Avian’s Blog

I guess my mail server is still a pretty quiet corner of the internet. Comparing to some scary statistics I saw recently on planet.debian.org this amount of spam is pretty tolerable. Unfortunately there is this rising trend that worries me.

Bogofilter works great by the way. I occasionally get one or two spam mails in my inbox and I haven't seen a false positive in almost a year.

Sometime ago I mounted the disk drive in my server on Cooltek rubber mounts. The hard disk was the loudest part after I installed a silent power supply and my CPU fan regulator.

Previously the heat was conducted away from the disk through contact with the metal case but that isn't possible now since there are two centimeters of rubber separating them. So the only way left is by air convection which is less efficient. To see just how much effect this would have on the drive temperature, I started monitoring drive temperature with SMART a few days before I installed the rubber mounts.

This is the temperature graph before:

and after the modification:

The spike on both graphs is when I stressed the disk for 3 hours using a tar command in an infinite loop.

You can see that the rubber mounts caused at least 4°C temperature increase. I believe 44°C is already a bit high (at least according to this Google paper) and it's was quite cold these days. According to SMART this disk already got as hot as 43°C sometime in the past when it was still screwed directly to the case.

I'll keep monitoring the temperature but I'm afraid this isn't going to work well in the summer.

Yesterday I went to Frisk, a "festival of computer science and modern communication" in Murska Sobota. Here are a few impressions:

This is the main hall - it was raining outside so people were gathering here instead of the open atrium that seemed to be prepared as a center of the event. Plus you could play some more and some less modern games here (there was one old PC and one Commodore 64 available).

At the back wall there was one Wii (left, surrounded by a loud crowd that was obviously having lots of fun) and one Playstation (right, with two guys nervously playing a FPS). The situation reminded me of a certain xkcd comic.

There was a talk about Apple on the schedule with an interesting title but boring contents (item by item description of their product line). Never thought I would see a room of people watching Apple "Hi, I'm a Mac" commercials on the big screen.

Last but not least there was an exhibition of old computers (some of which were from Cyberpipe's computer museum). It was the best part of the festival in my opinion, but not much I haven't seen before.

In the end I can say that it wasn't worth spending 8 hours on a train to get there (average speed was an amazing 40 km/h - hey at least nothing broke down). I did plan to make a short trip around Murska Sobota besides visiting Frisk, but the weather made that more or less impossible.

Yesterday I watched the BBC documentary Tetris: from Russia with love.

It was the first documentary in a long time that I enjoyed watching on TV. In constract with things that are called documentaries today it has more than 5 minutes of actual content, tells an interesting story and the narrator doesn't sound like he's commenting on a football game. Seriously, I don't know how anyone can stand watching an entire 1 hour show on Discovery or National Geographic channels when you see all original footage in the first 5 minutes and the narrator just repeats over and over again how this or that is awesome and/or extremely dangerous.

There are two things though that I missed though: I don't know if that was the fault of Slovenian broadcaster removing the original overlays, but when someone is talking to the camera I'm used to seeing his name printed somewhere on the screen. Only at the middle of the movie I connected all the faces with their names.

They could also be a bit more specific about technical details... What was that russian computer called on which the first version of Tetris ran? I'm quite sure I saw a screenshot of Sinclair Spectrum version of Tetris for a moment there, but all hardware was described only as "computers" or "consoles", not with specific names (except for Gameboy I guess).

Guess which operating system handles your cash?

(seen today in Ljubljana)

I found a video demonstrating how to use a glowing graphite pencil lead as an emergency light source. It seemed like a fun experiment to try. Unfortunately I didn't have a charged 12V car battery at hand. I started charging one and meanwhile tried the same thing with a 5V lab power supply.

The original video uses an ordinary pencil lead which has a diameter of something like 2mm. Since the power supply I was using wasn't rated for the current that would flow through such a thick rod of graphite I used a 0.7 mm pencil lead instead.

In the video you can see that even with 5V the lead glows nicely. You can also see the way it degrades: the middle of the lead is hottest because heat is conducted away from the ends by the metal clips. Since graphite will oxidize/ablate faster at higher temperatures the center part gets thinner with time. This increases the resistance of the center which means that 1) less current will flow through the lead and 2) the center starts to heat more than the ends. It takes around 40s for the center part to become so thin that it heats so much that the graphite vaporizes and breaks the circuit.

The instrument on the left shows current in Amperes (actually it shows a voltage drop across a 1mΩ resistor hence the mV mark at the top of the display). You can see that the current is decreasing as the lead degrades. Interestingly, it does not seem to fall significantly while the lead is heating up as is the case with a metal filament in an ordinary light bulb. Electrical power with a fresh lead is around 30W.

The spent lead is shaped into a cone.

Grep Linux kernel source for Klingon if you don't believe me. This is from 2.6.18 (I just found it yesterday when I was browsing kernel documentation):

Klingon language support
------------------------

In 1996, Linux was the first operating system in the world to add
support for the artificial language Klingon, created by Marc Okrand
for the "Star Trek" television series.

...

Some nice photographs of a circuit I have on my bench right now:

Google's bot did more than a gigabyte of traffic on tablix.org in a couple of days. What the hell is going on here?

From the logs it appears that it has been downloading and re-downloading my Galaksija demonstration video. I'm moving it away for now.

I usually recommend using Wikipedia. However today I found an example why you should still be skeptical when reading its articles:

While Gasoline-powered ICE cars have a fuel efficiency of 30%, steam engines are capable of 90% efficiency.

Well, I guess that's why all cars today are powered by steam engines, right?

Here's another gem from the talk page (some people there expressed doubt in the these figures on grounds of laws of thermodynamics):

I won't enter into this arcane "efficiency" debate, a time-honoured red herring that does not begin to explain why steam cars have always given a very good account of themselves when compared with internal combustion as regards fuel consumption, and emissions-wise have generally proved far superior. Surely this begs more searching questions as to why this should be in spite of all this "received theory"

There's also this British steam powered car that requires a 4 MW engine to reach 320 km/h. I think that says enough about efficiency of steam engines.

The new version of GNU General Public License is getting close (final draft was released by the FSF one week ago). There is quite a lot of discussion going on, so here are my two cents:

Since I read the first draft I've put all free software I released specifically under the GPL v2 (without that "or any later version" sentence - I hold the copyright so I can change the version later anyway if I change my mind). The reason for this is quite simple: I don't want to use a license if my understanding of it is based only on other people's interpretation. I want to read it and understand it myself.

Now, maybe my reading comprehension of legal documents is below average, but at around 5600 words the GPL v3 draft is too heavy for me. I understand some parts but I don't see the whole picture. On the other hand I have a feeling that I understand 2900 words of GPL v2 and that I know exactly under what set of conditions I allow redistribution of my code.

For a list of all the ways technology has failed to improve the quality of life, please press three.

--- Alice Kahn

(via WikiQuote)

Telephone plugs in Belgium are weird. First, they are gigantic compared to the RJ connectors. Second, the socket will happily accommodate a standard European mains plug if you plug it in at an angle.

Hint: there's something wrong with this picture (and no, my laptop's battery wouldn't charge that way).

I can't stand people (like surprisingly many people from IT departments I've met) calling free software "freeware".

Call it free software, FLOSS, FOSS, open source, linux (yeah, I know) or whatever.

In my dictionary freeware is windows-only binary-only software that:

• Dies after one or two releases and no-one even knows it existed or...
• gets really popular after which it's no longer free (people loose interest) after which it gets adware supported (people start to hate it) after which it either gets free again or dies which disappoints both remaining users or...
• it is a part of some greater evil plan for world domination.

Click

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