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