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  13  <h1>
  14      <a href="https://people.skolelinux.org/pere/blog/">Petter Reinholdtsen</a>
  15
  16  </h1>
  17
  18 </div>
  19
  20
  21
  22     <div class="entry">
  23       <div class="title"><a href="https://people.skolelinux.org/pere/blog/Opensnitch__the_application_level_interactive_firewall__heading_into_the_Debian_archive.html">Opensnitch, the application level interactive firewall, heading into the Debian archive</a></div>
  24       <div class="date">22nd January 2023</div>
  25       <div class="body"><p>While reading a
  26 <a href="https://sneak.berlin/20230115/macos-scans-your-local-files-now/">blog
  27 post claiming MacOS X recently started scanning local files and
  28 reporting information about them to Apple</a>, even on a machine where
  29 all such callback features had been disabled, I came across a
  30 description of the Little Snitch application for MacOS X.  It seemed
  31 like a very nice tool to have in the tool box, and I decided to see if
  32 something similar was available for Linux.</p>
  33
  34 <p>It did not took long to find
  35 <a href="https://github.com/evilsocket/opensnitch">the OpenSnitch
  36 package</a>, which has been in development since 2017, and now is in
  37 version 1.5.0.  It has had a
  38 <a href="https://bugs.debian.org/909567">request for Debian
  39 packaging</a> since 2018, but no-one completed the job so far.  Just
  40 for fun, I decided to see if I could help, and I was very happy to
  41 discover that
  42 <a href="https://github.com/evilsocket/opensnitch/issues/304">upstream
  43 want a Debian package too</a>.</p>
  44
  45 <p>After struggling a bit with getting the program to run, figuring
  46 out building Go programs (and a little failed detour to look at eBPF
  47 builds too - help needed), I am very happy to report that I am
  48 sponsoring upstream to maintain the package in Debian, and it has
  49 since this morning been waiting in NEW for the ftpmasters to have a
  50 look.  Perhaps it can get into the archive in time for the Bookworm
  51 release?</p>
  52
  53 <p>As usual, if you use Bitcoin and want to show your support of my
  54 activities, please send Bitcoin donations to my address
  55 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
  56 </div>
  57       <div class="tags">
  58
  59
  60         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="https://people.skolelinux.org/pere/blog/tags/english">english</a>.
  61
  62
  63       </div>
  64     </div>
  65     <div class="padding"></div>
  66
  67     <div class="entry">
  68       <div class="title"><a href="https://people.skolelinux.org/pere/blog/LinuxCNC_MQTT_publisher_component.html">LinuxCNC MQTT publisher component</a></div>
  69       <div class="date"> 8th January 2023</div>
  70       <div class="body"><p>I watched <a href="https://yewtu.be/watch?v=jmKUV3aNLjk">a 2015
  71 video from Andreas Schiffler</a> the other day, where he set up
  72 <a href="https://linuxcnc.org/">LinuxCNC</a> to send status
  73 information to the MQTT broker IBM Bluemix.  As I also use MQTT for
  74 graphing, it occured to me that a generic MQTT LinuxCNC component
  75 would be useful and I set out to implement it.  Today I got the first
  76 draft limping along and submitted as
  77 <a href="https://github.com/LinuxCNC/linuxcnc/pull/2253">a patch to the
  78 LinuxCNC project</a>.</p>
  79
  80 <p>The simple part was setting up the MQTT publishing code in Python.
  81 I already have set up other parts submitting data to my Mosquito MQTT
  82 broker, so I could reuse that code.  Writing a LinuxCNC component in
  83 Python as new to me, but using existing examples in the code
  84 repository and the extensive documentation, this was fairly straight
  85 forward.  The hardest part was creating a automated test for the
  86 component to ensure it was working.  Testing it in a simulated
  87 LinuxCNC machine proved very useful, as I discovered features I needed
  88 that I had not thought of yet, and adjusted the code quite a bit to
  89 make it easier to test without a operational MQTT broker
  90 available.</p>
  91
  92 <p>The draft is ready and working, but I am unsure which LinuxCNC HAL
  93 pins I should collect and publish by default (in other words, the
  94 default set of information pieces published), and how to get the
  95 machine name from the LinuxCNC INI file.  The latter is a minor
  96 detail, but I expect it would be useful in a setup with several
  97 machines available.  I am hoping for feedback from the experienced
  98 LinuxCNC developers and users, to make the component even better
  99 before it can go into the mainland LinuxCNC code base.</p>
 100
 101 <p>Since I started on the MQTT component, I came across
 102 <a href="https://yewtu.be/watch?v=Bqa2grG0XtA">another video from Kent
 103 VanderVelden</a> where he combine LinuxCNC with a set of screen glasses
 104 controlled by a Raspberry Pi, and it occured to me that it would
 105 be useful for such use cases if LinuxCNC also provided a REST API for
 106 querying its status.  I hope to start on such component once the MQTT
 107 component is working well.</p>
 108
 109 <p>As usual, if you use Bitcoin and want to show your support of my
 110 activities, please send Bitcoin donations to my address
 111 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 112 </div>
 113       <div class="tags">
 114
 115
 116         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="https://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="https://people.skolelinux.org/pere/blog/tags/linuxcnc">linuxcnc</a>, <a href="https://people.skolelinux.org/pere/blog/tags/robot">robot</a>.
 117
 118
 119       </div>
 120     </div>
 121     <div class="padding"></div>
 122
 123     <div class="entry">
 124       <div class="title"><a href="https://people.skolelinux.org/pere/blog/ONVIF_IP_camera_management_tool_finally_in_Debian.html">ONVIF IP camera management tool finally in Debian</a></div>
 125       <div class="date">24th December 2022</div>
 126       <div class="body"><p>Merry Christmas to you all.  Here is a small gift to all those with
 127 IP cameras following the <a href="https://www.onvif.org/">ONVIF
 128 specification</a>.  There is finally a nice command line and GUI tool
 129 in Debian to manage ONVIF IP cameras.  After working with upstream for
 130 a few months and sponsoring the upload, I am very happy to report that
 131 the <a href="https://tracker.debian.org/libonvif">libonvif package</a>
 132 entered Debian Sid last night.</p>
 133
 134 <p>The package provide a C library to communicate with such cameras, a
 135 command line tool to locate and update settings of (like password) the
 136 cameras and a GUI tool to configure and control the units as well as
 137 preview the video from the camera.  Libonvif is available on Both
 138 Linux and Windows and the GUI tool uses the Qt library.  The main
 139 competitors are non-free software, while libonvif is GNU GPL licensed.
 140 I am very glad Debian users in the future can control their cameras
 141 using a free software system provided by Debian.  But the ONVIF world
 142 is full of slightly broken firmware, where the cameras pretend to
 143 follow the ONVIF specification but fail to set some configuration
 144 values or refuse to provide video to more than one recipient at the
 145 time, and the onvif project is quite young and might take a while
 146 before it completely work with your camera.  Upstream seem eager to
 147 improve the library, so handling any broken camera might be just <a
 148 href="https://github.com/sr99622/libonvif/">a bug report away</a>.</p>
 149
 150 <p>The package just cleared NEW, and need a new source only upload
 151 before it can enter testing.  This will happen in the next few
 152 days.</p>
 153
 154 <p>As usual, if you use Bitcoin and want to show your support of my
 155 activities, please send Bitcoin donations to my address
 156 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 157 </div>
 158       <div class="tags">
 159
 160
 161         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="https://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="https://people.skolelinux.org/pere/blog/tags/multimedia">multimedia</a>, <a href="https://people.skolelinux.org/pere/blog/tags/standard">standard</a>, <a href="https://people.skolelinux.org/pere/blog/tags/surveillance">surveillance</a>.
 162
 163
 164       </div>
 165     </div>
 166     <div class="padding"></div>
 167
 168     <div class="entry">
 169       <div class="title"><a href="https://people.skolelinux.org/pere/blog/Managing_and_using_ONVIF_IP_cameras_with_Linux.html">Managing and using ONVIF IP cameras with Linux</a></div>
 170       <div class="date">19th October 2022</div>
 171       <div class="body"><p>Recently I have been looking at how to control and collect data
 172 from a handful IP cameras using Linux.  I both wanted to change their
 173 settings and to make their imagery available via a free software
 174 service under my control.  Here is a summary of the tools I found.</p>
 175
 176 <p>First I had to identify the cameras and their protocols.  As far as
 177 I could tell, they were using some SOAP looking protocol and their
 178 internal web server seem to only work with Microsoft Internet Explorer
 179 with some proprietary binary plugin, which in these days of course is
 180 a security disaster and also made it impossible for me to use the
 181 camera web interface.  Luckily I discovered that the SOAP looking
 182 protocol is actually following <a href="https://www.onvif.org/">the
 183 ONVIF specification</a>, which seem to be supported by a lot of IP
 184 cameras these days.</p>
 185
 186 <p>Once the protocol was identified, I was able to find what appear to
 187 be the most popular way to configure ONVIF cameras, the free software
 188 Windows tool named
 189 <a href="https://sourceforge.net/projects/onvifdm/">ONVIF Device
 190 Manager</a>.  Lacking any other options at the time, I tried
 191 unsuccessfully to get it running using Wine, but was missing a dotnet
 192 40 library and I found no way around it to run it on Linux.</p>
 193
 194 <p>The next tool I found to configure the cameras were a non-free Linux Qt
 195 client <a href="https://www.lingodigit.com/onvif_nvcdemo.html">ONVIF
 196 Device Tool</a>.  I did not like its terms of use, so did not spend
 197 much time on it.</p>
 198
 199 <p>To collect the video and make it available in a web interface, I
 200 found the Zoneminder tool in Debian.  A recent version was able to
 201 automatically detect and configure ONVIF devices, so I could use it to
 202 set up motion detection in and collection of the camera output.  I had
 203 initial problems getting the ONVIF autodetection to work, as both
 204 Firefox and Chromium <a href="https://bugs.debian.org/1001188">refused
 205 the inter-tab communication</a> being used by the Zoneminder web
 206 pages, but managed to get konqueror to work.  Apparently the "Enhanced
 207 Tracking Protection" in Firefox cause the problem.  I ended up
 208 upgrading to the Bookworm edition of Zoneminder in the process to try
 209 to fix the issue, and believe the problem might be solved now.</p>
 210
 211 <p>In the process I came across the nice Linux GUI tool
 212 <a href="https://gitlab.com/caspermeijn/onvifviewer/">ONVIF Viewer</a>
 213 allowing me to preview the camera output and validate the login
 214 passwords required.  Sadly its author has grown tired of maintaining
 215 the software, so it might not see any future updates.  Which is sad,
 216 as the viewer is sightly unstable and the picture tend to lock up.
 217 Note, this lockup might be due to limitations in the cameras and not
 218 the viewer implementation.  I suspect the camera is only able to
 219 provide pictures to one client at the time, and the Zoneminder feed
 220 might interfere with the GUI viewer.  I have
 221 <a href="https://bugs.debian.org/1000820">asked for the tool to be
 222 included in Debian</a>.</p>
 223
 224 <p>Finally, I found what appear to be very nice Linux free software
 225 replacement for the Windows tool, named
 226 <a href="https://github.com/sr99622/libonvif/">libonvif</a>.  It
 227 provide a C library to talk to ONVIF devices as well as a command line
 228 and GUI tool using the library.  Using the GUI tool I was able to change
 229 the admin passwords and update other settings of the cameras.  I have
 230 <a href="https://bugs.debian.org/1021980">asked for the package to be
 231 included in Debian</a>.</p>
 232
 233 <p>As usual, if you use Bitcoin and want to show your support of my
 234 activities, please send Bitcoin donations to my address
 235 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 236
 237 <p><strong>Update 2022-10-20</strong>: Since my initial publication of
 238 this text, I got several suggestions for more free software Linux
 239 tools.  There is <a href="https://github.com/quatanium/python-onvif">a
 240 ONVIF python library</a> (already
 241 <a href="https://bugs.debian.org/824240">requested into Debian</a>) and
 242 <a href="https://github.com/FalkTannhaeuser/python-onvif-zeep">a python 3
 243 fork</a> using a different SOAP dependency.  There is also
 244 <a href="https://www.home-assistant.io/integrations/onvif/">support for
 245 ONVIF in Home Assistant</a>, and there is an alternative to Zoneminder
 246 called <a href="https://www.shinobi.video/">Shinobi</a>.  The latter
 247 two are not included in Debian either.  I have not tested any of these
 248 so far.</p>
 249 </div>
 250       <div class="tags">
 251
 252
 253         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="https://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="https://people.skolelinux.org/pere/blog/tags/multimedia">multimedia</a>, <a href="https://people.skolelinux.org/pere/blog/tags/standard">standard</a>, <a href="https://people.skolelinux.org/pere/blog/tags/surveillance">surveillance</a>.
 254
 255
 256       </div>
 257     </div>
 258     <div class="padding"></div>
 259
 260     <div class="entry">
 261       <div class="title"><a href="https://people.skolelinux.org/pere/blog/Time_to_translate_the_Bullseye_edition_of_the_Debian_Administrator_s_Handbook.html">Time to translate the Bullseye edition of the Debian Administrator's Handbook</a></div>
 262       <div class="date">12th September 2022</div>
 263       <div class="body"><p align="center"><img align="center" src="http://people.skolelinux.org/pere/blog/images/2020-10-20-debian-handbook-nb-testprint.jpeg" width="60%"/></p>
 264
 265 <p>(The picture is of the previous edition.)</p>
 266
 267 <p>Almost two years after the previous Norwegian Bokmål translation of
 268 the "<a href="https://debian-handbook.info/">The Debian Administrator's
 269 Handbook</a>" was published, a new edition is finally being prepared.  The
 270 english text is updated, and it is time to start working on the
 271 translations.  Around 37 percent of the strings have been updated, one
 272 way or another, and the translations starting from a complete Debian Buster
 273 edition now need to bring their translation up from 63% to 100%.  The
 274 complete book is licensed using a Creative Commons license, and has
 275 been published in several languages over the years.  The translations
 276 are done by volunteers to bring Linux in their native tongue.  The
 277 last time I checked, it complete text was available in English,
 278 Norwegian Bokmål, German, Indonesian, Brazil Portuguese and Spanish.
 279 In addition, work has been started for Arabic (Morocco), Catalan,
 280 Chinese (Simplified), Chinese (Traditional), Croatian, Czech, Danish,
 281 Dutch, French, Greek, Italian, Japanese, Korean, Persian, Polish,
 282 Romanian, Russian, Swedish, Turkish and Vietnamese.</p>
 283
 284 <p>The translation is conducted on
 285 <a href="https://hosted.weblate.org/projects/debian-handbook/">the
 286 hosted weblate project page</a>.  Prospective translators are
 287 recommeded to subscribe to
 288 <a href="http://lists.alioth.debian.org/mailman/listinfo/debian-handbook-translators">the
 289 translators mailing list</a> and should also check out
 290 <a href="https://debian-handbook.info/contribute/">the instructions for
 291 contributors</a>.</p>
 292
 293 <p>I am one of the Norwegian Bokmål translators of this book, and we
 294 have just started.  Your contribution is most welcome.</p>
 295
 296 <p>As usual, if you use Bitcoin and want to show your support of my
 297 activities, please send Bitcoin donations to my address
 298 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 299 </div>
 300       <div class="tags">
 301
 302
 303         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="https://people.skolelinux.org/pere/blog/tags/debian-handbook">debian-handbook</a>, <a href="https://people.skolelinux.org/pere/blog/tags/english">english</a>.
 304
 305
 306       </div>
 307     </div>
 308     <div class="padding"></div>
 309
 310     <div class="entry">
 311       <div class="title"><a href="https://people.skolelinux.org/pere/blog/Automatic_LinuxCNC_servo_PID_tuning_.html">Automatic LinuxCNC servo PID tuning?</a></div>
 312       <div class="date">16th July 2022</div>
 313       <div class="body"><p>While working on a CNC with servo motors controlled by the
 314 <a href="https://en.wikipedia.org/wiki/LinuxCNC">LinuxCNC</a>
 315 <a href="https://en.wikipedia.org/wiki/PID_controller">PID
 316 controller</a>, I recently had to learn how to tune the collection of values
 317 that control such mathematical machinery that a PID controller is.  It
 318 proved to be a lot harder than I hoped, and I still have not succeeded
 319 in getting the Z PID controller to successfully defy gravity, nor X
 320 and Y to move accurately and reliably.  But while climbing up this
 321 rather steep learning curve, I discovered that some motor control
 322 systems are able to tune their PID controllers.  I got the impression
 323 from the documentation that LinuxCNC were not.  This proved to be not
 324 true.</p>
 325
 326 <p>The LinuxCNC
 327 <a href="http://linuxcnc.org/docs/html/man/man9/pid.9.html">pid
 328 component</a> is the recommended PID controller to use.  It uses eight
 329 constants <tt>Pgain</tt>, <tt>Igain</tt>, <tt>Dgain</tt>,
 330 <tt>bias</tt>, <tt>FF0</tt>, <tt>FF1</tt>, <tt>FF2</tt> and
 331 <tt>FF3</tt> to calculate the output value based on current and wanted
 332 state, and all of these need to have a sensible value for the
 333 controller to behave properly.  Note, there are even more values
 334 involved, theser are just the most important ones.  In my case I need
 335 the X, Y and Z axes to follow the requested path with little error.
 336 This has proved quite a challenge for someone who have never tuned a
 337 PID controller before, but there is at least some help to be found.
 338
 339 <p>I discovered that included in LinuxCNC was this old PID component
 340 at_pid claiming to have auto tuning capabilities.  Sadly it had been
 341 neglected since 2011, and could not be used as a plug in replacement
 342 for the default pid component.  One would have to rewriting the
 343 LinuxCNC HAL setup to test at_pid.  This was rather sad, when I wanted
 344 to quickly test auto tuning to see if it did a better job than me at
 345 figuring out good P, I and D values to use.</p>
 346
 347 <p>I decided to have a look if the situation could be improved.  This
 348 involved trying to understand the code and history of the pid and
 349 at_pid components.  Apparently they had a common ancestor, as code
 350 structure, comments and variable names were quite close to each other.
 351 Sadly this was not reflected in the git history, making it hard to
 352 figure out what really happened.  My guess is that the author of
 353 <a href="https://github.com/LinuxCNC/linuxcnc/blob/master/src/hal/components/at_pid.c">at_pid.c</a>
 354 took a version of
 355 <a href="https://github.com/LinuxCNC/linuxcnc/blob/master/src/hal/components/pid.c">pid.c</a>,
 356 rewrote it to follow the structure he wished pid.c to have, then added
 357 support for auto tuning and finally got it included into the LinuxCNC
 358 repository.  The restructuring and lack of early history made it
 359 harder to figure out which part of the code were relevant to the auto
 360 tuning, and which part of the code needed to be updated to work the
 361 same way as the current pid.c implementation.  I started by trying to
 362 isolate relevant changes in pid.c, and applying them to at_pid.c.  My
 363 aim was to make sure the at_pid component could replace the pid
 364 component with a simple change in the HAL setup loadrt line, without
 365 having to "rewire" the rest of the HAL configuration.  After a few
 366 hours following this approach, I had learned quite a lot about the
 367 code structure of both components, while concluding I was heading down
 368 the wrong rabbit hole, and should get back to the surface and find a
 369 different path.</p>
 370
 371 <p>For the second attempt, I decided to throw away all the PID control
 372 related part of the original at_pid.c, and instead isolate and lift
 373 the auto tuning part of the code and inject it into a copy of pid.c.
 374 This ensured compatibility with the current pid component, while
 375 adding auto tuning as a run time option.  To make it easier to identify
 376 the relevant parts in the future, I wrapped all the auto tuning code
 377 with '#ifdef AUTO_TUNER'.  The end result behave just like the current
 378 pid component by default, as that part of the code is identical.  The
 379 <a href="https://github.com/LinuxCNC/linuxcnc/pull/1820">end result
 380 entered the LinuxCNC master branch</a> a few days ago.</p>
 381
 382 <p>To enable auto tuning, one need to set a few HAL pins in the PID
 383 component.  The most important ones are <tt>tune-effort</tt>,
 384 <tt>tune-mode</tt> and <tt>tune-start</tt>.  But lets take a step
 385 back, and see what the auto tuning code will do.  I do not know the
 386 mathematical foundation of the at_pid algorithm, but from observation
 387 I can tell that the algorithm will, when enabled, produce a square
 388 wave pattern centered around the <tt>bias</tt> value on the output pin
 389 of the PID controller.  This can be seen using the HAL Scope provided
 390 by LinuxCNC.  In my case, this is translated into voltage (+-10V) sent
 391 to the motor controller, which in turn is translated into motor speed.
 392 So at_pid will ask the motor to move the axis back and forth.  The
 393 number of cycles in the pattern is controlled by the
 394 <tt>tune-cycles</tt> pin, and the extremes of the wave pattern is
 395 controlled by the <tt>tune-effort</tt> pin.  Of course, trying to
 396 change the direction of a physical object instantly (as in going
 397 directly from a positive voltage to the equivalent negative voltage)
 398 do not change velocity instantly, and it take some time for the object
 399 to slow down and move in the opposite direction.  This result in a
 400 more smooth movement wave form, as the axis in question were vibrating
 401 back and forth.  When the axis reached the target speed in the
 402 opposing direction, the auto tuner change direction again.  After
 403 several of these changes, the average time delay between the 'peaks'
 404 and 'valleys' of this movement graph is then used to calculate
 405 proposed values for Pgain, Igain and Dgain, and insert them into the
 406 HAL model to use by the pid controller.  The auto tuned settings are
 407 not great, but htye work a lot better than the values I had been able
 408 to cook up on my own, at least for the horizontal X and Y axis.  But I
 409 had to use very small <tt>tune-effort<tt> values, as my motor
 410 controllers error out if the voltage change too quickly.  I've been
 411 less lucky with the Z axis, which is moving a heavy object up and
 412 down, and seem to confuse the algorithm.  The Z axis movement became a
 413 lot better when I introduced a <tt>bias</tt> value to counter the
 414 gravitational drag, but I will have to work a lot more on the Z axis
 415 PID values.</p>
 416
 417 <p>Armed with this knowledge, it is time to look at how to do the
 418 tuning.  Lets say the HAL configuration in question load the PID
 419 component for X, Y and Z like this:</p>
 420
 421 <blockquote><pre>
 422 loadrt pid names=pid.x,pid.y,pid.z
 423 </pre></blockquote>
 424
 425 <p>Armed with the new and improved at_pid component, the new line will
 426 look like this:</p>
 427
 428 <blockquote><pre>
 429 loadrt at_pid names=pid.x,pid.y,pid.z
 430 </pre></blockquote>
 431
 432 <p>The rest of the HAL setup can stay the same.  This work because the
 433 components are referenced by name.  If the component had used count=3
 434 instead, all use of pid.# had to be changed to at_pid.#.</p>
 435
 436 <p>To start tuning the X axis, move the axis to the middle of its
 437 range, to make sure it do not hit anything when it start moving back
 438 and forth.  Next, set the <tt>tune-effort</tt> to a low number in the
 439 output range.  I used 0.1 as my initial value.  Next, assign 1 to the
 440 <tt>tune-mode</tt> value. Note, this will disable the pid controlling
 441 part and feed 0 to the output pin, which in my case initially caused a
 442 lot of drift.  In my case it proved to be a good idea with X and Y to
 443 tune the motor driver to make sure 0 voltage stopped the motor
 444 rotation.  On the other hand, for the Z axis this proved to be a bad
 445 idea, so it will depend on your setup.  It might help to set the
 446 <tt>bias</tt> value to a output value that reduce or eliminate the
 447 axis drift.  Finally, after setting <tt>tune-mode</tt>, set
 448 <tt>tune-start</tt> to 1 to activate the auto tuning.  If all go well,
 449 your axis will vibrate for a few seconds and when it is done, new
 450 values for Pgain, Igain and Dgain will be active.  To test them,
 451 change <tt>tune-mode</tt> back to 0.  Note that this might cause the
 452 machine to suddenly jerk as it bring the axis back to its commanded
 453 position, which it might have drifted away from during tuning.  To
 454 summarize with some halcmd lines:</p>
 455
 456 <blockquote><pre>
 457 setp pid.x.tune-effort 0.1
 458 setp pid.x.tune-mode 1
 459 setp pid.x.tune-start 1
 460 # wait for the tuning to complete
 461 setp pid.x.tune-mode 0
 462 </pre></blockquote>
 463
 464 <p>After doing this task quite a few times while trying to figure out
 465 how to properly tune the PID controllers on the machine in, I decided
 466 to figure out if this process could be automated, and wrote a script
 467 to do the entire tuning process from power on.  The end result will
 468 ensure the machine is powered on and ready to run, home all axis if it
 469 is not already done, check that the extra tuning pins are available,
 470 move the axis to its mid point, run the auto tuning and re-enable the
 471 pid controller when it is done.  It can be run several times.  Check
 472 out the
 473 <a href="https://github.com/SebKuzminsky/MazakVQC1540/blob/bon-dev/scripts/run-auto-pid-tuner">run-auto-pid-tuner</a>
 474 script on github if you want to learn how it is done.</p>
 475
 476 <p>My hope is that this little adventure can inspire someone who know
 477 more about motor PID controller tuning can implement even better
 478 algorithms for automatic PID tuning in LinuxCNC, making life easier
 479 for both me and all the others that want to use LinuxCNC but lack the
 480 in depth knowledge needed to tune PID controllers well.</p>
 481
 482 <p>As usual, if you use Bitcoin and want to show your support of my
 483 activities, please send Bitcoin donations to my address
 484 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 485 </div>
 486       <div class="tags">
 487
 488
 489         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer</a>, <a href="https://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="https://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="https://people.skolelinux.org/pere/blog/tags/linuxcnc">linuxcnc</a>, <a href="https://people.skolelinux.org/pere/blog/tags/robot">robot</a>.
 490
 491
 492       </div>
 493     </div>
 494     <div class="padding"></div>
 495
 496     <div class="entry">
 497       <div class="title"><a href="https://people.skolelinux.org/pere/blog/My_free_software_activity_of_late__2022_.html">My free software activity of late (2022)</a></div>
 498       <div class="date">20th June 2022</div>
 499       <div class="body"><p>I guess it is time to bring some light on the various free software
 500 and open culture activities and projects I have worked on or been
 501 involved in the last year and a half.</p>
 502
 503 <p>First, lets mention the book
 504 <a href="http://www.hungry.com/~pere/publisher/">releases I managed to
 505 publish</a>.  The Cory Doctorow book "Hvordan knuse
 506 overvåkningskapitalismen" argue that it is not the magic machine
 507 learning of the big technology companies that causes the surveillance
 508 capitalism to thrive, it is the lack of trust busting to enforce
 509 existing anti-monopoly laws.  I also published a family of
 510 dictionaries for machinists, one sorted on the English words, one
 511 sorted on the Norwegian and the last sorted on the North Sámi words.
 512 A bit on the back burner but not forgotten is the Debian
 513 Administrators Handbook, where a new edition is being worked on.  I
 514 have not spent as much time as I want to help bring it to completion,
 515 but hope I will get more spare time to look at it before the end of
 516 the year.</p>
 517
 518 <p>With my Debian had I have spent time on several projects, both
 519 updating existing packages, helping to bring in new packages and
 520 working with upstream projects to try to get them ready to go into
 521 Debian.  The list is rather long, and I will only mention my own
 522 isenkram, openmotor, vlc bittorrent plugin, xprintidle, norwegian
 523 letter style for latex, bs1770gain, and recordmydesktop.  In addition
 524 to these I have sponsored several packages into Debian, like audmes.</p>
 525
 526 <p>The last year I have looked at several infrastructure projects for
 527 collecting meter data and video surveillance recordings.  This include
 528 several ONVIF related tools like onvifviewer and zoneminder as well as
 529 rtl-433, wmbusmeters and rtl-wmbus.</p>
 530
 531 <p>In parallel with this I have looked at fabrication related free
 532 software solutions like pycam and LinuxCNC.  The latter recently
 533 gained improved translation support using po4a and weblate, which was
 534 a harder nut to crack that I had anticipated when I started.</p>
 535
 536 <p>Several hours have been spent translating free software to
 537 Norwegian Bokmål on the Weblate hosted service.  Do not have a
 538 complete list, but you will find my contributions in at least gnucash,
 539 minetest and po4a.</p>
 540
 541 <p>I also spent quite some time on the Norwegian archiving specification
 542 Noark 5, and its companion project Nikita implementing the API
 543 specification for Noark 5.</p>
 544
 545 <p>Recently I have been looking into free software tools to do company
 546 accounting here in Norway., which present an interesting mix between
 547 law, rules, regulations, format specifications and API interfaces.</p>
 548
 549 <p>I guess I should also mention the Norwegian community driven
 550 government interfacing projects Mimes Brønn and Fiksgatami, which have
 551 ended up in a kind of limbo while the future of the projects is being
 552 worked out.</p>
 553
 554 <p>These are just a few of the projects I have been involved it, and
 555 would like to give more visibility.  I'll stop here to avoid delaying
 556 this post.</p>
 557
 558 <p>As usual, if you use Bitcoin and want to show your support of my
 559 activities, please send Bitcoin donations to my address
 560 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 561 </div>
 562       <div class="tags">
 563
 564
 565         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/english">english</a>.
 566
 567
 568       </div>
 569     </div>
 570     <div class="padding"></div>
 571
 572     <div class="entry">
 573       <div class="title"><a href="https://people.skolelinux.org/pere/blog/LinuxCNC_translators_life_just_got_a_bit_easier.html">LinuxCNC translators life just got a bit easier</a></div>
 574       <div class="date"> 3rd June 2022</div>
 575       <div class="body"><p>Back in oktober last year, when I started looking at the
 576 <a href="https://en.wikipedia.org/wiki/LinuxCNC">LinuxCNC</a> system, I
 577 proposed to change the documentation build system make life easier for
 578 translators.  The original system consisted of independently written
 579 documentation files for each language, with no automated way to track
 580 changes done in other translations and no help for the translators to
 581 know how much was left to translated.  By using
 582 <a href="https://po4a.org/">the po4a system</a> to generate POT and PO
 583 files from the English documentation, this can be improved.  A small
 584 team of LinuxCNC contributors got together and today our labour
 585 finally payed off.  Since a few hours ago, it is now possible to
 586 translate <a href="https://hosted.weblate.org/projects/linuxcnc/">the
 587 LinuxCNC documentation on Weblate</a>, alongside the program itself.</p>
 588
 589 <p>The effort to migrate the documentation to use po4a has been both
 590 slow and frustrating.  I am very happy we finally made it.</p>
 591
 592 <p>As usual, if you use Bitcoin and want to show your support of my
 593 activities, please send Bitcoin donations to my address
 594 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 595 </div>
 596       <div class="tags">
 597
 598
 599         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer</a>, <a href="https://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="https://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="https://people.skolelinux.org/pere/blog/tags/linuxcnc">linuxcnc</a>, <a href="https://people.skolelinux.org/pere/blog/tags/robot">robot</a>.
 600
 601
 602       </div>
 603     </div>
 604     <div class="padding"></div>
 605
 606     <div class="entry">
 607       <div class="title"><a href="https://people.skolelinux.org/pere/blog/geteltorito_make_CD_firmware_upgrades_a_breeze.html">geteltorito make CD firmware upgrades a breeze</a></div>
 608       <div class="date">20th April 2022</div>
 609       <div class="body"><p>Recently I wanted to upgrade the firmware of my thinkpad, and
 610 located the firmware download page from Lenovo (which annoyingly do
 611 not allow access via Tor, forcing me to hand them more personal
 612 information that I would like).  The
 613 <a href="https://support.lenovo.com/no/en/search?query=thinkpad firmware bios upgrade iso&SearchType=Customer search&searchLocation=Masthead">download
 614 from Lenovo</a> is a bootable ISO image, which is a bit of a problem
 615 when all I got available is a USB memory stick.  I tried booting the
 616 ISO as a USB stick, but this did not work.  But genisoimage came to
 617 the rescue.</p>
 618
 619 <P>The geteltorito program in
 620 <a href="http://tracker.debian.org/cdrkit">the genisoimage binary
 621 package</a> is able to convert the bootable ISO image to a bootable
 622 USB stick using a simple command line recipe, which I then can write
 623 to the most recently inserted USB stick:</p>
 624
 625 <blockquote><pre>
 626 geteltorito -o usbstick.img lenovo-firmware.iso
 627 sudo dd bs=10M if=usbstick.img of=$(ls -tr /dev/sd?|tail -1)
 628 </pre></blockquote>
 629
 630 <p>This USB stick booted the firmware upgrader just fine, and in a few
 631 minutes my machine had the latest and greatest BIOS firmware in place.</p>
 632 </div>
 633       <div class="tags">
 634
 635
 636         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="https://people.skolelinux.org/pere/blog/tags/english">english</a>.
 637
 638
 639       </div>
 640     </div>
 641     <div class="padding"></div>
 642
 643     <div class="entry">
 644       <div class="title"><a href="https://people.skolelinux.org/pere/blog/Playing_and_encoding_AV1_in_Debian_Bullseye.html">Playing and encoding AV1 in Debian Bullseye</a></div>
 645       <div class="date">16th April 2022</div>
 646       <div class="body"><p>Inspired by the recent news of
 647 <a href="https://slashdot.org/story/22/04/03/2039219/intel-beats-amd-and-nvidia-with-arc-gpus-full-av1-support">AV1
 648 hardware encoding support from Intel</a>, I decided to look into
 649 the state of AV1 on Linux today.  AV1 is a
 650 <a href="https://web.archive.org/web/20160618103850/http://www.digistan.org/open-standard:definition">free
 651 and open standard</a> as defined by Digistan without any royalty
 652 payment requirement, unlike its much used competitor encoding
 653 H.264.  While looking, I came across an 5 year
 654 <a href="https://askubuntu.com/questions/1061908/how-to-encode-and-playback-video-with-the-av1-codec-on-bionic-beaver-18-04">old
 655 question on askubuntu.com</a> which in turn inspired me to check out
 656 how things are in Debian Stable regarding AV1.  The test file listed
 657 in the question (askubuntu_test_aom.mp4) did not exist any more, so I
 658 tracked down a different set of test files on
 659 <a href="https://av1.webmfiles.org/">av1.webmfiles.org</a> to test them
 660 with the various video tools I had installed on my machine.  I was
 661 happy to discover that AV1 decoding and playback worked with almost
 662 every tool I tested:
 663
 664 <table align="center">
 665 <tr><td>mediainfo</td>       <td>ok</td></tr>
 666 <tr><td>dragonplayer</td>    <td>ok</td></tr>
 667 <tr><td>ffmpeg / ffplay</td> <td>ok</td></tr>
 668 <tr><td>gnome-mplayer</td>   <td>fail</td></tr>
 669 <tr><td>mplayer</td>         <td>ok</td></tr>
 670 <tr><td>mpv</td>             <td>ok</td></tr>
 671 <tr><td>parole</td>          <td>ok</td></tr>
 672 <tr><td>vlc</td>             <td>ok</td></tr>
 673 <tr><td>firefox</td>         <td>ok</td></tr>
 674 <tr><td>chromium</td>        <td>ok</td></tr>
 675 </table>
 676
 677 <p>AV1 encoding is available in Debian Stable from the aom-tools
 678 version 1.0.0.errata1-3 package, using the aomenc tool.  The encoding
 679 using the package in Debian Stable is quite slow, with the frame rate
 680 for my 10 second test video at around 0.25 fps.  My 10 second video
 681 test took 16 minutes and 11 seconds on my test machine.</p>
 682
 683 <p>I tested by first running ffmpeg and then aomenc using the recipe
 684 provided by the askubuntu recipe above.  I had to remove the
 685 '--row-mt=1' option, as it was not supported in my 1.0.0 version.  The
 686 encoding only used a single thread, according to <tt>top</tt>.</p>
 687
 688 <blockquote><pre>
 689 ffmpeg -i some-old-video.ogv -t 10 -pix_fmt yuv420p video.y4m
 690 aomenc --fps=24/1 -u 0 --codec=av1 --target-bitrate=1000 \
 691   --lag-in-frames=25 --auto-alt-ref=1 -t 24 --cpu-used=8 \
 692   --tile-columns=2 --tile-rows=2 -o output.webm video.y4m
 693 </pre></blockquote>
 694
 695 <p>As version 1.0.0 currently have several
 696 <a href="https://security-tracker.debian.org/tracker/source-package/aom">unsolved
 697 security issues in Debian Stable</a>, and to see if the recent
 698 backport <a href="https://tracker.debian.org/pkg/aom">provided in
 699 Debian</a> is any quicker, I ran <tt>apt -t bullseye-backports install
 700 aom-tools</tt> to fetch the backported version and re-encoded the
 701 video using the latest version.  This time the '--row-mt=1' option
 702 worked, and the encoding was done in 46 seconds with a frame rate of
 703 around 5.22 fps.  This time it seem to be using all my four cores to
 704 encode.  Encoding speed is still too low for streaming and real time,
 705 which would require frame rates above 25 fps, but might be good enough
 706 for offline encoding.</p>
 707
 708 <p>I am very happy to see AV1 playback working so well with the
 709 default tools in Debian Stable.  I hope the encoding situation improve
 710 too, allowing even a slow old computer like my 10 year old laptop to
 711 be used for encoding.</p>
 712
 713 <p>As usual, if you use Bitcoin and want to show your support of my
 714 activities, please send Bitcoin donations to my address
 715 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 716 </div>
 717       <div class="tags">
 718
 719
 720         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="https://people.skolelinux.org/pere/blog/tags/standard">standard</a>, <a href="https://people.skolelinux.org/pere/blog/tags/video">video</a>.
 721
 722
 723       </div>
 724     </div>
 725     <div class="padding"></div>
 726
 727     <p style="text-align: right;"><a href="index.rss"><img src="https://people.skolelinux.org/pere/blog/xml.gif" alt="RSS feed" width="36" height="14" /></a></p>
 728     <div id="sidebar">
 729
 730
 731
 732 <h2>Archive</h2>
 733 <ul>
 734
 735 <li>2023
 736 <ul>
 737
 738 <li><a href="https://people.skolelinux.org/pere/blog/archive/2023/01/">January (2)</a></li>
 739
 740 </ul></li>
 741
 742 <li>2022
 743 <ul>
 744
 745 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/02/">February (1)</a></li>
 746
 747 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/03/">March (3)</a></li>
 748
 749 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/04/">April (2)</a></li>
 750
 751 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/06/">June (2)</a></li>
 752
 753 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/07/">July (1)</a></li>
 754
 755 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/09/">September (1)</a></li>
 756
 757 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/10/">October (1)</a></li>
 758
 759 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/12/">December (1)</a></li>
 760
 761 </ul></li>
 762
 763 <li>2021
 764 <ul>
 765
 766 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/01/">January (2)</a></li>
 767
 768 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/02/">February (1)</a></li>
 769
 770 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/05/">May (1)</a></li>
 771
 772 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/06/">June (1)</a></li>
 773
 774 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/07/">July (3)</a></li>
 775
 776 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/08/">August (1)</a></li>
 777
 778 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/09/">September (1)</a></li>
 779
 780 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/10/">October (1)</a></li>
 781
 782 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/12/">December (1)</a></li>
 783
 784 </ul></li>
 785
 786 <li>2020
 787 <ul>
 788
 789 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/02/">February (2)</a></li>
 790
 791 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/03/">March (2)</a></li>
 792
 793 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/04/">April (2)</a></li>
 794
 795 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/05/">May (3)</a></li>
 796
 797 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/06/">June (2)</a></li>
 798
 799 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/07/">July (1)</a></li>
 800
 801 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/09/">September (1)</a></li>
 802
 803 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/10/">October (1)</a></li>
 804
 805 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/11/">November (1)</a></li>
 806
 807 </ul></li>
 808
 809 <li>2019
 810 <ul>
 811
 812 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/01/">January (4)</a></li>
 813
 814 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/02/">February (3)</a></li>
 815
 816 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/03/">March (3)</a></li>
 817
 818 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/05/">May (2)</a></li>
 819
 820 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/06/">June (5)</a></li>
 821
 822 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/07/">July (2)</a></li>
 823
 824 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/08/">August (1)</a></li>
 825
 826 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/09/">September (1)</a></li>
 827
 828 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/11/">November (1)</a></li>
 829
 830 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/12/">December (4)</a></li>
 831
 832 </ul></li>
 833
 834 <li>2018
 835 <ul>
 836
 837 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/01/">January (1)</a></li>
 838
 839 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/02/">February (5)</a></li>
 840
 841 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/03/">March (5)</a></li>
 842
 843 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/04/">April (3)</a></li>
 844
 845 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/06/">June (2)</a></li>
 846
 847 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/07/">July (5)</a></li>
 848
 849 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/08/">August (3)</a></li>
 850
 851 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/09/">September (3)</a></li>
 852
 853 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/10/">October (5)</a></li>
 854
 855 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/11/">November (2)</a></li>
 856
 857 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/12/">December (4)</a></li>
 858
 859 </ul></li>
 860
 861 <li>2017
 862 <ul>
 863
 864 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/01/">January (4)</a></li>
 865
 866 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/02/">February (3)</a></li>
 867
 868 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/03/">March (5)</a></li>
 869
 870 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/04/">April (2)</a></li>
 871
 872 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/06/">June (5)</a></li>
 873
 874 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/07/">July (1)</a></li>
 875
 876 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/08/">August (1)</a></li>
 877
 878 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/09/">September (3)</a></li>
 879
 880 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/10/">October (5)</a></li>
 881
 882 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/11/">November (3)</a></li>
 883
 884 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/12/">December (4)</a></li>
 885
 886 </ul></li>
 887
 888 <li>2016
 889 <ul>
 890
 891 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/01/">January (3)</a></li>
 892
 893 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/02/">February (2)</a></li>
 894
 895 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/03/">March (3)</a></li>
 896
 897 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/04/">April (8)</a></li>
 898
 899 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/05/">May (8)</a></li>
 900
 901 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/06/">June (2)</a></li>
 902
 903 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/07/">July (2)</a></li>
 904
 905 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/08/">August (5)</a></li>
 906
 907 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/09/">September (2)</a></li>
 908
 909 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/10/">October (3)</a></li>
 910
 911 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/11/">November (8)</a></li>
 912
 913 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/12/">December (5)</a></li>
 914
 915 </ul></li>
 916
 917 <li>2015
 918 <ul>
 919
 920 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/01/">January (7)</a></li>
 921
 922 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/02/">February (6)</a></li>
 923
 924 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/03/">March (1)</a></li>
 925
 926 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/04/">April (4)</a></li>
 927
 928 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/05/">May (3)</a></li>
 929
 930 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/06/">June (4)</a></li>
 931
 932 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/07/">July (6)</a></li>
 933
 934 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/08/">August (2)</a></li>
 935
 936 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/09/">September (2)</a></li>
 937
 938 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/10/">October (9)</a></li>
 939
 940 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/11/">November (6)</a></li>
 941
 942 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/12/">December (3)</a></li>
 943
 944 </ul></li>
 945
 946 <li>2014
 947 <ul>
 948
 949 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/01/">January (2)</a></li>
 950
 951 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/02/">February (3)</a></li>
 952
 953 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/03/">March (8)</a></li>
 954
 955 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/04/">April (7)</a></li>
 956
 957 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/05/">May (1)</a></li>
 958
 959 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/06/">June (2)</a></li>
 960
 961 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/07/">July (2)</a></li>
 962
 963 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/08/">August (2)</a></li>
 964
 965 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/09/">September (5)</a></li>
 966
 967 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/10/">October (6)</a></li>
 968
 969 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/11/">November (3)</a></li>
 970
 971 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/12/">December (5)</a></li>
 972
 973 </ul></li>
 974
 975 <li>2013
 976 <ul>
 977
 978 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/01/">January (11)</a></li>
 979
 980 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/02/">February (9)</a></li>
 981
 982 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/03/">March (9)</a></li>
 983
 984 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/04/">April (6)</a></li>
 985
 986 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/05/">May (9)</a></li>
 987
 988 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/06/">June (10)</a></li>
 989
 990 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/07/">July (7)</a></li>
 991
 992 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/08/">August (3)</a></li>
 993
 994 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/09/">September (5)</a></li>
 995
 996 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/10/">October (7)</a></li>
 997
 998 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/11/">November (9)</a></li>
 999
1000 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/12/">December (3)</a></li>
1001
1002 </ul></li>
1003
1004 <li>2012
1005 <ul>
1006
1007 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/01/">January (7)</a></li>
1008
1009 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/02/">February (10)</a></li>
1010
1011 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/03/">March (17)</a></li>
1012
1013 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/04/">April (12)</a></li>
1014
1015 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/05/">May (12)</a></li>
1016
1017 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/06/">June (20)</a></li>
1018
1019 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/07/">July (17)</a></li>
1020
1021 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/08/">August (6)</a></li>
1022
1023 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/09/">September (9)</a></li>
1024
1025 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/10/">October (17)</a></li>
1026
1027 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/11/">November (10)</a></li>
1028
1029 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/12/">December (7)</a></li>
1030
1031 </ul></li>
1032
1033 <li>2011
1034 <ul>
1035
1036 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
1037
1038 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
1039
1040 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/03/">March (6)</a></li>
1041
1042 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/04/">April (7)</a></li>
1043
1044 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/05/">May (3)</a></li>
1045
1046 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/06/">June (2)</a></li>
1047
1048 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/07/">July (7)</a></li>
1049
1050 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/08/">August (6)</a></li>
1051
1052 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/09/">September (4)</a></li>
1053
1054 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/10/">October (2)</a></li>
1055
1056 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/11/">November (3)</a></li>
1057
1058 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
1059
1060 </ul></li>
1061
1062 <li>2010
1063 <ul>
1064
1065 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
1066
1067 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
1068
1069 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/03/">March (3)</a></li>
1070
1071 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/04/">April (3)</a></li>
1072
1073 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
1074
1075 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/06/">June (14)</a></li>
1076
1077 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
1078
1079 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/08/">August (13)</a></li>
1080
1081 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
1082
1083 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
1084
1085 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
1086
1087 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
1088
1089 </ul></li>
1090
1091 <li>2009
1092 <ul>
1093
1094 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
1095
1096 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
1097
1098 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/03/">March (12)</a></li>
1099
1100 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
1101
1102 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/05/">May (9)</a></li>
1103
1104 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/06/">June (3)</a></li>
1105
1106 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/07/">July (4)</a></li>
1107
1108 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/08/">August (3)</a></li>
1109
1110 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
1111
1112 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
1113
1114 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
1115
1116 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
1117
1118 </ul></li>
1119
1120 <li>2008
1121 <ul>
1122
1123 <li><a href="https://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
1124
1125 <li><a href="https://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
1126
1127 </ul></li>
1128
1129 </ul>
1130
1131
1132
1133 <h2>Tags</h2>
1134 <ul>
1135
1136  <li><a href="https://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (19)</a></li>
1137
1138  <li><a href="https://people.skolelinux.org/pere/blog/tags/amiga">amiga (1)</a></li>
1139
1140  <li><a href="https://people.skolelinux.org/pere/blog/tags/aros">aros (1)</a></li>
1141
1142  <li><a href="https://people.skolelinux.org/pere/blog/tags/bankid">bankid (4)</a></li>
1143
1144  <li><a href="https://people.skolelinux.org/pere/blog/tags/betalkontant">betalkontant (9)</a></li>
1145
1146  <li><a href="https://people.skolelinux.org/pere/blog/tags/bitcoin">bitcoin (12)</a></li>
1147
1148  <li><a href="https://people.skolelinux.org/pere/blog/tags/bootsystem">bootsystem (17)</a></li>
1149
1150  <li><a href="https://people.skolelinux.org/pere/blog/tags/bsa">bsa (2)</a></li>
1151
1152  <li><a href="https://people.skolelinux.org/pere/blog/tags/chrpath">chrpath (2)</a></li>
1153
1154  <li><a href="https://people.skolelinux.org/pere/blog/tags/debian">debian (186)</a></li>
1155
1156  <li><a href="https://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (159)</a></li>
1157
1158  <li><a href="https://people.skolelinux.org/pere/blog/tags/debian-handbook">debian-handbook (9)</a></li>
1159
1160  <li><a href="https://people.skolelinux.org/pere/blog/tags/digistan">digistan (11)</a></li>
1161
1162  <li><a href="https://people.skolelinux.org/pere/blog/tags/dld">dld (18)</a></li>
1163
1164  <li><a href="https://people.skolelinux.org/pere/blog/tags/docbook">docbook (30)</a></li>
1165
1166  <li><a href="https://people.skolelinux.org/pere/blog/tags/drivstoffpriser">drivstoffpriser (4)</a></li>
1167
1168  <li><a href="https://people.skolelinux.org/pere/blog/tags/english">english (442)</a></li>
1169
1170  <li><a href="https://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (23)</a></li>
1171
1172  <li><a href="https://people.skolelinux.org/pere/blog/tags/fildeling">fildeling (14)</a></li>
1173
1174  <li><a href="https://people.skolelinux.org/pere/blog/tags/freeculture">freeculture (34)</a></li>
1175
1176  <li><a href="https://people.skolelinux.org/pere/blog/tags/freedombox">freedombox (9)</a></li>
1177
1178  <li><a href="https://people.skolelinux.org/pere/blog/tags/frikanalen">frikanalen (20)</a></li>
1179
1180  <li><a href="https://people.skolelinux.org/pere/blog/tags/h264">h264 (20)</a></li>
1181
1182  <li><a href="https://people.skolelinux.org/pere/blog/tags/intervju">intervju (43)</a></li>
1183
1184  <li><a href="https://people.skolelinux.org/pere/blog/tags/isenkram">isenkram (16)</a></li>
1185
1186  <li><a href="https://people.skolelinux.org/pere/blog/tags/kart">kart (23)</a></li>
1187
1188  <li><a href="https://people.skolelinux.org/pere/blog/tags/kodi">kodi (4)</a></li>
1189
1190  <li><a href="https://people.skolelinux.org/pere/blog/tags/ldap">ldap (9)</a></li>
1191
1192  <li><a href="https://people.skolelinux.org/pere/blog/tags/lego">lego (5)</a></li>
1193
1194  <li><a href="https://people.skolelinux.org/pere/blog/tags/lenker">lenker (8)</a></li>
1195
1196  <li><a href="https://people.skolelinux.org/pere/blog/tags/linuxcnc">linuxcnc (4)</a></li>
1197
1198  <li><a href="https://people.skolelinux.org/pere/blog/tags/lsdvd">lsdvd (2)</a></li>
1199
1200  <li><a href="https://people.skolelinux.org/pere/blog/tags/ltsp">ltsp (1)</a></li>
1201
1202  <li><a href="https://people.skolelinux.org/pere/blog/tags/madewithcc">madewithcc (3)</a></li>
1203
1204  <li><a href="https://people.skolelinux.org/pere/blog/tags/mesh network">mesh network (8)</a></li>
1205
1206  <li><a href="https://people.skolelinux.org/pere/blog/tags/multimedia">multimedia (44)</a></li>
1207
1208  <li><a href="https://people.skolelinux.org/pere/blog/tags/nice free software">nice free software (13)</a></li>
1209
1210  <li><a href="https://people.skolelinux.org/pere/blog/tags/noark5">noark5 (23)</a></li>
1211
1212  <li><a href="https://people.skolelinux.org/pere/blog/tags/norsk">norsk (320)</a></li>
1213
1214  <li><a href="https://people.skolelinux.org/pere/blog/tags/nuug">nuug (198)</a></li>
1215
1216  <li><a href="https://people.skolelinux.org/pere/blog/tags/offentlig innsyn">offentlig innsyn (40)</a></li>
1217
1218  <li><a href="https://people.skolelinux.org/pere/blog/tags/open311">open311 (2)</a></li>
1219
1220  <li><a href="https://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett (75)</a></li>
1221
1222  <li><a href="https://people.skolelinux.org/pere/blog/tags/personvern">personvern (114)</a></li>
1223
1224  <li><a href="https://people.skolelinux.org/pere/blog/tags/raid">raid (2)</a></li>
1225
1226  <li><a href="https://people.skolelinux.org/pere/blog/tags/reactos">reactos (1)</a></li>
1227
1228  <li><a href="https://people.skolelinux.org/pere/blog/tags/reprap">reprap (11)</a></li>
1229
1230  <li><a href="https://people.skolelinux.org/pere/blog/tags/rfid">rfid (3)</a></li>
1231
1232  <li><a href="https://people.skolelinux.org/pere/blog/tags/robot">robot (17)</a></li>
1233
1234  <li><a href="https://people.skolelinux.org/pere/blog/tags/rss">rss (1)</a></li>
1235
1236  <li><a href="https://people.skolelinux.org/pere/blog/tags/ruter">ruter (7)</a></li>
1237
1238  <li><a href="https://people.skolelinux.org/pere/blog/tags/scraperwiki">scraperwiki (2)</a></li>
1239
1240  <li><a href="https://people.skolelinux.org/pere/blog/tags/sikkerhet">sikkerhet (59)</a></li>
1241
1242  <li><a href="https://people.skolelinux.org/pere/blog/tags/sitesummary">sitesummary (4)</a></li>
1243
1244  <li><a href="https://people.skolelinux.org/pere/blog/tags/skepsis">skepsis (5)</a></li>
1245
1246  <li><a href="https://people.skolelinux.org/pere/blog/tags/standard">standard (74)</a></li>
1247
1248  <li><a href="https://people.skolelinux.org/pere/blog/tags/stavekontroll">stavekontroll (7)</a></li>
1249
1250  <li><a href="https://people.skolelinux.org/pere/blog/tags/stortinget">stortinget (14)</a></li>
1251
1252  <li><a href="https://people.skolelinux.org/pere/blog/tags/surveillance">surveillance (64)</a></li>
1253
1254  <li><a href="https://people.skolelinux.org/pere/blog/tags/sysadmin">sysadmin (5)</a></li>
1255
1256  <li><a href="https://people.skolelinux.org/pere/blog/tags/usenix">usenix (2)</a></li>
1257
1258  <li><a href="https://people.skolelinux.org/pere/blog/tags/valg">valg (9)</a></li>
1259
1260  <li><a href="https://people.skolelinux.org/pere/blog/tags/verkidetfri">verkidetfri (20)</a></li>
1261
1262  <li><a href="https://people.skolelinux.org/pere/blog/tags/video">video (77)</a></li>
1263
1264  <li><a href="https://people.skolelinux.org/pere/blog/tags/vitenskap">vitenskap (4)</a></li>
1265
1266  <li><a href="https://people.skolelinux.org/pere/blog/tags/web">web (42)</a></li>
1267
1268 </ul>
1269
1270
1271     </div>
1272     <p style="text-align: right">
1273  Created by <a href="http://steve.org.uk/Software/chronicle">Chronicle v4.6</a>
1274 </p>
1275
1276   </body>
1277 </html>