Older blog entries for claudio (starting at number 66)

Umm. It seems that Mesa is very, very broken. My OpenGL robot simulator works fine with the TNT2 Debian box at school, but forgets to render some quads and quadrics in a software-rendering Debian box. In the Conectiva Linux box it gets all confused with the quad face normals but renders the quadrics.

Still in the TNT2 box (where the robot is correctly rendered) glReadPixels() doesn't work -- so I can't generate MPEGs. Half of the points of a starfield are not plotted. And it crashes sometimes. Yuck.

Tried to order a Timmy! t-shirt, but I won't pay $35 S&H for a $18 product! Blah.

RAPT works nicely! Now I want services stopped, started and configured automatically like in Debian.

Rivas are crap. I want an SGI box!

Blah. My name servers suffered a DOS attack and stayed down the weekend. If you tried to send me email you may have gotten an invalid domain error. This sucks.

More issues sorted out in the new xmp design: multiple file archives, individual component parameters, multi-depacker shortcut, and more.

Work on the PUMA 560 simulator is going well. Triangle-shaped trajectory tonight.

As a kind of manic-depressive, I'm in manic phase again, and it makes me very productive. I've been producing a lot at work, at school and at home. My new test box is almost up with several new niceties, the robot simulator is working, and the new xmp has better and better format support, through Pro-Wizard for UNIX and shd's UADE. Wow. UADE is really great! I wonder why the binary is so huge.

With one year delay, the South Park movie finally is in the local theatres. Satan was in the movie, and God let The Mole die! I watched it yesterday with chaos, Mrs. Chaos and Andreas. The Windows 98 scene was hilarious, and quite unexpected. Really really good. And we stayed in the room until the end of the credits (after everyone else left) so we could see Ike's grand finale with the mouse. Now I'd like to have a Timmy! t-shirt, but it's expensive! Hmm.

Woohoo. The serial chain dynamics simulator successfully followed a straight line in the space, at constant speed, using the kinematic and dynamic model of a PUMA 560 manipulator and a computed torque controller using Recursive Newton-Euler inverse dynamics computation. The forward dynamics can be computed using the Composite Rigid-Body Method (CRBM), or Walker-Orin method, and Roy Featherstone's Articulated Body Method. In the CRBM case we get the accelerations using a Cholesky decomposition followed by a second-order Runge-Kutta-Nyström integration. See the screenshots!

• Screenshot 1
• Screenshot 2

In both screenshots the path is marked by the yellow line (they're more visible in the full size images: 1 2). Ok, they're not perfectly straight, but that's caused by dynamic effects. At the end of the trajectory, for example, the robot can't stop immediately -- instead, it goes ahead for a few centimeters before stopping. Having the simulator working is so great. My advisor doesn't want to kill me anymore.

By the way: new pokey strip released. New characters. Lots of action. Don't miss it!

I want a lava lamp. And SMAC.

Following a holy war thread in a local linux mailing list, I realized that the religious issues about operating systems are quite complex:

Orthodox unixers follow the tradition, sync three times before rebooting, and use green or amber xterms running Korn or C shell. Ultra-orthodox believe that any software written in the last ten years is worthless, the mouse is an abomination and run Bourne shell in serial consoles. All good software comes in tar.Z packages. To Reformist unixers, any design more than a couple of years old is obsolete. They run bash2 in the latest fancy terminal emulator with the latest fancy window manager. All good software come in RPM packages.

The Libertarians won't allow any piece of non-free software in their disks, including Netscape, pine and mpg123. The radical faction won't allow anything that isn't GPLd. Earn money with software is a deadly sin. Mercantilists see free software as low-quality, bug-infested ugly crocks with no value at all, including Netscape, pine and mpg123.

The Obscurantists want the OS to be as cryptic and hard to use as possible. Anything that is easy to use is, of course, worthless. They don't trust anything they can actually understand. Documentation is evil, anyone who needs documentation is an idiot. And the Pragmatists want everything to be done at a click of the mouse, and end users who don't remember their own names should be able to get everything the system can offer. Documentation is evil, anything that actually needs documentation is non-intuitive and ill-designed.

The "real programmer" stereotype is an Ultra-Orthodox Obscurantist, while the clueless luser is a Reformist Pragmatist. Plotting these three scales in a 3D graph and normalizing them to a cubic space, any point near the faces are dangerous. Edges are even more dangerous, and is advisable to stay away from the vertexes.

Still no DSL. lalala.

The new xmp is going quite nicely, and minor flaws in the design are being fixed in the player prototype. Hipolito is currently working on the mixer engine and driver components, and we'll put it in sourceforge after merging his patches.

Some thoughts:

• Initrds are interesting.
• Installing a system from scratch with the root filesystem in LVM is even more fun than installing debian on the iMac.
• My Quantum disk is coughing again. I hate Quantum disks.
• Will anyone write a gimp-equivalent for sound?
• latex2html is cool! But it doesn't understand verbatimtab.
• Should I buy a Palm?
• The (new) lkml finally accepted my subscription.
• I'm receiving the Time magazine every week, and I'm not a subscriber. I don't complain.
• Renewed my Scientific American subscription.
• The MasterCard people are bugging me. They want me to upgrade my poor man's card to a mega-ultra-card-pro gold I can't afford (and even if I could, I don't want to upgrade! Leave me alone!).

I like the linked list helper functions from the Linux kernel so much I used them in my robot dynamics simulator. And in the new xmp too.

Also enjoyed Roxen Challenger's excellent configuration interface to set up my personal debian mirror built with apt-move. No doubt apache has better performance and memory footprint, but sometimes painless administration is more important than performance. And administration interface is where Roxen really shines!

Sent a couple of patches to the XRally maintainer, adding sound, a new radar mode and a new tileset. XRally is a cool clone of Namco's classic Rally-X. Hmm. A PalmOS port would be cool!

Interesting stuff being prepared for the upcoming release of Conectiva Linux.

Bought a Zip drive and a Matrox card. Oh boy, I'll finally get rid of this horrid 89 Hz interlaced video mode and 80 MHz dot clock limit in 16 bpp of the ATI Mach64 card I'm using.

I hate Loki. They released a 200 turn demo version of SMAC. Now I'm trying to actually win a match within the 200 turn limit.

Still no DSL. This sucks.

[root@mrnutty:/] cat /etc/debian_version
2.2
[root@mrnutty:/] cat /proc/cpuinfo
processor       : 0
cpu             : 750
temperature     : 0 C
clock           : 350MHz
revision        : 2.2
bogomips        : 697.96
zero pages      : total 0 (0Kb) current: 0 (0Kb) hits: 0/759
(0%)
machine         : PowerMac2,1
motherboard     : PowerMac2,1 MacRISC Power Macintosh
L2 cache        : 512K unified
memory          : 64MB
pmac-generation : NewWorld

Sweet.

Installing Debian in a blueberry iMac DV is a highly enjoyable experience everyone should try. If you're a clueless newbie (like me) it may take a few hours, but it may be fun even for more experienced users or for people that played with an iMac before.

First of all, BootX won't work in the DV (after a few frustrated attempts, you come to that conclusion), so you'll have to use yaboot. The installation procedure is simple: just get the installation kit of LinuxPPC and the Debian base system tarball, boot using the provided ramdisk image, create some files in /dev, make the partitions and filesystems, open the tarball, do some minor configuration and presto!, you're running Debian!

Except that the LinuxPPC installation disk doesn't include tar. It can't mount NFS volumes read-write. But that's a minor hassle because you can repackage the tarball with cpio, no problem.The boot partition must be HFS. fstab must be created by hand. And the worst part, you must know that, after entering Open Firmware pressing apple+option+o+f, the command to boot yaboot is boot hd:X,yaboot.tbxi where X is your partition number.

BTW the reset button if the iMac is concealed in its side, disguised as a "play" button.

I wish I had the user's manual.

I'm trying to install Debian in a blueberry iMac. Wow, that's an interesting experience. Everyone who complain about how difficult it is to install Linux should be forc^H^H^H^Hencouraged to try an iMac. >:)

I also realized that Conectiva is a terribly bad name for spoofs. Think of "Red Hat", and you immediately envision dozens of funny names: Red Rat. Mad Rat. Mad Hatter. Pinky Rat. Red Herring, whatever. Basically anything with a color and an article of clothing would work. Now Conectiva doesn't sound like anything that would inspire a joke. I've made a spoof of the old Conectiva Linux box but in that case I just replaced the word "Conectiva" for "South Park" and the Conectiva spoofing was in the box design and typefaces. Too bad these Conectiva boxes have such a distinctive, easily spoofable design, but a name that can't be distorted into something recognizable :\

I'm now working in the same room of Alfredo Kojima of WindowMaker fame. Wow, when I see all those women around him, the shiny cars and everything, I finally decided that I must write a window manager!