blog/index.html

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
   2           "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
   3 <html xmlns="http://www.w3.org/1999/xhtml" dir="ltr">
   4   <head>
   5     <meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
   6     <title>Petter Reinholdtsen</title>
   7     <link rel="stylesheet" type="text/css" media="screen" href="https://people.skolelinux.org/pere/blog/style.css" />
   8     <link rel="stylesheet" type="text/css" media="screen" href="https://people.skolelinux.org/pere/blog/vim.css" />
   9     <link rel="alternate" title="RSS Feed" href="https://people.skolelinux.org/pere/blog/index.rss" type="application/rss+xml" />
  10   </head>
  11   <body>
  12     <div class="title">
  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/Managing_and_using_ONVIF_IP_cameras_with_Linux.html">Managing and using ONVIF IP cameras with Linux</a></div>
  24       <div class="date">19th October 2022</div>
  25       <div class="body"><p>Recently I have been looking at how to control and collect data
  26 from a handful IP cameras using Linux.  I both wanted to change their
  27 settings and to make their imagery available via a free software
  28 service under my control.  Here is a summary of the tools I found.</p>
  29
  30 <p>First I had to identify the cameras and their protocols.  As far as
  31 I could tell, they were using some SOAP looking protocol and their
  32 internal web server seem to only work with Microsoft Internet Explorer
  33 with some proprietary binary plugin, which in these days of course is
  34 a security disaster and also made it impossible for me to use the
  35 camera web interface.  Luckily I discovered that the SOAP looking
  36 protocol is actually following <a href="https://www.onvif.org/">the
  37 ONVIF specification</a>, which seem to be supported by a lot of IP
  38 cameras these days.</p>
  39
  40 <p>Once the protocol was identified, I was able to find what appear to
  41 be the most popular way to configure ONVIF cameras, the free software
  42 Windows tool named
  43 <a href="https://sourceforge.net/projects/onvifdm/">ONVIF Device
  44 Manager</a>.  Lacking any other options at the time, I tried
  45 unsuccessfully to get it running using Wine, but was missing a dotnet
  46 40 library and I found no way around it to run it on Linux.</p>
  47
  48 <p>The next tool I found to configure the cameras were a non-free Linux Qt
  49 client <a href="https://www.lingodigit.com/onvif_nvcdemo.html">ONVIF
  50 Device Tool</a>.  I did not like its terms of use, so did not spend
  51 much time on it.</p>
  52
  53 <p>To collect the video and make it available in a web interface, I
  54 found the Zoneminder tool in Debian.  A recent version was able to
  55 automatically detect and configure ONVIF devices, so I could use it to
  56 set up motion detection in and collection of the camera output.  I had
  57 initial problems getting the ONVIF autodetection to work, as both
  58 Firefox and Chromium <a href="https://bugs.debian.org/1001188">refused
  59 the inter-tab communication</a> being used by the Zoneminder web
  60 pages, but managed to get konqueror to work.  Apparently the "Enhanced
  61 Tracking Protection" in Firefox cause the problem.  I ended up
  62 upgrading to the Bookworm edition of Zoneminder in the process to try
  63 to fix the issue, and believe the problem might be solved now.</p>
  64
  65 <p>In the process I came across the nice Linux GUI tool
  66 <a href="https://gitlab.com/caspermeijn/onvifviewer/">ONVIF Viewer</a>
  67 allowing me to preview the camera output and validate the login
  68 passwords required.  Sadly its author has grown tired of maintaining
  69 the software, so it might not see any future updates.  Which is sad,
  70 as the viewer is sightly unstable and the picture tend to lock up.
  71 Note, this lockup might be due to limitations in the cameras and not
  72 the viewer implementation.  I suspect the camera is only able to
  73 provide pictures to one client at the time, and the Zoneminder feed
  74 might interfere with the GUI viewer.  I have
  75 <a href="https://bugs.debian.org/1000820">asked for the tool to be
  76 included in Debian</a>.</p>
  77
  78 <p>Finally, I found what appear to be very nice Linux free software
  79 replacement for the Windows tool, named
  80 <a href="https://github.com/sr99622/libonvif/">libonvif</a>.  It
  81 provide a C library to talk to ONVIF devices as well as a command line
  82 and GUI tool using the library.  Using the GUI tool I was able to change
  83 the admin passwords and update other settings of the cameras.  I have
  84 <a href="https://bugs.debian.org/1021980">asked for the package to be
  85 included in Debian</a>.</p>
  86
  87 <p>As usual, if you use Bitcoin and want to show your support of my
  88 activities, please send Bitcoin donations to my address
  89 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
  90
  91 <p><strong>Update 2022-10-20</strong>: Since my initial publication of
  92 this text, I got several suggestions for more free software Linux
  93 tools.  There is <a href="https://github.com/quatanium/python-onvif">a
  94 ONVIF python library</a> (already
  95 <a href="https://bugs.debian.org/824240">requested into Debian</a>) and
  96 <a href="https://github.com/FalkTannhaeuser/python-onvif-zeep">a python 3
  97 fork</a> using a different SOAP dependency.  There is also
  98 <a href="https://www.home-assistant.io/integrations/onvif/">support for
  99 ONVIF in Home Assistant</a>, and there is an alternative to Zoneminder
 100 called <a href="https://www.shinobi.video/">Shinobi</a>.  The latter
 101 two are not included in Debian either.  I have not tested any of these
 102 so far.</p>
 103 </div>
 104       <div class="tags">
 105
 106
 107         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>.
 108
 109
 110       </div>
 111     </div>
 112     <div class="padding"></div>
 113
 114     <div class="entry">
 115       <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>
 116       <div class="date">12th September 2022</div>
 117       <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>
 118
 119 <p>(The picture is of the previous edition.)</p>
 120
 121 <p>Almost two years after the previous Norwegian Bokmål translation of
 122 the "<a href="https://debian-handbook.info/">The Debian Administrator's
 123 Handbook</a>" was published, a new edition is finally being prepared.  The
 124 english text is updated, and it is time to start working on the
 125 translations.  Around 37 percent of the strings have been updated, one
 126 way or another, and the translations starting from a complete Debian Buster
 127 edition now need to bring their translation up from 63% to 100%.  The
 128 complete book is licensed using a Creative Commons license, and has
 129 been published in several languages over the years.  The translations
 130 are done by volunteers to bring Linux in their native tongue.  The
 131 last time I checked, it complete text was available in English,
 132 Norwegian Bokmål, German, Indonesian, Brazil Portuguese and Spanish.
 133 In addition, work has been started for Arabic (Morocco), Catalan,
 134 Chinese (Simplified), Chinese (Traditional), Croatian, Czech, Danish,
 135 Dutch, French, Greek, Italian, Japanese, Korean, Persian, Polish,
 136 Romanian, Russian, Swedish, Turkish and Vietnamese.</p>
 137
 138 <p>The translation is conducted on
 139 <a href="https://hosted.weblate.org/projects/debian-handbook/">the
 140 hosted weblate project page</a>.  Prospective translators are
 141 recommeded to subscribe to
 142 <a href="http://lists.alioth.debian.org/mailman/listinfo/debian-handbook-translators">the
 143 translators mailing list</a> and should also check out
 144 <a href="https://debian-handbook.info/contribute/">the instructions for
 145 contributors</a>.</p>
 146
 147 <p>I am one of the Norwegian Bokmål translators of this book, and we
 148 have just started.  Your contribution is most welcome.</p>
 149
 150 <p>As usual, if you use Bitcoin and want to show your support of my
 151 activities, please send Bitcoin donations to my address
 152 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 153 </div>
 154       <div class="tags">
 155
 156
 157         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>.
 158
 159
 160       </div>
 161     </div>
 162     <div class="padding"></div>
 163
 164     <div class="entry">
 165       <div class="title"><a href="https://people.skolelinux.org/pere/blog/Automatic_LinuxCNC_servo_PID_tuning_.html">Automatic LinuxCNC servo PID tuning?</a></div>
 166       <div class="date">16th July 2022</div>
 167       <div class="body"><p>While working on a CNC with servo motors controlled by the
 168 <a href="https://en.wikipedia.org/wiki/LinuxCNC">LinuxCNC</a>
 169 <a href="https://en.wikipedia.org/wiki/PID_controller">PID
 170 controller</a>, I recently had to learn how to tune the collection of values
 171 that control such mathematical machinery that a PID controller is.  It
 172 proved to be a lot harder than I hoped, and I still have not succeeded
 173 in getting the Z PID controller to successfully defy gravity, nor X
 174 and Y to move accurately and reliably.  But while climbing up this
 175 rather steep learning curve, I discovered that some motor control
 176 systems are able to tune their PID controllers.  I got the impression
 177 from the documentation that LinuxCNC were not.  This proved to be not
 178 true</p>
 179
 180 <p>The LinuxCNC
 181 <a href="http://linuxcnc.org/docs/html/man/man9/pid.9.html">pid
 182 component</a> is the recommended PID controller to use.  It uses eight
 183 constants <tt>Pgain</tt>, <tt>Igain</tt>, <tt>Dgain</tt>,
 184 <tt>bias</tt>, <tt>FF0</tt>, <tt>FF1</tt>, <tt>FF2</tt> and
 185 <tt>FF3</tt> to calculate the output value based on current and wanted
 186 state, and all of these need to have a sensible value for the
 187 controller to behave properly.  Note, there are even more values
 188 involved, theser are just the most important ones.  In my case I need
 189 the X, Y and Z axes to follow the requested path with little error.
 190 This has proved quite a challenge for someone who have never tuned a
 191 PID controller before, but there is at least some help to be found.
 192
 193 <p>I discovered that included in LinuxCNC was this old PID component
 194 at_pid claiming to have auto tuning capabilities.  Sadly it had been
 195 neglected since 2011, and could not be used as a plug in replacement
 196 for the default pid component.  One would have to rewriting the
 197 LinuxCNC HAL setup to test at_pid.  This was rather sad, when I wanted
 198 to quickly test auto tuning to see if it did a better job than me at
 199 figuring out good P, I and D values to use.</p>
 200
 201 <p>I decided to have a look if the situation could be improved.  This
 202 involved trying to understand the code and history of the pid and
 203 at_pid components.  Apparently they had a common ancestor, as code
 204 structure, comments and variable names were quite close to each other.
 205 Sadly this was not reflected in the git history, making it hard to
 206 figure out what really happened.  My guess is that the author of
 207 <a href="https://github.com/LinuxCNC/linuxcnc/blob/master/src/hal/components/at_pid.c">at_pid.c</a>
 208 took a version of
 209 <a href="https://github.com/LinuxCNC/linuxcnc/blob/master/src/hal/components/pid.c">pid.c</a>,
 210 rewrote it to follow the structure he wished pid.c to have, then added
 211 support for auto tuning and finally got it included into the LinuxCNC
 212 repository.  The restructuring and lack of early history made it
 213 harder to figure out which part of the code were relevant to the auto
 214 tuning, and which part of the code needed to be updated to work the
 215 same way as the current pid.c implementation.  I started by trying to
 216 isolate relevant changes in pid.c, and applying them to at_pid.c.  My
 217 aim was to make sure the at_pid component could replace the pid
 218 component with a simple change in the HAL setup loadrt line, without
 219 having to "rewire" the rest of the HAL configuration.  After a few
 220 hours following this approach, I had learned quite a lot about the
 221 code structure of both components, while concluding I was heading down
 222 the wrong rabbit hole, and should get back to the surface and find a
 223 different path.</p>
 224
 225 <p>For the second attempt, I decided to throw away all the PID control
 226 related part of the original at_pid.c, and instead isolate and lift
 227 the auto tuning part of the code and inject it into a copy of pid.c.
 228 This ensured compatibility with the current pid component, while
 229 adding auto tuning as a run time option.  To make it easier to identify
 230 the relevant parts in the future, I wrapped all the auto tuning code
 231 with '#ifdef AUTO_TUNER'.  The end result behave just like the current
 232 pid component by default, as that part of the code is identical.  The
 233 <a href="https://github.com/LinuxCNC/linuxcnc/pull/1820">end result
 234 entered the LinuxCNC master branch</a> a few days ago.</p>
 235
 236 <p>To enable auto tuning, one need to set a few HAL pins in the PID
 237 component.  The most important ones are <tt>tune-effort</tt>,
 238 <tt>tune-mode</tt> and <tt>tune-start</tt>.  But lets take a step
 239 back, and see what the auto tuning code will do.  I do not know the
 240 mathematical foundation of the at_pid algorithm, but from observation
 241 I can tell that the algorithm will, when enabled, produce a square
 242 wave pattern centered around the <tt>bias</tt> value on the output pin
 243 of the PID controller.  This can be seen using the HAL Scope provided
 244 by LinuxCNC.  In my case, this is translated into voltage (+-10V) sent
 245 to the motor controller, which in turn is translated into motor speed.
 246 So at_pid will ask the motor to move the axis back and forth.  The
 247 number of cycles in the pattern is controlled by the
 248 <tt>tune-cycles</tt> pin, and the extremes of the wave pattern is
 249 controlled by the <tt>tune-effort</tt> pin.  Of course, trying to
 250 change the direction of a physical object instantly (as in going
 251 directly from a positive voltage to the equivalent negative voltage)
 252 do not change velocity instantly, and it take some time for the object
 253 to slow down and move in the opposite direction.  This result in a
 254 more smooth movement wave form, as the axis in question were vibrating
 255 back and forth.  When the axis reached the target speed in the
 256 opposing direction, the auto tuner change direction again.  After
 257 several of these changes, the average time delay between the 'peaks'
 258 and 'valleys' of this movement graph is then used to calculate
 259 proposed values for Pgain, Igain and Dgain, and insert them into the
 260 HAL model to use by the pid controller.  The auto tuned settings are
 261 not great, but htye work a lot better than the values I had been able
 262 to cook up on my own, at least for the horizontal X and Y axis.  But I
 263 had to use very small <tt>tune-effort<tt> values, as my motor
 264 controllers error out if the voltage change too quickly.  I've been
 265 less lucky with the Z axis, which is moving a heavy object up and
 266 down, and seem to confuse the algorithm.  The Z axis movement became a
 267 lot better when I introduced a <tt>bias</tt> value to counter the
 268 gravitational drag, but I will have to work a lot more on the Z axis
 269 PID values.</p>
 270
 271 <p>Armed with this knowledge, it is time to look at how to do the
 272 tuning.  Lets say the HAL configuration in question load the PID
 273 component for X, Y and Z like this:</p>
 274
 275 <blockquote><pre>
 276 loadrt pid names=pid.x,pid.y,pid.z
 277 </pre></blockquote>
 278
 279 <p>Armed with the new and improved at_pid component, the new line will
 280 look like this:</p>
 281
 282 <blockquote><pre>
 283 loadrt at_pid names=pid.x,pid.y,pid.z
 284 </pre></blockquote>
 285
 286 <p>The rest of the HAL setup can stay the same.  This work because the
 287 components are referenced by name.  If the component had used count=3
 288 instead, all use of pid.# had to be changed to at_pid.#.</p>
 289
 290 <p>To start tuning the X axis, move the axis to the middle of its
 291 range, to make sure it do not hit anything when it start moving back
 292 and forth.  Next, set the <tt>tune-effort</tt> to a low number in the
 293 output range.  I used 0.1 as my initial value.  Next, assign 1 to the
 294 <tt>tune-mode</tt> value. Note, this will disable the pid controlling
 295 part and feed 0 to the output pin, which in my case initially caused a
 296 lot of drift.  In my case it proved to be a good idea with X and Y to
 297 tune the motor driver to make sure 0 voltage stopped the motor
 298 rotation.  On the other hand, for the Z axis this proved to be a bad
 299 idea, so it will depend on your setup.  It might help to set the
 300 <tt>bias</tt> value to a output value that reduce or eliminate the
 301 axis drift.  Finally, after setting <tt>tune-mode</tt>, set
 302 <tt>tune-start</tt> to 1 to activate the auto tuning.  If all go well,
 303 your axis will vibrate for a few seconds and when it is done, new
 304 values for Pgain, Igain and Dgain will be active.  To test them,
 305 change <tt>tune-mode</tt> back to 0.  Note that this might cause the
 306 machine to suddenly jerk as it bring the axis back to its commanded
 307 position, which it might have drifted away from during tuning.  To
 308 summarize with some halcmd lines:</p>
 309
 310 <blockquote><pre>
 311 setp pid.x.tune-effort 0.1
 312 setp pid.x.tune-mode 1
 313 setp pid.x.tune-start 1
 314 # wait for the tuning to complete
 315 setp pid.x.tune-mode 0
 316 </pre></blockquote>
 317
 318 <p>After doing this task quite a few times while trying to figure out
 319 how to properly tune the PID controllers on the machine in, I decided
 320 to figure out if this process could be automated, and wrote a script
 321 to do the entire tuning process from power on.  The end result will
 322 ensure the machine is powered on and ready to run, home all axis if it
 323 is not already done, check that the extra tuning pins are available,
 324 move the axis to its mid point, run the auto tuning and re-enable the
 325 pid controller when it is done.  It can be run several times.  Check
 326 out the
 327 <a href="https://github.com/SebKuzminsky/MazakVQC1540/blob/bon-dev/scripts/run-auto-pid-tuner">run-auto-pid-tuner</a>
 328 script on github if you want to learn how it is done.</p>
 329
 330 <p>My hope is that this little adventure can inspire someone who know
 331 more about motor PID controller tuning can implement even better
 332 algorithms for automatic PID tuning in LinuxCNC, making life easier
 333 for both me and all the others that want to use LinuxCNC but lack the
 334 in depth knowledge needed to tune PID controllers well.</p>
 335
 336 <p>As usual, if you use Bitcoin and want to show your support of my
 337 activities, please send Bitcoin donations to my address
 338 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 339 </div>
 340       <div class="tags">
 341
 342
 343         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/robot">robot</a>.
 344
 345
 346       </div>
 347     </div>
 348     <div class="padding"></div>
 349
 350     <div class="entry">
 351       <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>
 352       <div class="date">20th June 2022</div>
 353       <div class="body"><p>I guess it is time to bring some light on the various free software
 354 and open culture activities and projects I have worked on or been
 355 involved in the last year and a half.</p>
 356
 357 <p>First, lets mention the book
 358 <a href="http://www.hungry.com/~pere/publisher/">releases I managed to
 359 publish</a>.  The Cory Doctorow book "Hvordan knuse
 360 overvåkningskapitalismen" argue that it is not the magic machine
 361 learning of the big technology companies that causes the surveillance
 362 capitalism to thrive, it is the lack of trust busting to enforce
 363 existing anti-monopoly laws.  I also published a family of
 364 dictionaries for machinists, one sorted on the English words, one
 365 sorted on the Norwegian and the last sorted on the North Sámi words.
 366 A bit on the back burner but not forgotten is the Debian
 367 Administrators Handbook, where a new edition is being worked on.  I
 368 have not spent as much time as I want to help bring it to completion,
 369 but hope I will get more spare time to look at it before the end of
 370 the year.</p>
 371
 372 <p>With my Debian had I have spent time on several projects, both
 373 updating existing packages, helping to bring in new packages and
 374 working with upstream projects to try to get them ready to go into
 375 Debian.  The list is rather long, and I will only mention my own
 376 isenkram, openmotor, vlc bittorrent plugin, xprintidle, norwegian
 377 letter style for latex, bs1770gain, and recordmydesktop.  In addition
 378 to these I have sponsored several packages into Debian, like audmes.</p>
 379
 380 <p>The last year I have looked at several infrastructure projects for
 381 collecting meter data and video surveillance recordings.  This include
 382 several ONVIF related tools like onvifviewer and zoneminder as well as
 383 rtl-433, wmbusmeters and rtl-wmbus.</p>
 384
 385 <p>In parallel with this I have looked at fabrication related free
 386 software solutions like pycam and LinuxCNC.  The latter recently
 387 gained improved translation support using po4a and weblate, which was
 388 a harder nut to crack that I had anticipated when I started.</p>
 389
 390 <p>Several hours have been spent translating free software to
 391 Norwegian Bokmål on the Weblate hosted service.  Do not have a
 392 complete list, but you will find my contributions in at least gnucash,
 393 minetest and po4a.</p>
 394
 395 <p>I also spent quite some time on the Norwegian archiving specification
 396 Noark 5, and its companion project Nikita implementing the API
 397 specification for Noark 5.</p>
 398
 399 <p>Recently I have been looking into free software tools to do company
 400 accounting here in Norway., which present an interesting mix between
 401 law, rules, regulations, format specifications and API interfaces.</p>
 402
 403 <p>I guess I should also mention the Norwegian community driven
 404 government interfacing projects Mimes Brønn and Fiksgatami, which have
 405 ended up in a kind of limbo while the future of the projects is being
 406 worked out.</p>
 407
 408 <p>These are just a few of the projects I have been involved it, and
 409 would like to give more visibility.  I'll stop here to avoid delaying
 410 this post.</p>
 411
 412 <p>As usual, if you use Bitcoin and want to show your support of my
 413 activities, please send Bitcoin donations to my address
 414 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 415 </div>
 416       <div class="tags">
 417
 418
 419         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/english">english</a>.
 420
 421
 422       </div>
 423     </div>
 424     <div class="padding"></div>
 425
 426     <div class="entry">
 427       <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>
 428       <div class="date"> 3rd June 2022</div>
 429       <div class="body"><p>Back in oktober last year, when I started looking at the
 430 <a href="https://en.wikipedia.org/wiki/LinuxCNC">LinuxCNC</a> system, I
 431 proposed to change the documentation build system make life easier for
 432 translators.  The original system consisted of independently written
 433 documentation files for each language, with no automated way to track
 434 changes done in other translations and no help for the translators to
 435 know how much was left to translated.  By using
 436 <a href="https://po4a.org/">the po4a system</a> to generate POT and PO
 437 files from the English documentation, this can be improved.  A small
 438 team of LinuxCNC contributors got together and today our labour
 439 finally payed off.  Since a few hours ago, it is now possible to
 440 translate <a href="https://hosted.weblate.org/projects/linuxcnc/">the
 441 LinuxCNC documentation on Weblate</a>, alongside the program itself.</p>
 442
 443 <p>The effort to migrate the documentation to use po4a has been both
 444 slow and frustrating.  I am very happy we finally made it.</p>
 445
 446 <p>As usual, if you use Bitcoin and want to show your support of my
 447 activities, please send Bitcoin donations to my address
 448 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 449 </div>
 450       <div class="tags">
 451
 452
 453         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/robot">robot</a>.
 454
 455
 456       </div>
 457     </div>
 458     <div class="padding"></div>
 459
 460     <div class="entry">
 461       <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>
 462       <div class="date">20th April 2022</div>
 463       <div class="body"><p>Recently I wanted to upgrade the firmware of my thinkpad, and
 464 located the firmware download page from Lenovo (which annoyingly do
 465 not allow access via Tor, forcing me to hand them more personal
 466 information that I would like).  The
 467 <a href="https://support.lenovo.com/no/en/search?query=thinkpad firmware bios upgrade iso&SearchType=Customer search&searchLocation=Masthead">download
 468 from Lenovo</a> is a bootable ISO image, which is a bit of a problem
 469 when all I got available is a USB memory stick.  I tried booting the
 470 ISO as a USB stick, but this did not work.  But genisoimage came to
 471 the rescue.</p>
 472
 473 <P>The geteltorito program in
 474 <a href="http://tracker.debian.org/cdrkit">the genisoimage binary
 475 package</a> is able to convert the bootable ISO image to a bootable
 476 USB stick using a simple command line recipe, which I then can write
 477 to the most recently inserted USB stick:</p>
 478
 479 <blockquote><pre>
 480 geteltorito -o usbstick.img lenovo-firmware.iso
 481 sudo dd bs=10M if=usbstick.img of=$(ls -tr /dev/sd?|tail -1)
 482 </pre></blockquote>
 483
 484 <p>This USB stick booted the firmware upgrader just fine, and in a few
 485 minutes my machine had the latest and greatest BIOS firmware in place.</p>
 486 </div>
 487       <div class="tags">
 488
 489
 490         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>.
 491
 492
 493       </div>
 494     </div>
 495     <div class="padding"></div>
 496
 497     <div class="entry">
 498       <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>
 499       <div class="date">16th April 2022</div>
 500       <div class="body"><p>Inspired by the recent news of
 501 <a href="https://slashdot.org/story/22/04/03/2039219/intel-beats-amd-and-nvidia-with-arc-gpus-full-av1-support">AV1
 502 hardware encoding support from Intel</a>, I decided to look into
 503 the state of AV1 on Linux today.  AV1 is a
 504 <a href="https://web.archive.org/web/20160618103850/http://www.digistan.org/open-standard:definition">free
 505 and open standard</a> as defined by Digistan without any royalty
 506 payment requirement, unlike its much used competitor encoding
 507 H.264.  While looking, I came across an 5 year
 508 <a href="https://askubuntu.com/questions/1061908/how-to-encode-and-playback-video-with-the-av1-codec-on-bionic-beaver-18-04">old
 509 question on askubuntu.com</a> which in turn inspired me to check out
 510 how things are in Debian Stable regarding AV1.  The test file listed
 511 in the question (askubuntu_test_aom.mp4) did not exist any more, so I
 512 tracked down a different set of test files on
 513 <a href="https://av1.webmfiles.org/">av1.webmfiles.org</a> to test them
 514 with the various video tools I had installed on my machine.  I was
 515 happy to discover that AV1 decoding and playback worked with almost
 516 every tool I tested:
 517
 518 <table align="center">
 519 <tr><td>mediainfo</td>       <td>ok</td></tr>
 520 <tr><td>dragonplayer</td>    <td>ok</td></tr>
 521 <tr><td>ffmpeg / ffplay</td> <td>ok</td></tr>
 522 <tr><td>gnome-mplayer</td>   <td>fail</td></tr>
 523 <tr><td>mplayer</td>         <td>ok</td></tr>
 524 <tr><td>mpv</td>             <td>ok</td></tr>
 525 <tr><td>parole</td>          <td>ok</td></tr>
 526 <tr><td>vlc</td>             <td>ok</td></tr>
 527 <tr><td>firefox</td>         <td>ok</td></tr>
 528 <tr><td>chromium</td>        <td>ok</td></tr>
 529 </table>
 530
 531 <p>AV1 encoding is available in Debian Stable from the aom-tools
 532 version 1.0.0.errata1-3 package, using the aomenc tool.  The encoding
 533 using the package in Debian Stable is quite slow, with the frame rate
 534 for my 10 second test video at around 0.25 fps.  My 10 second video
 535 test took 16 minutes and 11 seconds on my test machine.</p>
 536
 537 <p>I tested by first running ffmpeg and then aomenc using the recipe
 538 provided by the askubuntu recipe above.  I had to remove the
 539 '--row-mt=1' option, as it was not supported in my 1.0.0 version.  The
 540 encoding only used a single thread, according to <tt>top</tt>.</p>
 541
 542 <blockquote><pre>
 543 ffmpeg -i some-old-video.ogv -t 10 -pix_fmt yuv420p video.y4m
 544 aomenc --fps=24/1 -u 0 --codec=av1 --target-bitrate=1000 \
 545   --lag-in-frames=25 --auto-alt-ref=1 -t 24 --cpu-used=8 \
 546   --tile-columns=2 --tile-rows=2 -o output.webm video.y4m
 547 </pre></blockquote>
 548
 549 <p>As version 1.0.0 currently have several
 550 <a href="https://security-tracker.debian.org/tracker/source-package/aom">unsolved
 551 security issues in Debian Stable</a>, and to see if the recent
 552 backport <a href="https://tracker.debian.org/pkg/aom">provided in
 553 Debian</a> is any quicker, I ran <tt>apt -t bullseye-backports install
 554 aom-tools</tt> to fetch the backported version and re-encoded the
 555 video using the latest version.  This time the '--row-mt=1' option
 556 worked, and the encoding was done in 46 seconds with a frame rate of
 557 around 5.22 fps.  This time it seem to be using all my four cores to
 558 encode.  Encoding speed is still too low for streaming and real time,
 559 which would require frame rates above 25 fps, but might be good enough
 560 for offline encoding.</p>
 561
 562 <p>I am very happy to see AV1 playback working so well with the
 563 default tools in Debian Stable.  I hope the encoding situation improve
 564 too, allowing even a slow old computer like my 10 year old laptop to
 565 be used for encoding.</p>
 566
 567 <p>As usual, if you use Bitcoin and want to show your support of my
 568 activities, please send Bitcoin donations to my address
 569 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 570 </div>
 571       <div class="tags">
 572
 573
 574         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>.
 575
 576
 577       </div>
 578     </div>
 579     <div class="padding"></div>
 580
 581     <div class="entry">
 582       <div class="title"><a href="https://people.skolelinux.org/pere/blog/F__en_slutt_p__Digitale_utslipp.html">Få en slutt på Digitale utslipp</a></div>
 583       <div class="date">14th March 2022</div>
 584       <div class="body"><p>På onsdag sendte jeg følgende epost til Utdanningsetaten i Oslo
 585 kommune (UDE).  Fikk beskjed om at min henvendelse har saksnummer
 586 22/7559-1 i den
 587 <a href="https://www.oslo.kommune.no/etater-foretak-og-ombud/utdanningsetaten/postjournal-utdanningsetaten/">offentlige
 588 postjournalen til UDE</a>.  Jeg er spent på hva slags respons jeg får.
 589 Mistenker jo de fleste som sprer sine nettsideleseres
 590 personopplysninger til utlandet ikke har tenkt så nøye igjennom hva de
 591 gjør, og at det er håp om at de tenker seg litt nøyere om hvis de blir
 592 klar over problemstillingen.  Vet du noen som burde få tilsvarede
 593 beskjed og spørsmål?  Kanskje du kan sende dem en epost.  Hvis alle
 594 bidrar blir det kanskje litt bedre.</p>
 595
 596 <blockquote>
 597 <p>To: postmottak (at) osloskolen.no
 598 <br>Subject: Digitale utslipp fra osloskolens nettsider</p>
 599
 600 <p>Hei.</p>
 601
 602 <p>Jeg ser at osloskolens nettsider har digitale utslipp av
 603 personopplysninger til Google, Facebook og andre, blant annet omtalt
 604 på &lt;URL: <a href="https://aktuelt.osloskolen.no/personvernerklaring-for-osloskolen/informasjonskapsler/">https://aktuelt.osloskolen.no/personvernerklaring-for-osloskolen/informasjonskapsler/</a>
 605 >.</p>
 606
 607 <p>&lt;URL: <a href="https://webbkoll.dataskydd.net/">https://webbkoll.dataskydd.net/</a> > kan være et nyttig verktøy for å holde øye med utslippsomfanget på ulike sider.</p>
 608
 609 <p>Kanskje det er en ide å gjøre noe med det, jamfør &lt;URL: <a href="https://www.digi.no/artikler/debatt-det-enkleste-tiltaket-er-a-skru-av-google-analytics/517378">https://www.digi.no/artikler/debatt-det-enkleste-tiltaket-er-a-skru-av-google-analytics/517378</a> >?</p>
 610
 611 <p>Et alternativ til Google Analytics kan være en lokalt installert
 612 utgave av &lt;URL:
 613 <a href="https://matomo.org/">https://matomo.org/</a> >.  Den og flere
 614 andre alternativer kan finnes via
 615 &lt;URL: <a href="https://www.digi.no/artikler/sverige-vil-skrote-amerikansk-skytjeneste-her-er-alternativene/516223?key=5QsV0wRG">https://www.digi.no/artikler/sverige-vil-skrote-amerikansk-skytjeneste-her-er-alternativene/516223?key=5QsV0wRG</a> >
 616 på bakgrunn av at svenske myndigheter har innsett at dagens praksis
 617 nok er både lite lur og ulovlig.  Der henger Norge litt etter, men
 618 osloskolen har her mulighet til å være litt i forkant. :)</p>
 619
 620 <p>Fint om dere kan gi beskjed hvilket saksnummer denne henvendelsen får i
 621 offentlig postjournal når den er mottatt.</p>
 622
 623 </blockquote>
 624
 625 </p>Flere og flere innser at slik spredning av personopplysninger er
 626 ugreit.  Det har pågått i mange år.  Ser jeg blogget
 627 <a href="https://people.skolelinux.org/pere/blog/Det_er_jo_makta_som_er_mest_s_rbar_ved_massiv_overv_kning_av_Internett.html">første
 628 gang om Google Analytics i 2013</a> og
 629 <a href="https://people.skolelinux.org/pere/blog/Snurpenot_overv_kning_av_sensitiv_personinformasjon.html">analyserte
 630 omfanget i 2015</a>, men det er et langt lerret å bleke.</p>
 631
 632 <p>Som vanlig, hvis du bruker Bitcoin og ønsker å vise din støtte til
 633 det jeg driver med, setter jeg pris på om du sender Bitcoin-donasjoner
 634 til min adresse
 635 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.
 636 Merk, betaling med bitcoin er ikke anonymt. :)</p>
 637 </div>
 638       <div class="tags">
 639
 640
 641         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/norsk">norsk</a>, <a href="https://people.skolelinux.org/pere/blog/tags/personvern">personvern</a>, <a href="https://people.skolelinux.org/pere/blog/tags/surveillance">surveillance</a>.
 642
 643
 644       </div>
 645     </div>
 646     <div class="padding"></div>
 647
 648     <div class="entry">
 649       <div class="title"><a href="https://people.skolelinux.org/pere/blog/Publish_Hargassner_wood_chip_boiler_state_to_MQTT.html">Publish Hargassner wood chip boiler state to MQTT</a></div>
 650       <div class="date">12th March 2022</div>
 651       <div class="body"><p>Recently I had a look at a
 652 <a href="https://www.hargassner.at/">Hargassner</a>
 653 <a href="https://www.hargassner.at/en/products/wood-chip-boiler.html">wood
 654 chip boiler</a>, and what kind of free software can be used to monitor
 655 and control it.  The boiler can be connected to some cloud service via
 656 what the producer call an Internet Gateway, which seem to be a
 657 computer connecting to the boiler and passing the information gathered
 658 to the cloud.  I discovered the boiler controller got an IP address on
 659 the local network and listen on TCP port 23 to provide status
 660 information as a text line of numbers.  It also provide a HTTP server
 661 listening on port 80, but I have not yet figured out what it can do
 662 beside return an error code.</p>
 663
 664 <p>If I am to believe various free software implementations talking to
 665 such boiler, the interpretation of the line of numbers differ between
 666 type of boiler and software version on the boiler.  By comparing the
 667 list of numbers on the front panel of the boiler with the numbers
 668 returned via TCP, I have been able to figure out several of the
 669 numbers, but there are a lot left to understand.  I've located several
 670 temperature measurements and hours running values, as well as oxygen
 671 measurements and counters.</p>
 672
 673 I decided to write a simple parser in Python for the values I figured
 674 out so far, and a simple MQTT injector publishing both the interpreted
 675 and the unknown values on a MQTT bus to make collecting and graphing
 676 simpler.  The end result is available from the
 677 <a href="https://gitlab.com/petterreinholdtsen/hargassner2mqtt">hargassner2mqtt
 678 project page</a> on gitlab.  I very much welcome patches extending the
 679 parser to understand more values, boiler types and software versions.
 680 I do not really expect very few free software developers got their
 681 hands on such unit to experiment, but it would be fun if others too find
 682 this project useful.</p>
 683
 684 <p>As usual, if you use Bitcoin and want to show your support of my
 685 activities, please send Bitcoin donations to my address
 686 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 687 </div>
 688       <div class="tags">
 689
 690
 691         Tags: <a href="https://people.skolelinux.org/pere/blog/tags/english">english</a>.
 692
 693
 694       </div>
 695     </div>
 696     <div class="padding"></div>
 697
 698     <div class="entry">
 699       <div class="title"><a href="https://people.skolelinux.org/pere/blog/Run_your_industrial_metal_working_machine_using_Debian_.html">Run your industrial metal working machine using Debian?</a></div>
 700       <div class="date"> 2nd March 2022</div>
 701       <div class="body"><p>After many months of hard work by the good people involved in
 702 <a href="https://en.wikipedia.org/wiki/LinuxCNC">LinuxCNC</a>, the
 703 system was accepted Sunday
 704 <a href="https://tracker.debian.org/pkg/linuxcnc">into Debian</a>.
 705 Once it was available from Debian, I was surprised to discover from
 706 <a href="https://qa.debian.org/popcon.php?package=linuxcnc">its
 707 popularity-contest numbers</a> that people have been reporting its use
 708 since 2012.  <a href="http://linuxcnc.org/">Its project site</a> might
 709 be a good place to check out, but sadly is not working when visiting
 710 via Tor.</p>
 711
 712 <p>But what is LinuxCNC, you are probably wondering?  Perhaps a
 713 Wikipedia quote is in place?</p>
 714
 715 <blockquote>
 716 "LinuxCNC is a software system for numerical control of
 717 machines such as milling machines, lathes, plasma cutters, routers,
 718 cutting machines, robots and hexapods. It can control up to 9 axes or
 719 joints of a CNC machine using G-code (RS-274NGC) as input. It has
 720 several GUIs suited to specific kinds of usage (touch screen,
 721 interactive development)."
 722 </blockquote>
 723
 724 <p>It can even control 3D printers.  And even though the Wikipedia
 725 page indicate that it can only work with hard real time kernel
 726 features, it can also work with the user space soft real time features
 727 provided by the Debian kernel.
 728 <a href="https://github.com/linuxcnc/linuxcnc">The source code</a> is
 729 available from Github.  The last few months I've been involved in the
 730 translation setup for the program and documentation.  Translators are
 731 most welcome to
 732 <a href="https://hosted.weblate.org/engage/linuxcnc/">join the
 733 effort</a> using Weblate.</p>
 734
 735 <p>As usual, if you use Bitcoin and want to show your support of my
 736 activities, please send Bitcoin donations to my address
 737 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
 738 </div>
 739       <div class="tags">
 740
 741
 742         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/robot">robot</a>.
 743
 744
 745       </div>
 746     </div>
 747     <div class="padding"></div>
 748
 749     <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>
 750     <div id="sidebar">
 751
 752
 753
 754 <h2>Archive</h2>
 755 <ul>
 756
 757 <li>2022
 758 <ul>
 759
 760 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/02/">February (1)</a></li>
 761
 762 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/03/">March (3)</a></li>
 763
 764 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/04/">April (2)</a></li>
 765
 766 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/06/">June (2)</a></li>
 767
 768 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/07/">July (1)</a></li>
 769
 770 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/09/">September (1)</a></li>
 771
 772 <li><a href="https://people.skolelinux.org/pere/blog/archive/2022/10/">October (1)</a></li>
 773
 774 </ul></li>
 775
 776 <li>2021
 777 <ul>
 778
 779 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/01/">January (2)</a></li>
 780
 781 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/02/">February (1)</a></li>
 782
 783 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/05/">May (1)</a></li>
 784
 785 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/06/">June (1)</a></li>
 786
 787 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/07/">July (3)</a></li>
 788
 789 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/08/">August (1)</a></li>
 790
 791 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/09/">September (1)</a></li>
 792
 793 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/10/">October (1)</a></li>
 794
 795 <li><a href="https://people.skolelinux.org/pere/blog/archive/2021/12/">December (1)</a></li>
 796
 797 </ul></li>
 798
 799 <li>2020
 800 <ul>
 801
 802 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/02/">February (2)</a></li>
 803
 804 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/03/">March (2)</a></li>
 805
 806 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/04/">April (2)</a></li>
 807
 808 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/05/">May (3)</a></li>
 809
 810 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/06/">June (2)</a></li>
 811
 812 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/07/">July (1)</a></li>
 813
 814 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/09/">September (1)</a></li>
 815
 816 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/10/">October (1)</a></li>
 817
 818 <li><a href="https://people.skolelinux.org/pere/blog/archive/2020/11/">November (1)</a></li>
 819
 820 </ul></li>
 821
 822 <li>2019
 823 <ul>
 824
 825 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/01/">January (4)</a></li>
 826
 827 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/02/">February (3)</a></li>
 828
 829 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/03/">March (3)</a></li>
 830
 831 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/05/">May (2)</a></li>
 832
 833 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/06/">June (5)</a></li>
 834
 835 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/07/">July (2)</a></li>
 836
 837 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/08/">August (1)</a></li>
 838
 839 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/09/">September (1)</a></li>
 840
 841 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/11/">November (1)</a></li>
 842
 843 <li><a href="https://people.skolelinux.org/pere/blog/archive/2019/12/">December (4)</a></li>
 844
 845 </ul></li>
 846
 847 <li>2018
 848 <ul>
 849
 850 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/01/">January (1)</a></li>
 851
 852 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/02/">February (5)</a></li>
 853
 854 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/03/">March (5)</a></li>
 855
 856 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/04/">April (3)</a></li>
 857
 858 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/06/">June (2)</a></li>
 859
 860 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/07/">July (5)</a></li>
 861
 862 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/08/">August (3)</a></li>
 863
 864 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/09/">September (3)</a></li>
 865
 866 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/10/">October (5)</a></li>
 867
 868 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/11/">November (2)</a></li>
 869
 870 <li><a href="https://people.skolelinux.org/pere/blog/archive/2018/12/">December (4)</a></li>
 871
 872 </ul></li>
 873
 874 <li>2017
 875 <ul>
 876
 877 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/01/">January (4)</a></li>
 878
 879 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/02/">February (3)</a></li>
 880
 881 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/03/">March (5)</a></li>
 882
 883 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/04/">April (2)</a></li>
 884
 885 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/06/">June (5)</a></li>
 886
 887 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/07/">July (1)</a></li>
 888
 889 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/08/">August (1)</a></li>
 890
 891 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/09/">September (3)</a></li>
 892
 893 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/10/">October (5)</a></li>
 894
 895 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/11/">November (3)</a></li>
 896
 897 <li><a href="https://people.skolelinux.org/pere/blog/archive/2017/12/">December (4)</a></li>
 898
 899 </ul></li>
 900
 901 <li>2016
 902 <ul>
 903
 904 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/01/">January (3)</a></li>
 905
 906 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/02/">February (2)</a></li>
 907
 908 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/03/">March (3)</a></li>
 909
 910 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/04/">April (8)</a></li>
 911
 912 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/05/">May (8)</a></li>
 913
 914 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/06/">June (2)</a></li>
 915
 916 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/07/">July (2)</a></li>
 917
 918 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/08/">August (5)</a></li>
 919
 920 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/09/">September (2)</a></li>
 921
 922 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/10/">October (3)</a></li>
 923
 924 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/11/">November (8)</a></li>
 925
 926 <li><a href="https://people.skolelinux.org/pere/blog/archive/2016/12/">December (5)</a></li>
 927
 928 </ul></li>
 929
 930 <li>2015
 931 <ul>
 932
 933 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/01/">January (7)</a></li>
 934
 935 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/02/">February (6)</a></li>
 936
 937 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/03/">March (1)</a></li>
 938
 939 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/04/">April (4)</a></li>
 940
 941 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/05/">May (3)</a></li>
 942
 943 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/06/">June (4)</a></li>
 944
 945 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/07/">July (6)</a></li>
 946
 947 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/08/">August (2)</a></li>
 948
 949 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/09/">September (2)</a></li>
 950
 951 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/10/">October (9)</a></li>
 952
 953 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/11/">November (6)</a></li>
 954
 955 <li><a href="https://people.skolelinux.org/pere/blog/archive/2015/12/">December (3)</a></li>
 956
 957 </ul></li>
 958
 959 <li>2014
 960 <ul>
 961
 962 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/01/">January (2)</a></li>
 963
 964 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/02/">February (3)</a></li>
 965
 966 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/03/">March (8)</a></li>
 967
 968 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/04/">April (7)</a></li>
 969
 970 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/05/">May (1)</a></li>
 971
 972 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/06/">June (2)</a></li>
 973
 974 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/07/">July (2)</a></li>
 975
 976 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/08/">August (2)</a></li>
 977
 978 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/09/">September (5)</a></li>
 979
 980 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/10/">October (6)</a></li>
 981
 982 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/11/">November (3)</a></li>
 983
 984 <li><a href="https://people.skolelinux.org/pere/blog/archive/2014/12/">December (5)</a></li>
 985
 986 </ul></li>
 987
 988 <li>2013
 989 <ul>
 990
 991 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/01/">January (11)</a></li>
 992
 993 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/02/">February (9)</a></li>
 994
 995 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/03/">March (9)</a></li>
 996
 997 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/04/">April (6)</a></li>
 998
 999 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/05/">May (9)</a></li>
1000
1001 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/06/">June (10)</a></li>
1002
1003 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/07/">July (7)</a></li>
1004
1005 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/08/">August (3)</a></li>
1006
1007 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/09/">September (5)</a></li>
1008
1009 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/10/">October (7)</a></li>
1010
1011 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/11/">November (9)</a></li>
1012
1013 <li><a href="https://people.skolelinux.org/pere/blog/archive/2013/12/">December (3)</a></li>
1014
1015 </ul></li>
1016
1017 <li>2012
1018 <ul>
1019
1020 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/01/">January (7)</a></li>
1021
1022 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/02/">February (10)</a></li>
1023
1024 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/03/">March (17)</a></li>
1025
1026 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/04/">April (12)</a></li>
1027
1028 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/05/">May (12)</a></li>
1029
1030 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/06/">June (20)</a></li>
1031
1032 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/07/">July (17)</a></li>
1033
1034 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/08/">August (6)</a></li>
1035
1036 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/09/">September (9)</a></li>
1037
1038 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/10/">October (17)</a></li>
1039
1040 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/11/">November (10)</a></li>
1041
1042 <li><a href="https://people.skolelinux.org/pere/blog/archive/2012/12/">December (7)</a></li>
1043
1044 </ul></li>
1045
1046 <li>2011
1047 <ul>
1048
1049 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
1050
1051 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
1052
1053 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/03/">March (6)</a></li>
1054
1055 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/04/">April (7)</a></li>
1056
1057 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/05/">May (3)</a></li>
1058
1059 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/06/">June (2)</a></li>
1060
1061 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/07/">July (7)</a></li>
1062
1063 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/08/">August (6)</a></li>
1064
1065 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/09/">September (4)</a></li>
1066
1067 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/10/">October (2)</a></li>
1068
1069 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/11/">November (3)</a></li>
1070
1071 <li><a href="https://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
1072
1073 </ul></li>
1074
1075 <li>2010
1076 <ul>
1077
1078 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
1079
1080 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
1081
1082 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/03/">March (3)</a></li>
1083
1084 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/04/">April (3)</a></li>
1085
1086 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
1087
1088 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/06/">June (14)</a></li>
1089
1090 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
1091
1092 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/08/">August (13)</a></li>
1093
1094 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
1095
1096 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
1097
1098 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
1099
1100 <li><a href="https://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
1101
1102 </ul></li>
1103
1104 <li>2009
1105 <ul>
1106
1107 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
1108
1109 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
1110
1111 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/03/">March (12)</a></li>
1112
1113 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
1114
1115 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/05/">May (9)</a></li>
1116
1117 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/06/">June (3)</a></li>
1118
1119 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/07/">July (4)</a></li>
1120
1121 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/08/">August (3)</a></li>
1122
1123 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
1124
1125 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
1126
1127 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
1128
1129 <li><a href="https://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
1130
1131 </ul></li>
1132
1133 <li>2008
1134 <ul>
1135
1136 <li><a href="https://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
1137
1138 <li><a href="https://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
1139
1140 </ul></li>
1141
1142 </ul>
1143
1144
1145
1146 <h2>Tags</h2>
1147 <ul>
1148
1149  <li><a href="https://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (19)</a></li>
1150
1151  <li><a href="https://people.skolelinux.org/pere/blog/tags/amiga">amiga (1)</a></li>
1152
1153  <li><a href="https://people.skolelinux.org/pere/blog/tags/aros">aros (1)</a></li>
1154
1155  <li><a href="https://people.skolelinux.org/pere/blog/tags/bankid">bankid (4)</a></li>
1156
1157  <li><a href="https://people.skolelinux.org/pere/blog/tags/betalkontant">betalkontant (9)</a></li>
1158
1159  <li><a href="https://people.skolelinux.org/pere/blog/tags/bitcoin">bitcoin (12)</a></li>
1160
1161  <li><a href="https://people.skolelinux.org/pere/blog/tags/bootsystem">bootsystem (17)</a></li>
1162
1163  <li><a href="https://people.skolelinux.org/pere/blog/tags/bsa">bsa (2)</a></li>
1164
1165  <li><a href="https://people.skolelinux.org/pere/blog/tags/chrpath">chrpath (2)</a></li>
1166
1167  <li><a href="https://people.skolelinux.org/pere/blog/tags/debian">debian (183)</a></li>
1168
1169  <li><a href="https://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (159)</a></li>
1170
1171  <li><a href="https://people.skolelinux.org/pere/blog/tags/debian-handbook">debian-handbook (9)</a></li>
1172
1173  <li><a href="https://people.skolelinux.org/pere/blog/tags/digistan">digistan (11)</a></li>
1174
1175  <li><a href="https://people.skolelinux.org/pere/blog/tags/dld">dld (18)</a></li>
1176
1177  <li><a href="https://people.skolelinux.org/pere/blog/tags/docbook">docbook (30)</a></li>
1178
1179  <li><a href="https://people.skolelinux.org/pere/blog/tags/drivstoffpriser">drivstoffpriser (4)</a></li>
1180
1181  <li><a href="https://people.skolelinux.org/pere/blog/tags/english">english (439)</a></li>
1182
1183  <li><a href="https://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (23)</a></li>
1184
1185  <li><a href="https://people.skolelinux.org/pere/blog/tags/fildeling">fildeling (14)</a></li>
1186
1187  <li><a href="https://people.skolelinux.org/pere/blog/tags/freeculture">freeculture (34)</a></li>
1188
1189  <li><a href="https://people.skolelinux.org/pere/blog/tags/freedombox">freedombox (9)</a></li>
1190
1191  <li><a href="https://people.skolelinux.org/pere/blog/tags/frikanalen">frikanalen (20)</a></li>
1192
1193  <li><a href="https://people.skolelinux.org/pere/blog/tags/h264">h264 (20)</a></li>
1194
1195  <li><a href="https://people.skolelinux.org/pere/blog/tags/intervju">intervju (43)</a></li>
1196
1197  <li><a href="https://people.skolelinux.org/pere/blog/tags/isenkram">isenkram (16)</a></li>
1198
1199  <li><a href="https://people.skolelinux.org/pere/blog/tags/kart">kart (23)</a></li>
1200
1201  <li><a href="https://people.skolelinux.org/pere/blog/tags/kodi">kodi (4)</a></li>
1202
1203  <li><a href="https://people.skolelinux.org/pere/blog/tags/ldap">ldap (9)</a></li>
1204
1205  <li><a href="https://people.skolelinux.org/pere/blog/tags/lego">lego (5)</a></li>
1206
1207  <li><a href="https://people.skolelinux.org/pere/blog/tags/lenker">lenker (8)</a></li>
1208
1209  <li><a href="https://people.skolelinux.org/pere/blog/tags/lsdvd">lsdvd (2)</a></li>
1210
1211  <li><a href="https://people.skolelinux.org/pere/blog/tags/ltsp">ltsp (1)</a></li>
1212
1213  <li><a href="https://people.skolelinux.org/pere/blog/tags/madewithcc">madewithcc (3)</a></li>
1214
1215  <li><a href="https://people.skolelinux.org/pere/blog/tags/mesh network">mesh network (8)</a></li>
1216
1217  <li><a href="https://people.skolelinux.org/pere/blog/tags/multimedia">multimedia (43)</a></li>
1218
1219  <li><a href="https://people.skolelinux.org/pere/blog/tags/nice free software">nice free software (13)</a></li>
1220
1221  <li><a href="https://people.skolelinux.org/pere/blog/tags/noark5">noark5 (23)</a></li>
1222
1223  <li><a href="https://people.skolelinux.org/pere/blog/tags/norsk">norsk (320)</a></li>
1224
1225  <li><a href="https://people.skolelinux.org/pere/blog/tags/nuug">nuug (198)</a></li>
1226
1227  <li><a href="https://people.skolelinux.org/pere/blog/tags/offentlig innsyn">offentlig innsyn (40)</a></li>
1228
1229  <li><a href="https://people.skolelinux.org/pere/blog/tags/open311">open311 (2)</a></li>
1230
1231  <li><a href="https://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett (75)</a></li>
1232
1233  <li><a href="https://people.skolelinux.org/pere/blog/tags/personvern">personvern (114)</a></li>
1234
1235  <li><a href="https://people.skolelinux.org/pere/blog/tags/raid">raid (2)</a></li>
1236
1237  <li><a href="https://people.skolelinux.org/pere/blog/tags/reactos">reactos (1)</a></li>
1238
1239  <li><a href="https://people.skolelinux.org/pere/blog/tags/reprap">reprap (11)</a></li>
1240
1241  <li><a href="https://people.skolelinux.org/pere/blog/tags/rfid">rfid (3)</a></li>
1242
1243  <li><a href="https://people.skolelinux.org/pere/blog/tags/robot">robot (16)</a></li>
1244
1245  <li><a href="https://people.skolelinux.org/pere/blog/tags/rss">rss (1)</a></li>
1246
1247  <li><a href="https://people.skolelinux.org/pere/blog/tags/ruter">ruter (7)</a></li>
1248
1249  <li><a href="https://people.skolelinux.org/pere/blog/tags/scraperwiki">scraperwiki (2)</a></li>
1250
1251  <li><a href="https://people.skolelinux.org/pere/blog/tags/sikkerhet">sikkerhet (59)</a></li>
1252
1253  <li><a href="https://people.skolelinux.org/pere/blog/tags/sitesummary">sitesummary (4)</a></li>
1254
1255  <li><a href="https://people.skolelinux.org/pere/blog/tags/skepsis">skepsis (5)</a></li>
1256
1257  <li><a href="https://people.skolelinux.org/pere/blog/tags/standard">standard (73)</a></li>
1258
1259  <li><a href="https://people.skolelinux.org/pere/blog/tags/stavekontroll">stavekontroll (7)</a></li>
1260
1261  <li><a href="https://people.skolelinux.org/pere/blog/tags/stortinget">stortinget (14)</a></li>
1262
1263  <li><a href="https://people.skolelinux.org/pere/blog/tags/surveillance">surveillance (63)</a></li>
1264
1265  <li><a href="https://people.skolelinux.org/pere/blog/tags/sysadmin">sysadmin (5)</a></li>
1266
1267  <li><a href="https://people.skolelinux.org/pere/blog/tags/usenix">usenix (2)</a></li>
1268
1269  <li><a href="https://people.skolelinux.org/pere/blog/tags/valg">valg (9)</a></li>
1270
1271  <li><a href="https://people.skolelinux.org/pere/blog/tags/verkidetfri">verkidetfri (20)</a></li>
1272
1273  <li><a href="https://people.skolelinux.org/pere/blog/tags/video">video (77)</a></li>
1274
1275  <li><a href="https://people.skolelinux.org/pere/blog/tags/vitenskap">vitenskap (4)</a></li>
1276
1277  <li><a href="https://people.skolelinux.org/pere/blog/tags/web">web (42)</a></li>
1278
1279 </ul>
1280
1281
1282     </div>
1283     <p style="text-align: right">
1284  Created by <a href="http://steve.org.uk/Software/chronicle">Chronicle v4.6</a>
1285 </p>
1286
1287   </body>
1288 </html>