLPC effort a while ago).

My first thought after I've seen it was how small it is. It's barely half the size of my 12" Powerbook. Unfortunately this prototype didn't have the revolutionary LCD display they are planning for production models (or at least I haven't found a way to enable the back-light-off mode). The user interface is quite confusing - it's completely different from any other desktop environment I've used. I've watched some demonstration videos that were published by the OLPC team some time ago and still I didn't know how to do anything with it.

The center of attention in the Art & Beauty section of the Congress are again various things made out of blinking LED diodes. This year people from the Lochraster joined people from the Blinkenlights project which I remember from the 21C3.

Here's the newest invention from the Blinkenlights project: the Pocketlights. This beta version disintegrates when picked up but the final version should enable you to bring LED displays where none thought possible :).

This is a complicated simulation of one of the simplest toys. Unfortunately you can't see how it works from this (terrible) still picture. It has a two-axis accelerometer and simulates a tiny ball placed on a flat surface. The position of the ball is indicated by a lit led on the dot-matrix display. The final effect is that you can move the pixel by tilting the circuit.

This is the back of the shirt worn by Martin Ongsiek, author of the Borg 3D. It displays scrolling text on a dot-matrix display.

This is Borg 3D. I've seen its simpler predecessor on 21C3. It's basically a 3D display made of LEDs in a metal wire matrix with 8x8x8 pixels. It's controlled by an Atmega microcontroller which drives the display with the help of some multiplexing circuitry (multiplexer "rows" are connected to 8 horizontal planes of LEDs and "columns" are connected to 64 vertical columns).

The conference started today with the keynote about trust in the hacker community by John Perry Barlow from the Electronic Frontier Foundation.

Here are some of the most interesting things I've seen today:

Sputnik is an active RFID tag that contains a PIC microcontroller and a 2.4 GHz transceiver. It's firmware is free software and can be programmed for a number of purposes. There is a live demonstration running currently here in the Berliner Congress Center where the location of each tag (they are selling them for 10€) is displayed on a screen. The location is determined with a grid of receivers that send signal strength data to a central server that then triangulates the position.

This thing is on display in the Art & Beauty part and projects a live video stream to a shaped white screen. The result is a kind-of three dimensional projection of some of the places in (I think) Berlin - the buildings look like textured objects in a computer game while people on the streets are like sprites painted on the floor..

The 23rd CCC starts tommorow. Tickets should have been available since 18:00 but it seems there are some problems because there's a big sign saying that maybe they'll start selling them around 20:00. I'm currently sitting at the Congress Center and trying to publish this through a half-working wireless connection (there's a gigabit switch right in front of me but it doesn't seem to be working right now).

Anyway, here are some of today's pictures:

We had a miniature LAN party on the train from München to Berlin.

I'll be on board the train to Berlin in a couple of hours.

There will be a lot of interesting things going on in the 23rd Chaos Communication Congress. First of all some free software groups will be present there: for example Debian (I look forward to leaving a few euros at their booth in exchange for a badge or something - they deserve it) and GIMP.

The Fahrplan also contains a lot of interesting talks. I'm also happy that there aren't too many talks on the schedule I wouldn't want to miss - this way at least I'll also have time to meet some interesting people.

Anyway, I'll try to post here some highlights of the next few days. I just hope that I'll get net access. I've heard that the wireless network actually worked last year and I'll also bring an ethernet switch with me in case I'll have to stick to the wires.

I must again admit that I was again defeated by spammers. My clever plan to use bogofilter to separate real comments from spam wasn't exactly successful. Here are some reasons why:

• Spammers got sophisticated and inserted random prose into comments (just like they're doing it in email these days.
• Sheer amount of spam bots browsing the site was quite a load for my limited net connection.
• Spam comments were still available through the link show comments marked as spam and were so still indexed by Googlebot. Although the comments contained no links I still don't want my site to be known to Google as a giant advertisement for questionable products. It wasn't possible to prevent Googlebot from going through these comments with robots.txt.

Currently I just don't want to bother with this any more. I feel I already spent way too much time trying to find a way to get comments working on this site without spam (and without CAPTCHAs) and honestly I just don't think it's worth it. If you have a comment, just send it by email (I'm already used to getting tons of spam there).

Cyberpipe's computer museum got some pretty impressive hardware earlier this week. I've had time today and went for a quick look.

It looks like this thing can actually run Linux. However somehow I doubt that you can stick a Ubuntu Live CD in it - at least I haven't found anything resembling a CD drive. You probably need a 2 month beginner's course just to find the master On/Off switch.

More pictures.

This xkcd comic reminds me of an evening a few weeks ago.

Except that the OS was Mac OS X (which doesn't give you the tools to save your date) and I ended up moving the mouse every 5 minutes for the duration of the movie.

Later I found out that Require password to wake this computer from sleep or screen save option in Security preferences caused the screen saver to come up even when a DVD was playing.

I'll be using laminates made by Bungard for Galaksija's printed circuit boards (they were the only ones I could get that were big enough for the motherboard). I usually buy plain laminates and coat them myself with Positiv 20, but these laminates come pre-coated with Bungard's own photoresist.

I was pleasantly surprised at the quality of the coating (when I bought these plates I thought I would remove the factory coating and apply my own). It is much more even and has less flaws (dust particles, etc.) than what I could ever do with Positiv 20 on such a large surface. I also found out that the photoresist's properties are a bit different than what I'm used to. Here are some notes that might be useful for anyone else using this material:

Exposure

4 minutes under a 500W halogen reflector 30cm away. Exposed parts of the photoresist turn green just like with Positiv 20.

Development

The usual concentration (4g NaOH per 500ml water) seems to be to low. I used 10g per 500ml and it took something like 10 minutes to fully develop. Bungard also offers a special developer that isn't based on sodium hydroxide.

Etching

Photoresist seemed to hold fine in the HCl / H₂O₂ solution I use.

Here's a fine example of targeted advertising at work:

Searching for a gift for a technologically inclined person? Here's a suggestion: Buy him or her a mop and broom rack!

I just tried to order some electronic components through one of the Slovenian electronic web shops (I've been in their real-life shop yesterday, where they've told me that I will get my stuff a lot faster if I order it from their web site).

So when I got to the page where I had to enter my name and address, their super advanced software told me that I've made a mistake in my title (Red text says: "Your title does not match your first name. Please check your data." There are two choices for the title: "Mr" and "Ms" and I've chosen "Mr").

So, if their software is smart enough to figure out my gender better than I can, why do I need to enter it myself? Interestingly, I always thought my first name is a male name.

My experience with this shop went mostly downhill from there. The last straw was when they expected me to enter my credit card number on an unencrypted page (however they did display a fancy-looking long hex number called a "data security fingerprint" - it probably makes them feel all fuzy inside, I'm just not sure how that number would prevent my data from getting into wrong hands).

I guess I'll continue to buy my electronics the old-fashioned way.

I will make sure that my doomsday device is up to code and properly grounded.

-- from Peter's Evil Overlord List

Everything is not as smart as you.

-- Megahal v8r6, POSIX time 1164319354

Two weeks after I enabled comments on this page (and after two actual comments posted), I caught the first (futile) attempt to exploit an XSS vulnerability in my comment system. This is quite an improvement over my previous try with the stock cgicomment installation which took only a couple of days before bots started posting unmanageable amounts of spam and other nasty stuff.

Hi, Jonny. You'll have to try harder than that this time.

Today I went on a tour of the power plant Krško, the only Slovenian nuclear power plant (the trip was organized by EESTEC).

We weren't allowed to bring anything with us on the tour (hence a lack of pictures of the most interesting stuff in this post). They also performed some kind of a biometric scan of my right hand, gave me a temporary RFID tag and assigned an armed guard to each group of visitors. No dosimeters were given though (like when I visited the small research reactor in Podgorica a few years ago). But then we also didn't visit any of the areas where they handle radioactive stuff.

A model of the fuel bundle that contains pellets of enriched uranium oxide.

They gave us a complimentary nuclear power plant starter kit containing three (fake) fuel pellets. Now I only need some 7 million more of them to get enough for the whole bundle :)

Our guides really took their time and answered all of our questions, even some that probably weren't very pleasant from their point of view. It seemed to me that they are working hard to present the power plant to the public in the friendliest way possible. They explained the basic principles (Krško uses a PWR-type reactor) and also told us quite a few things that were surprising to me.

• Every physics book I read says that the power output of the reactor is controlled by moving the control rods in and out of the reactor. I learned that this isn't so, because having control rods only partially inserted would burn the uranium fuel at the bottom of the reactor faster than at the top. This is a bad thing (they try very hard to keep the reaction rate constant throughout the volume of the reactor). So a better way to do this is to vary the concentration of a neutron absorber in the coolant. Rods are only used for fast changes (like in an emergency). Interestingly the Wikipedia article linked above gets this right.
• The plant was designed by the Westinghouse company, while the actual work was done by workers and specialists from local (then Yugoslavian) companies. The design specifications were so strict that all markings on the equipment, pipelines, etc. are in English. For example even the color codes of the wires used in the buildings are according to American standards instead of European. I'm surprised they managed to adapt the plans to the 50 Hz frequency we use here :)
• Hruske writes how nuclear power plants run on QNX. Krško actually doesn't run on anything. All control loops are still implemented with analog electronics (which is considered a Good Thing by the maintenance engineer I talked to). They recently installed a new digital monitoring system though. It runs on some software that nobody there actually knew how it was called (but they all agreed it wasn't Windows). The main control room is full of switches, analog gauges and warning lights.
• New fuel elements are transported to the plant from USA first by a ship and then by trucks. A couple of times they also flew them in on an airplane. It's interesting that usually our newspapers are full of reports how a convoy of trucks carrying nuclear fuel will be traveling through this-or-that distant country but I never seen an article about how they transported fuel for Krško. On the second though this may be a good thing or there would be people chaining themselves to trucks and things like that.

I've just blacklisted the following blocks of IPs on mail.tablix.org:

196.217.0.0/16
196.206.0.0/16
41.250.0.0/16

According to the Whois database, they all belong to some Moroccan ISP.

Last week I've been getting incredible amount of spam from there. I can handle spam sent to my personal email account (it gets filtered anyway), but these guys have been sending spam to the tablix.org's mailing list manager address with my address in the Sender field. That way I got some 200 bounces from my own machine telling me I issued a wrong mailing list command.

Luckily they only used my address. I would hate to think that other people would be getting such mails from my server because of some stupid spammer.

So, if you're from Morocco and can't send mail to any mail accounts at tablix.org, go bug your ISP or something. I'll try to remove the blacklist entries when I don't see any rejected messages in my logs for a month or so.

By the way, these IPs are from the same block as those that caused problems with the mailing list manager this June.

Almost every single time I hear a discussion about the OLPC project somebody says that people should focus on providing food and other things that are more urgently needed by children in undeveloped countries before giving them a computer.

I think that this comment on Slashdot should give those people some idea why such arguments don't hold water.

Hello, world!

First post using Nanoblogger 3.3RC5.

RSS feed seems to be broken. Sorry, will look into that soon. Upgrade also changed the URLs of all archived posts. On the other hand I can now enable user comments.

Please report any broken links. Thanks.

My recent work on the redesign of the Galaksija computer reminded me of some old books about Spectrum I have on my bookshelf. One of them is the The Complete Spectrum ROM Disassembly. I never actually read it before. Back when I was playing with Spectrum the lack of pictures and confusing assembly language was enough remove all my interest.

Now when I'm reading it, I am surprised at how much has changed since then. Here is a book with the complete contents of Spectrum's ROM (its "operating system"), together with detailed commentary for each function and each line of code. All that from authors that were not affiliated with Sinclair in any way (as far as I can see from the book).

Publishing a book like that today would probably be like taping a big sign "Sue me" on your forehead. Reverse engineering is not something people usually like being connected to (not to mention that it can be even illegal in some weird countries). It is either done in laboratories of big companies (from which you don't hear much but I'm sure they exist) or more or less anonymously on various internet forums (just look for example at game console modders). Imagine how a XBox complete ROM dissasembly book would be welcomed by Microsoft.

In a few days I will stop receiving mail sent to my old email address tomaz.solc@siol.net.

So, from now on please send any mail to my new address (replace siol.net part with tablix.org).

In case you don't know already:

I've managed to read those old floppies without errors and I've put the contents on-line. You can download them from here.

All games more or less work in DOSBox. Nethack has some problems with display (it says it needs some driver loaded in config.sys to work correctly). Spacewar works best if you use Hercules emulation (dosbox -machine hercules)

To run Ranadinn in DOSBox, follow these steps:

1. Run DOSBox: dosbox -machine hercules
2. Mount C drive in DOS: mount c /path/to/ranadinn
3. c:
4. Run SIMCGA (for some reason DOSBox CGA emulation isn't good enough for this games): simcga40.com
5. Run Ranadinn. You will have to type this blindly because SIMCGA messes up DOSBox' prompt: ranadinn.com
6. Enjoy.

I just found this set of 5¼" floppies with shareware games on them. I remembered that my father bought a couple of these many years ago.

We had a 286 computer with monochrome graphics at home back then (our first Intel compatible). It was made by Mlacom, a Slovenian computer company that still exists (although I think they lost all good reputation by now).

These disks contain three games: Ranadinn was a graphical role-playing game (there's a screenshot on the cover) where you wandered around in forests, entered cities and usually died of hunger after playing 5 minutes. Spacewar was something similar to KSpaceduel. Then there was Hack, a predecessor of NetHack.

Apart from multiplayer Spacewar I don't remember playing these games a lot. That's interesting because Nethack is now the only game that I still occasionally play. It seems that I met my favorite Unix game long before I even knew what Unix and internet was.

I wonder if these disks can still be read. I don't have a 5¼" drive at hand so I can't try them out.

Previous weekend we removed a large window in the room with my server because some wooden parts of the roof had to be painted.

It's interesting how this was reflected on the lm-sensors graphs. The CPU has a temperature controlled fan installed, so its temperature is nearly constant. The "system temperature" (I don't know where this is measured on this motherboard) on the other hand fell for almost 10°C during the night.

What Colour are your bits? by Matthew Skala is a very interesting article about the so-called intellectual property and copyright of data in digital form. It explains in a simple way why copyright is a purely subjective matter without any logic background and why people that do not have a background in mathematics and computer science usually do not see that.

The Monolith project (linked from the article) is also worth a look.

Believe it or not, this is an automatic cat feeder constructed by my dad and my uncle.

The electronics is made of a modified light timer, battery charger, 12V sealed lead battery and some custom electronics. It is fully programmable and can cope even with the most complicated diet a cat can have.

The food is dispensed by an old drilling machine that opens and closes a valve in the stainless steel container.

• Loot: $152
• DHL shipping: $70
• Having to explain to the customs officer what a generic humanoid carbon unit is: priceless

Seriously, Thinkgeek should give better descriptions of the package contents to the DHL. T-shirts, for example, were labeled only by the text that is printed on them. There was no obvious sign that the package contains apparel and not some weird organic stuff. The same goes for the plush microbes. The customs officers would probably understand the English word "toy", but "giant plush kissing disease" probably rang some alarm bells. So I had to describe each and every item in the package to the (otherwise very friendly) customs officer.

But I guess it could also be worse. After all, the package also contained stuff that could be misidentified as a plastic explosive, an ignition device and a book with "for the evil genius" in the title.

OTP-EPROM: One Time Programmable Erasable Programmable Read Only Memory

You are likely to be eaten by a grue.

Seriously, this scene from the Mahorčičeva jama near Škocjan reminds of old style adventure games. You know, the ones where you would have to go back to the village and give this-and-that to the local carpenter so he can then give you some planks which you could then use to repair this path and get to the next screen.

I'm waiting for my bus to Birmingham which leaves in approximately an hour and a half and I'm slightly bored. I've been browsing through my photographs and I found this photo of a poster I saw in a window in the administration building. I guess Japanese animation also has its fans in Lancaster.

It was really nice staying here and I hope I will come back soon.

Every time I go to sleep in my room and turn off the lights I get the impression of seeing little points of light on the ceiling. They look a bit like stars on the night's sky, but are a lot fainter.

At first I thought it was only my eyes adapting to the dark. But once I turned off the light when I was still standing and the lights remained on the ceiling, not floating in front as a typical residual image on the retina. I decided to investigate this further.

First I had to make sure this wasn't some kind of an optical illusion. I took my digital camera, put it on my bed facing upwards and set it to maximum sensitivity (ISO 800) and longest exposure time (4s). I then took two pictures: one with the protective cap on the lens and one without the cap. This way I could then remove any camera artifacts by subtracting the first image from the second. Following is the resulting image:

There is still a lot of noise in the image, but you can clearly see some green dots. These dots are larger than one pixel across so I guess they can't be caused by CCD sensor noise.

So if this is not an illusion, what is it? I can't see any significant features on the ceiling when the light is turned on. It could be light from a room above coming through the floor. This would be possible if the ceiling would be wooden and had cracks in it, but as far as I can see, the building is concrete and also all rooms have thick carpets on the floor.

Another possibility would be that the ceiling finish contains pieces of some phosphorescent material. I believe this is more likely, since I don't remember seeing these dots when I wake in the middle of the night when the light has been switched off a couple of hours. However in that case it is weird that the dots only appear above the bed. I looked for them on other parts of the ceiling but haven't seen any.

I think the following advice should be added to the next revision of the Lonely Planet guide:

Do not photograph large buildings standing in the middle of nowhere. It may turn out that one of them is a nuclear power station and then otherwise friendly local people start to ask weird questions like "Are you going to blow it up?".

In my case, it later turned out that I had found the Heysham power station while walking along the coast from Morecambe. I guessed it has something to do with large amounts of electrical power since there was a large high voltage line coming out of it, but as far as I knew it could have been a fish processing factory (I could see no cooling towers or containment buildings that you usually see near things that run on nuclear power). Anyway, only the third person I asked actually answered me what the building is (right before asking me back what my evil intentions are). The previous two just looked at me suspiciously.

Last Sunday I went to Lake District with my supervisor and two other professors from the Department of Physics. We had plans to go hiking, but it turned out we were a bit short on time because we had to go to Manchester in the evening. So in the end we only went for a short walk around the Castlerigg stone circle. Any way, the view very still fantastic.

Lake District is a national park in Cumbria, north of Lancaster. I guess the name is quite appropriate because basically every deeper valley between hills is filled with water. The mountains aren't very high compared to what you see in Slovenia and you hardly see any exposed rocks. If there's no grass the rocks are covered with moss.

The weather changes very rapidly here. In an interval of two hours it went from snow through rain to a clear sky and back to rain again.

This is the view of some of the higher peaks from the Castlerigg stone circle.

University underpass (bus for Lancaster city center stops here).

Somewhere between Engineering department and Grizedale college.

A view of Grizedale college from the building I'm staying in.

Yesterday I finally got internet access here at Lancaster University. It took me three days to find the proper way of doing this: first I tried to get my Eduroam account working here (University's web page said that visitors should use it to get internet access), but after some phone calls and visits to various help desks it turned out that the English Eduroam database isn't actually connected to the continental one. So much for the universal access provided by Eduroam.

Now I have a temporary computer account for visiting students and for which I got some 15 pages of instructions on how to use it (it includes stuff like email, Unix shell and Windows accounts, storage space, etc.). So far I figured that the internet access I'm used to doesn't exist here - web traffic is only allowed through a proxy (which may be monitored and/or recorded). Anything that is not HTTP traffic is mostly filtered out. Email for example is only allowed through their official web interface (SMTP port is blocked). Luckily SSH appears to work.

Here are some pictures of the room I'll be using for the next two weeks. It has a network connection (20-something pounds per day extra if you want to use it - I don't), phone (I don't even want to know how much that costs) and a cleverly placed electrical socket behind the curtain, which I only found yesterday.

This is an interesting way of forcing the user to use as little hot water as possible. Give exactly two choices: cold or scalding hot water. Guess which one you're going to use? Oh, and the green faucet is for the hot water.

At least they tell you about it...

Fabricated using 1.2 micron CMOS technology, this chip holds a unique Cyberpipe logo on the 3rd metal layer. The logo measures approximately 20 μm on the side and is located over some of the digital signal lines entering the integrated circuit in hope of guarding it from the bad carma outside.

The chip is a must-have (in much the same way as the CP Cap) for any Cyberpipe member and is available for sale at the manufacturing price of 2.5€ per die. Only one wafer of these one-of-a-kind chips have been fabricated, so hurry while the stock lasts.

Yes, this was a joke. The image was made in GIMP, using this microphotograph as background.

My server that runs services at tablix.org will be down tomorrow for a few hours because of a number of hardware and software repairs. DNS resolving problems, bounced emails, unavailable web pages and all sorts of other weird phenomena can be expected.

It turned out that my EN-X temperature control circuit has a bug and can burn out one of the operational amplifiers if you turn the temperature setting knob too fast in either direction. This problem didn't look very serious when I first noticed it a few months ago because temperature regulation still seems to be working. However I'm not really happy with one of my machines running with a half-working CPU fan. And since I now also have a list of some other tasks that involve a reset (like a kernel upgrade and some UPS rewiring) I decided it's finally time to trow away those 200 days of uptime.

My refrigerator light bulb works better with the door closed.

-- jcostantino on Slashdot

Robotfindskitten (apt-get install robotfindskittten on Debian) is another free software game with a profoundly deep background. The similarity of the default user interface with Nethack is just another plus that adds to the experience (although there are a lot of other interfaces available, for example a fancy 3D accelerated OpenGL port for the ASCII challenged).

"GO!" I told the box as it began to roll out of my workshop into the frozen desert beyond. "FIND KITTEN!"

-- The Book of Found Kittens, pages 43-4, author unknown

Good stuff :)

While I agree that these videos look really great and all I think GNOME developers should really take John Williams' proposal seriously.

Making "an intuitive and attractive desktop" isn't only about removing some buttons from dialog boxes and reordering the rest. A usable desktop is also a desktop in which you don't have click through a couple of error messages before you can begin working.

Such a desktop also doesn't replace a working PDF viewer with a broken one just because the latter is "simpler and more convenient".

Compare a PDF document in Gnome 2.10:

with the same document in Gnome 2.12:

LEGO Technic difference engine

GNOME Bugzilla presents the Ultimate Bug Report.

I have just found an amusing little program by Taper Wickel on my (half-broken) hard disk. It uses some simple math to predict how long it will take for humanity to destroy itself. And if your simulated little earth manages to survive the next 500 years (which in my case is yet to happen) you win.

It's a fine replacement for fortune in your .bashrc.

Here is the link to source (it is in the public domain). Have fun.

Last August a 6 year old 13GB Seagate Medalist failed in my server. In October, a 5 year old 30GB IBM Deskstar failed in my desktop.

Now, my desktop won't boot from a three months old 200GB Western Digital because of the infamous { DriveReady SeekComplete Error }

Before August, none the disks in my machines have ever died. Should I expect this row of failures since I was cheating on the specified mean time between failures for the drives I have been using?

The road to hell is paved with NAND gates.

-- J. Gooding

I still can't find the cause of XKB error messages, but I'm getting close.

I suspect there is a race condition when something runs xkbcomp to compile the XKB keymap, but I can't find who exactly is doing that. After going through the source or gnome-settings-daemon, libgswitchit and libxklavier I filled a bug report at Debian BTS.

To be continued...

This is the condition of the road to Javornik near Črni vrh (that round thing is the top of a road sign).

One fact about computers that even technical people often forget: The job of the computer is to make your job/task easier - it is not the other way around.

-- Joeytsai on Slashdot

My friendly incompetent internet service provider is again blocking all external mail traffic. So don't be surprised if you can't send me a mail or use one of the mailing lists at tablix.org.

This time I'll restrain myself from calling their support line. Everytime I call and complain about mail problems the marketing droid on the other side wants me to open my Dial-up networking properties and Outlook express settings. After I tell him that I don't have this stuff on my machine and that their mail server is returning 450 Unable to find domain after MAIL FROM SMTP command he simply rewinds his tape and starts again: OK, I understand. Now click on the Start button and open the Control panel...

After some reading of the stuff in /usr/share/doc/udev I found out that putting lp into /etc/modules brings back the lp0 device. Suddenly things don't look that bleak anymore.

Still have to figure out how to get /dev/ttyS0 and friends back though.

It's almost midnight, I've just spent 5 straight hours writing a report for one of the term projects I've been working on and now I just have to print it.

No problem. I click on the Print button, but the printer remains silent. Great, why must things always break when you need them the most? Some 5 minutes later, I dig out this from /dev/log:

Jan 18 23:38:50 orion lpd[9645]: /dev/lp0: No such file or directory
Jan 18 23:39:30 orion lpd[9669]: /dev/lp0: No such file or directory
Jan 18 23:40:18 orion lpd[10641]: /dev/lp0: No such file or directory

WTF?!

Ok, no problem. Some broken script obviously wiped out some of my device files. Luckily, I still have MAKEDEV, right?

orion:/dev# MAKEDEV lp
.udevdb presence implies active udev.  Aborting MAKEDEV invocation.

Argh. So MAKEDEV thinks that udev should take care of device files and udev obviously only cares about fancy new stuff like USB and Firewire. How on earth am I supposed to use my printer on the parallel port? I don't remember the major and minor numbers for the lp0 device and I don't feel like greping the kernel source right now. Maybe there's another lp0 somewhere?

avian@orion:/dev$ locate lp0
/home/avian/morphix/live/dev/lp0

Finally! I knew that all that junk in my home directory will someday turn useful. A quick edit of the /etc/printcap and the printer begins churning out first pages of my report.

I guess it's time to switch to CUPS or something.

Today was the last day of lectures in my five year undergraduate study program. Basically this means that I'm getting near the end of step one in the three-steps to profit of the new economy:

1. Study
2. ????
3. Profit!

The only problem is that I still haven't quite figured out what step two is supposed to be.

I heard several (mostly older) people say that the electric current is "stronger" in the evening. This was usually said in reference to cooking on electric stoves - for example you need to set the stove on a lower setting in the evening to get the same effect as with a higher setting in the morning. Recently I got into an lengthy argument about whether this is true or just an urban myth, so I decided to check it myself.

The UPS on my server keeps logs of the RMS voltage in the electricity distribution network so this seems to be a good point to start.

As you can see the voltage in the socket can vary as much 15V during a day and is far from the declared 240V.

On the other hand the digital voltmeter in the UPS can't be trusted, since it wasn't designed for such precise measurements (its only purpose is to tell the UPS when to switch to battery power). Because of this I double checked these values with a true-RMS voltmeter and it looks like the UPS measurements are constantly off by 10 volts (UPS shows 228.0V, voltmeter shows 238.0V), however the relative values seem to be quite accurate.

So let's say that I want to boil 2 liters of water on a 1kW electric stove. Such an electric stove has a heater with resistance of R=(240V)²/1kW=57.6Ω. To heat 2 liters of water from a room temperature of 20ºC to 100ºC you need Q=m·c·ΔT=4200J/kgK·2kg·80K=672kJ of heat. If the electric stove is operating at its declared power it will provide this quantity of heat (if we ignore the heat loss) in t=Q/P=672s=11.2min.

Now let's see how much time it would take to boil the water if we take into the account the swings in the line voltage. The graph shows that the lowest voltage measured is 222.2V. This is U_min=232.2V when corrected for the UPS measurement offset. At this voltage, the stove has a power output of P_min=U_min²/R=936W. It will heat 2 liters of water to boiling point in t_max=12.0min.

On the other hand the highest measured voltage is U_max=247.5V. This gives the power output of P_max=1063W and the water will boil after t_min=10.5min.

The maximum difference is obviously 1.5min or around 13%. This is value falls somewhere in the middle: I can't say that I would notice if the water for my spaghetti would begin to boil 90 seconds too early, but it is quite possible that some people can notice that. On the other hand most modern electric stoves have thermostatic control. This means that the temperature of the stove is controlled with some kind of a feedback loop. This loop should attenuate any effects of the line voltage swings to such a degree that I'm sure noone could notice (even if with a stopwatch I don't think you could measure any effects but I'll try to prove that at some later time).

Happy winter solstice everyone.

It seems that with the recent addition of Tablix package to Debian Unstable, http://www.tablix.org finally became the first hit on Google for tablix. Until now the first hit for this query was the old page at www.kiss.si which only contains a link to the new page.

It took 10 months for Google to find out that the page has moved, which is kind of interesting. Also interesting is that Tablix Systems, which appears to be a Danish software company that has nothing to do with my timetabling software, barely gets on the first page of results.

Tablix is now also the 19th hit (second page) for query timetabling, a great deal behind FET, a free software project similar to Tablix, which is