<link>https://people.skolelinux.org/pere/blog/</link>
<atom:link href="https://people.skolelinux.org/pere/blog/index.rss" rel="self" type="application/rss+xml" />
+ <item>
+ <title>«Virkninger av angrefristloven», hovedfagsoppgaven som fikk endret en lov</title>
+ <link>https://people.skolelinux.org/pere/blog/_Virkninger_av_angrefristloven___hovedfagsoppgaven_som_fikk_endret_en_lov.html</link>
+ <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/_Virkninger_av_angrefristloven___hovedfagsoppgaven_som_fikk_endret_en_lov.html</guid>
+ <pubDate>Sun, 29 Oct 2023 22:00:00 +0100</pubDate>
+ <description><img src="http://people.skolelinux.org/pere/blog/images/2023-10-29-bok-angrefrist.svg" width="20%" align="center"></a>
+
+<p>I 1979 leverte Ole-Erik Yrvin en hovedfagsoppgave for Cand. Scient.
+ ved Institutt for sosiologi på Universitetet i Oslo på oppdrag fra
+ Forbruker- og administrasjonsdepartementet. Oppgaven evaluerte
+ Angrefristloven fra 1972, og det han oppdaget førte til at loven ble
+ endret fire år senere.</p>
+
+<p>Jeg har kjent Ole-Erik en stund, og synes det var trist at hans
+ oppgave ikke lenger er tilgjengelig, hverken fra oppdragsgiver
+ eller fra universitetet. Hans forsøk på å få den avbildet og lagt
+ ut på Internett har vist seg fånyttes, så derfor tilbød jeg meg for
+ en stund tilbake å publisere den og gjøre den tilgjengelig med
+ fribruksvilkår på Internett. Det er nå klart, og hovedfagsoppgaven
+ er tilgjengelig blant annet via <a
+ href="http://www.hungry.com/~pere/publisher/">min liste over
+ publiserte bøker</a>, både som nettside,
+ <a href="https://www.lulu.com/search?contributor=Ole-Erik+Yrvin">digital
+ bok i ePub-format og på papir fra lulu.com</a>. Jeg regner med at
+ den også vil dukke opp på nettbokhandlere i løpet av en måned eller
+ to.</p>
+
+<p>Alle tabeller og figurer er gjenskapt for bedre lesbarhet, noen
+ skrivefeil rettet opp og mange referanser har fått flere detaljer
+ som ISBN-nummer og DOI-referanse. Selv om jeg ikke regner med at
+ dette blir en kioskvelter, så håper jeg denne nye utgaven kan komme
+ fremtiden til glede.</p>
+
+<p>Som vanlig, hvis du bruker Bitcoin og ønsker å vise din støtte til
+det jeg driver med, setter jeg pris på om du sender Bitcoin-donasjoner
+til min adresse
+<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>. Merk,
+betaling med bitcoin er ikke anonymt. :)</p>
+</description>
+ </item>
+
+ <item>
+ <title>«underordnet tjenestemann blir inhabil fordi en overordnet er inhabil».</title>
+ <link>https://people.skolelinux.org/pere/blog/_underordnet_tjenestemann_blir_inhabil_fordi_en_overordnet_er_inhabil__.html</link>
+ <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/_underordnet_tjenestemann_blir_inhabil_fordi_en_overordnet_er_inhabil__.html</guid>
+ <pubDate>Thu, 7 Sep 2023 09:10:00 +0200</pubDate>
+ <description><p>Medlemmene av Norges regjering har demonstert de siste månedene at
+habilitetsvureringer ikke er deres sterke side og det gjelder både
+Arbeiderpartiets og Senterpartiers representater. Det er heldigvis
+enklere i det private, da inhabilitetsreglene kun gjelder de som
+jobber for folket, ikke seg selv. Sist ut er utenriksminister
+Huitfeldt. I går kom nyheten om at
+<a href="https://www.nrk.no/nyheter/riksadvokaten_-okokrim-nestsjef-kan-behandle-huitfeldt-saken-1.16545162">Riksadvokaten
+har konkludert med at nestsjefen i Økokrim kan behandle sak om
+habilitet og innsidekunnskap</a> for Huitfeldt, på tross av at hans
+overordnede, sjefen for Økokrim, har meldt seg inhabil i saken. Dette
+er litt rart. I veilednigen
+«<a href="https://www.regjeringen.no/globalassets/upload/krd/vedlegg/komm/veiledere/habilitet_i_kommuner_og_fylkeskommuner.pdf">Habilitet
+i kommuner og fylkeskommuner</a>» av Kommunal- og regionaldepartementet
+forteller de hva som gjelder, riktig nok gjelder veiledningen ikke for
+Økokrim som jo ikke er kommune eller fylkeskommune, men jeg får ikke
+inntrykk av at dette er regler som kun gjelder for kommune og
+fylkeskommune:
+
+<blockquote>
+<p>«<strong>2.1 Oversikt over inhabilitetsgrunnlagene</strong>
+
+<p>De alminnelige reglene om inhabilitet for den offentlige
+forvaltningen er gitt i
+<a href="https://lovdata.no/dokument/NL/lov/1967-02-10/KAPITTEL_2#KAPITTEL_2">forvaltningsloven
+§§ 6 til 10</a>. Forvaltningslovens hovedregel om inhabilitet framgår
+av § 6. Her er det gitt tre ulike grunnlag som kan føre til at en
+tjenestemann eller folkevalgt blir inhabil. I § 6 første ledd
+bokstavene a til e er det oppstilt konkrete tilknytningsforhold mellom
+tjenestemannen og saken eller sakens parter som automatisk fører til
+inhabilitet. Annet ledd oppstiller en skjønnsmessig regel om at
+tjenestemannen også kan bli inhabil etter en konkret vurdering av
+inhabilitetsspørsmålet, der en lang rekke momenter kan være
+relevante. I tredje ledd er det regler om såkalt avledet
+inhabilitet. Det vil si at en underordnet tjenestemann blir inhabil
+fordi en overordnet er inhabil.»</p>
+</blockquote>
+
+<p>Loven sier ganske enkelt «Er den overordnede tjenestemann ugild,
+kan avgjørelse i saken heller ikke treffes av en direkte underordnet
+tjenestemann i samme forvaltningsorgan.» Jeg antar tanken er at en
+underordnet vil stå i fare for å tilpasse sine konklusjoner til det
+overordnet vil ha fordel av, for å fortsatt ha et godt forhold til sin
+overordnede. Men jeg er ikke jurist og forstår nok ikke kompliserte
+juridiske vurderinger. For å sitere «Kamerat Napoleon» av George
+Orwell: «Alle dyr er like, men noen dyr er likere enn andre».
+</description>
+ </item>
+
+ <item>
+ <title>Invidious add-on for Kodi 20</title>
+ <link>https://people.skolelinux.org/pere/blog/Invidious_add_on_for_Kodi_20.html</link>
+ <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Invidious_add_on_for_Kodi_20.html</guid>
+ <pubDate>Thu, 10 Aug 2023 19:50:00 +0200</pubDate>
+ <description><p>I still enjoy <a href="https://kodi.tv/">Kodi</a> and
+<a href="https://libreelec.tv/">LibreELEC</a> as my multimedia center
+at home. Sadly two of the services I really would like to use from
+within Kodi are not easily available. The most wanted add-on would be
+one making <a href="https://archive.org/">The Internet Archive</a>
+available, and it has
+<a href="https://kodi.wiki/view/Add-on:Internet_Archive">not been
+working</a> for many years. The second most wanted add-on is one
+using <a href="https://invidious.io/">the Invidious privacy enhanced
+Youtube frontent</a>. A plugin for this has been partly working, but
+not been kept up to date in the Kodi add-on repository, and its
+upstream seem to have given it up in April this year, when the git
+repository was closed. A few days ago I got tired of this sad state
+of affairs and decided to
+<a href="https://github.com/petterreinholdtsen/kodi-invidious-plugin">have
+a go at improving the Invidious add-on</a>. As
+<a href="https://github.com/iv-org/invidious/issues/3872">Google has
+already attacked</a> the Invidious concept, so it need all the support
+if can get. My small contribution here is to improve the service
+status on Kodi.</p>
+
+<p>I added support to the Invidious add-on for automatically picking a
+working Invidious instance, instead of requiring the user to specify
+the URL to a specific instance after installation. I also had a look
+at the set of patches floating around in the various forks on github,
+and decided to clean up at least some of the features I liked and
+integrate them into my new release branch. Now the plugin can handle
+channel and short video items in search results. Earlier it could
+only handle single video instances in the search response. I also
+brushed up the set of metadata displayed a bit, but hope I can figure
+out how to get more relevant metadata displayed.</p>
+
+<p>Because I only use Kodi 20 myself, I only test on version 20 and am
+only motivated to ensure version 20 is working. Because of API changes
+between version 19 and 20, I suspect it will fail with earlier Kodi
+versions.</p>
+
+<p>I already
+<a href="https://github.com/xbmc/repo-plugins/pull/4363">asked to have
+the add-on added</a> to the official Kodi 20 repository, and is
+waiting to heard back from the repo maintainers.</p>
+
+<p>As usual, if you use Bitcoin and want to show your support of my
+activities, please send Bitcoin donations to my address
+<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
+</description>
+ </item>
+
+ <item>
+ <title>What did I learn from OpenSnitch this summer?</title>
+ <link>https://people.skolelinux.org/pere/blog/What_did_I_learn_from_OpenSnitch_this_summer_.html</link>
+ <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/What_did_I_learn_from_OpenSnitch_this_summer_.html</guid>
+ <pubDate>Sun, 11 Jun 2023 08:30:00 +0200</pubDate>
+ <description><p>With yesterdays
+<a href="https://www.debian.org/News/2023/20230610">release of Debian
+12 Bookworm</a>, I am happy to know the
+<a href="https://tracker.debian.org/pkg/opensnitch">the interactive
+application firewall OpenSnitch</a> is available for a wider audience.
+I have been running it for a few weeks now, and have been surprised
+about some of the programs connecting to the Internet. Some programs
+are obviously calling out from my machine, like the NTP network based
+clock adjusting system and Tor to reach other Tor clients, but others
+were more dubious. For example, the KDE Window manager try to look up
+the host name in DNS, for no apparent reason, but if this lookup is
+blocked the KDE desktop get periodically stuck when I use it. Another
+surprise was how much Firefox call home directly to mozilla.com,
+mozilla.net and googleapis.com, to mention a few, when I visit other
+web pages. This direct connection happen even if I told Firefox to
+always use a proxy, and the proxy setting is ignored for this traffic.
+Other surprising connections come from audacity and dirmngr (I do not
+use Gnome). It took some trial and error to get a good default set of
+permissions. Without it, I would get popups asking for permissions at
+any time, also the most inconvenient ones where I am in the middle of
+a time sensitive gaming session.</p>
+
+<p>I suspect some application developers should rethink when then need
+to use network connections or DNS lookups, and recommend testing
+OpenSnitch (only <tt>apt install opensnitch</tt> away in Debian
+Bookworm) to locate and report any surprising Internet connections on
+your desktop machine.</p>
+
+<p>At the moment the upstream developer and Debian package maintainer
+is working on making the system more reliable in Debian, by enabling
+the eBPF kernel module to track processes and connections instead of
+depending in content in /proc/. This should enter unstable fairly
+soon.</p>
+
+<p>As usual, if you use Bitcoin and want to show your support of my
+activities, please send Bitcoin donations to my address
+<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
+
+<p><strong>Update 2023-06-12</strong>: I got a tip about
+<a href="https://wiki.debian.org/PrivacyIssues">a list of privacy
+issues in Free Software</a> and the
+<a href="irc://irc.debian.org/%23debian-privacy">#debian-privacy IRC
+channel</a> discussing these topics.</p>
+
+</description>
+ </item>
+
+ <item>
+ <title>wmbusmeters, parse data from your utility meter - nice free software</title>
+ <link>https://people.skolelinux.org/pere/blog/wmbusmeters__parse_data_from_your_utility_meter___nice_free_software.html</link>
+ <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/wmbusmeters__parse_data_from_your_utility_meter___nice_free_software.html</guid>
+ <pubDate>Fri, 19 May 2023 21:50:00 +0200</pubDate>
+ <description><p>There is a European standard for reading utility meters like water,
+gas, electricity or heat distribution meters. The
+<a href="https://en.wikipedia.org/wiki/Meter-Bus">Meter-Bus standard
+(EN 13757-2, EN 13757-3 and EN 13757–4)</a> provide a cross vendor way
+to talk to and collect meter data. I ran into this standard when I
+wanted to monitor some heat distribution meters, and managed to find
+free software that could do the job. The meters in question broadcast
+encrypted messages with meter information via radio, and the hardest
+part was to track down the encryption keys from the vendor. With this
+in place I could set up a MQTT gateway to submit the meter data for
+graphing.</p>
+
+<p>The free software systems in question,
+<a href="https://tracker.debian.org/pkg/rtl-wmbus">rtl-wmbus</a> to
+read the messages from a software defined radio, and
+<a href="https://tracker.debian.org/pkg/wmbusmeters">wmbusmeters</a> to
+decrypt and decode the content of the messages, is working very well
+and allowe me to get frequent updates from my meters. I got in touch
+with upstream last year to see if there was any interest in publishing
+the packages via Debian. I was very happy to learn that Fredrik
+Öhrström volunteered to maintain the packages, and I have since
+assisted him in getting Debian package build rules in place as well as
+sponsoring the packages into the Debian archive. Sadly we completed
+it too late for them to become part of the next stable Debian release
+(Bookworm). The wmbusmeters package just cleared the NEW queue. It
+will need some work to fix a built problem, but I expect Fredrik will
+find a solution soon.</p>
+
+<p>If you got a infrastructure meter supporting the Meter Bus
+standard, I strongly recommend having a look at these nice
+packages.</p>
+
+<p>As usual, if you use Bitcoin and want to show your support of my
+activities, please send Bitcoin donations to my address
+<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
+</description>
+ </item>
+
+ <item>
+ <title>The 2023 LinuxCNC Norwegian developer gathering</title>
+ <link>https://people.skolelinux.org/pere/blog/The_2023_LinuxCNC_Norwegian_developer_gathering.html</link>
+ <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/The_2023_LinuxCNC_Norwegian_developer_gathering.html</guid>
+ <pubDate>Sun, 14 May 2023 20:30:00 +0200</pubDate>
+ <description><p>The LinuxCNC project is making headway these days. A lot of
+patches and issues have seen activity on
+<a href="https://github.com/LinuxCNC/linuxcnc/">the project github
+pages</a> recently. A few weeks ago there was a developer gathering
+over at the <a href="https://tormach.com/">Tormach</a> headquarter in
+Wisconsin, and now we are planning a new gathering in Norway. If you
+wonder what LinuxCNC is, lets quote Wikipedia:</p>
+
+<blockquote>
+"LinuxCNC is a software system for numerical control of
+machines such as milling machines, lathes, plasma cutters, routers,
+cutting machines, robots and hexapods. It can control up to 9 axes or
+joints of a CNC machine using G-code (RS-274NGC) as input. It has
+several GUIs suited to specific kinds of usage (touch screen,
+interactive development)."
+</blockquote>
+
+<p>The Norwegian developer gathering take place the weekend June 16th
+to 18th this year, and is open for everyone interested in contributing
+to LinuxCNC. Up to date information about the gathering can be found
+in
+<a href="https://sourceforge.net/p/emc/mailman/emc-developers/thread/sa64jp06nob.fsf%40hjemme.reinholdtsen.name/#msg37837251">the
+developer mailing list thread</a> where the gathering was announced.
+Thanks to the good people at
+<a href="https://www.debian.org/">Debian</a>,
+<a href="https://www.redpill-linpro.com/">Redpill-Linpro</a> and
+<a href="https://www.nuugfoundation.no/no/">NUUG Foundation</a>, we
+have enough sponsor funds to pay for food, and shelter for the people
+traveling from afar to join us. If you would like to join the
+gathering, get in touch.</p>
+
+<p>As usual, if you use Bitcoin and want to show your support of my
+activities, please send Bitcoin donations to my address
+<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
+</description>
+ </item>
+
+ <item>
+ <title>OpenSnitch in Debian ready for prime time</title>
+ <link>https://people.skolelinux.org/pere/blog/OpenSnitch_in_Debian_ready_for_prime_time.html</link>
+ <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/OpenSnitch_in_Debian_ready_for_prime_time.html</guid>
+ <pubDate>Sat, 13 May 2023 12:10:00 +0200</pubDate>
+ <description><p>A bit delayed,
+<a href="https://tracker.debian.org/pkg/opensnitch">the interactive
+application firewall OpenSnitch</a> package in Debian now got the
+latest fixes ready for Debian Bookworm. Because it depend on a
+package missing on some architectures, the autopkgtest check of the
+testing migration script did not understand that the tests were
+actually working, so the migration was delayed. A bug in the package
+dependencies is also fixed, so those installing the firewall package
+(opensnitch) now also get the GUI admin tool (python3-opensnitch-ui)
+installed by default. I am very grateful to Gustavo Iñiguez Goya for
+his work on getting the package ready for Debian Bookworm.</p>
+
+<p>Armed with this package I have discovered some surprising
+connections from programs I believed were able to work completly
+offline, and it has already proven its worth, at least to me. If you
+too want to get more familiar with the kind of programs using
+Internett connections on your machine, I recommend testing <tt>apt
+install opensnitch</tt> in Bookworm and see what you think.</p>
+
+<p>The package is still not able to build its eBPF module within
+Debian. Not sure how much work it would be to get it working, but
+suspect some kernel related packages need to be extended with more
+header files to get it working.</p>
+
+<p>As usual, if you use Bitcoin and want to show your support of my
+activities, please send Bitcoin donations to my address
+<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
+</description>
+ </item>
+
<item>
<title>Speech to text, she APTly whispered, how hard can it be?</title>
<link>https://people.skolelinux.org/pere/blog/Speech_to_text__she_APTly_whispered__how_hard_can_it_be_.html</link>
<guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Speech_to_text__she_APTly_whispered__how_hard_can_it_be_.html</guid>
<pubDate>Sun, 23 Apr 2023 09:40:00 +0200</pubDate>
- <description><p>While visiting a convention during Eastern, it occurred to me that
+ <description><p>While visiting a convention during Easter, it occurred to me that
it would be great if I could have a digital Dictaphone with
transcribing capabilities, providing me with texts to cut-n-paste into
stuff I need to write. The background is that long drives often bring
audio recording. It handle multiple languages and according to its
creators even can translate into a different language than the spoken
one. I have not tested the latter feature. It can either use the CPU
-or a GPU with CODA support. As far as I can tell, CODA in practice
+or a GPU with CUDA support. As far as I can tell, CUDA in practice
limit that feature to NVidia graphics cards. I have few of those, as
they do not work great with free software drivers, and have not tested
the GPU option. While looking into the matter, I did discover some
-work to provide CODA support on non-NVidia GPUs, and some work with
+work to provide CUDA support on non-NVidia GPUs, and some work with
the library used by Whisper to port it to other GPUs, but have not
spent much time looking into GPU support yet. I've so far used an old
X220 laptop as my test machine, and only transcribed using its
build eBPF modules on build daemons in Debian, possibly without the full
kernel source.</p>
-<p>As usual, if you use Bitcoin and want to show your support of my
-activities, please send Bitcoin donations to my address
-<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
-</description>
- </item>
-
- <item>
- <title>Is the desktop recommending your program for opening its files?</title>
- <link>https://people.skolelinux.org/pere/blog/Is_the_desktop_recommending_your_program_for_opening_its_files_.html</link>
- <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Is_the_desktop_recommending_your_program_for_opening_its_files_.html</guid>
- <pubDate>Sun, 29 Jan 2023 11:00:00 +0100</pubDate>
- <description><p>Linux desktop systems
-<a href="https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html">have
-standardized</a> how programs present themselves to the desktop
-system. If a package include a .desktop file in
-/usr/share/applications/, Gnome, KDE, LXDE, Xfce and the other desktop
-environments will pick up the file and use its content to generate the
-menu of available programs in the system. A lesser known fact is that
-a package can also explain to the desktop system how to recognize the
-files created by the program in question, and use it to open these
-files on request, for example via a GUI file browser.</p>
-
-<p>A while back I ran into a package that did not tell the desktop
-system how to recognize its files and was not used to open its files
-in the file browser and fixed it. In the process I wrote a simple
-debian/tests/ script to ensure the setup keep working. It might be
-useful for other packages too, to ensure any future version of the
-package keep handling its own files.</p>
-
-<p>For this to work the file format need a useful MIME type that can
-be used to identify the format. If the file format do not yet have a
-MIME type, it should define one and preferably also
-<a href="https://www.iana.org/assignments/media-types/media-types.xhtml">register
-it with IANA</a> to ensure the MIME type string is reserved.</p>
-
-<p>The script uses the <tt>xdg-mime</tt> program from xdg-utils to
-query the database of standardized package information and ensure it
-return sensible values. It also need the location of an example file
-for xdg-mime to guess the format of.</p>
-
-<pre>
-#!/bin/sh
-#
-# Author: Petter Reinholdtsen
-# License: GPL v2 or later at your choice.
-#
-# Validate the MIME setup, making sure motor types have
-# application/vnd.openmotor+yaml associated with them and is connected
-# to the openmotor desktop file.
-
-retval=0
-
-mimetype="application/vnd.openmotor+yaml"
-testfile="test/data/real/o3100/motor.ric"
-mydesktopfile="openmotor.desktop"
-
-filemime="$(xdg-mime query filetype "$testfile")"
-
-if [ "$mimetype" != "$filemime" ] ; then
- retval=1
- echo "error: xdg-mime claim motor file MIME type is $filemine, not $mimetype"
-else
- echo "success: xdg-mime report correct mime type $mimetype for motor file"
-fi
-
-desktop=$(xdg-mime query default "$mimetype")
-
-if [ "$mydesktopfile" != "$desktop" ]; then
- retval=1
- echo "error: xdg-mime claim motor file should be handled by $desktop, not $mydesktopfile"
-else
- echo "success: xdg-mime agree motor file should be handled by $mydesktopfile"
-fi
-
-exit $retval
-</pre>
-
-<p>It is a simple way to ensure your users are not very surprised when
-they try to open one of your file formats in their file browser.</p>
-
-<p>As usual, if you use Bitcoin and want to show your support of my
-activities, please send Bitcoin donations to my address
-<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
-</description>
- </item>
-
- <item>
- <title>Opensnitch, the application level interactive firewall, heading into the Debian archive</title>
- <link>https://people.skolelinux.org/pere/blog/Opensnitch__the_application_level_interactive_firewall__heading_into_the_Debian_archive.html</link>
- <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Opensnitch__the_application_level_interactive_firewall__heading_into_the_Debian_archive.html</guid>
- <pubDate>Sun, 22 Jan 2023 23:55:00 +0100</pubDate>
- <description><p>While reading a
-<a href="https://sneak.berlin/20230115/macos-scans-your-local-files-now/">blog
-post claiming MacOS X recently started scanning local files and
-reporting information about them to Apple</a>, even on a machine where
-all such callback features had been disabled, I came across a
-description of the Little Snitch application for MacOS X. It seemed
-like a very nice tool to have in the tool box, and I decided to see if
-something similar was available for Linux.</p>
-
-<p>It did not take long to find
-<a href="https://github.com/evilsocket/opensnitch">the OpenSnitch
-package</a>, which has been in development since 2017, and now is in
-version 1.5.0. It has had a
-<a href="https://bugs.debian.org/909567">request for Debian
-packaging</a> since 2018, but no-one completed the job so far. Just
-for fun, I decided to see if I could help, and I was very happy to
-discover that
-<a href="https://github.com/evilsocket/opensnitch/issues/304">upstream
-want a Debian package too</a>.</p>
-
-<p>After struggling a bit with getting the program to run, figuring
-out building Go programs (and a little failed detour to look at eBPF
-builds too - help needed), I am very happy to report that I am
-sponsoring upstream to maintain the package in Debian, and it has
-since this morning been waiting in NEW for the ftpmasters to have a
-look. Perhaps it can get into the archive in time for the Bookworm
-release?</p>
-
-<p>As usual, if you use Bitcoin and want to show your support of my
-activities, please send Bitcoin donations to my address
-<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
-</description>
- </item>
-
- <item>
- <title>LinuxCNC MQTT publisher component</title>
- <link>https://people.skolelinux.org/pere/blog/LinuxCNC_MQTT_publisher_component.html</link>
- <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/LinuxCNC_MQTT_publisher_component.html</guid>
- <pubDate>Sun, 8 Jan 2023 19:30:00 +0100</pubDate>
- <description><p>I watched <a href="https://yewtu.be/watch?v=jmKUV3aNLjk">a 2015
-video from Andreas Schiffler</a> the other day, where he set up
-<a href="https://linuxcnc.org/">LinuxCNC</a> to send status
-information to the MQTT broker IBM Bluemix. As I also use MQTT for
-graphing, it occured to me that a generic MQTT LinuxCNC component
-would be useful and I set out to implement it. Today I got the first
-draft limping along and submitted as
-<a href="https://github.com/LinuxCNC/linuxcnc/pull/2253">a patch to the
-LinuxCNC project</a>.</p>
-
-<p>The simple part was setting up the MQTT publishing code in Python.
-I already have set up other parts submitting data to my Mosquito MQTT
-broker, so I could reuse that code. Writing a LinuxCNC component in
-Python as new to me, but using existing examples in the code
-repository and the extensive documentation, this was fairly straight
-forward. The hardest part was creating a automated test for the
-component to ensure it was working. Testing it in a simulated
-LinuxCNC machine proved very useful, as I discovered features I needed
-that I had not thought of yet, and adjusted the code quite a bit to
-make it easier to test without a operational MQTT broker
-available.</p>
-
-<p>The draft is ready and working, but I am unsure which LinuxCNC HAL
-pins I should collect and publish by default (in other words, the
-default set of information pieces published), and how to get the
-machine name from the LinuxCNC INI file. The latter is a minor
-detail, but I expect it would be useful in a setup with several
-machines available. I am hoping for feedback from the experienced
-LinuxCNC developers and users, to make the component even better
-before it can go into the mainland LinuxCNC code base.</p>
-
-<p>Since I started on the MQTT component, I came across
-<a href="https://yewtu.be/watch?v=Bqa2grG0XtA">another video from Kent
-VanderVelden</a> where he combine LinuxCNC with a set of screen glasses
-controlled by a Raspberry Pi, and it occured to me that it would
-be useful for such use cases if LinuxCNC also provided a REST API for
-querying its status. I hope to start on such component once the MQTT
-component is working well.</p>
-
-<p>As usual, if you use Bitcoin and want to show your support of my
-activities, please send Bitcoin donations to my address
-<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
-</description>
- </item>
-
- <item>
- <title>ONVIF IP camera management tool finally in Debian</title>
- <link>https://people.skolelinux.org/pere/blog/ONVIF_IP_camera_management_tool_finally_in_Debian.html</link>
- <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/ONVIF_IP_camera_management_tool_finally_in_Debian.html</guid>
- <pubDate>Sat, 24 Dec 2022 08:00:00 +0100</pubDate>
- <description><p>Merry Christmas to you all. Here is a small gift to all those with
-IP cameras following the <a href="https://www.onvif.org/">ONVIF
-specification</a>. There is finally a nice command line and GUI tool
-in Debian to manage ONVIF IP cameras. After working with upstream for
-a few months and sponsoring the upload, I am very happy to report that
-the <a href="https://tracker.debian.org/libonvif">libonvif package</a>
-entered Debian Sid last night.</p>
-
-<p>The package provide a C library to communicate with such cameras, a
-command line tool to locate and update settings of (like password) the
-cameras and a GUI tool to configure and control the units as well as
-preview the video from the camera. Libonvif is available on Both
-Linux and Windows and the GUI tool uses the Qt library. The main
-competitors are non-free software, while libonvif is GNU GPL licensed.
-I am very glad Debian users in the future can control their cameras
-using a free software system provided by Debian. But the ONVIF world
-is full of slightly broken firmware, where the cameras pretend to
-follow the ONVIF specification but fail to set some configuration
-values or refuse to provide video to more than one recipient at the
-time, and the onvif project is quite young and might take a while
-before it completely work with your camera. Upstream seem eager to
-improve the library, so handling any broken camera might be just <a
-href="https://github.com/sr99622/libonvif/">a bug report away</a>.</p>
-
-<p>The package just cleared NEW, and need a new source only upload
-before it can enter testing. This will happen in the next few
-days.</p>
-
-<p>As usual, if you use Bitcoin and want to show your support of my
-activities, please send Bitcoin donations to my address
-<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
-</description>
- </item>
-
- <item>
- <title>Managing and using ONVIF IP cameras with Linux</title>
- <link>https://people.skolelinux.org/pere/blog/Managing_and_using_ONVIF_IP_cameras_with_Linux.html</link>
- <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Managing_and_using_ONVIF_IP_cameras_with_Linux.html</guid>
- <pubDate>Wed, 19 Oct 2022 12:30:00 +0200</pubDate>
- <description><p>Recently I have been looking at how to control and collect data
-from a handful IP cameras using Linux. I both wanted to change their
-settings and to make their imagery available via a free software
-service under my control. Here is a summary of the tools I found.</p>
-
-<p>First I had to identify the cameras and their protocols. As far as
-I could tell, they were using some SOAP looking protocol and their
-internal web server seem to only work with Microsoft Internet Explorer
-with some proprietary binary plugin, which in these days of course is
-a security disaster and also made it impossible for me to use the
-camera web interface. Luckily I discovered that the SOAP looking
-protocol is actually following <a href="https://www.onvif.org/">the
-ONVIF specification</a>, which seem to be supported by a lot of IP
-cameras these days.</p>
-
-<p>Once the protocol was identified, I was able to find what appear to
-be the most popular way to configure ONVIF cameras, the free software
-Windows tool named
-<a href="https://sourceforge.net/projects/onvifdm/">ONVIF Device
-Manager</a>. Lacking any other options at the time, I tried
-unsuccessfully to get it running using Wine, but was missing a dotnet
-40 library and I found no way around it to run it on Linux.</p>
-
-<p>The next tool I found to configure the cameras were a non-free Linux Qt
-client <a href="https://www.lingodigit.com/onvif_nvcdemo.html">ONVIF
-Device Tool</a>. I did not like its terms of use, so did not spend
-much time on it.</p>
-
-<p>To collect the video and make it available in a web interface, I
-found the Zoneminder tool in Debian. A recent version was able to
-automatically detect and configure ONVIF devices, so I could use it to
-set up motion detection in and collection of the camera output. I had
-initial problems getting the ONVIF autodetection to work, as both
-Firefox and Chromium <a href="https://bugs.debian.org/1001188">refused
-the inter-tab communication</a> being used by the Zoneminder web
-pages, but managed to get konqueror to work. Apparently the "Enhanced
-Tracking Protection" in Firefox cause the problem. I ended up
-upgrading to the Bookworm edition of Zoneminder in the process to try
-to fix the issue, and believe the problem might be solved now.</p>
-
-<p>In the process I came across the nice Linux GUI tool
-<a href="https://gitlab.com/caspermeijn/onvifviewer/">ONVIF Viewer</a>
-allowing me to preview the camera output and validate the login
-passwords required. Sadly its author has grown tired of maintaining
-the software, so it might not see any future updates. Which is sad,
-as the viewer is sightly unstable and the picture tend to lock up.
-Note, this lockup might be due to limitations in the cameras and not
-the viewer implementation. I suspect the camera is only able to
-provide pictures to one client at the time, and the Zoneminder feed
-might interfere with the GUI viewer. I have
-<a href="https://bugs.debian.org/1000820">asked for the tool to be
-included in Debian</a>.</p>
-
-<p>Finally, I found what appear to be very nice Linux free software
-replacement for the Windows tool, named
-<a href="https://github.com/sr99622/libonvif/">libonvif</a>. It
-provide a C library to talk to ONVIF devices as well as a command line
-and GUI tool using the library. Using the GUI tool I was able to change
-the admin passwords and update other settings of the cameras. I have
-<a href="https://bugs.debian.org/1021980">asked for the package to be
-included in Debian</a>.</p>
-
-<p>As usual, if you use Bitcoin and want to show your support of my
-activities, please send Bitcoin donations to my address
-<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
-
-<p><strong>Update 2022-10-20</strong>: Since my initial publication of
-this text, I got several suggestions for more free software Linux
-tools. There is <a href="https://github.com/quatanium/python-onvif">a
-ONVIF python library</a> (already
-<a href="https://bugs.debian.org/824240">requested into Debian</a>) and
-<a href="https://github.com/FalkTannhaeuser/python-onvif-zeep">a python 3
-fork</a> using a different SOAP dependency. There is also
-<a href="https://www.home-assistant.io/integrations/onvif/">support for
-ONVIF in Home Assistant</a>, and there is an alternative to Zoneminder
-called <a href="https://www.shinobi.video/">Shinobi</a>. The latter
-two are not included in Debian either. I have not tested any of these
-so far.</p>
-</description>
- </item>
-
- <item>
- <title>Time to translate the Bullseye edition of the Debian Administrator's Handbook</title>
- <link>https://people.skolelinux.org/pere/blog/Time_to_translate_the_Bullseye_edition_of_the_Debian_Administrator_s_Handbook.html</link>
- <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Time_to_translate_the_Bullseye_edition_of_the_Debian_Administrator_s_Handbook.html</guid>
- <pubDate>Mon, 12 Sep 2022 15:45:00 +0200</pubDate>
- <description><p align="center"><img align="center" src="http://people.skolelinux.org/pere/blog/images/2020-10-20-debian-handbook-nb-testprint.jpeg" width="60%"/></p>
-
-<p>(The picture is of the previous edition.)</p>
-
-<p>Almost two years after the previous Norwegian Bokmål translation of
-the "<a href="https://debian-handbook.info/">The Debian Administrator's
-Handbook</a>" was published, a new edition is finally being prepared. The
-english text is updated, and it is time to start working on the
-translations. Around 37 percent of the strings have been updated, one
-way or another, and the translations starting from a complete Debian Buster
-edition now need to bring their translation up from 63% to 100%. The
-complete book is licensed using a Creative Commons license, and has
-been published in several languages over the years. The translations
-are done by volunteers to bring Linux in their native tongue. The
-last time I checked, it complete text was available in English,
-Norwegian Bokmål, German, Indonesian, Brazil Portuguese and Spanish.
-In addition, work has been started for Arabic (Morocco), Catalan,
-Chinese (Simplified), Chinese (Traditional), Croatian, Czech, Danish,
-Dutch, French, Greek, Italian, Japanese, Korean, Persian, Polish,
-Romanian, Russian, Swedish, Turkish and Vietnamese.</p>
-
-<p>The translation is conducted on
-<a href="https://hosted.weblate.org/projects/debian-handbook/">the
-hosted weblate project page</a>. Prospective translators are
-recommeded to subscribe to
-<a href="http://lists.alioth.debian.org/mailman/listinfo/debian-handbook-translators">the
-translators mailing list</a> and should also check out
-<a href="https://debian-handbook.info/contribute/">the instructions for
-contributors</a>.</p>
-
-<p>I am one of the Norwegian Bokmål translators of this book, and we
-have just started. Your contribution is most welcome.</p>
-
-<p>As usual, if you use Bitcoin and want to show your support of my
-activities, please send Bitcoin donations to my address
-<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
-</description>
- </item>
-
- <item>
- <title>Automatic LinuxCNC servo PID tuning?</title>
- <link>https://people.skolelinux.org/pere/blog/Automatic_LinuxCNC_servo_PID_tuning_.html</link>
- <guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Automatic_LinuxCNC_servo_PID_tuning_.html</guid>
- <pubDate>Sat, 16 Jul 2022 22:30:00 +0200</pubDate>
- <description><p>While working on a CNC with servo motors controlled by the
-<a href="https://en.wikipedia.org/wiki/LinuxCNC">LinuxCNC</a>
-<a href="https://en.wikipedia.org/wiki/PID_controller">PID
-controller</a>, I recently had to learn how to tune the collection of values
-that control such mathematical machinery that a PID controller is. It
-proved to be a lot harder than I hoped, and I still have not succeeded
-in getting the Z PID controller to successfully defy gravity, nor X
-and Y to move accurately and reliably. But while climbing up this
-rather steep learning curve, I discovered that some motor control
-systems are able to tune their PID controllers. I got the impression
-from the documentation that LinuxCNC were not. This proved to be not
-true.</p>
-
-<p>The LinuxCNC
-<a href="http://linuxcnc.org/docs/html/man/man9/pid.9.html">pid
-component</a> is the recommended PID controller to use. It uses eight
-constants <tt>Pgain</tt>, <tt>Igain</tt>, <tt>Dgain</tt>,
-<tt>bias</tt>, <tt>FF0</tt>, <tt>FF1</tt>, <tt>FF2</tt> and
-<tt>FF3</tt> to calculate the output value based on current and wanted
-state, and all of these need to have a sensible value for the
-controller to behave properly. Note, there are even more values
-involved, theser are just the most important ones. In my case I need
-the X, Y and Z axes to follow the requested path with little error.
-This has proved quite a challenge for someone who have never tuned a
-PID controller before, but there is at least some help to be found.
-
-<p>I discovered that included in LinuxCNC was this old PID component
-at_pid claiming to have auto tuning capabilities. Sadly it had been
-neglected since 2011, and could not be used as a plug in replacement
-for the default pid component. One would have to rewriting the
-LinuxCNC HAL setup to test at_pid. This was rather sad, when I wanted
-to quickly test auto tuning to see if it did a better job than me at
-figuring out good P, I and D values to use.</p>
-
-<p>I decided to have a look if the situation could be improved. This
-involved trying to understand the code and history of the pid and
-at_pid components. Apparently they had a common ancestor, as code
-structure, comments and variable names were quite close to each other.
-Sadly this was not reflected in the git history, making it hard to
-figure out what really happened. My guess is that the author of
-<a href="https://github.com/LinuxCNC/linuxcnc/blob/master/src/hal/components/at_pid.c">at_pid.c</a>
-took a version of
-<a href="https://github.com/LinuxCNC/linuxcnc/blob/master/src/hal/components/pid.c">pid.c</a>,
-rewrote it to follow the structure he wished pid.c to have, then added
-support for auto tuning and finally got it included into the LinuxCNC
-repository. The restructuring and lack of early history made it
-harder to figure out which part of the code were relevant to the auto
-tuning, and which part of the code needed to be updated to work the
-same way as the current pid.c implementation. I started by trying to
-isolate relevant changes in pid.c, and applying them to at_pid.c. My
-aim was to make sure the at_pid component could replace the pid
-component with a simple change in the HAL setup loadrt line, without
-having to "rewire" the rest of the HAL configuration. After a few
-hours following this approach, I had learned quite a lot about the
-code structure of both components, while concluding I was heading down
-the wrong rabbit hole, and should get back to the surface and find a
-different path.</p>
-
-<p>For the second attempt, I decided to throw away all the PID control
-related part of the original at_pid.c, and instead isolate and lift
-the auto tuning part of the code and inject it into a copy of pid.c.
-This ensured compatibility with the current pid component, while
-adding auto tuning as a run time option. To make it easier to identify
-the relevant parts in the future, I wrapped all the auto tuning code
-with '#ifdef AUTO_TUNER'. The end result behave just like the current
-pid component by default, as that part of the code is identical. The
-<a href="https://github.com/LinuxCNC/linuxcnc/pull/1820">end result
-entered the LinuxCNC master branch</a> a few days ago.</p>
-
-<p>To enable auto tuning, one need to set a few HAL pins in the PID
-component. The most important ones are <tt>tune-effort</tt>,
-<tt>tune-mode</tt> and <tt>tune-start</tt>. But lets take a step
-back, and see what the auto tuning code will do. I do not know the
-mathematical foundation of the at_pid algorithm, but from observation
-I can tell that the algorithm will, when enabled, produce a square
-wave pattern centered around the <tt>bias</tt> value on the output pin
-of the PID controller. This can be seen using the HAL Scope provided
-by LinuxCNC. In my case, this is translated into voltage (+-10V) sent
-to the motor controller, which in turn is translated into motor speed.
-So at_pid will ask the motor to move the axis back and forth. The
-number of cycles in the pattern is controlled by the
-<tt>tune-cycles</tt> pin, and the extremes of the wave pattern is
-controlled by the <tt>tune-effort</tt> pin. Of course, trying to
-change the direction of a physical object instantly (as in going
-directly from a positive voltage to the equivalent negative voltage)
-do not change velocity instantly, and it take some time for the object
-to slow down and move in the opposite direction. This result in a
-more smooth movement wave form, as the axis in question were vibrating
-back and forth. When the axis reached the target speed in the
-opposing direction, the auto tuner change direction again. After
-several of these changes, the average time delay between the 'peaks'
-and 'valleys' of this movement graph is then used to calculate
-proposed values for Pgain, Igain and Dgain, and insert them into the
-HAL model to use by the pid controller. The auto tuned settings are
-not great, but htye work a lot better than the values I had been able
-to cook up on my own, at least for the horizontal X and Y axis. But I
-had to use very small <tt>tune-effort<tt> values, as my motor
-controllers error out if the voltage change too quickly. I've been
-less lucky with the Z axis, which is moving a heavy object up and
-down, and seem to confuse the algorithm. The Z axis movement became a
-lot better when I introduced a <tt>bias</tt> value to counter the
-gravitational drag, but I will have to work a lot more on the Z axis
-PID values.</p>
-
-<p>Armed with this knowledge, it is time to look at how to do the
-tuning. Lets say the HAL configuration in question load the PID
-component for X, Y and Z like this:</p>
-
-<blockquote><pre>
-loadrt pid names=pid.x,pid.y,pid.z
-</pre></blockquote>
-
-<p>Armed with the new and improved at_pid component, the new line will
-look like this:</p>
-
-<blockquote><pre>
-loadrt at_pid names=pid.x,pid.y,pid.z
-</pre></blockquote>
-
-<p>The rest of the HAL setup can stay the same. This work because the
-components are referenced by name. If the component had used count=3
-instead, all use of pid.# had to be changed to at_pid.#.</p>
-
-<p>To start tuning the X axis, move the axis to the middle of its
-range, to make sure it do not hit anything when it start moving back
-and forth. Next, set the <tt>tune-effort</tt> to a low number in the
-output range. I used 0.1 as my initial value. Next, assign 1 to the
-<tt>tune-mode</tt> value. Note, this will disable the pid controlling
-part and feed 0 to the output pin, which in my case initially caused a
-lot of drift. In my case it proved to be a good idea with X and Y to
-tune the motor driver to make sure 0 voltage stopped the motor
-rotation. On the other hand, for the Z axis this proved to be a bad
-idea, so it will depend on your setup. It might help to set the
-<tt>bias</tt> value to a output value that reduce or eliminate the
-axis drift. Finally, after setting <tt>tune-mode</tt>, set
-<tt>tune-start</tt> to 1 to activate the auto tuning. If all go well,
-your axis will vibrate for a few seconds and when it is done, new
-values for Pgain, Igain and Dgain will be active. To test them,
-change <tt>tune-mode</tt> back to 0. Note that this might cause the
-machine to suddenly jerk as it bring the axis back to its commanded
-position, which it might have drifted away from during tuning. To
-summarize with some halcmd lines:</p>
-
-<blockquote><pre>
-setp pid.x.tune-effort 0.1
-setp pid.x.tune-mode 1
-setp pid.x.tune-start 1
-# wait for the tuning to complete
-setp pid.x.tune-mode 0
-</pre></blockquote>
-
-<p>After doing this task quite a few times while trying to figure out
-how to properly tune the PID controllers on the machine in, I decided
-to figure out if this process could be automated, and wrote a script
-to do the entire tuning process from power on. The end result will
-ensure the machine is powered on and ready to run, home all axis if it
-is not already done, check that the extra tuning pins are available,
-move the axis to its mid point, run the auto tuning and re-enable the
-pid controller when it is done. It can be run several times. Check
-out the
-<a href="https://github.com/SebKuzminsky/MazakVQC1540/blob/bon-dev/scripts/run-auto-pid-tuner">run-auto-pid-tuner</a>
-script on github if you want to learn how it is done.</p>
-
-<p>My hope is that this little adventure can inspire someone who know
-more about motor PID controller tuning can implement even better
-algorithms for automatic PID tuning in LinuxCNC, making life easier
-for both me and all the others that want to use LinuxCNC but lack the
-in depth knowledge needed to tune PID controllers well.</p>
-
<p>As usual, if you use Bitcoin and want to show your support of my
activities, please send Bitcoin donations to my address
<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>
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