- <title>The life and death of a laptop battery</title>
- <link>http://people.skolelinux.org/pere/blog/The_life_and_death_of_a_laptop_battery.html</link>
- <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/The_life_and_death_of_a_laptop_battery.html</guid>
- <pubDate>Thu, 24 Sep 2015 16:00:00 +0200</pubDate>
- <description><p>When I get a new laptop, the battery life time at the start is OK.
-But this do not last. The last few laptops gave me a feeling that
-within a year, the life time is just a fraction of what it used to be,
-and it slowly become painful to use the laptop without power connected
-all the time. Because of this, when I got a new Thinkpad X230 laptop
-about two years ago, I decided to monitor its battery state to have
-more hard facts when the battery started to fail.</p>
-
-<img src="http://people.skolelinux.org/pere/blog/images/2015-09-24-laptop-battery-graph.png"/>
-
-<p>First I tried to find a sensible Debian package to record the
-battery status, assuming that this must be a problem already handled
-by someone else. I found
-<a href="https://tracker.debian.org/pkg/battery-stats">battery-stats</a>,
-which collects statistics from the battery, but it was completely
-broken. I sent a few suggestions to the maintainer, but decided to
-write my own collector as a shell script while I waited for feedback
-from him. Via
-<a href="http://www.ifweassume.com/2013/08/the-de-evolution-of-my-laptop-battery.html">a
-blog post about the battery development on a MacBook Air</a> I also
-discovered
-<a href="https://github.com/jradavenport/batlog.git">batlog</a>, not
-available in Debian.</p>
-
-<p>I started my collector 2013-07-15, and it has been collecting
-battery stats ever since. Now my
-/var/log/hjemmenett-battery-status.log file contain around 115,000
-measurements, from the time the battery was working great until now,
-when it is unable to charge above 7% of original capacity. My
-collector shell script is quite simple and look like this:</p>
-
-<pre>
-#!/bin/sh
-# Inspired by
-# http://www.ifweassume.com/2013/08/the-de-evolution-of-my-laptop-battery.html
-# See also
-# http://blog.sleeplessbeastie.eu/2013/01/02/debian-how-to-monitor-battery-capacity/
-logfile=/var/log/hjemmenett-battery-status.log
-
-files="manufacturer model_name technology serial_number \
- energy_full energy_full_design energy_now cycle_count status"
-
-if [ ! -e "$logfile" ] ; then
- (
- printf "timestamp,"
- for f in $files; do
- printf "%s," $f
- done
- echo
- ) > "$logfile"
-fi
-
-log_battery() {
- # Print complete message in one echo call, to avoid race condition
- # when several log processes run in parallel.
- msg=$(printf "%s," $(date +%s); \
- for f in $files; do \
- printf "%s," $(cat $f); \
- done)
- echo "$msg"
-}
-
-cd /sys/class/power_supply
-
-for bat in BAT*; do
- (cd $bat && log_battery >> "$logfile")
-done
-</pre>
-
-<p>The script is called when the power management system detect a
-change in the power status (power plug in or out), and when going into
-and out of hibernation and suspend. In addition, it collect a value
-every 10 minutes. This make it possible for me know when the battery
-is discharging, charging and how the maximum charge change over time.
-The code for the Debian package
-<a href="https://github.com/petterreinholdtsen/battery-status">is now
-available on github</a>.</p>
-
-<p>The collected log file look like this:</p>
-
-<pre>
-timestamp,manufacturer,model_name,technology,serial_number,energy_full,energy_full_design,energy_now,cycle_count,status,
-1376591133,LGC,45N1025,Li-ion,974,62800000,62160000,39050000,0,Discharging,
-[...]
-1443090528,LGC,45N1025,Li-ion,974,4900000,62160000,4900000,0,Full,
-1443090601,LGC,45N1025,Li-ion,974,4900000,62160000,4900000,0,Full,
-</pre>
-
-<p>I wrote a small script to create a graph of the charge development
-over time. This graph depicted above show the slow death of my laptop
-battery.</p>
-
-<p>But why is this happening? Why are my laptop batteries always
-dying in a year or two, while the batteries of space probes and
-satellites keep working year after year. If we are to believe
-<a href="http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries">Battery
-University</a>, the cause is me charging the battery whenever I have a
-chance, and the fix is to not charge the Lithium-ion batteries to 100%
-all the time, but to stay below 90% of full charge most of the time.
-I've been told that the Tesla electric cars
-<a href="http://my.teslamotors.com/de_CH/forum/forums/battery-charge-limit">limit
-the charge of their batteries to 80%</a>, with the option to charge to
-100% when preparing for a longer trip (not that I would want a car
-like Tesla where rights to privacy is abandoned, but that is another
-story), which I guess is the option we should have for laptops on
-Linux too.</p>
-
-<p>Is there a good and generic way with Linux to tell the battery to
-stop charging at 80%, unless requested to charge to 100% once in
-preparation for a longer trip? I found
-<a href="http://askubuntu.com/questions/34452/how-can-i-limit-battery-charging-to-80-capacity">one
-recipe on askubuntu for Ubuntu to limit charging on Thinkpad to
-80%</a>, but could not get it to work (kernel module refused to
-load).</p>
-
-<p>I wonder why the battery capacity was reported to be more than 100%
-at the start. I also wonder why the "full capacity" increases some
-times, and if it is possible to repeat the process to get the battery
-back to design capacity. And I wonder if the discharge and charge
-speed change over time, or if this stay the same. I did not yet try
-to write a tool to calculate the derivative values of the battery
-level, but suspect some interesting insights might be learned from
-those.</p>
-
-<p>Update 2015-09-24: I got a tip to install the packages
-acpi-call-dkms and tlp (unfortunately missing in Debian stable)
-packages instead of the tp-smapi-dkms package I had tried to use
-initially, and use 'tlp setcharge 40 80' to change when charging start
-and stop. I've done so now, but expect my existing battery is toast
-and need to be replaced. The proposal is unfortunately Thinkpad
-specific.</p>
+ <title>The GNU General Public License is not magic pixie dust</title>
+ <link>http://people.skolelinux.org/pere/blog/The_GNU_General_Public_License_is_not_magic_pixie_dust.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/The_GNU_General_Public_License_is_not_magic_pixie_dust.html</guid>
+ <pubDate>Mon, 30 Nov 2015 09:55:00 +0100</pubDate>
+ <description><p>A blog post from my fellow Debian developer Paul Wise titled
+"<a href="http://bonedaddy.net/pabs3/log/2015/11/27/sfc-supporter/">The
+GPL is not magic pixie dust</a>" explain the importance of making sure
+the <a href="http://www.gnu.org/copyleft/gpl.html">GPL</a> is enforced.
+I quote the blog post from Paul in full here with his permission:<p>
+
+<blockquote>
+
+<p><a href="https://sfconservancy.org/supporter/"><img src="https://sfconservancy.org/img/supporter-badge.png" width="194" height="90" alt="Become a Software Freedom Conservancy Supporter!" align="right" border="0" /></a></p>
+
+<blockquote>
+The GPL is not magic pixie dust. It does not work by itself.<br/>
+
+The first step is to choose a
+<a href="https://copyleft.org/">copyleft</a> license for your
+code.<br/>
+
+The next step is, when someone fails to follow that copyleft license,
+<b>it must be enforced</b><br/>
+
+and its a simple fact of our modern society that such type of
+work<br/>
+
+is incredibly expensive to do and incredibly difficult to do.
+</blockquote>
+
+<p><small>-- <a href="http://ebb.org/bkuhn/">Bradley Kuhn</a>, in
+<a href="http://faif.us/" title="Free as in Freedom">FaiF</a>
+<a href="http://faif.us/cast/2015/nov/24/0x57/">episode
+0x57</a></small></p>
+
+<p>As the Debian Website
+<a href="https://bugs.debian.org/794116">used</a>
+<a href="https://anonscm.debian.org/viewvc/webwml/webwml/english/intro/free.wml?r1=1.24&amp;r2=1.25">to</a>
+imply, public domain and permissively licensed software can lead to
+the production of more proprietary software as people discover useful
+software, extend it and or incorporate it into their hardware or
+software products. Copyleft licenses such as the GNU GPL were created
+to close off this avenue to the production of proprietary software but
+such licenses are not enough. With the ongoing adoption of Free
+Software by individuals and groups, inevitably the community's
+expectations of license compliance are violated, usually out of
+ignorance of the way Free Software works, but not always. As Karen
+and Bradley explained in <a href="http://faif.us/" title="Free as in
+Freedom">FaiF</a>
+<a href="http://faif.us/cast/2015/nov/24/0x57/">episode 0x57</a>,
+copyleft is nothing if no-one is willing and able to stand up in court
+to protect it. The reality of today's world is that legal
+representation is expensive, difficult and time consuming. With
+<a href="http://gpl-violations.org/">gpl-violations.org</a> in hiatus
+<a href="http://gpl-violations.org/news/20151027-homepage-recovers/">until</a>
+some time in 2016, the <a href="https://sfconservancy.org/">Software
+Freedom Conservancy</a> (a tax-exempt charity) is the major defender
+of the Linux project, Debian and other groups against GPL violations.
+In March the SFC supported a
+<a href="https://sfconservancy.org/news/2015/mar/05/vmware-lawsuit/">lawsuit
+by Christoph Hellwig</a> against VMware for refusing to
+<a href="https://sfconservancy.org/linux-compliance/vmware-lawsuit-faq.html">comply
+with the GPL</a> in relation to their use of parts of the Linux
+kernel. Since then two of their sponsors pulled corporate funding and
+conferences
+<a href="https://sfconservancy.org/blog/2015/nov/24/faif-carols-fundraiser/">blocked
+or cancelled their talks</a>. As a result they have decided to rely
+less on corporate funding and more on the broad community of
+individuals who support Free Software and copyleft. So the SFC has
+<a href="https://sfconservancy.org/news/2015/nov/23/2015fundraiser/">launched</a>
+a <a href="https://sfconservancy.org/supporter/">campaign</a> to create
+a community of folks who stand up for copyleft and the GPL by
+supporting their work on promoting and supporting copyleft and Free
+Software.</p>
+
+<p>If you support Free Software,
+<a href="https://sfconservancy.org/blog/2015/nov/26/like-what-I-do/">like</a>
+what the SFC do, agree with their
+<a href="https://sfconservancy.org/linux-compliance/principles.html">compliance
+principles</a>, are happy about their
+<a href="https://sfconservancy.org/supporter/">successes</a> in 2015,
+work on a project that is an SFC
+<a href="https://sfconservancy.org/members/current/">member</a> and or
+just want to stand up for copyleft, please join
+<a href="https://identi.ca/cwebber/image/JQGPA4qbTyyp3-MY8QpvuA">Christopher
+Allan Webber</a>,
+<a href="https://sfconservancy.org/blog/2015/nov/24/faif-carols-fundraiser/">Carol
+Smith</a>,
+<a href="http://www.jonobacon.org/2015/11/25/supporting-software-freedom-conservancy/">Jono
+Bacon</a>, myself and
+<a href="https://sfconservancy.org/sponsors/#supporters">others</a> in
+becoming a
+<a href="https://sfconservancy.org/supporter/">supporter</a>. For the
+next week your donation will be
+<a href="https://sfconservancy.org/news/2015/nov/27/black-friday/">matched</a>
+by an anonymous donor. Please also consider asking your employer to
+match your donation or become a sponsor of SFC. Don't forget to
+spread the word about your support for SFC via email, your blog and or
+social media accounts.</p>
+
+</blockquote>
+
+<p>I agree with Paul on this topic and just signed up as a Supporter
+of Software Freedom Conservancy myself. Perhaps you should be a
+supporter too?</p>