Here's a quick intro to what I'm hacking on at university. This is a new omnidirectional robot platform we got in the lab. It's controlled via CanOpen-over-EtherCAT (which is a realtime Ethernet protocol "extension", more or less). As we don't want to deal with any of the Windows software that's usually used for such stuff, we're employing the IGH EtherCAT Master (r1549) implementation (GPL/LGPL) on Linux and it works quite nicely.
I hacked together a few shell scripts that invoke the ethercat command line tool with certain parameters to control the motor velocities "by hand", which then soon turned into a "dancing" demo of the robot ;-)
See http://www.youtube.com/watch?v=n_vF4NK26fM for the YouTube video of the dancing bot. It's just a quick (hardcoded) hack for now, there's lots of room for improvements, of course (e.g. detect baselines of random music you throw at it). The demo in the background is the fantastic Masagin by Farbrausch.
I've also hacked up a small Python script to control the robot with a Wiimote (using cwiid on Linux), which also works quite nicely. I further plan to make a small program for controlling it via a 3D mouse or the like in the future...
The longer-term plan for the robot platform is that it'll get a "backbone" and two very nice robot arms for grabbing stuff etc.
$ apt-get install wine (as root) $ winecfg
The winecfg (graphical) utility will setup some config file defaults in your ~/.wine directory. Click on Graphics and activate Allow DirectX apps to stop the mouse leaving their window. Also, click on Audio (a dialog will pop up, just click OK). This will autodect your soundcard and setup Wine to use it. Under Drives click Add (this will add D:) and change the path to /media/cdrom, so that Wine knows about your CD-ROM drive. Finally click OK to close winecfg and save the settings.
The next step is to insert the Starcraft CD-ROM into the drive and start the installer using Wine:
$ mount /media/cdrom (as root) $ wine /media/cdrom/setup.exe
Follow the instructions in the installer until the Starcraft install is finished (you'll need your CD key number), then exit the installer (don't start playing Starcraft right away).
The next step is to get the latest patch and get rid of the need to insert the CD-ROM every time.
$ wget http://ftp.blizzard.com/pub/starcraft/patches/PC/SC-1161.exe $ wine SC-1161.exe
After the patch is installed click OK and Starcraft will be started (very annoying). Leave the game again. We'll get rid of the CD-ROM requirement now:
$ cp /media/cdrom/install.exe ~/.wine/drive_c/Programme/Starcraft/StarCraft.mpq
That's a pretty big file, it may take a while. You might have to change "Programme" in the path (I have the German Starcraft version). That's it. You can now play Starcraft (without needing the CD-ROM) using:
$ wine ~/.wine/drive_c/Programme/Starcraft/StarCraft.exe
A good thing is, it even works nice and fast with the open-source nv NVIDIA driver (no need to install the proprietary driver).
I noticed one very annoying "bug" with the mouse behaviour at first. The mouse would sometimes just get stuck during the game (which is a total disaster of course, if you're in the middle of a fast-paced game). Left-clicking somewhere would "unstuck" the mouse, but it's still very bad. After many, many hours of reading bugreports and trying various patches I finally found out the root cause for the problem.
It's somehow related to my window manager (IceWM); whenever you move the mouse to the bottom of the Starcraft screen (where the IceWM status bar is, even though it's not on top or even visible, and even though Wine/Starcraft runs in full-screen mode!), something funny happens with X11/IceWM and the mouse gets stuck. I haven't yet found out if/which IceWM option could fix this behavior, but I have a small work-around. Just start Wine directly on a second X11 server with Starcraft (without any window manager being involved):
$ xinit -e '/usr/bin/wine ~/.wine/drive_c/Programme/Starcraft/StarCraft.exe' -- :1
No patches needed (stock Wine from Debian unstable works fine, that's version 1.0.1 right now). I hope this saves other people some debugging time...
In order to play the Brood War expansion you can follow a similar procedure. Insert the Brood War CD-ROM, then:
$ mount /media/cdrom (as root) $ wine /media/cdrom/setup.exe $ cp /media/cdrom/install.exe ~/.wine/drive_c/Programme/Starcraft/BroodWar.mpq $ wget http://ftp.blizzard.com/pub/broodwar/patches/PC/BW-1161.exe $ wine BW-1161.exe
After you've done that, you can start both Starcraft (classic) and Brood War via:
$ wine ~/.wine/drive_c/Programme/Starcraft/StarCraft.exe
You will be asked in the game whether you want to actually play the Starcraft or Brood War variant.
As of version 1161 for the Starcraft / Brood War patch, there's a new game option which can drastically lower the CPU load while playing Starcraft. First fire up Starcraft and start any game. Then, press F10, select Options / Game speed, and check the "Enable CPU Throttling box". You'll probably need to restart Starcraft afterwards.
Multiplayer LAN games work just fine (didn't try BattleNet that much yet), but if you use a strict firewall rule set as I do (which blocks most ingress as well as egress traffic) you have to open a number of different ports. Here's what I added to my firewall script:
$IPTABLES -A OUTPUT -m state --state NEW -p udp --dport 6111 -j ACCEPT $IPTABLES -A INPUT -m state --state NEW -p udp --dport 6111 -j ACCEPT $IPTABLES -A OUTPUT -m state --state NEW -p udp --dport 6112 -j ACCEPT $IPTABLES -A OUTPUT -m state --state NEW -p tcp --dport 6112 -j ACCEPT # BattleNet
Starcraft works just fine on various netbooks; for instance, I tested it on my One A110 netbook (VIA VX800) with 256 MB of RAM, and the whole .wine directory being on a USB thumb drive (thus slow; but my internal SSD was already full). I bet it'll also work fine on the
Audio works fine, and game speed is quite OK, the only minor "problem" is that you should use an external USB mouse, the touchpad is just too small (and too slow to use) for such a fast-paced game.
The full Wine package (and all dependencies) consume quite a lot of space on the (usually very small) hard drive or SSD of a netbook, but luckily you can get away with only a minimal Wine install for playing Starcraft:
$ apt-get install wine-bin libwine-alsa (as root)
That's sufficient, and a lot smaller than installing the full wine package.
Update 2010-06-23: There's a contributed Hungarian translation now (thanks!)
Update 2009-03-04: Added info about patch 1161 and CPU load reduction.
Update 2008-12-19: Added Starcraft-on-netbooks section.
Update 2008-12-13: Added BroodWar and multiplayer info.
$ apt-get install jhead
It can display/extract a great amount of metadata fields from JPEG files and also extract the thumbnails stored in JPEG files (if any). The following will list all known metadata fields from a sample photo:
$ wget http://farm4.static.flickr.com/3173/3061542361_60acb0904b_o.jpg $ jhead *.jpg File name : 3061542361_60acb0904b_o.jpg File size : 1074172 bytes File date : 2008:11:26 23:38:04 Camera make : Panasonic Camera model : DMC-FZ18 Date/Time : 2008:03:05 15:45:52 Resolution : 3264 x 2448 Flash used : No Focal length : 4.6mm (35mm equivalent: 28mm) Exposure time: 0.0100 s (1/100) Aperture : f/3.6 ISO equiv. : 100 Whitebalance : Auto Metering Mode: matrix Exposure : program (auto) GPS Latitude : N %:.7fd %;.8fm %;.8fs GPS Longitude: E %;.8fd %:.7fm %;.8fs GPS Altitude : 174.00m Comment : Aufgenommen auf dem <a href="http://www.froutes.de/TT00000014_Ars_Natura">Kunstweg Ars Natura</a>. ======= IPTC data: ======= Record vers. : 4 Headline : Felsburg auf dem Felsberg (C)Notice : www.froutes.de Caption : Aufgenommen auf dem <a href="http://www.froutes.de/TT00000014_Ars_Natura">Kunstweg Ars Natura</a>.
As you can see there's a huge amount of potentially privacy-sensitive metadata in your typical JPEG as generated by your camera (including camera type, settings, date/time, maybe even GPS coordinates of your location, etc).
You can extract the thumbnail stored in all JPEGs in the current directory with:
$ jhead -st "&i_t.jpg" *.jpg Created: '3061542361_60acb0904b_o.jpg_t.jpg'
Note that the JPEG thumbnail does not necessarily show the same picture as the JPEG itself. Depending on the image manipulation software that was used to create the edited/fixed/cropped JPEG, the thumbnail may still reflect the original JPEG contents (see sample image on the right-hand side). This is a huge potential privacy issue. There have been a number of articles about this some years ago, in case you missed them:
Thus, an important jhead command line to know is the following, which removes all metadata (including any thumbnails) from all JPEG images in the current directory:
$ jhead -purejpg *.jpg Modified: 3061542361_60acb0904b_o.jpg
As you can see the result is that only very basic information can be gathered from the file afterwards:
$ jhead *.jpg File name : 3061542361_60acb0904b_o.jpg File size : 1052506 bytes File date : 2008:11:26 23:38:04 Resolution : 3264 x 2448 $ jhead -st "&i_t.jpg" *.jpg Image contains no thumbnail
I recommend doing this for most photos you make publically available on sites like flickr etc. (unless you have a good reason not to). Finally, see the jhead(1) manpage for lots more options that the tool supports.
Today I had to work with a really old svn repository again, which was still in the old bdb format (not in the newer and recommended fsfs one). This caused quite some problems, like, um... you cannot checkout, update, or commit anything.
$ svn co file:///path/to/myrepo
svn: Unable to open an ra_local session to URL
svn: Unable to open repository 'file:///path/to/myrepo'
svn: Berkeley DB error for filesystem '/path/to/myrepo/db' while opening environment:
svn: DB_VERSION_MISMATCH: Database environment version mismatch
svn: bdb: Program version 4.6 doesn't match environment version 4.4
A quick search revealed that this is bug #342508, a solution is/was supposedly mentioned in /usr/share/doc/subversion/README.db4.3 (which does no longer exist in the Debian unstable package). Luckily this blogpost has some details.
So, the short HOWTO for upgrading an svn repository of one Berkeley DB version to another one is:
$ cd /path/to/myrepo/db
$ db4.4_checkpoint -1
$ svnlook youngest ..
$ db4.6_archive -d
In this case I upgraded from 4.4 to 4.6 (do "apt-get install db4.4-util db4.6-util" if necessary).
While I was at it, I also switched the repository to the fsfs format then:
$ svnadmin dump /path/to/myrepo > myrepo.dump
$ mv /path/to/myrepo /path/to/myrepo.bak
$ svnadmin create --fs-type fsfs /path/to/myrepo
$ svnadmin load /path/to/myrepo < myrepo.dump
Maybe this is helpful for some other people out there.
Now for a change in music style, but staying with ccmixter.org stuff...