blog/The_life_and_death_of_a_laptop_battery.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: The life and death of a laptop battery</title>
   7     <link rel="stylesheet" type="text/css" media="screen" href="http://people.skolelinux.org/pere/blog/style.css" />
   8     <link rel="stylesheet" type="text/css" media="screen" href="http://people.skolelinux.org/pere/blog/vim.css" />
   9
  10
  11   </head>
  12   <body>
  13     <div class="title">
  14  <h1>
  15      <a href="http://people.skolelinux.org/pere/blog/">Petter Reinholdtsen</a>
  16
  17  </h1>
  18
  19 </div>
  20
  21
  22     <div class="entry">
  23       <div class="title">The life and death of a laptop battery</div>
  24       <div class="date">24th September 2015</div>
  25       <div class="body"><p>When I get a new laptop, the battery life time at the start is OK.
  26 But this do not last.  The last few laptops gave me a feeling that
  27 within a year, the life time is just a fraction of what it used to be,
  28 and it slowly become painful to use the laptop without power connected
  29 all the time.  Because of this, when I got a new Thinkpad X230 laptop
  30 about two years ago, I decided to monitor its battery state to have
  31 more hard facts when the battery started to fail.</p>
  32
  33 <img src="http://people.skolelinux.org/pere/blog/images/2015-09-24-laptop-battery-graph.png"/>
  34
  35 <p>First I tried to find a sensible Debian package to record the
  36 battery status, assuming that this must be a problem already handled
  37 by someone else.  I found
  38 <a href="https://tracker.debian.org/pkg/battery-stats">battery-stats</a>,
  39 which collects statistics from the battery, but it was completely
  40 broken.  I sent a few suggestions to the maintainer, but decided to
  41 write my own collector as a shell script while I waited for feedback
  42 from him.  Via
  43 <a href="http://www.ifweassume.com/2013/08/the-de-evolution-of-my-laptop-battery.html">a
  44 blog post about the battery development on a MacBook Air</a> I also
  45 discovered
  46 <a href="https://github.com/jradavenport/batlog.git">batlog</a>, not
  47 available in Debian.</p>
  48
  49 <p>I started my collector 2013-07-15, and it has been collecting
  50 battery stats ever since. Now my
  51 /var/log/hjemmenett-battery-status.log file contain around 115,000
  52 measurements, from the time the battery was working great until now,
  53 when it is unable to charge above 7% of original capacity.  My
  54 collector shell script is quite simple and look like this:</p>
  55
  56 <pre>
  57 #!/bin/sh
  58 # Inspired by
  59 # http://www.ifweassume.com/2013/08/the-de-evolution-of-my-laptop-battery.html
  60 # See also
  61 # http://blog.sleeplessbeastie.eu/2013/01/02/debian-how-to-monitor-battery-capacity/
  62 logfile=/var/log/hjemmenett-battery-status.log
  63
  64 files="manufacturer model_name technology serial_number \
  65     energy_full energy_full_design energy_now cycle_count status"
  66
  67 if [ ! -e "$logfile" ] ; then
  68     (
  69         printf "timestamp,"
  70         for f in $files; do
  71             printf "%s," $f
  72         done
  73         echo
  74     ) > "$logfile"
  75 fi
  76
  77 log_battery() {
  78     # Print complete message in one echo call, to avoid race condition
  79     # when several log processes run in parallel.
  80     msg=$(printf "%s," $(date +%s); \
  81         for f in $files; do \
  82             printf "%s," $(cat $f); \
  83         done)
  84     echo "$msg"
  85 }
  86
  87 cd /sys/class/power_supply
  88
  89 for bat in BAT*; do
  90     (cd $bat && log_battery >> "$logfile")
  91 done
  92 </pre>
  93
  94 <p>The script is called when the power management system detect a
  95 change in the power status (power plug in or out), and when going into
  96 and out of hibernation and suspend.  In addition, it collect a value
  97 every 10 minutes.  This make it possible for me know when the battery
  98 is discharging, charging and how the maximum charge change over time.
  99 The code for the Debian package
 100 <a href="https://github.com/petterreinholdtsen/battery-status">is now
 101 available on github</a>.</p>
 102
 103 <p>The collected log file look like this:</p>
 104
 105 <pre>
 106 timestamp,manufacturer,model_name,technology,serial_number,energy_full,energy_full_design,energy_now,cycle_count,status,
 107 1376591133,LGC,45N1025,Li-ion,974,62800000,62160000,39050000,0,Discharging,
 108 [...]
 109 1443090528,LGC,45N1025,Li-ion,974,4900000,62160000,4900000,0,Full,
 110 1443090601,LGC,45N1025,Li-ion,974,4900000,62160000,4900000,0,Full,
 111 </pre>
 112
 113 <p>I wrote a small script to create a graph of the charge development
 114 over time.  This graph depicted above show the slow death of my laptop
 115 battery.</p>
 116
 117 <p>But why is this happening?  Why are my laptop batteries always
 118 dying in a year or two, while the batteries of space probes and
 119 satellites keep working year after year.  If we are to believe
 120 <a href="http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries">Battery
 121 University</a>, the cause is me charging the battery whenever I have a
 122 chance, and the fix is to not charge the Lithium-ion batteries to 100%
 123 all the time, but to stay below 90% of full charge most of the time.
 124 I've been told that the Tesla electric cars
 125 <a href="http://my.teslamotors.com/de_CH/forum/forums/battery-charge-limit">limit
 126 the charge of their batteries to 80%</a>, with the option to charge to
 127 100% when preparing for a longer trip (not that I would want a car
 128 like Tesla where rights to privacy is abandoned, but that is another
 129 story), which I guess is the option we should have for laptops on
 130 Linux too.</p>
 131
 132 <p>Is there a good and generic way with Linux to tell the battery to
 133 stop charging at 80%, unless requested to charge to 100% once in
 134 preparation for a longer trip?  I found
 135 <a href="http://askubuntu.com/questions/34452/how-can-i-limit-battery-charging-to-80-capacity">one
 136 recipe on askubuntu for Ubuntu to limit charging on Thinkpad to
 137 80%</a>, but could not get it to work (kernel module refused to
 138 load).</p>
 139
 140 <p>I wonder why the battery capacity was reported to be more than 100%
 141 at the start.  I also wonder why the "full capacity" increases some
 142 times, and if it is possible to repeat the process to get the battery
 143 back to design capacity.  And I wonder if the discharge and charge
 144 speed change over time, or if this stay the same.  I did not yet try
 145 to write a tool to calculate the derivative values of the battery
 146 level, but suspect some interesting insights might be learned from
 147 those.</p>
 148
 149 <p>Update 2015-09-24: I got a tip to install the packages
 150 acpi-call-dkms and tlp (unfortunately missing in Debian stable)
 151 packages instead of the tp-smapi-dkms package I had tried to use
 152 initially, and use 'tlp setcharge 40 80' to change when charging start
 153 and stop.  I've done so now, but expect my existing battery is toast
 154 and need to be replaced.  The proposal is unfortunately Thinkpad
 155 specific.</p>
 156 </div>
 157
 158       <div class="tags">Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>.</div>
 159
 160
 161     </div>
 162
 163
 164
 165
 166     <div id="sidebar">
 167
 168
 169
 170 <h2>Archive</h2>
 171 <ul>
 172
 173 <li>2019
 174 <ul>
 175
 176 <li><a href="http://people.skolelinux.org/pere/blog/archive/2019/01/">January (4)</a></li>
 177
 178 <li><a href="http://people.skolelinux.org/pere/blog/archive/2019/02/">February (3)</a></li>
 179
 180 </ul></li>
 181
 182 <li>2018
 183 <ul>
 184
 185 <li><a href="http://people.skolelinux.org/pere/blog/archive/2018/01/">January (1)</a></li>
 186
 187 <li><a href="http://people.skolelinux.org/pere/blog/archive/2018/02/">February (5)</a></li>
 188
 189 <li><a href="http://people.skolelinux.org/pere/blog/archive/2018/03/">March (5)</a></li>
 190
 191 <li><a href="http://people.skolelinux.org/pere/blog/archive/2018/04/">April (3)</a></li>
 192
 193 <li><a href="http://people.skolelinux.org/pere/blog/archive/2018/06/">June (2)</a></li>
 194
 195 <li><a href="http://people.skolelinux.org/pere/blog/archive/2018/07/">July (5)</a></li>
 196
 197 <li><a href="http://people.skolelinux.org/pere/blog/archive/2018/08/">August (3)</a></li>
 198
 199 <li><a href="http://people.skolelinux.org/pere/blog/archive/2018/09/">September (3)</a></li>
 200
 201 <li><a href="http://people.skolelinux.org/pere/blog/archive/2018/10/">October (5)</a></li>
 202
 203 <li><a href="http://people.skolelinux.org/pere/blog/archive/2018/11/">November (2)</a></li>
 204
 205 <li><a href="http://people.skolelinux.org/pere/blog/archive/2018/12/">December (4)</a></li>
 206
 207 </ul></li>
 208
 209 <li>2017
 210 <ul>
 211
 212 <li><a href="http://people.skolelinux.org/pere/blog/archive/2017/01/">January (4)</a></li>
 213
 214 <li><a href="http://people.skolelinux.org/pere/blog/archive/2017/02/">February (3)</a></li>
 215
 216 <li><a href="http://people.skolelinux.org/pere/blog/archive/2017/03/">March (5)</a></li>
 217
 218 <li><a href="http://people.skolelinux.org/pere/blog/archive/2017/04/">April (2)</a></li>
 219
 220 <li><a href="http://people.skolelinux.org/pere/blog/archive/2017/06/">June (5)</a></li>
 221
 222 <li><a href="http://people.skolelinux.org/pere/blog/archive/2017/07/">July (1)</a></li>
 223
 224 <li><a href="http://people.skolelinux.org/pere/blog/archive/2017/08/">August (1)</a></li>
 225
 226 <li><a href="http://people.skolelinux.org/pere/blog/archive/2017/09/">September (3)</a></li>
 227
 228 <li><a href="http://people.skolelinux.org/pere/blog/archive/2017/10/">October (5)</a></li>
 229
 230 <li><a href="http://people.skolelinux.org/pere/blog/archive/2017/11/">November (3)</a></li>
 231
 232 <li><a href="http://people.skolelinux.org/pere/blog/archive/2017/12/">December (4)</a></li>
 233
 234 </ul></li>
 235
 236 <li>2016
 237 <ul>
 238
 239 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/01/">January (3)</a></li>
 240
 241 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/02/">February (2)</a></li>
 242
 243 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/03/">March (3)</a></li>
 244
 245 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/04/">April (8)</a></li>
 246
 247 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/05/">May (8)</a></li>
 248
 249 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/06/">June (2)</a></li>
 250
 251 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/07/">July (2)</a></li>
 252
 253 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/08/">August (5)</a></li>
 254
 255 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/09/">September (2)</a></li>
 256
 257 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/10/">October (3)</a></li>
 258
 259 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/11/">November (8)</a></li>
 260
 261 <li><a href="http://people.skolelinux.org/pere/blog/archive/2016/12/">December (5)</a></li>
 262
 263 </ul></li>
 264
 265 <li>2015
 266 <ul>
 267
 268 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/01/">January (7)</a></li>
 269
 270 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/02/">February (6)</a></li>
 271
 272 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/03/">March (1)</a></li>
 273
 274 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/04/">April (4)</a></li>
 275
 276 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/05/">May (3)</a></li>
 277
 278 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/06/">June (4)</a></li>
 279
 280 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/07/">July (6)</a></li>
 281
 282 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/08/">August (2)</a></li>
 283
 284 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/09/">September (2)</a></li>
 285
 286 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/10/">October (9)</a></li>
 287
 288 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/11/">November (6)</a></li>
 289
 290 <li><a href="http://people.skolelinux.org/pere/blog/archive/2015/12/">December (3)</a></li>
 291
 292 </ul></li>
 293
 294 <li>2014
 295 <ul>
 296
 297 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/01/">January (2)</a></li>
 298
 299 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/02/">February (3)</a></li>
 300
 301 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/03/">March (8)</a></li>
 302
 303 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/04/">April (7)</a></li>
 304
 305 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/05/">May (1)</a></li>
 306
 307 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/06/">June (2)</a></li>
 308
 309 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/07/">July (2)</a></li>
 310
 311 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/08/">August (2)</a></li>
 312
 313 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/09/">September (5)</a></li>
 314
 315 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/10/">October (6)</a></li>
 316
 317 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/11/">November (3)</a></li>
 318
 319 <li><a href="http://people.skolelinux.org/pere/blog/archive/2014/12/">December (5)</a></li>
 320
 321 </ul></li>
 322
 323 <li>2013
 324 <ul>
 325
 326 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/01/">January (11)</a></li>
 327
 328 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/02/">February (9)</a></li>
 329
 330 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/03/">March (9)</a></li>
 331
 332 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/04/">April (6)</a></li>
 333
 334 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/05/">May (9)</a></li>
 335
 336 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/06/">June (10)</a></li>
 337
 338 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/07/">July (7)</a></li>
 339
 340 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/08/">August (3)</a></li>
 341
 342 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/09/">September (5)</a></li>
 343
 344 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/10/">October (7)</a></li>
 345
 346 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/11/">November (9)</a></li>
 347
 348 <li><a href="http://people.skolelinux.org/pere/blog/archive/2013/12/">December (3)</a></li>
 349
 350 </ul></li>
 351
 352 <li>2012
 353 <ul>
 354
 355 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/01/">January (7)</a></li>
 356
 357 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/02/">February (10)</a></li>
 358
 359 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/03/">March (17)</a></li>
 360
 361 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/04/">April (12)</a></li>
 362
 363 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/05/">May (12)</a></li>
 364
 365 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/06/">June (20)</a></li>
 366
 367 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/07/">July (17)</a></li>
 368
 369 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/08/">August (6)</a></li>
 370
 371 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/09/">September (9)</a></li>
 372
 373 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/10/">October (17)</a></li>
 374
 375 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/11/">November (10)</a></li>
 376
 377 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/12/">December (7)</a></li>
 378
 379 </ul></li>
 380
 381 <li>2011
 382 <ul>
 383
 384 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
 385
 386 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
 387
 388 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/03/">March (6)</a></li>
 389
 390 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/04/">April (7)</a></li>
 391
 392 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/05/">May (3)</a></li>
 393
 394 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/06/">June (2)</a></li>
 395
 396 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/07/">July (7)</a></li>
 397
 398 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/08/">August (6)</a></li>
 399
 400 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/09/">September (4)</a></li>
 401
 402 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/10/">October (2)</a></li>
 403
 404 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/11/">November (3)</a></li>
 405
 406 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
 407
 408 </ul></li>
 409
 410 <li>2010
 411 <ul>
 412
 413 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
 414
 415 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
 416
 417 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/03/">March (3)</a></li>
 418
 419 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/04/">April (3)</a></li>
 420
 421 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
 422
 423 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/06/">June (14)</a></li>
 424
 425 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
 426
 427 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/08/">August (13)</a></li>
 428
 429 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
 430
 431 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
 432
 433 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
 434
 435 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
 436
 437 </ul></li>
 438
 439 <li>2009
 440 <ul>
 441
 442 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
 443
 444 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
 445
 446 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/03/">March (12)</a></li>
 447
 448 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
 449
 450 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/05/">May (9)</a></li>
 451
 452 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/06/">June (3)</a></li>
 453
 454 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/07/">July (4)</a></li>
 455
 456 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/08/">August (3)</a></li>
 457
 458 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
 459
 460 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
 461
 462 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
 463
 464 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
 465
 466 </ul></li>
 467
 468 <li>2008
 469 <ul>
 470
 471 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
 472
 473 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
 474
 475 </ul></li>
 476
 477 </ul>
 478
 479
 480
 481 <h2>Tags</h2>
 482 <ul>
 483
 484  <li><a href="http://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (16)</a></li>
 485
 486  <li><a href="http://people.skolelinux.org/pere/blog/tags/amiga">amiga (1)</a></li>
 487
 488  <li><a href="http://people.skolelinux.org/pere/blog/tags/aros">aros (1)</a></li>
 489
 490  <li><a href="http://people.skolelinux.org/pere/blog/tags/bankid">bankid (4)</a></li>
 491
 492  <li><a href="http://people.skolelinux.org/pere/blog/tags/bitcoin">bitcoin (11)</a></li>
 493
 494  <li><a href="http://people.skolelinux.org/pere/blog/tags/bootsystem">bootsystem (17)</a></li>
 495
 496  <li><a href="http://people.skolelinux.org/pere/blog/tags/bsa">bsa (2)</a></li>
 497
 498  <li><a href="http://people.skolelinux.org/pere/blog/tags/chrpath">chrpath (2)</a></li>
 499
 500  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (167)</a></li>
 501
 502  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (158)</a></li>
 503
 504  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian-handbook">debian-handbook (4)</a></li>
 505
 506  <li><a href="http://people.skolelinux.org/pere/blog/tags/digistan">digistan (10)</a></li>
 507
 508  <li><a href="http://people.skolelinux.org/pere/blog/tags/dld">dld (17)</a></li>
 509
 510  <li><a href="http://people.skolelinux.org/pere/blog/tags/docbook">docbook (25)</a></li>
 511
 512  <li><a href="http://people.skolelinux.org/pere/blog/tags/drivstoffpriser">drivstoffpriser (4)</a></li>
 513
 514  <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (398)</a></li>
 515
 516  <li><a href="http://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (23)</a></li>
 517
 518  <li><a href="http://people.skolelinux.org/pere/blog/tags/fildeling">fildeling (14)</a></li>
 519
 520  <li><a href="http://people.skolelinux.org/pere/blog/tags/freeculture">freeculture (33)</a></li>
 521
 522  <li><a href="http://people.skolelinux.org/pere/blog/tags/freedombox">freedombox (9)</a></li>
 523
 524  <li><a href="http://people.skolelinux.org/pere/blog/tags/frikanalen">frikanalen (20)</a></li>
 525
 526  <li><a href="http://people.skolelinux.org/pere/blog/tags/h264">h264 (20)</a></li>
 527
 528  <li><a href="http://people.skolelinux.org/pere/blog/tags/intervju">intervju (42)</a></li>
 529
 530  <li><a href="http://people.skolelinux.org/pere/blog/tags/isenkram">isenkram (16)</a></li>
 531
 532  <li><a href="http://people.skolelinux.org/pere/blog/tags/kart">kart (20)</a></li>
 533
 534  <li><a href="http://people.skolelinux.org/pere/blog/tags/kodi">kodi (4)</a></li>
 535
 536  <li><a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap (9)</a></li>
 537
 538  <li><a href="http://people.skolelinux.org/pere/blog/tags/lego">lego (4)</a></li>
 539
 540  <li><a href="http://people.skolelinux.org/pere/blog/tags/lenker">lenker (8)</a></li>
 541
 542  <li><a href="http://people.skolelinux.org/pere/blog/tags/lsdvd">lsdvd (2)</a></li>
 543
 544  <li><a href="http://people.skolelinux.org/pere/blog/tags/ltsp">ltsp (1)</a></li>
 545
 546  <li><a href="http://people.skolelinux.org/pere/blog/tags/mesh network">mesh network (8)</a></li>
 547
 548  <li><a href="http://people.skolelinux.org/pere/blog/tags/multimedia">multimedia (42)</a></li>
 549
 550  <li><a href="http://people.skolelinux.org/pere/blog/tags/nice free software">nice free software (11)</a></li>
 551
 552  <li><a href="http://people.skolelinux.org/pere/blog/tags/norsk">norsk (304)</a></li>
 553
 554  <li><a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug (192)</a></li>
 555
 556  <li><a href="http://people.skolelinux.org/pere/blog/tags/offentlig innsyn">offentlig innsyn (35)</a></li>
 557
 558  <li><a href="http://people.skolelinux.org/pere/blog/tags/open311">open311 (2)</a></li>
 559
 560  <li><a href="http://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett (73)</a></li>
 561
 562  <li><a href="http://people.skolelinux.org/pere/blog/tags/personvern">personvern (108)</a></li>
 563
 564  <li><a href="http://people.skolelinux.org/pere/blog/tags/raid">raid (2)</a></li>
 565
 566  <li><a href="http://people.skolelinux.org/pere/blog/tags/reactos">reactos (1)</a></li>
 567
 568  <li><a href="http://people.skolelinux.org/pere/blog/tags/reprap">reprap (11)</a></li>
 569
 570  <li><a href="http://people.skolelinux.org/pere/blog/tags/rfid">rfid (3)</a></li>
 571
 572  <li><a href="http://people.skolelinux.org/pere/blog/tags/robot">robot (11)</a></li>
 573
 574  <li><a href="http://people.skolelinux.org/pere/blog/tags/rss">rss (1)</a></li>
 575
 576  <li><a href="http://people.skolelinux.org/pere/blog/tags/ruter">ruter (7)</a></li>
 577
 578  <li><a href="http://people.skolelinux.org/pere/blog/tags/scraperwiki">scraperwiki (2)</a></li>
 579
 580  <li><a href="http://people.skolelinux.org/pere/blog/tags/sikkerhet">sikkerhet (55)</a></li>
 581
 582  <li><a href="http://people.skolelinux.org/pere/blog/tags/sitesummary">sitesummary (4)</a></li>
 583
 584  <li><a href="http://people.skolelinux.org/pere/blog/tags/skepsis">skepsis (5)</a></li>
 585
 586  <li><a href="http://people.skolelinux.org/pere/blog/tags/standard">standard (58)</a></li>
 587
 588  <li><a href="http://people.skolelinux.org/pere/blog/tags/stavekontroll">stavekontroll (6)</a></li>
 589
 590  <li><a href="http://people.skolelinux.org/pere/blog/tags/stortinget">stortinget (12)</a></li>
 591
 592  <li><a href="http://people.skolelinux.org/pere/blog/tags/surveillance">surveillance (55)</a></li>
 593
 594  <li><a href="http://people.skolelinux.org/pere/blog/tags/sysadmin">sysadmin (4)</a></li>
 595
 596  <li><a href="http://people.skolelinux.org/pere/blog/tags/usenix">usenix (2)</a></li>
 597
 598  <li><a href="http://people.skolelinux.org/pere/blog/tags/valg">valg (9)</a></li>
 599
 600  <li><a href="http://people.skolelinux.org/pere/blog/tags/verkidetfri">verkidetfri (15)</a></li>
 601
 602  <li><a href="http://people.skolelinux.org/pere/blog/tags/video">video (73)</a></li>
 603
 604  <li><a href="http://people.skolelinux.org/pere/blog/tags/vitenskap">vitenskap (4)</a></li>
 605
 606  <li><a href="http://people.skolelinux.org/pere/blog/tags/web">web (42)</a></li>
 607
 608 </ul>
 609
 610
 611     </div>
 612     <p style="text-align: right">
 613  Created by <a href="http://steve.org.uk/Software/chronicle">Chronicle v4.6</a>
 614 </p>
 615
 616   </body>
 617 </html>