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        <channel>
                <title>Petter Reinholdtsen - Entries tagged nice free software</title>
                <description>Entries tagged nice free software</description>
                <link>http://people.skolelinux.org/pere/blog/</link>

        
        <item>
                <title>PlantUML for text based UML diagram modelling - nice free software</title>
                <link>http://people.skolelinux.org/pere/blog/PlantUML_for_text_based_UML_diagram_modelling___nice_free_software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/PlantUML_for_text_based_UML_diagram_modelling___nice_free_software.html</guid>
                <pubDate>Mon, 25 Mar 2019 09:35:00 +0100</pubDate>
                <description>&lt;p&gt;As part of my involvement with the
&lt;a href=&quot;https://gitlab.com/OsloMet-ABI/nikita-noark5-core/&quot;&gt;Nikita
Noark 5 core project&lt;/a&gt;, I have been proposing improvements to the
API specification created by &lt;a href=&quot;https://www.arkivverket.no/&quot;&gt;The
National Archives of Norway&lt;/a&gt; and helped migrating the text from a
version control system unfriendly binary format (docx) to Markdown in
git.  Combined with the migration to a public git repository (on
github), this has made it possible for anyone to suggest improvement
to the text.&lt;/p&gt;

&lt;p&gt;The specification is filled with UML diagrams.  I believe the
original diagrams were modelled using Sparx Systems Enterprise
Architect, and exported as EMF files for import into docx.  This
approach make it very hard to track changes using a version control
system.  To improve the situation I have been looking for a good text
based UML format with associated command line free software tools on
Linux and Windows, to allow anyone to send in corrections to the UML
diagrams in the specification.  The tool must be text based to work
with git, and command line to be able to run it automatically to
generate the diagram images.  Finally, it must be free software to
allow anyone, even those that can not accept a non-free software
license, to contribute.&lt;/p&gt;

&lt;p&gt;I did not know much about free software UML modelling tools when I
started.  I have used dia and inkscape for simple modelling in the
past, but neither are available on Windows, as far as I could tell.  I
came across a nice
&lt;a href=&quot;https://modeling-languages.com/text-uml-tools-complete-list/&quot;&gt;list
of text mode uml tools&lt;/a&gt;, and tested out a few of the tools listed
there.  &lt;a href=&quot;http://plantuml.com/&quot;&gt;The PlantUML tool&lt;/a&gt; seemed
most promising.  After verifying that the packages
&lt;a href=&quot;https://tracker.debian.org/pkg/plantuml&quot;&gt;is available in
Debian&lt;/a&gt; and found &lt;a href=&quot;https://github.com/plantuml/plantuml&quot;&gt;its
Java source&lt;/a&gt; under a GPL license on github, I set out to test if it
could represent the diagrams we needed, ie the ones currently in
&lt;a href=&quot;https://github.com/arkivverket/noark5-tjenestegrensesnitt-standard/&quot;&gt;the
Noark 5 Tjenestegrensesnitt specification&lt;/a&gt;.  I am happy to report
that it could represent them, even thought it have a few warts here
and there.&lt;/p&gt;

&lt;p&gt;After a few days of modelling I completed the task this weekend.  A
temporary link to the complete set of diagrams (original and from
PlantUML) is available in
&lt;a href=&quot;https://github.com/arkivverket/noark5-tjenestegrensesnitt-standard/issues/76&quot;&gt;the
github issue discussing the need for a text based UML format&lt;/a&gt;, but
please note I lack a sensible tool to convert EMF files to PNGs, so
the &quot;original&quot; rendering is not as good as the original was in the
publised PDF.&lt;/p&gt;

&lt;p&gt;Here is an example UML diagram, showing the core classes for
keeping metadata about archived documents:&lt;/p&gt;

&lt;pre&gt;
@startuml
skinparam classAttributeIconSize 0

!include media/uml-class-arkivskaper.iuml
!include media/uml-class-arkiv.iuml
!include media/uml-class-klassifikasjonssystem.iuml
!include media/uml-class-klasse.iuml
!include media/uml-class-arkivdel.iuml
!include media/uml-class-mappe.iuml
!include media/uml-class-merknad.iuml
!include media/uml-class-registrering.iuml
!include media/uml-class-basisregistrering.iuml
!include media/uml-class-dokumentbeskrivelse.iuml
!include media/uml-class-dokumentobjekt.iuml
!include media/uml-class-konvertering.iuml
!include media/uml-datatype-elektronisksignatur.iuml

Arkivstruktur.Arkivskaper &quot;+arkivskaper 1..*&quot; &lt;-o &quot;+arkiv 0..*&quot; Arkivstruktur.Arkiv
Arkivstruktur.Arkiv o--&gt; &quot;+underarkiv 0..*&quot; Arkivstruktur.Arkiv
Arkivstruktur.Arkiv &quot;+arkiv 1&quot; o--&gt; &quot;+arkivdel 0..*&quot; Arkivstruktur.Arkivdel
Arkivstruktur.Klassifikasjonssystem &quot;+klassifikasjonssystem [0..1]&quot; &lt;--o &quot;+arkivdel 1..*&quot; Arkivstruktur.Arkivdel
Arkivstruktur.Klassifikasjonssystem &quot;+klassifikasjonssystem [0..1]&quot; o--&gt; &quot;+klasse 0..*&quot; Arkivstruktur.Klasse
Arkivstruktur.Arkivdel &quot;+arkivdel 0..1&quot; o--&gt; &quot;+mappe 0..*&quot; Arkivstruktur.Mappe
Arkivstruktur.Arkivdel &quot;+arkivdel 0..1&quot; o--&gt; &quot;+registrering 0..*&quot; Arkivstruktur.Registrering
Arkivstruktur.Klasse &quot;+klasse 0..1&quot; o--&gt; &quot;+mappe 0..*&quot; Arkivstruktur.Mappe
Arkivstruktur.Klasse &quot;+klasse 0..1&quot; o--&gt; &quot;+registrering 0..*&quot; Arkivstruktur.Registrering
Arkivstruktur.Mappe --&gt; &quot;+undermappe 0..*&quot; Arkivstruktur.Mappe
Arkivstruktur.Mappe &quot;+mappe 0..1&quot; o--&gt; &quot;+registrering 0..*&quot; Arkivstruktur.Registrering
Arkivstruktur.Merknad &quot;+merknad 0..*&quot; &lt;--* Arkivstruktur.Mappe
Arkivstruktur.Merknad &quot;+merknad 0..*&quot; &lt;--* Arkivstruktur.Dokumentbeskrivelse
Arkivstruktur.Basisregistrering -|&gt; Arkivstruktur.Registrering
Arkivstruktur.Merknad &quot;+merknad 0..*&quot; &lt;--* Arkivstruktur.Basisregistrering
Arkivstruktur.Registrering &quot;+registrering 1..*&quot; o--&gt; &quot;+dokumentbeskrivelse 0..*&quot; Arkivstruktur.Dokumentbeskrivelse
Arkivstruktur.Dokumentbeskrivelse &quot;+dokumentbeskrivelse 1&quot; o-&gt; &quot;+dokumentobjekt 0..*&quot; Arkivstruktur.Dokumentobjekt
Arkivstruktur.Dokumentobjekt *-&gt; &quot;+konvertering 0..*&quot; Arkivstruktur.Konvertering
Arkivstruktur.ElektroniskSignatur -[hidden]-&gt; Arkivstruktur.Dokumentobjekt
@enduml
&lt;/pre&gt;

&lt;p&gt;&lt;a href=&quot;http://plantuml.com/class-diagram&quot;&gt;The format&lt;/a&gt; is quite
compact, with little redundant information.  The text expresses
entities and relations, and there is little layout related fluff.  One
can reuse content by using include files, allowing for consistent
naming across several diagrams.  The include files can be standalone
PlantUML too.  Here is the content of
&lt;tt&gt;media/uml-class-arkivskaper.iuml&lt;/tt&gt;:&lt;/p&gt;

&lt;pre&gt;
@startuml
class Arkivstruktur.Arkivskaper &lt;Arkivenhet&gt; {
  +arkivskaperID : string
  +arkivskaperNavn : string
  +beskrivelse : string [0..1]
}
@enduml
&lt;/pre&gt;

&lt;p&gt;This is what the complete diagram for the PlantUML notation above
look like:&lt;/p&gt;

&lt;p&gt;&lt;img width=&quot;80%&quot; src=&quot;http://people.skolelinux.org/pere/blog/images/2019-03-25-noark5-plantuml-diagrameksempel.png&quot;&gt;&lt;/p&gt;

&lt;p&gt;A cool feature of PlantUML is that the generated PNG files include
the entire original source diagram as text.  The source (with include
statements expanded) can be extracted using for example
&lt;tt&gt;exiftool&lt;/tt&gt;.  Another cool feature is that parts of the entities
can be hidden after inclusion.  This allow to use include files with
all attributes listed, even for UML diagrams that should not list any
attributes.&lt;/p&gt;

&lt;p&gt;The diagram also show some of the warts.  Some times the layout
engine place text labels on top of each other, and some times it place
the class boxes too close to each other, not leaving room for the
labels on the relationship arrows.  The former can be worked around by
placing extra newlines in the labes (ie &quot;\n&quot;).  I did not do it here
to be able to demonstrate the issue.  I have not found a good way
around the latter, so I normally try to reduce the problem by changing
from vertical to horizontal links to improve the layout.&lt;/p&gt;

&lt;p&gt;All in all, I am quite happy with PlantUML, and very impressed with
how quickly its lead developer responds to questions.  So far I got an
answer to my questions in a few hours when I send an email.  I
definitely recommend looking at PlantUML if you need to make UML
diagrams.  Note, PlantUML can draw a lot more than class relations.
Check out the documention for a complete list. :)&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Measuring the speaker frequency response using the AUDMES free software GUI - nice free software</title>
                <link>http://people.skolelinux.org/pere/blog/Measuring_the_speaker_frequency_response_using_the_AUDMES_free_software_GUI___nice_free_software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Measuring_the_speaker_frequency_response_using_the_AUDMES_free_software_GUI___nice_free_software.html</guid>
                <pubDate>Mon, 22 Oct 2018 08:40:00 +0200</pubDate>
                <description>&lt;p&gt;&lt;img src=&quot;http://people.skolelinux.org/pere/blog/images/2018-10-22-audmes-measure-speakers.png&quot; align=&quot;right&quot; width=&quot;40%&quot;/&gt;&lt;/p&gt;

&lt;p&gt;My current home stereo is a patchwork of various pieces I got on
flee markeds over the years.  It is amazing what kind of equipment
show up there.  I&#39;ve been wondering for a while if it was possible to
measure how well this equipment is working together, and decided to
see how far I could get using free software.  After trawling the web I
came across an article from DIY Audio and Video on
&lt;a href=&quot;https://www.diyaudioandvideo.com/Tutorial/SpeakerResponseTesting/&quot;&gt;Speaker
Testing and Analysis&lt;/a&gt; describing how to test speakers, and it listing
several software options, among them
&lt;a href=&quot;https://sourceforge.net/projects/audmes/&quot;&gt;AUDio MEasurement
System (AUDMES)&lt;/a&gt;.  It is the only free software system I could find
focusing on measuring speakers and audio frequency response.  In the
process I also found an interesting article from NOVO on
&lt;a href=&quot;http://novo.press/understanding-speaker-specifications-and-frequency-response/&quot;&gt;Understanding
Speaker Specifications and Frequency Response&lt;/a&gt; and an article from
ecoustics on
&lt;a href=&quot;https://www.ecoustics.com/articles/understanding-speaker-frequency-response/&quot;&gt;Understanding
Speaker Frequency Response&lt;/a&gt;, with a lot of information on what to
look for and how to interpret the graphs.  Armed with this knowledge,
I set out to measure the state of my speakers.&lt;/p&gt;

&lt;p&gt;The first hurdle was that AUDMES hadn&#39;t seen a commit for 10 years
and did not build with current compilers and libraries.  I got in
touch with its author, who no longer was spending time on the program
but gave me write access to the subversion repository on Sourceforge.
The end result is that now the code build on Linux and is capable of
saving and loading the collected frequency response data in CSV
format.  The application is quite nice and flexible, and I was able to
select the input and output audio interfaces independently.  This made
it possible to use a USB mixer as the input source, while sending
output via my laptop headphone connection.  I lacked the hardware and
cabling to figure out a different way to get independent cabling to
speakers and microphone.&lt;/p&gt;

&lt;p&gt;Using this setup I could see how a large range of high frequencies
apparently were not making it out of my speakers.  The picture show
the frequency response measurement of one of the speakers.  Note the
frequency lines seem to be slightly misaligned, compared to the CSV
output from the program.  I can not hear several of these are high
frequencies, according to measurement from
&lt;a href=&quot;http://freehearingtestsoftware.com&quot;&gt;Free Hearing Test
Software&lt;/a&gt;, an freeware system to measure your hearing (still
looking for a free software alternative), so I do not know if they are
coming out out the speakers.  I thus do not quite know how to figure
out if the missing frequencies is a problem with the microphone, the
amplifier or the speakers, but I managed to rule out the audio card in my
PC by measuring my Bose noise canceling headset using its own
microphone.  This setup was able to see the high frequency tones, so
the problem with my stereo had to be in the amplifier or speakers.&lt;/p&gt;

&lt;p&gt;Anyway, to try to role out one factor I ended up picking up a new
set of speakers at a flee marked, and these work a lot better than the
old speakers, so I guess the microphone and amplifier is OK.  If you
need to measure your own speakers, check out AUDMES.  If more people
get involved, perhaps the project could become good enough to
&lt;a href=&quot;https://bugs.debian.org/910876&quot;&gt;include in Debian&lt;/a&gt;?  And if
you know of some other free software to measure speakers and amplifier
performance, please let me know.  I am aware of the freeware option
&lt;a href=&quot;https://www.roomeqwizard.com/&quot;&gt;REW&lt;/a&gt;, but I want something
that can be developed also when the vendor looses interest.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>youtube-dl for nedlasting fra NRK med undertekster - nice free software</title>
                <link>http://people.skolelinux.org/pere/blog/youtube_dl_for_nedlasting_fra_NRK_med_undertekster___nice_free_software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/youtube_dl_for_nedlasting_fra_NRK_med_undertekster___nice_free_software.html</guid>
                <pubDate>Sat, 28 Apr 2018 10:30:00 +0200</pubDate>
                <description>&lt;p&gt;I &lt;a href=&quot;https://no.wikipedia.org/wiki/VHS&quot;&gt;VHS-kassettenes&lt;/a&gt;
tid var det rett frem å ta vare på et TV-program en ønsket å kunne se
senere, uten å være avhengig av at programmet ble sendt på nytt.
Kanskje ønsket en å se programmet på hytten der det ikke var
TV-signal, eller av andre grunner ha det tilgjengelig for fremtidig
fornøyelse.  Dette er blitt vanskeligere med introduksjon av
digital-TV og webstreaming, der opptak til harddisk er utenfor de
flestes kontroll hvis de bruker ufri programvare og bokser kontrollert
av andre.  Men for NRK her i Norge, finnes det heldigvis flere fri
programvare-alternativer, som jeg har
&lt;a href=&quot;http://people.skolelinux.org/pere/blog/Hvordan_enkelt_laste_ned_filmer_fra_NRK.html&quot;&gt;skrevet&lt;/a&gt;
&lt;a href=&quot;http://people.skolelinux.org/pere/blog/Hvordan_enkelt_laste_ned_filmer_fra_NRK_med_den__nye__l_sningen.html&quot;&gt;om&lt;/a&gt;
&lt;a href=&quot;http://people.skolelinux.org/pere/blog/Nedlasting_fra_NRK__som_Matroska_med_undertekster.html&quot;&gt;før&lt;/a&gt;.
Så lenge kilden for nedlastingen er lovlig lagt ut på nett (hvilket
jeg antar NRK gjør), så er slik lagring til privat bruk også lovlig i
Norge.&lt;/p&gt;

&lt;p&gt;Sist jeg så på saken, i 2016, nevnte jeg at
&lt;a href=&quot;https://rg3.github.com/youtube-dl/&quot;&gt;youtube-dl&lt;/a&gt; ikke kunne
bake undertekster fra NRK inn i videofilene, og at jeg derfor
foretrakk andre alternativer.  Nylig oppdaget jeg at dette har endret
seg.  Fordelen med youtube-dl er at den er tilgjengelig direkte fra
Linux-distribusjoner som &lt;a href=&quot;https://www.debian.org/&quot;&gt;Debian&lt;/a&gt;
og &lt;a href=&quot;https://www.ubuntu.com/&quot;&gt;Ubuntu&lt;/a&gt;, slik at en slipper å
finne ut selv hvordan en skal få dem til å virke.&lt;/p&gt;

&lt;p&gt;For å laste ned et NRK-innslag med undertekster, og få den norske
underteksten pakket inn i videofilen, så kan følgende kommando
brukes:&lt;/p&gt;

&lt;p&gt;&lt;pre&gt;
youtube-dl --write-sub --sub-format ttml \
  --convert-subtitles srt --embed-subs \
  https://tv.nrk.no/serie/ramm-ferdig-gaa/MUHU11000316/27-04-2018
&lt;/pre&gt;&lt;/p&gt;

&lt;p&gt;URL-eksemplet er dagens toppsak på tv.nrk.no.  Resultatet er en
MP4-fil med filmen og undertekster som kan spilles av med VLC.  Merk
at VLC ikke viser frem undertekster før du aktiverer dem.  For å gjøre
det, høyreklikk med musa i fremviservinduet, velg menyvalget for
undertekst og så norsk språk.  Jeg testet også &#39;--write-auto-sub&#39;,
men det kommandolinjeargumentet ser ikke ut til å fungere, så jeg
endte opp med settet med argumentlisten over, som jeg fant i en
feilrapport i youtube-dl-prosjektets samling over feilrapporter.&lt;/p&gt;

&lt;p&gt;Denne støtten i youtube-dl gjør det svært enkelt å lagre
NRK-innslag, det være seg nyheter, filmer, serier eller dokumentater,
for å ha dem tilgjengelig for fremtidig referanse og bruk, uavhengig
av hvor lenge innslagene ligger tilgjengelig hos NRK.  Så får det ikke
hjelpe at NRKs jurister mener at det er
&lt;a href=&quot;http://people.skolelinux.org/pere/blog/Best___ikke_fortelle_noen_at_streaming_er_nedlasting___.html&quot;&gt;vesensforskjellig
å legge tilgjengelig for nedlasting og for streaming&lt;/a&gt;, når det rent
teknisk er samme sak.&lt;/p&gt;

&lt;p&gt;Programmet youtube-dl støtter også en rekke andre nettsteder, se
prosjektoversikten for
&lt;a href=&quot;http://rg3.github.io/youtube-dl/supportedsites.html&quot;&gt;en
komplett liste&lt;/a&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Oolite, a life in space as vagabond and mercenary - nice free software</title>
                <link>http://people.skolelinux.org/pere/blog/Oolite__a_life_in_space_as_vagabond_and_mercenary___nice_free_software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Oolite__a_life_in_space_as_vagabond_and_mercenary___nice_free_software.html</guid>
                <pubDate>Sun, 11 Dec 2016 11:40:00 +0100</pubDate>
                <description>&lt;p align=&quot;center&quot;&gt;&lt;img width=&quot;70%&quot; src=&quot;http://people.skolelinux.org/pere/blog/images/2016-12-11-nice-oolite.png&quot;/&gt;&lt;/p&gt;

&lt;p&gt;In my early years, I played
&lt;a href=&quot;http://wiki.alioth.net/index.php/Classic_Elite&quot;&gt;the epic game
Elite&lt;/a&gt; on my PC.  I spent many months trading and fighting in
space, and reached the &#39;elite&#39; fighting status before I moved on.  The
original Elite game was available on Commodore 64 and the IBM PC
edition I played had a 64 KB executable.  I am still impressed today
that the authors managed to squeeze both a 3D engine and details about
more than 2000 planet systems across 7 galaxies into a binary so
small.&lt;/p&gt;

&lt;p&gt;I have known about &lt;a href=&quot;http://www.oolite.org/&quot;&gt;the free
software game Oolite inspired by Elite&lt;/a&gt; for a while, but did not
really have time to test it properly until a few days ago.  It was
great to discover that my old knowledge about trading routes were
still valid.  But my fighting and flying abilities were gone, so I had
to retrain to be able to dock on a space station.  And I am still not
able to make much resistance when I am attacked by pirates, so I
bougth and mounted the most powerful laser in the rear to be able to
put up at least some resistance while fleeing for my life. :)&lt;/p&gt;

&lt;p&gt;When playing Elite in the late eighties, I had to discover
everything on my own, and I had long lists of prices seen on different
planets to be able to decide where to trade what.  This time I had the
advantages of the
&lt;a href=&quot;http://wiki.alioth.net/index.php/Main_Page&quot;&gt;Elite wiki&lt;/a&gt;,
where information about each planet is easily available with common
price ranges and suggested trading routes.  This improved my ability
to earn money and I have been able to earn enough to buy a lot of
useful equipent in a few days.  I believe I originally played for
months before I could get a docking computer, while now I could get it
after less then a week.&lt;/p&gt;

&lt;p&gt;If you like science fiction and dreamed of a life as a vagabond in
space, you should try out Oolite.  It is available for Linux, MacOSX
and Windows, and is included in Debian and derivatives since 2011.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Coz can help you find bottlenecks in multi-threaded software - nice free software</title>
                <link>http://people.skolelinux.org/pere/blog/Coz_can_help_you_find_bottlenecks_in_multi_threaded_software___nice_free_software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Coz_can_help_you_find_bottlenecks_in_multi_threaded_software___nice_free_software.html</guid>
                <pubDate>Thu, 11 Aug 2016 12:00:00 +0200</pubDate>
                <description>&lt;p&gt;This summer, I read a great article
&quot;&lt;a href=&quot;https://www.usenix.org/publications/login/summer2016/curtsinger&quot;&gt;coz:
This Is the Profiler You&#39;re Looking For&lt;/a&gt;&quot; in USENIX ;login: about
how to profile multi-threaded programs.  It presented a system for
profiling software by running experiences in the running program,
testing how run time performance is affected by &quot;speeding up&quot; parts of
the code to various degrees compared to a normal run.  It does this by
slowing down parallel threads while the &quot;faster up&quot; code is running
and measure how this affect processing time.  The processing time is
measured using probes inserted into the code, either using progress
counters (COZ_PROGRESS) or as latency meters (COZ_BEGIN/COZ_END).  It
can also measure unmodified code by measuring complete the program
runtime and running the program several times instead.&lt;/p&gt;

&lt;p&gt;The project and presentation was so inspiring that I would like to
get the system into Debian.  I
&lt;a href=&quot;https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=830708&quot;&gt;created
a WNPP request for it&lt;/a&gt; and contacted upstream to try to make the
system ready for Debian by sending patches.  The build process need to
be changed a bit to avoid running &#39;git clone&#39; to get dependencies, and
to include the JavaScript web page used to visualize the collected
profiling information included in the source package.
But I expect that should work out fairly soon.&lt;/p&gt;

&lt;p&gt;The way the system work is fairly simple.  To run an coz experiment
on a binary with debug symbols available, start the program like this:

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
coz run --- program-to-run
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;This will create a text file profile.coz with the instrumentation
information.  To show what part of the code affect the performance
most, use a web browser and either point it to
&lt;a href=&quot;http://plasma-umass.github.io/coz/&quot;&gt;http://plasma-umass.github.io/coz/&lt;/a&gt;
or use the copy from git (in the gh-pages branch).  Check out this web
site to have a look at several example profiling runs and get an idea what the end result from the profile runs look like.  To make the
profiling more useful you include &amp;lt;coz.h&amp;gt; and insert the
COZ_PROGRESS or COZ_BEGIN and COZ_END at appropriate places in the
code, rebuild and run the profiler.  This allow coz to do more
targeted experiments.&lt;/p&gt;

&lt;p&gt;A video published by ACM
&lt;a href=&quot;https://www.youtube.com/watch?v=jE0V-p1odPg&quot;&gt;presenting the
Coz profiler&lt;/a&gt; is available from Youtube.  There is also a paper
from the 25th Symposium on Operating Systems Principles available
titled
&lt;a href=&quot;https://www.usenix.org/conference/atc16/technical-sessions/presentation/curtsinger&quot;&gt;Coz:
finding code that counts with causal profiling&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;&lt;a href=&quot;https://github.com/plasma-umass/coz&quot;&gt;The source code&lt;/a&gt;
for Coz is available from github.  It will only build with clang
because it uses a
&lt;a href=&quot;https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55606&quot;&gt;C++
feature missing in GCC&lt;/a&gt;, but I&#39;ve submitted
&lt;a href=&quot;https://github.com/plasma-umass/coz/pull/67&quot;&gt;a patch to solve
it&lt;/a&gt; and hope it will be included in the upstream source soon.&lt;/p&gt;

&lt;p&gt;Please get in touch if you, like me, would like to see this piece
of software in Debian.  I would very much like some help with the
packaging effort, as I lack the in depth knowledge on how to package
C++ libraries.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Creepy, visualise geotagged social media information - nice free software</title>
                <link>http://people.skolelinux.org/pere/blog/Creepy__visualise_geotagged_social_media_information___nice_free_software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Creepy__visualise_geotagged_social_media_information___nice_free_software.html</guid>
                <pubDate>Sun, 24 Jan 2016 10:50:00 +0100</pubDate>
                <description>&lt;p&gt;Most people seem not to realise that every time they walk around
with the computerised radio beacon known as a mobile phone their
position is tracked by the phone company and often stored for a long
time (like every time a SMS is received or sent).  And if their
computerised radio beacon is capable of running programs (often called
mobile apps) downloaded from the Internet, these programs are often
also capable of tracking their location (if the app requested access
during installation).  And when these programs send out information to
central collection points, the location is often included, unless
extra care is taken to not send the location.  The provided
information is used by several entities, for good and bad (what is
good and bad, depend on your point of view).  What is certain, is that
the private sphere and the right to free movement is challenged and
perhaps even eradicated for those announcing their location this way,
when they share their whereabouts with private and public
entities.&lt;/p&gt;

&lt;p align=&quot;center&quot;&gt;&lt;img width=&quot;70%&quot; src=&quot;http://people.skolelinux.org/pere/blog/images/2016-01-24-nice-creepy-desktop-window.png&quot;&gt;&lt;/p&gt;

&lt;p&gt;The phone company logs provide a register of locations to check out
when one want to figure out what the tracked person was doing.  It is
unavailable for most of us, but provided to selected government
officials, company staff, those illegally buying information from
unfaithful servants and crackers stealing the information.  But the
public information can be collected and analysed, and a free software
tool to do so is called
&lt;a href=&quot;http://www.geocreepy.com/&quot;&gt;Creepy or Cree.py&lt;/a&gt;.  I
discovered it when I read
&lt;a href=&quot;http://www.aftenposten.no/kultur/Slik-kan-du-bli-overvaket-pa-Twitter-og-Instagram-uten-a-ane-det-7787884.html&quot;&gt;an
article about Creepy&lt;/a&gt; in the Norwegian newspaper Aftenposten i
November 2014, and decided to check if it was available in Debian.
The python program was in Debian, but
&lt;a href=&quot;https://tracker.debian.org/pkg/creepy&quot;&gt;the version in
Debian&lt;/a&gt; was completely broken and practically unmaintained.  I
uploaded a new version which did not work quite right, but did not
have time to fix it then.  This Christmas I decided to finally try to
get Creepy operational in Debian.  Now a fixed version is available in
Debian unstable and testing, and almost all Debian specific patches
are now included
&lt;a href=&quot;https://github.com/jkakavas/creepy&quot;&gt;upstream&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;The Creepy program visualises geolocation information fetched from
Twitter, Instagram, Flickr and Google+, and allow one to get a
complete picture of every social media message posted recently in a
given area, or track the movement of a given individual across all
these services.  Earlier it was possible to use the search API of at
least some of these services without identifying oneself, but these
days it is impossible.  This mean that to use Creepy, you need to
configure it to log in as yourself on these services, and provide
information to them about your search interests.  This should be taken
into account when using Creepy, as it will also share information
about yourself with the services.&lt;/p&gt;

&lt;p&gt;The picture above show the twitter messages sent from (or at least
geotagged with a position from) the city centre of Oslo, the capital
of Norway.  One useful way to use Creepy is to first look at
information tagged with an area of interest, and next look at all the
information provided by one or more individuals who was in the area.
I tested it by checking out which celebrity provide their location in
twitter messages by checkout out who sent twitter messages near a
Norwegian TV station, and next could track their position over time,
making it possible to locate their home and work place, among other
things.  A similar technique have been
&lt;a href=&quot;http://www.buzzfeed.com/maxseddon/does-this-soldiers-instagram-account-prove-russia-is-covertl&quot;&gt;used
to locate Russian soldiers in Ukraine&lt;/a&gt;, and it is both a powerful
tool to discover lying governments, and a useful tool to help people
understand the value of the private information they provide to the
public.&lt;/p&gt;

&lt;p&gt;The package is not trivial to backport to Debian Stable/Jessie, as
it depend on several python modules currently missing in Jessie (at
least python-instagram, python-flickrapi and
python-requests-toolbelt).&lt;/p&gt;

&lt;p&gt;(I have uploaded
&lt;a href=&quot;https://screenshots.debian.net/package/creepy&quot;&gt;the image to
screenshots.debian.net&lt;/a&gt; and licensed it under the same terms as the
Creepy program in Debian.)&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>OpenALPR, find car license plates in video streams - nice free software</title>
                <link>http://people.skolelinux.org/pere/blog/OpenALPR__find_car_license_plates_in_video_streams___nice_free_software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/OpenALPR__find_car_license_plates_in_video_streams___nice_free_software.html</guid>
                <pubDate>Wed, 23 Dec 2015 01:00:00 +0100</pubDate>
                <description>&lt;p&gt;When I was a kid, we used to collect &quot;car numbers&quot;, as we used to
call the car license plate numbers in those days.  I would write the
numbers down in my little book and compare notes with the other kids
to see how many region codes we had seen and if we had seen some
exotic or special region codes and numbers.  It was a fun game to pass
time, as we kids have plenty of it.&lt;/p&gt;

&lt;p&gt;A few days I came across
&lt;a href=&quot;https://github.com/openalpr/openalpr&quot;&gt;the OpenALPR
project&lt;/a&gt;, a free software project to automatically discover and
report license plates in images and video streams, and provide the
&quot;car numbers&quot; in a machine readable format.  I&#39;ve been looking for
such system for a while now, because I believe it is a bad idea that the
&lt;a href=&quot;https://en.wikipedia.org/wiki/Automatic_number_plate_recognition&quot;&gt;automatic
number plate recognition&lt;/a&gt; tool only is available in the hands of
the powerful, and want it to be available also for the powerless to
even the score when it comes to surveillance and sousveillance.  I
discovered the developer
&lt;a href=&quot;https://bugs.debian.org/747509&quot;&gt;wanted to get the tool into
Debian&lt;/a&gt;, and as I too wanted it to be in Debian, I volunteered to
help him get it into shape to get the package uploaded into the Debian
archive.&lt;/p&gt;

&lt;p&gt;Today we finally managed to get the package into shape and uploaded
it into Debian, where it currently
&lt;a href=&quot;https://ftp-master.debian.org//new/openalpr_2.2.1-1.html&quot;&gt;waits
in the NEW queue&lt;/a&gt; for review by the Debian ftpmasters.&lt;/p&gt;

&lt;p&gt;I guess you are wondering why on earth such tool would be useful
for the common folks, ie those not running a large government
surveillance system?  Well, I plan to put it in a computer on my bike
and in my car, tracking the cars nearby and allowing me to be notified
when number plates on my watch list are discovered.  Another use case
was suggested by a friend of mine, who wanted to set it up at his home
to open the car port automatically when it discovered the plate on his
car.  When I mentioned it perhaps was a bit foolhardy to allow anyone
capable of placing his license plate number of a piece of cardboard to
open his car port, men replied that it was always unlocked anyway.  I
guess for such use case it make sense.  I am sure there are other use
cases too, for those with imagination and a vision.&lt;/p&gt;

&lt;p&gt;If you want to build your own version of the Debian package, check
out the upstream git source and symlink ./distros/debian to ./debian/
before running &quot;debuild&quot; to build the source.  Or wait a bit until the
package show up in unstable.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>listadmin, the quick way to moderate mailman lists - nice free software</title>
                <link>http://people.skolelinux.org/pere/blog/listadmin__the_quick_way_to_moderate_mailman_lists___nice_free_software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/listadmin__the_quick_way_to_moderate_mailman_lists___nice_free_software.html</guid>
                <pubDate>Wed, 22 Oct 2014 20:00:00 +0200</pubDate>
                <description>&lt;p&gt;If you ever had to moderate a mailman list, like the ones on
alioth.debian.org, you know the web interface is fairly slow to
operate.  First you visit one web page, enter the moderation password
and get a new page shown with a list of all the messages to moderate
and various options for each email address.  This take a while for
every list you moderate, and you need to do it regularly to do a good
job as a list moderator.  But there is a quick alternative,
&lt;a href=&quot;http://heim.ifi.uio.no/kjetilho/hacks/#listadmin&quot;&gt;the
listadmin program&lt;/a&gt;.  It allow you to check lists for new messages
to moderate in a fraction of a second.  Here is a test run on two
lists I recently took over:&lt;/p&gt;

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
% time listadmin xiph
fetching data for pkg-xiph-commits@lists.alioth.debian.org ... nothing in queue
fetching data for pkg-xiph-maint@lists.alioth.debian.org ... nothing in queue

real    0m1.709s
user    0m0.232s
sys     0m0.012s
%
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;In 1.7 seconds I had checked two mailing lists and confirmed that
there are no message in the moderation queue.  Every morning I
currently moderate 68 mailman lists, and it normally take around two
minutes.  When I took over the two pkg-xiph lists above a few days
ago, there were 400 emails waiting in the moderator queue.  It took me
less than 15 minutes to process them all using the listadmin
program.&lt;/p&gt;

&lt;p&gt;If you install
&lt;a href=&quot;https://tracker.debian.org/pkg/listadmin&quot;&gt;the listadmin
package&lt;/a&gt; from Debian and create a file &lt;tt&gt;~/.listadmin.ini&lt;/tt&gt;
with content like this, the moderation task is a breeze:&lt;/p&gt;

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
username username@example.org
spamlevel 23
default discard
discard_if_reason &quot;Posting restricted to members only. Remove us from your mail list.&quot;

password secret
adminurl https://{domain}/mailman/admindb/{list}
mailman-list@lists.example.com

password hidden
other-list@otherserver.example.org
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;There are other options to set as well.  Check the manual page to
learn the details.&lt;/p&gt;

&lt;p&gt;If you are forced to moderate lists on a mailman installation where
the SSL certificate is self signed or not properly signed by a
generally accepted signing authority, you can set a environment
variable when calling listadmin to disable SSL verification:&lt;/p&gt;

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
PERL_LWP_SSL_VERIFY_HOSTNAME=0 listadmin
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;If you want to moderate a subset of the lists you take care of, you
can provide an argument to the listadmin script like I do in the
initial screen dump (the xiph argument).  Using an argument, only
lists matching the argument string will be processed.  This make it
quick to accept messages if you notice the moderation request in your
email.&lt;/p&gt;

&lt;p&gt;Without the listadmin program, I would never be the moderator of 68
mailing lists, as I simply do not have time to spend on that if the
process was any slower. The listadmin program have saved me hours of
time I could spend elsewhere over the years.  It truly is nice free
software.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;

&lt;p&gt;Update 2014-10-27: Added missing &#39;username&#39; statement in
configuration example.  Also, I&#39;ve been told that the
PERL_LWP_SSL_VERIFY_HOSTNAME=0 setting do not work for everyone.  Not
sure why.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>S3QL, a locally mounted cloud file system - nice free software</title>
                <link>http://people.skolelinux.org/pere/blog/S3QL__a_locally_mounted_cloud_file_system___nice_free_software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/S3QL__a_locally_mounted_cloud_file_system___nice_free_software.html</guid>
                <pubDate>Wed, 9 Apr 2014 11:30:00 +0200</pubDate>
                <description>&lt;p&gt;For a while now, I have been looking for a sensible offsite backup
solution for use at home.  My requirements are simple, it must be
cheap and locally encrypted (in other words, I keep the encryption
keys, the storage provider do not have access to my private files).
One idea me and my friends had many years ago, before the cloud
storage providers showed up, was to use Google mail as storage,
writing a Linux block device storing blocks as emails in the mail
service provided by Google, and thus get heaps of free space.  On top
of this one can add encryption, RAID and volume management to have
lots of (fairly slow, I admit that) cheap and encrypted storage.  But
I never found time to implement such system.  But the last few weeks I
have looked at a system called
&lt;a href=&quot;https://bitbucket.org/nikratio/s3ql/&quot;&gt;S3QL&lt;/a&gt;, a locally
mounted network backed file system with the features I need.&lt;/p&gt;

&lt;p&gt;S3QL is a fuse file system with a local cache and cloud storage,
handling several different storage providers, any with Amazon S3,
Google Drive or OpenStack API.  There are heaps of such storage
providers.  S3QL can also use a local directory as storage, which
combined with sshfs allow for file storage on any ssh server.  S3QL
include support for encryption, compression, de-duplication, snapshots
and immutable file systems, allowing me to mount the remote storage as
a local mount point, look at and use the files as if they were local,
while the content is stored in the cloud as well.  This allow me to
have a backup that should survive fire.  The file system can not be
shared between several machines at the same time, as only one can
mount it at the time, but any machine with the encryption key and
access to the storage service can mount it if it is unmounted.&lt;/p&gt;

&lt;p&gt;It is simple to use.  I&#39;m using it on Debian Wheezy, where the
package is included already.  So to get started, run &lt;tt&gt;apt-get
install s3ql&lt;/tt&gt;.  Next, pick a storage provider.  I ended up picking
Greenqloud, after reading their nice recipe on
&lt;a href=&quot;https://greenqloud.zendesk.com/entries/44611757-How-To-Use-S3QL-to-mount-a-StorageQloud-bucket-on-Debian-Wheezy&quot;&gt;how
to use S3QL with their Amazon S3 service&lt;/a&gt;, because I trust the laws
in Iceland more than those in USA when it come to keeping my personal
data safe and private, and thus would rather spend money on a company
in Iceland.  Another nice recipe is available from the article
&lt;a href=&quot;http://www.admin-magazine.com/HPC/Articles/HPC-Cloud-Storage&quot;&gt;S3QL
Filesystem for HPC Storage&lt;/a&gt; by Jeff Layton in the HPC section of
Admin magazine.  When the provider is picked, figure out how to get
the API key needed to connect to the storage API.  With Greencloud,
the key did not show up until I had added payment details to my
account.&lt;/p&gt;

&lt;p&gt;Armed with the API access details, it is time to create the file
system.  First, create a new bucket in the cloud.  This bucket is the
file system storage area.  I picked a bucket name reflecting the
machine that was going to store data there, but any name will do.
I&#39;ll refer to it as &lt;tt&gt;bucket-name&lt;/tt&gt; below.  In addition, one need
the API login and password, and a locally created password.  Store it
all in ~root/.s3ql/authinfo2 like this:

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
[s3c]
storage-url: s3c://s.greenqloud.com:443/bucket-name
backend-login: API-login
backend-password: API-password
fs-passphrase: local-password
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;I create my local passphrase using &lt;tt&gt;pwget 50&lt;/tt&gt; or similar,
but any sensible way to create a fairly random password should do it.
Armed with these details, it is now time to run mkfs, entering the API
details and password to create it:&lt;/p&gt;

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
# mkdir -m 700 /var/lib/s3ql-cache
# mkfs.s3ql --cachedir /var/lib/s3ql-cache --authfile /root/.s3ql/authinfo2 \
  --ssl s3c://s.greenqloud.com:443/bucket-name
Enter backend login: 
Enter backend password: 
Before using S3QL, make sure to read the user&#39;s guide, especially
the &#39;Important Rules to Avoid Loosing Data&#39; section.
Enter encryption password: 
Confirm encryption password: 
Generating random encryption key...
Creating metadata tables...
Dumping metadata...
..objects..
..blocks..
..inodes..
..inode_blocks..
..symlink_targets..
..names..
..contents..
..ext_attributes..
Compressing and uploading metadata...
Wrote 0.00 MB of compressed metadata.
# &lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;The next step is mounting the file system to make the storage available.

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
# mount.s3ql --cachedir /var/lib/s3ql-cache --authfile /root/.s3ql/authinfo2 \
  --ssl --allow-root s3c://s.greenqloud.com:443/bucket-name /s3ql
Using 4 upload threads.
Downloading and decompressing metadata...
Reading metadata...
..objects..
..blocks..
..inodes..
..inode_blocks..
..symlink_targets..
..names..
..contents..
..ext_attributes..
Mounting filesystem...
# df -h /s3ql
Filesystem                              Size  Used Avail Use% Mounted on
s3c://s.greenqloud.com:443/bucket-name  1.0T     0  1.0T   0% /s3ql
#
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;The file system is now ready for use.  I use rsync to store my
backups in it, and as the metadata used by rsync is downloaded at
mount time, no network traffic (and storage cost) is triggered by
running rsync.  To unmount, one should not use the normal umount
command, as this will not flush the cache to the cloud storage, but
instead running the umount.s3ql command like this:

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
# umount.s3ql /s3ql
# 
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;There is a fsck command available to check the file system and
correct any problems detected.  This can be used if the local server
crashes while the file system is mounted, to reset the &quot;already
mounted&quot; flag.  This is what it look like when processing a working
file system:&lt;/p&gt;

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
# fsck.s3ql --force --ssl s3c://s.greenqloud.com:443/bucket-name
Using cached metadata.
File system seems clean, checking anyway.
Checking DB integrity...
Creating temporary extra indices...
Checking lost+found...
Checking cached objects...
Checking names (refcounts)...
Checking contents (names)...
Checking contents (inodes)...
Checking contents (parent inodes)...
Checking objects (reference counts)...
Checking objects (backend)...
..processed 5000 objects so far..
..processed 10000 objects so far..
..processed 15000 objects so far..
Checking objects (sizes)...
Checking blocks (referenced objects)...
Checking blocks (refcounts)...
Checking inode-block mapping (blocks)...
Checking inode-block mapping (inodes)...
Checking inodes (refcounts)...
Checking inodes (sizes)...
Checking extended attributes (names)...
Checking extended attributes (inodes)...
Checking symlinks (inodes)...
Checking directory reachability...
Checking unix conventions...
Checking referential integrity...
Dropping temporary indices...
Backing up old metadata...
Dumping metadata...
..objects..
..blocks..
..inodes..
..inode_blocks..
..symlink_targets..
..names..
..contents..
..ext_attributes..
Compressing and uploading metadata...
Wrote 0.89 MB of compressed metadata.
# 
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;Thanks to the cache, working on files that fit in the cache is very
quick, about the same speed as local file access.  Uploading large
amount of data is to me limited by the bandwidth out of and into my
house.  Uploading 685 MiB with a 100 MiB cache gave me 305 kiB/s,
which is very close to my upload speed, and downloading the same
Debian installation ISO gave me 610 kiB/s, close to my download speed.
Both were measured using &lt;tt&gt;dd&lt;/tt&gt;.  So for me, the bottleneck is my
network, not the file system code.  I do not know what a good cache
size would be, but suspect that the cache should e larger than your
working set.&lt;/p&gt;

&lt;p&gt;I mentioned that only one machine can mount the file system at the
time.  If another machine try, it is told that the file system is
busy:&lt;/p&gt;

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
# mount.s3ql --cachedir /var/lib/s3ql-cache --authfile /root/.s3ql/authinfo2 \
  --ssl --allow-root s3c://s.greenqloud.com:443/bucket-name /s3ql
Using 8 upload threads.
Backend reports that fs is still mounted elsewhere, aborting.
#
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;The file content is uploaded when the cache is full, while the
metadata is uploaded once every 24 hour by default.  To ensure the
file system content is flushed to the cloud, one can either umount the
file system, or ask S3QL to flush the cache and metadata using
s3qlctrl:

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
# s3qlctrl upload-meta /s3ql
# s3qlctrl flushcache /s3ql
# 
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;If you are curious about how much space your data uses in the
cloud, and how much compression and deduplication cut down on the
storage usage, you can use s3qlstat on the mounted file system to get
a report:&lt;/p&gt;

&lt;p&gt;&lt;blockquote&gt;&lt;pre&gt;
# s3qlstat /s3ql
Directory entries:    9141
Inodes:               9143
Data blocks:          8851
Total data size:      22049.38 MB
After de-duplication: 21955.46 MB (99.57% of total)
After compression:    21877.28 MB (99.22% of total, 99.64% of de-duplicated)
Database size:        2.39 MB (uncompressed)
(some values do not take into account not-yet-uploaded dirty blocks in cache)
#
&lt;/pre&gt;&lt;/blockquote&gt;&lt;/p&gt;

&lt;p&gt;I mentioned earlier that there are several possible suppliers of
storage.  I did not try to locate them all, but am aware of at least
&lt;a href=&quot;https://www.greenqloud.com/&quot;&gt;Greenqloud&lt;/a&gt;,
&lt;a href=&quot;http://drive.google.com/&quot;&gt;Google Drive&lt;/a&gt;,
&lt;a href=&quot;http://aws.amazon.com/s3/&quot;&gt;Amazon S3 web serivces&lt;/a&gt;,
&lt;a href=&quot;http://www.rackspace.com/&quot;&gt;Rackspace&lt;/a&gt; and
&lt;a href=&quot;http://crowncloud.net/&quot;&gt;Crowncloud&lt;/A&gt;.  The latter even
accept payment in Bitcoin.  Pick one that suit your need.  Some of
them provide several GiB of free storage, but the prize models are
quite different and you will have to figure out what suits you
best.&lt;/p&gt;

&lt;p&gt;While researching this blog post, I had a look at research papers
and posters discussing the S3QL file system.  There are several, which
told me that the file system is getting a critical check by the
science community and increased my confidence in using it.  One nice
poster is titled
&quot;&lt;a href=&quot;http://www.lanl.gov/orgs/adtsc/publications/science_highlights_2013/docs/pg68_69.pdf&quot;&gt;An
Innovative Parallel Cloud Storage System using OpenStack’s SwiftObject
Store and Transformative Parallel I/O Approach&lt;/a&gt;&quot; by Hsing-Bung
Chen, Benjamin McClelland, David Sherrill, Alfred Torrez, Parks Fields
and Pamela Smith.  Please  have a look.&lt;/p&gt;

&lt;p&gt;Given my problems with different file systems earlier, I decided to
check out the mounted S3QL file system to see if it would be usable as
a home directory (in other word, that it provided POSIX semantics when
it come to locking and umask handling etc).  Running
&lt;a href=&quot;http://people.skolelinux.org/pere/blog/Testing_if_a_file_system_can_be_used_for_home_directories___.html&quot;&gt;my
test code to check file system semantics&lt;/a&gt;, I was happy to discover that
no error was found.  So the file system can be used for home
directories, if one chooses to do so.&lt;/p&gt;

&lt;p&gt;If you do not want a locally file system, and want something that
work without the Linux fuse file system, I would like to mention the
&lt;a href=&quot;http://www.tarsnap.com/&quot;&gt;Tarsnap service&lt;/a&gt;, which also
provide locally encrypted backup using a command line client.  It have
a nicer access control system, where one can split out read and write
access, allowing some systems to write to the backup and others to
only read from it.&lt;/p&gt;

&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>ReactOS Windows clone - nice free software</title>
                <link>http://people.skolelinux.org/pere/blog/ReactOS_Windows_clone___nice_free_software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/ReactOS_Windows_clone___nice_free_software.html</guid>
                <pubDate>Tue, 1 Apr 2014 12:10:00 +0200</pubDate>
                <description>&lt;p&gt;Microsoft have announced that Windows XP reaches its end of life
2014-04-08, in 7 days.  But there are heaps of machines still running
Windows XP, and depending on Windows XP to run their applications, and
upgrading will be expensive, both when it comes to money and when it
comes to the amount of effort needed to migrate from Windows XP to a
new operating system.  Some obvious options (buy new a Windows
machine, buy a MacOSX machine, install Linux on the existing machine)
are already well known and covered elsewhere.  Most of them involve
leaving the user applications installed on Windows XP behind and
trying out replacements or updated versions. In this blog post I want
to mention one strange bird that allow people to keep the hardware and
the existing Windows XP applications and run them on a free software
operating system that is Windows XP compatible.&lt;/p&gt;

&lt;p&gt;&lt;a href=&quot;http://www.reactos.org/&quot;&gt;ReactOS&lt;/a&gt; is a free software
operating system (GNU GPL licensed) working on providing a operating
system that is binary compatible with Windows, able to run windows
programs directly and to use Windows drivers for hardware directly.
The project goal is for Windows user to keep their existing machines,
drivers and software, and gain the advantages from user a operating
system without usage limitations caused by non-free licensing.  It is
a Windows clone running directly on the hardware, so quite different
from the approach taken by &lt;a href=&quot;http://www.winehq.org/&quot;&gt;the Wine
project&lt;/a&gt;, which make it possible to run Windows binaries on
Linux.&lt;/p&gt;

&lt;p&gt;The ReactOS project share code with the Wine project, so most
shared libraries available on Windows are already implemented already.
There is also a software manager like the one we are used to on Linux,
allowing the user to install free software applications with a simple
click directly from the Internet.  Check out the
&lt;a href=&quot;http://www.reactos.org/screenshots&quot;&gt;screen shots on the
project web site&lt;/a&gt; for an idea what it look like (it looks just like
Windows before metro).&lt;/p&gt;

&lt;p&gt;I do not use ReactOS myself, preferring Linux and Unix like
operating systems.  I&#39;ve tested it, and it work fine in a virt-manager
virtual machine.  The browser, minesweeper, notepad etc is working
fine as far as I can tell.  Unfortunately, my main test application
is the software included on a CD with the Lego Mindstorms NXT, which
seem to install just fine from CD but fail to leave any binaries on
the disk after the installation.  So no luck with that test software.
No idea why, but hope someone else figure out and fix the problem.
I&#39;ve tried the ReactOS Live ISO on a physical machine, and it seemed
to work just fine.  If you like Windows and want to keep running your
old Windows binaries, check it out by
&lt;a href=&quot;http://www.reactos.org/download&quot;&gt;downloading&lt;/a&gt; the
installation CD, the live CD or the preinstalled virtual machine
image.&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Video DVD reader library / python-dvdvideo - nice free software</title>
                <link>http://people.skolelinux.org/pere/blog/Video_DVD_reader_library___python_dvdvideo___nice_free_software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Video_DVD_reader_library___python_dvdvideo___nice_free_software.html</guid>
                <pubDate>Fri, 21 Mar 2014 15:25:00 +0100</pubDate>
                <description>&lt;p&gt;Keeping your DVD collection safe from scratches and curious
children fingers while still having it available when you want to see a
movie is not straight forward.  My preferred method at the moment is
to store a full copy of the ISO on a hard drive, and use VLC, Popcorn
Hour or other useful players to view the resulting file.  This way the
subtitles and bonus material are still available and using the ISO is
just like inserting the original DVD record in the DVD player.&lt;/p&gt;

&lt;p&gt;Earlier I used dd for taking security copies, but it do not handle
DVDs giving read errors (which are quite a few of them).  I&#39;ve also
tried using
&lt;a href=&quot;http://people.skolelinux.org/pere/blog/Ripping_problematic_DVDs_using_dvdbackup_and_genisoimage.html&quot;&gt;dvdbackup
and genisoimage&lt;/a&gt;, but these days I use the marvellous python library
and program
&lt;a href=&quot;http://bblank.thinkmo.de/blog/new-software-python-dvdvideo&quot;&gt;python-dvdvideo&lt;/a&gt;
written by Bastian Blank.  It is
&lt;a href=&quot;http://packages.qa.debian.org/p/python-dvdvideo.html&quot;&gt;in Debian
already&lt;/a&gt; and the binary package name is python3-dvdvideo. Instead
of trying to read every block from the DVD, it parses the file
structure and figure out which block on the DVD is actually in used,
and only read those blocks from the DVD.  This work surprisingly well,
and I have been able to almost backup my entire DVD collection using
this method.&lt;/p&gt;

&lt;p&gt;So far, python-dvdvideo have failed on between 10 and
20 DVDs, which is a small fraction of my collection.  The most common
problem is
&lt;a href=&quot;https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=720831&quot;&gt;DVDs
using UTF-16 instead of UTF-8 characters&lt;/a&gt;, which according to
Bastian is against the DVD specification (and seem to cause some
players to fail too).  A rarer problem is what seem to be inconsistent
DVD structures, as the python library
&lt;a href=&quot;https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=723079&quot;&gt;claim
there is a overlap between objects&lt;/a&gt;.  An equally rare problem claim
&lt;a href=&quot;https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=741878&quot;&gt;some
value is out of range&lt;/a&gt;.  No idea what is going on there.  I wish I
knew enough about the DVD format to fix these, to ensure my movie
collection will stay with me in the future.&lt;/p&gt;

&lt;p&gt;So, if you need to keep your DVDs safe, back them up using
python-dvdvideo. :)&lt;/p&gt;
</description>
        </item>
        
        <item>
                <title>Free Timetabling Software - nice free software</title>
                <link>http://people.skolelinux.org/pere/blog/Free_Timetabling_Software___nice_free_software.html</link>
                <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Free_Timetabling_Software___nice_free_software.html</guid>
                <pubDate>Sat, 7 Jul 2012 09:50:00 +0200</pubDate>
                <description>&lt;p&gt;Included in &lt;a href=&quot;http://www.skolelinux.org/&quot;&gt;Debian Edu /
Skolelinux&lt;/a&gt; is a large collection of end user and school specific
software.  It is one of the packages not installed by default but
provided in the Debian archive for schools to install if they want to,
is a system to automatically plan the school time table using
information about available teachers, classes and rooms, combined with
the list of required courses and how many hours each topic should
receive.  The software is

&lt;a href=&quot;http://lalescu.ro/liviu/fet/&quot;&gt;named FET&lt;/a&gt;, and it provide a
graphical user interface to input the required information, save the
result in a fairly simple XML format, and generate time tables for
both teachers and students.  It is available both for
&lt;a href=&quot;http://lalescu.ro/liviu/fet/download.html&quot;&gt;Linux, MacOSX and
Windows&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;This is &lt;a href=&quot;http://lalescu.ro/liviu/fet/features.html&quot;&gt;the
feature list&lt;/a&gt;, liftet from the project web site:&lt;/p&gt;

&lt;p&gt;&lt;ul&gt;

  &lt;li&gt;FET is free software, licensed under the GNU GPL v2 or later.
    You can freely use, copy, modify and redistribute it &lt;/li&gt;
        
  &lt;li&gt;Localized to en_US (US English, default), ar (Arabic), ca
    (Catalan), da (Danish), de (German), el (Greek), es (Spanish), fa
    (Persian), fr (French), gl (Galician), he (Hebrew), hu
    (Hungarian), id (Indonesian), it (Italian), lt (Lithuanian), mk
    (Macedonian), ms (Malay), nl (Dutch), pl (Polish), pt_BR
    (Brazilian Portuguese), ro (Romanian), ru (Russian), si (Sinhala),
    sk (Slovak), sr (Serbian), tr (Turkish), uk (Ukrainian), uz
    (Uzbek) and vi (Vietnamese) (incompletely for some languages)
    &lt;/li&gt;
        
  &lt;li&gt;Fully automatic generation algorithm, allowing also
    semi-automatic or manual allocation&lt;/li&gt;
        
  &lt;li&gt;Platform independent implementation, allowing running on
    GNU/Linux, Windows, Mac and any system that Qt supports &lt;/li&gt;
        
  &lt;li&gt;Flexible modular XML format for the input file, allowing editing
    with an XML editor or by hand (besides FET interface)&lt;/li&gt;
        
  &lt;li&gt;Import/export from CSV format&lt;/li&gt;
        
  &lt;li&gt;The resulted timetables are exported into HTML, XML and CSV
    formats &lt;/li&gt;
        
  &lt;li&gt;Flexible students structure, organized into sets: years, groups
    and subgroups. FET allows overlapping years and groups and
    non-overlapping subgroups. You can even define individual students
    (as separate sets)&lt;/li&gt;
        
  &lt;li&gt;Each constraint has a weight percentage, from 0.0% to 100.0%
    (but some special constraints are allowed to have only 100% weight
    percentage)&lt;/li&gt;
        
  &lt;li&gt;Limits for the algorithm (all these limits can be increased on
    demand, as a custom version, because this would require a bit more
    memory):
    &lt;ul&gt;
      &lt;li&gt;Maximum total number of hours (periods) per day: 60&lt;/li&gt;
      &lt;li&gt;Maximum number of working days per week: 35&lt;/li&gt;
      &lt;li&gt;Maximum total number of teachers: 6000&lt;/li&gt;
      &lt;li&gt;Maximum total number of sets of students: 30000&lt;/li&gt;
      &lt;li&gt;Maximum total number of subjects: 6000&lt;/li&gt;
      &lt;li&gt;Virtually unlimited number of activity tags&lt;/li&gt;
      &lt;li&gt;Maximum number of activities: 30000&lt;/li&gt;
      &lt;li&gt;Maximum number of rooms: 6000&lt;/li&gt;
      &lt;li&gt;Maximum number of buildings: 6000&lt;/li&gt;
      &lt;li&gt;Possibility of adding multiple teachers and
          students sets for each activity.  (it is possible
          also to have no teachers or no students sets for an
          activity)&lt;/li&gt;
      &lt;li&gt;Virtually unlimited number of time constraints&lt;/li&gt;
      &lt;li&gt;Virtually unlimited number of space constraints&lt;/li&gt;
    &lt;/ul&gt;&lt;/li&gt;

  &lt;li&gt;A large and flexible palette of time constraints:
    &lt;ul&gt;
      &lt;li&gt;Break periods&lt;/li&gt;
      &lt;li&gt;For teacher(s):
        &lt;ul&gt;
          &lt;li&gt;Not available periods&lt;/li&gt;
          &lt;li&gt;Max/min days per week&lt;/li&gt;
          &lt;li&gt;Max gaps per day/week&lt;/li&gt;
          &lt;li&gt;Max hours daily/continuously&lt;/li&gt;
          &lt;li&gt;Min hours daily&lt;/li&gt;
          &lt;li&gt;Max hours daily/continuously with an activity tag&lt;/li&gt;

          &lt;li&gt;Respect working in an hourly interval a max number of
            days per week&lt;/li&gt;
        &lt;/ul&gt;&lt;/li&gt;
      &lt;li&gt;For students (sets):
        &lt;ul&gt;
          &lt;li&gt;Not available periods&lt;/li&gt;
          &lt;li&gt;Begins early (specify max allowed beginnings at second hour)&lt;/li&gt;
          &lt;li&gt;Max gaps per day/week&lt;/li&gt;
          &lt;li&gt;Max hours daily/continuously&lt;/li&gt;
          &lt;li&gt;Min hours daily&lt;/li&gt;
          &lt;li&gt;Max hours daily/continuously with an activity tag&lt;/li&gt;

          &lt;li&gt;Respect working in an hourly interval a max number of
            days per week&lt;/li&gt;
        &lt;/ul&gt;&lt;/li&gt;
      &lt;li&gt;For an activity or a set of activities/subactivities:
        &lt;ul&gt;
          &lt;li&gt;A single preferred starting time&lt;/li&gt;
          &lt;li&gt;A set of preferred starting times&lt;/li&gt;
          &lt;li&gt;A set of preferred time slots&lt;/li&gt;
          &lt;li&gt;Min/max days between them&lt;/li&gt;
          &lt;li&gt;End(s) students day&lt;/li&gt;
          &lt;li&gt;Same starting time/day/hour&lt;/li&gt;
          &lt;li&gt;Occupy max time slots from selection (a complex and
            flexible constraint, useful in many situations)&lt;/li&gt;
          &lt;li&gt;Consecutive, ordered, grouped (for 2 or 3 (sub)activities)&lt;/li&gt;
          &lt;li&gt;Not overlapping&lt;/li&gt;
          &lt;li&gt;Max simultaneous in selected time slots&lt;/li&gt;
          &lt;li&gt;Min gaps between a set of (sub)activities&lt;/li&gt;
        &lt;/ul&gt;&lt;/li&gt;
    &lt;/ul&gt;&lt;/li&gt;

  &lt;li&gt;A large and flexible palette of space constraints:
    &lt;ul&gt;
      &lt;li&gt;Room not available periods&lt;/li&gt;
      &lt;li&gt;For teacher(s):
        &lt;ul&gt;
          &lt;li&gt;Home room(s)&lt;/li&gt;
          &lt;li&gt;Max building changes per day/week&lt;/li&gt;
          &lt;li&gt;Min gaps between building changes&lt;/li&gt;
        &lt;/ul&gt;
      &lt;/li&gt;
                
      &lt;li&gt;For students (sets):
        &lt;ul&gt;
          &lt;li&gt;Home room(s)&lt;/li&gt;
          &lt;li&gt;Max building changes per day/week&lt;/li&gt;
          &lt;li&gt;Min gaps between building changes&lt;/li&gt;
        &lt;/ul&gt;
      &lt;/li&gt;
      &lt;li&gt;Preferred room(s):
        &lt;ul&gt;
          &lt;li&gt;For a subject&lt;/li&gt;
          &lt;li&gt;For an activity tag&lt;/li&gt;
          &lt;li&gt;For a subject and an activity tag&lt;/li&gt;
          &lt;li&gt;Individually for a (sub)activity&lt;/li&gt;
        &lt;/ul&gt;
      &lt;/li&gt;

      &lt;li&gt;For a set of activities:
        &lt;ul&gt;
          &lt;li&gt;Occupy a maximum number of different rooms&lt;/li&gt;
        &lt;/ul&gt;
      &lt;/li&gt;
    &lt;/ul&gt;
  &lt;/li&gt;
&lt;/ul&gt;&lt;/p&gt;

&lt;p&gt;I have not used it myself, as I am not involved in time table
planning at a school, but it seem to work fine when I test it.  If you
need to set up your schools time table, and is tired of doing it
manually, check it out. 

A quick summary on how to use it can be found in
&lt;a href=&quot;http://marvelsoft.co.in/wp/2012/03/generate-timetable-for-state-cbse-icse-igcse-schools-free/&quot;&gt;a
blog post from MarvelSoft&lt;/a&gt;.  If you find FET useful, please provide
a recipe for the Debian Edu project in the
&lt;a href=&quot;http://wiki.debian.org/DebianEdu#Howtos&quot;&gt;Debian Edu HowTo
section&lt;/a&gt;.&lt;/p&gt;
</description>
        </item>
        
        </channel>
</rss>