1 <?xml version=
"1.0" encoding=
"utf-8"?>
2 <rss version='
2.0' xmlns:lj='http://www.livejournal.org/rss/lj/
1.0/' xmlns:
atom=
"http://www.w3.org/2005/Atom">
4 <title>Petter Reinholdtsen
</title>
5 <description></description>
6 <link>http://people.skolelinux.org/pere/blog/
</link>
7 <atom:link href=
"http://people.skolelinux.org/pere/blog/index.rss" rel=
"self" type=
"application/rss+xml" />
10 <title>Some notes on fault tolerant storage systems
</title>
11 <link>http://people.skolelinux.org/pere/blog/Some_notes_on_fault_tolerant_storage_systems.html
</link>
12 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/Some_notes_on_fault_tolerant_storage_systems.html
</guid>
13 <pubDate>Wed,
1 Nov
2017 15:
35:
00 +
0100</pubDate>
14 <description><p
>If you care about how fault tolerant your storage is, you might
15 find these articles and papers interesting. They have formed how I
16 think of when designing a storage system.
</p
>
20 <li
>USENIX :login;
<a
21 href=
"https://www.usenix.org/publications/login/summer2017/ganesan
">Redundancy
22 Does Not Imply Fault Tolerance. Analysis of Distributed Storage
23 Reactions to Single Errors and Corruptions
</a
> by Aishwarya Ganesan,
24 Ramnatthan Alagappan, Andrea C. Arpaci-Dusseau, and Remzi
25 H. Arpaci-Dusseau
</li
>
28 <a href=
"http://www.zdnet.com/article/why-raid-
5-stops-working-in-
2009/
">Why
29 RAID
5 stops working in
2009</a
> by Robin Harris
</li
>
32 <a href=
"http://www.zdnet.com/article/why-raid-
6-stops-working-in-
2019/
">Why
33 RAID
6 stops working in
2019</a
> by Robin Harris
</li
>
35 <li
>USENIX FAST
'07
36 <a href=
"http://research.google.com/archive/disk_failures.pdf
">Failure
37 Trends in a Large Disk Drive Population
</a
> by Eduardo Pinheiro,
38 Wolf-Dietrich Weber and Luiz André Barroso
</li
>
40 <li
>USENIX ;login:
<a
41 href=
"https://www.usenix.org/system/files/login/articles/hughes12-
04.pdf
">Data
42 Integrity. Finding Truth in a World of Guesses and Lies
</a
> by Doug
45 <li
>USENIX FAST
'08
46 <a href=
"https://www.usenix.org/events/fast08/tech/full_papers/bairavasundaram/bairavasundaram_html/
">An
47 cAnalysis of Data Corruption in the Storage Stack
</a
> -
48 L. N. Bairavasundaram, G. R. Goodson, B. Schroeder, A. C.
49 Arpaci-Dusseau, and R. H. Arpaci-Dusseau
</li
>
51 <li
>USENIX FAST
'07 <a
52 href=
"https://www.usenix.org/legacy/events/fast07/tech/schroeder/schroeder_html/
">Disk
53 failures in the real world: what does an MTTF of
1,
000,
000 hours mean
54 to you?
</a
> by B. Schroeder and G. A. Gibson.
</li
>
56 <li
>USENIX ;login:
<a
57 href=
"https://www.usenix.org/events/fast08/tech/full_papers/jiang/jiang_html/
">Are
58 Disks the Dominant Contributor for Storage Failures? A Comprehensive
59 Study of Storage Subsystem Failure Characteristics
</a
> by Weihang
60 Jiang, Chongfeng Hu, Yuanyuan Zhou, and Arkady Kanevsky
</li
>
62 <li
>SIGMETRICS
2007
63 <a href=
"http://research.cs.wisc.edu/adsl/Publications/latent-sigmetrics07.pdf
">An
64 analysis of latent sector errors in disk drives
</a
> -
65 L. N. Bairavasundaram, G. R. Goodson, S. Pasupathy, and J. Schindler
</li
>
69 <p
>Several of these research papers are based on data collected from
70 hundred thousands or millions of disk, and their findings are eye
71 opening. The short story is simply do not implicitly trust RAID or
72 redundant storage systems. Details matter. And unfortunately there
73 are few options on Linux addressing all the identified issues. Both
74 ZFS and Btrfs are doing a fairly good job, but have legal and
75 practical issues on their own. I wonder how cluster file systems like
76 Ceph do in this regard.
</p
>
78 <p
>Just remember, in the end, it do not matter how redundant, or how
79 fault tolerant your storage is, if you do not continuously monitor its
80 status to detect and replace failed disks.
</p
>
85 <title>Web services for writing academic LaTeX papers as a team
</title>
86 <link>http://people.skolelinux.org/pere/blog/Web_services_for_writing_academic_LaTeX_papers_as_a_team.html
</link>
87 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/Web_services_for_writing_academic_LaTeX_papers_as_a_team.html
</guid>
88 <pubDate>Tue,
31 Oct
2017 21:
00:
00 +
0100</pubDate>
89 <description><p
>I was surprised today to learn that a friend in academia did not
90 know there are easily available web services available for writing
91 LaTeX documents as a team. I thought it was common knowledge, but to
92 make sure at least my readers are aware of it, I would like to mention
93 these useful services for writing LaTeX documents. Some of them even
94 provide a WYSIWYG editor to ease writing even further.
</p
>
96 <p
>There are two commercial services available,
97 <a href=
"https://sharelatex.com
">ShareLaTeX
</a
> and
98 <a href=
"https://overleaf.com
">Overleaf
</a
>. They are very easy to
99 use. Just start a new document, select which publisher to write for
100 (ie which LaTeX style to use), and start writing. Note, these two
101 have announced their intention to join forces, so soon it will only be
102 one joint service. I
've used both for different documents, and they
103 work just fine. While
104 <a href=
"https://github.com/sharelatex/sharelatex
">ShareLaTeX is free
105 software
</a
>, while the latter is not. According to
<a
106 href=
"https://www.overleaf.com/help/
17-is-overleaf-open-source
">a
107 announcement from Overleaf
</a
>, they plan to keep the ShareLaTeX code
108 base maintained as free software.
</p
>
110 But these two are not the only alternatives.
111 <a href=
"https://app.fiduswriter.org/
">Fidus Writer
</a
> is another free
112 software solution with
<a href=
"https://github.com/fiduswriter
">the
113 source available on github
</a
>. I have not used it myself. Several
114 others can be found on the nice
115 <a href=
"https://alternativeto.net/software/sharelatex/
">alterntiveTo
116 web service
</a
>.
118 <p
>If you like Google Docs or Etherpad, but would like to write
119 documents in LaTeX, you should check out these services. You can even
120 host your own, if you want to. :)
</p
>
126 <title>Locating IMDB IDs of movies in the Internet Archive using Wikidata
</title>
127 <link>http://people.skolelinux.org/pere/blog/Locating_IMDB_IDs_of_movies_in_the_Internet_Archive_using_Wikidata.html
</link>
128 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/Locating_IMDB_IDs_of_movies_in_the_Internet_Archive_using_Wikidata.html
</guid>
129 <pubDate>Wed,
25 Oct
2017 12:
20:
00 +
0200</pubDate>
130 <description><p
>Recently, I needed to automatically check the copyright status of a
131 set of
<a href=
"http://www.imdb.com/
">The Internet Movie database
132 (IMDB)
</a
> entries, to figure out which one of the movies they refer
133 to can be freely distributed on the Internet. This proved to be
134 harder than it sounds. IMDB for sure list movies without any
135 copyright protection, where the copyright protection has expired or
136 where the movie is lisenced using a permissive license like one from
137 Creative Commons. These are mixed with copyright protected movies,
138 and there seem to be no way to separate these classes of movies using
139 the information in IMDB.
</p
>
141 <p
>First I tried to look up entries manually in IMDB,
142 <a href=
"https://www.wikipedia.org/
">Wikipedia
</a
> and
143 <a href=
"https://www.archive.org/
">The Internet Archive
</a
>, to get a
144 feel how to do this. It is hard to know for sure using these sources,
145 but it should be possible to be reasonable confident a movie is
"out
146 of copyright
" with a few hours work per movie. As I needed to check
147 almost
20,
000 entries, this approach was not sustainable. I simply
148 can not work around the clock for about
6 years to check this data
151 <p
>I asked the people behind The Internet Archive if they could
152 introduce a new metadata field in their metadata XML for IMDB ID, but
153 was told that they leave it completely to the uploaders to update the
154 metadata. Some of the metadata entries had IMDB links in the
155 description, but I found no way to download all metadata files in bulk
156 to locate those ones and put that approach aside.
</p
>
158 <p
>In the process I noticed several Wikipedia articles about movies
159 had links to both IMDB and The Internet Archive, and it occured to me
160 that I could use the Wikipedia RDF data set to locate entries with
161 both, to at least get a lower bound on the number of movies on The
162 Internet Archive with a IMDB ID. This is useful based on the
163 assumption that movies distributed by The Internet Archive can be
164 legally distributed on the Internet. With some help from the RDF
165 community (thank you DanC), I was able to come up with this query to
166 pass to
<a href=
"https://query.wikidata.org/
">the SPARQL interface on
170 SELECT ?work ?imdb ?ia ?when ?label
173 ?work wdt:P31/wdt:P279* wd:Q11424.
174 ?work wdt:P345 ?imdb.
177 ?work wdt:P577 ?when.
178 ?work rdfs:label ?label.
179 FILTER(LANG(?label) =
"en
").
182 </pre
></p
>
184 <p
>If I understand the query right, for every film entry anywhere in
185 Wikpedia, it will return the IMDB ID and The Internet Archive ID, and
186 when the movie was released and its English title, if either or both
187 of the latter two are available. At the moment the result set contain
188 2338 entries. Of course, it depend on volunteers including both
189 correct IMDB and The Internet Archive IDs in the wikipedia articles
190 for the movie. It should be noted that the result will include
191 duplicates if the movie have entries in several languages. There are
192 some bogus entries, either because The Internet Archive ID contain a
193 typo or because the movie is not available from The Internet Archive.
194 I did not verify the IMDB IDs, as I am unsure how to do that
195 automatically.
</p
>
197 <p
>I wrote a small python script to extract the data set from Wikidata
198 and check if the XML metadata for the movie is available from The
199 Internet Archive, and after around
1.5 hour it produced a list of
2097
200 free movies and their IMDB ID. In total,
171 entries in Wikidata lack
201 the refered Internet Archive entry. I assume the
70 "disappearing
"
202 entries (ie
2338-
2097-
171) are duplicate entries.
</p
>
204 <p
>This is not too bad, given that The Internet Archive report to
205 contain
<a href=
"https://archive.org/details/feature_films
">5331
206 feature films
</a
> at the moment, but it also mean more than
3000
207 movies are missing on Wikipedia or are missing the pair of references
208 on Wikipedia.
</p
>
210 <p
>I was curious about the distribution by release year, and made a
211 little graph to show how the amount of free movies is spread over the
214 <p
><img src=
"http://people.skolelinux.org/pere/blog/images/
2017-
10-
25-verk-i-det-fri-filmer.png
"></p
>
216 <p
>I expect the relative distribution of the remaining
3000 movies to
217 be similar.
</p
>
219 <p
>If you want to help, and want to ensure Wikipedia can be used to
220 cross reference The Internet Archive and The Internet Movie Database,
221 please make sure entries like this are listed under the
"External
222 links
" heading on the Wikipedia article for the movie:
</p
>
225 * {{Internet Archive film|id=FightingLady}}
226 * {{IMDb title|id=
0036823|title=The Fighting Lady}}
227 </pre
></p
>
229 <p
>Please verify the links on the final page, to make sure you did not
230 introduce a typo.
</p
>
232 <p
>Here is the complete list, if you want to correct the
171
233 identified Wikipedia entries with broken links to The Internet
234 Archive:
<a href=
"http://www.wikidata.org/entity/Q1140317
">Q1140317
</a
>,
235 <a href=
"http://www.wikidata.org/entity/Q458656
">Q458656
</a
>,
236 <a href=
"http://www.wikidata.org/entity/Q458656
">Q458656
</a
>,
237 <a href=
"http://www.wikidata.org/entity/Q470560
">Q470560
</a
>,
238 <a href=
"http://www.wikidata.org/entity/Q743340
">Q743340
</a
>,
239 <a href=
"http://www.wikidata.org/entity/Q822580
">Q822580
</a
>,
240 <a href=
"http://www.wikidata.org/entity/Q480696
">Q480696
</a
>,
241 <a href=
"http://www.wikidata.org/entity/Q128761
">Q128761
</a
>,
242 <a href=
"http://www.wikidata.org/entity/Q1307059
">Q1307059
</a
>,
243 <a href=
"http://www.wikidata.org/entity/Q1335091
">Q1335091
</a
>,
244 <a href=
"http://www.wikidata.org/entity/Q1537166
">Q1537166
</a
>,
245 <a href=
"http://www.wikidata.org/entity/Q1438334
">Q1438334
</a
>,
246 <a href=
"http://www.wikidata.org/entity/Q1479751
">Q1479751
</a
>,
247 <a href=
"http://www.wikidata.org/entity/Q1497200
">Q1497200
</a
>,
248 <a href=
"http://www.wikidata.org/entity/Q1498122
">Q1498122
</a
>,
249 <a href=
"http://www.wikidata.org/entity/Q865973
">Q865973
</a
>,
250 <a href=
"http://www.wikidata.org/entity/Q834269
">Q834269
</a
>,
251 <a href=
"http://www.wikidata.org/entity/Q841781
">Q841781
</a
>,
252 <a href=
"http://www.wikidata.org/entity/Q841781
">Q841781
</a
>,
253 <a href=
"http://www.wikidata.org/entity/Q1548193
">Q1548193
</a
>,
254 <a href=
"http://www.wikidata.org/entity/Q499031
">Q499031
</a
>,
255 <a href=
"http://www.wikidata.org/entity/Q1564769
">Q1564769
</a
>,
256 <a href=
"http://www.wikidata.org/entity/Q1585239
">Q1585239
</a
>,
257 <a href=
"http://www.wikidata.org/entity/Q1585569
">Q1585569
</a
>,
258 <a href=
"http://www.wikidata.org/entity/Q1624236
">Q1624236
</a
>,
259 <a href=
"http://www.wikidata.org/entity/Q4796595
">Q4796595
</a
>,
260 <a href=
"http://www.wikidata.org/entity/Q4853469
">Q4853469
</a
>,
261 <a href=
"http://www.wikidata.org/entity/Q4873046
">Q4873046
</a
>,
262 <a href=
"http://www.wikidata.org/entity/Q915016
">Q915016
</a
>,
263 <a href=
"http://www.wikidata.org/entity/Q4660396
">Q4660396
</a
>,
264 <a href=
"http://www.wikidata.org/entity/Q4677708
">Q4677708
</a
>,
265 <a href=
"http://www.wikidata.org/entity/Q4738449
">Q4738449
</a
>,
266 <a href=
"http://www.wikidata.org/entity/Q4756096
">Q4756096
</a
>,
267 <a href=
"http://www.wikidata.org/entity/Q4766785
">Q4766785
</a
>,
268 <a href=
"http://www.wikidata.org/entity/Q880357
">Q880357
</a
>,
269 <a href=
"http://www.wikidata.org/entity/Q882066
">Q882066
</a
>,
270 <a href=
"http://www.wikidata.org/entity/Q882066
">Q882066
</a
>,
271 <a href=
"http://www.wikidata.org/entity/Q204191
">Q204191
</a
>,
272 <a href=
"http://www.wikidata.org/entity/Q204191
">Q204191
</a
>,
273 <a href=
"http://www.wikidata.org/entity/Q1194170
">Q1194170
</a
>,
274 <a href=
"http://www.wikidata.org/entity/Q940014
">Q940014
</a
>,
275 <a href=
"http://www.wikidata.org/entity/Q946863
">Q946863
</a
>,
276 <a href=
"http://www.wikidata.org/entity/Q172837
">Q172837
</a
>,
277 <a href=
"http://www.wikidata.org/entity/Q573077
">Q573077
</a
>,
278 <a href=
"http://www.wikidata.org/entity/Q1219005
">Q1219005
</a
>,
279 <a href=
"http://www.wikidata.org/entity/Q1219599
">Q1219599
</a
>,
280 <a href=
"http://www.wikidata.org/entity/Q1643798
">Q1643798
</a
>,
281 <a href=
"http://www.wikidata.org/entity/Q1656352
">Q1656352
</a
>,
282 <a href=
"http://www.wikidata.org/entity/Q1659549
">Q1659549
</a
>,
283 <a href=
"http://www.wikidata.org/entity/Q1660007
">Q1660007
</a
>,
284 <a href=
"http://www.wikidata.org/entity/Q1698154
">Q1698154
</a
>,
285 <a href=
"http://www.wikidata.org/entity/Q1737980
">Q1737980
</a
>,
286 <a href=
"http://www.wikidata.org/entity/Q1877284
">Q1877284
</a
>,
287 <a href=
"http://www.wikidata.org/entity/Q1199354
">Q1199354
</a
>,
288 <a href=
"http://www.wikidata.org/entity/Q1199354
">Q1199354
</a
>,
289 <a href=
"http://www.wikidata.org/entity/Q1199451
">Q1199451
</a
>,
290 <a href=
"http://www.wikidata.org/entity/Q1211871
">Q1211871
</a
>,
291 <a href=
"http://www.wikidata.org/entity/Q1212179
">Q1212179
</a
>,
292 <a href=
"http://www.wikidata.org/entity/Q1238382
">Q1238382
</a
>,
293 <a href=
"http://www.wikidata.org/entity/Q4906454
">Q4906454
</a
>,
294 <a href=
"http://www.wikidata.org/entity/Q320219
">Q320219
</a
>,
295 <a href=
"http://www.wikidata.org/entity/Q1148649
">Q1148649
</a
>,
296 <a href=
"http://www.wikidata.org/entity/Q645094
">Q645094
</a
>,
297 <a href=
"http://www.wikidata.org/entity/Q5050350
">Q5050350
</a
>,
298 <a href=
"http://www.wikidata.org/entity/Q5166548
">Q5166548
</a
>,
299 <a href=
"http://www.wikidata.org/entity/Q2677926
">Q2677926
</a
>,
300 <a href=
"http://www.wikidata.org/entity/Q2698139
">Q2698139
</a
>,
301 <a href=
"http://www.wikidata.org/entity/Q2707305
">Q2707305
</a
>,
302 <a href=
"http://www.wikidata.org/entity/Q2740725
">Q2740725
</a
>,
303 <a href=
"http://www.wikidata.org/entity/Q2024780
">Q2024780
</a
>,
304 <a href=
"http://www.wikidata.org/entity/Q2117418
">Q2117418
</a
>,
305 <a href=
"http://www.wikidata.org/entity/Q2138984
">Q2138984
</a
>,
306 <a href=
"http://www.wikidata.org/entity/Q1127992
">Q1127992
</a
>,
307 <a href=
"http://www.wikidata.org/entity/Q1058087
">Q1058087
</a
>,
308 <a href=
"http://www.wikidata.org/entity/Q1070484
">Q1070484
</a
>,
309 <a href=
"http://www.wikidata.org/entity/Q1080080
">Q1080080
</a
>,
310 <a href=
"http://www.wikidata.org/entity/Q1090813
">Q1090813
</a
>,
311 <a href=
"http://www.wikidata.org/entity/Q1251918
">Q1251918
</a
>,
312 <a href=
"http://www.wikidata.org/entity/Q1254110
">Q1254110
</a
>,
313 <a href=
"http://www.wikidata.org/entity/Q1257070
">Q1257070
</a
>,
314 <a href=
"http://www.wikidata.org/entity/Q1257079
">Q1257079
</a
>,
315 <a href=
"http://www.wikidata.org/entity/Q1197410
">Q1197410
</a
>,
316 <a href=
"http://www.wikidata.org/entity/Q1198423
">Q1198423
</a
>,
317 <a href=
"http://www.wikidata.org/entity/Q706951
">Q706951
</a
>,
318 <a href=
"http://www.wikidata.org/entity/Q723239
">Q723239
</a
>,
319 <a href=
"http://www.wikidata.org/entity/Q2079261
">Q2079261
</a
>,
320 <a href=
"http://www.wikidata.org/entity/Q1171364
">Q1171364
</a
>,
321 <a href=
"http://www.wikidata.org/entity/Q617858
">Q617858
</a
>,
322 <a href=
"http://www.wikidata.org/entity/Q5166611
">Q5166611
</a
>,
323 <a href=
"http://www.wikidata.org/entity/Q5166611
">Q5166611
</a
>,
324 <a href=
"http://www.wikidata.org/entity/Q324513
">Q324513
</a
>,
325 <a href=
"http://www.wikidata.org/entity/Q374172
">Q374172
</a
>,
326 <a href=
"http://www.wikidata.org/entity/Q7533269
">Q7533269
</a
>,
327 <a href=
"http://www.wikidata.org/entity/Q970386
">Q970386
</a
>,
328 <a href=
"http://www.wikidata.org/entity/Q976849
">Q976849
</a
>,
329 <a href=
"http://www.wikidata.org/entity/Q7458614
">Q7458614
</a
>,
330 <a href=
"http://www.wikidata.org/entity/Q5347416
">Q5347416
</a
>,
331 <a href=
"http://www.wikidata.org/entity/Q5460005
">Q5460005
</a
>,
332 <a href=
"http://www.wikidata.org/entity/Q5463392
">Q5463392
</a
>,
333 <a href=
"http://www.wikidata.org/entity/Q3038555
">Q3038555
</a
>,
334 <a href=
"http://www.wikidata.org/entity/Q5288458
">Q5288458
</a
>,
335 <a href=
"http://www.wikidata.org/entity/Q2346516
">Q2346516
</a
>,
336 <a href=
"http://www.wikidata.org/entity/Q5183645
">Q5183645
</a
>,
337 <a href=
"http://www.wikidata.org/entity/Q5185497
">Q5185497
</a
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409 <title>A one-way wall on the border?
</title>
410 <link>http://people.skolelinux.org/pere/blog/A_one_way_wall_on_the_border_.html
</link>
411 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/A_one_way_wall_on_the_border_.html
</guid>
412 <pubDate>Sat,
14 Oct
2017 22:
10:
00 +
0200</pubDate>
413 <description><p
>I find it fascinating how many of the people being locked inside
414 the proposed border wall between USA and Mexico support the idea. The
415 proposal to keep Mexicans out reminds me of
416 <a href=
"http://www.history.com/news/
10-things-you-may-not-know-about-the-berlin-wall
">the
417 propaganda twist from the East Germany government
</a
> calling the wall
418 the “Antifascist Bulwark” after erecting the Berlin Wall, claiming
419 that the wall was erected to keep enemies from creeping into East
420 Germany, while it was obvious to the people locked inside it that it
421 was erected to keep the people from escaping.
</p
>
423 <p
>Do the people in USA supporting this wall really believe it is a
424 one way wall, only keeping people on the outside from getting in,
425 while not keeping people in the inside from getting out?
</p
>
430 <title>Generating
3D prints in Debian using Cura and Slic3r(-prusa)
</title>
431 <link>http://people.skolelinux.org/pere/blog/Generating_3D_prints_in_Debian_using_Cura_and_Slic3r__prusa_.html
</link>
432 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/Generating_3D_prints_in_Debian_using_Cura_and_Slic3r__prusa_.html
</guid>
433 <pubDate>Mon,
9 Oct
2017 10:
50:
00 +
0200</pubDate>
434 <description><p
>At my nearby maker space,
435 <a href=
"http://sonen.ifi.uio.no/
">Sonen
</a
>, I heard the story that it
436 was easier to generate gcode files for theyr
3D printers (Ultimake
2+)
437 on Windows and MacOS X than Linux, because the software involved had
438 to be manually compiled and set up on Linux while premade packages
439 worked out of the box on Windows and MacOS X. I found this annoying,
440 as the software involved,
441 <a href=
"https://github.com/Ultimaker/Cura
">Cura
</a
>, is free software
442 and should be trivial to get up and running on Linux if someone took
443 the time to package it for the relevant distributions. I even found
444 <a href=
"https://bugs.debian.org/
706656">a request for adding into
445 Debian
</a
> from
2013, which had seem some activity over the years but
446 never resulted in the software showing up in Debian. So a few days
447 ago I offered my help to try to improve the situation.
</p
>
449 <p
>Now I am very happy to see that all the packages required by a
450 working Cura in Debian are uploaded into Debian and waiting in the NEW
451 queue for the ftpmasters to have a look. You can track the progress
453 <a href=
"https://qa.debian.org/developer.php?email=
3dprinter-general%
40lists.alioth.debian.org
">the
454 status page for the
3D printer team
</a
>.
</p
>
456 <p
>The uploaded packages are a bit behind upstream, and was uploaded
457 now to get slots in
<a href=
"https://ftp-master.debian.org/new.html
">the NEW
458 queue
</a
> while we work up updating the packages to the latest
459 upstream version.
</p
>
461 <p
>On a related note, two competitors for Cura, which I found harder
462 to use and was unable to configure correctly for Ultimaker
2+ in the
463 short time I spent on it, are already in Debian. If you are looking
464 for
3D printer
"slicers
" and want something already available in
466 <a href=
"https://tracker.debian.org/pkg/slic3r
">slic3r
</a
> and
467 <a href=
"https://tracker.debian.org/pkg/slic3r-prusa
">slic3r-prusa
</a
>.
468 The latter is a fork of the former.
</p
>
473 <title>Mangler du en skrue, eller har du en skrue løs?
</title>
474 <link>http://people.skolelinux.org/pere/blog/Mangler_du_en_skrue__eller_har_du_en_skrue_l_s_.html
</link>
475 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/Mangler_du_en_skrue__eller_har_du_en_skrue_l_s_.html
</guid>
476 <pubDate>Wed,
4 Oct
2017 09:
40:
00 +
0200</pubDate>
477 <description>Når jeg holder på med ulike prosjekter, så trenger jeg stadig ulike
478 skruer. Det siste prosjektet jeg holder på med er å lage
479 <a href=
"https://www.thingiverse.com/thing:
676916">en boks til en
480 HDMI-touch-skjerm
</a
> som skal brukes med Raspberry Pi. Boksen settes
481 sammen med skruer og bolter, og jeg har vært i tvil om hvor jeg kan
482 få tak i de riktige skruene. Clas Ohlson og Jernia i nærheten har
483 sjelden hatt det jeg trenger. Men her om dagen fikk jeg et fantastisk
484 tips for oss som bor i Oslo.
485 <a href=
"http://www.zachskruer.no/
">Zachariassen Jernvare AS
</a
> i
486 <a href=
"http://www.openstreetmap.org/?mlat=
59.93421&mlon=
10.76795#map=
19/
59.93421/
10.76795">Hegermannsgate
487 23A på Torshov
</a
> har et fantastisk utvalg, og åpent mellom
09:
00 og
488 17:
00. De selger skruer, muttere, bolter, skiver etc i løs vekt, og
489 så langt har jeg fått alt jeg har lett etter. De har i tillegg det
490 meste av annen jernvare, som verktøy, lamper, ledninger, etc. Jeg
491 håper de har nok kunder til å holde det gående lenge, da dette er en
492 butikk jeg kommer til å besøke ofte. Butikken er et funn å ha i
493 nabolaget for oss som liker å bygge litt selv. :)
</p
>
498 <title>Visualizing GSM radio chatter using gr-gsm and Hopglass
</title>
499 <link>http://people.skolelinux.org/pere/blog/Visualizing_GSM_radio_chatter_using_gr_gsm_and_Hopglass.html
</link>
500 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/Visualizing_GSM_radio_chatter_using_gr_gsm_and_Hopglass.html
</guid>
501 <pubDate>Fri,
29 Sep
2017 10:
30:
00 +
0200</pubDate>
502 <description><p
>Every mobile phone announce its existence over radio to the nearby
503 mobile cell towers. And this radio chatter is available for anyone
504 with a radio receiver capable of receiving them. Details about the
505 mobile phones with very good accuracy is of course collected by the
506 phone companies, but this is not the topic of this blog post. The
507 mobile phone radio chatter make it possible to figure out when a cell
508 phone is nearby, as it include the SIM card ID (IMSI). By paying
509 attention over time, one can see when a phone arrive and when it leave
510 an area. I believe it would be nice to make this information more
511 available to the general public, to make more people aware of how
512 their phones are announcing their whereabouts to anyone that care to
515 <p
>I am very happy to report that we managed to get something
516 visualizing this information up and running for
517 <a href=
"http://norwaymakers.org/osf17
">Oslo Skaperfestival
2017</a
>
518 (Oslo Makers Festival) taking place today and tomorrow at Deichmanske
519 library. The solution is based on the
520 <a href=
"http://people.skolelinux.org/pere/blog/Easier_recipe_to_observe_the_cell_phones_around_you.html
">simple
521 recipe for listening to GSM chatter
</a
> I posted a few days ago, and
522 will show up at the stand of
<a href=
"http://sonen.ifi.uio.no/
">Åpen
523 Sone from the Computer Science department of the University of
524 Oslo
</a
>. The presentation will show the nearby mobile phones (aka
525 IMSIs) as dots in a web browser graph, with lines to the dot
526 representing mobile base station it is talking to. It was working in
527 the lab yesterday, and was moved into place this morning.
</p
>
529 <p
>We set up a fairly powerful desktop machine using Debian
530 Buster/Testing with several (five, I believe) RTL2838 DVB-T receivers
531 connected and visualize the visible cell phone towers using an
532 <a href=
"https://github.com/marlow925/hopglass
">English version of
533 Hopglass
</a
>. A fairly powerfull machine is needed as the
534 grgsm_livemon_headless processes from
535 <a href=
"https://tracker.debian.org/pkg/gr-gsm
">gr-gsm
</a
> converting
536 the radio signal to data packages is quite CPU intensive.
</p
>
538 <p
>The frequencies to listen to, are identified using a slightly
539 patched scan-and-livemon (to set the --args values for each receiver),
540 and the Hopglass data is generated using the
541 <a href=
"https://github.com/petterreinholdtsen/IMSI-catcher/tree/meshviewer-output
">patches
542 in my meshviewer-output branch
</a
>. For some reason we could not get
543 more than four SDRs working. There is also a geographical map trying
544 to show the location of the base stations, but I believe their
545 coordinates are hardcoded to some random location in Germany, I
546 believe. The code should be replaced with code to look up location in
547 a text file, a sqlite database or one of the online databases
549 <a href=
"https://github.com/Oros42/IMSI-catcher/issues/
14">the github
550 issue for the topic
</a
>.
552 <p
>If this sound interesting, visit the stand at the festival!
</p
>
557 <title>Easier recipe to observe the cell phones around you
</title>
558 <link>http://people.skolelinux.org/pere/blog/Easier_recipe_to_observe_the_cell_phones_around_you.html
</link>
559 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/Easier_recipe_to_observe_the_cell_phones_around_you.html
</guid>
560 <pubDate>Sun,
24 Sep
2017 08:
30:
00 +
0200</pubDate>
561 <description><p
>A little more than a month ago I wrote
562 <a href=
"http://people.skolelinux.org/pere/blog/Simpler_recipe_on_how_to_make_a_simple__7_IMSI_Catcher_using_Debian.html
">how
563 to observe the SIM card ID (aka IMSI number) of mobile phones talking
564 to nearby mobile phone base stations using Debian GNU/Linux and a
565 cheap USB software defined radio
</a
>, and thus being able to pinpoint
566 the location of people and equipment (like cars and trains) with an
567 accuracy of a few kilometer. Since then we have worked to make the
568 procedure even simpler, and it is now possible to do this without any
569 manual frequency tuning and without building your own packages.
</p
>
571 <p
>The
<a href=
"https://tracker.debian.org/pkg/gr-gsm
">gr-gsm
</a
>
572 package is now included in Debian testing and unstable, and the
573 IMSI-catcher code no longer require root access to fetch and decode
574 the GSM data collected using gr-gsm.
</p
>
576 <p
>Here is an updated recipe, using packages built by Debian and a git
577 clone of two python scripts:
</p
>
581 <li
>Start with a Debian machine running the Buster version (aka
584 <li
>Run
'<tt
>apt install gr-gsm python-numpy python-scipy
585 python-scapy
</tt
>' as root to install required packages.
</li
>
587 <li
>Fetch the code decoding GSM packages using
'<tt
>git clone
588 github.com/Oros42/IMSI-catcher.git
</tt
>'.
</li
>
590 <li
>Insert USB software defined radio supported by GNU Radio.
</li
>
592 <li
>Enter the IMSI-catcher directory and run
'<tt
>python
593 scan-and-livemon
</tt
>' to locate the frequency of nearby base
594 stations and start listening for GSM packages on one of them.
</li
>
596 <li
>Enter the IMSI-catcher directory and run
'<tt
>python
597 simple_IMSI-catcher.py
</tt
>' to display the collected information.
</li
>
601 <p
>Note, due to a bug somewhere the scan-and-livemon program (actually
602 <a href=
"https://github.com/ptrkrysik/gr-gsm/issues/
336">its underlying
603 program grgsm_scanner
</a
>) do not work with the HackRF radio. It does
604 work with RTL
8232 and other similar USB radio receivers you can get
606 (
<a href=
"https://www.ebay.com/sch/items/?_nkw=rtl+
2832">for example
607 from ebay
</a
>), so for now the solution is to scan using the RTL radio
608 and only use HackRF for fetching GSM data.
</p
>
610 <p
>As far as I can tell, a cell phone only show up on one of the
611 frequencies at the time, so if you are going to track and count every
612 cell phone around you, you need to listen to all the frequencies used.
613 To listen to several frequencies, use the --numrecv argument to
614 scan-and-livemon to use several receivers. Further, I am not sure if
615 phones using
3G or
4G will show as talking GSM to base stations, so
616 this approach might not see all phones around you. I typically see
617 0-
400 IMSI numbers an hour when looking around where I live.
</p
>
619 <p
>I
've tried to run the scanner on a
620 <a href=
"https://wiki.debian.org/RaspberryPi
">Raspberry Pi
2 and
3
621 running Debian Buster
</a
>, but the grgsm_livemon_headless process seem
622 to be too CPU intensive to keep up. When GNU Radio print
'O
' to
623 stdout, I am told there it is caused by a buffer overflow between the
624 radio and GNU Radio, caused by the program being unable to read the
625 GSM data fast enough. If you see a stream of
'O
's from the terminal
626 where you started scan-and-livemon, you need a give the process more
627 CPU power. Perhaps someone are able to optimize the code to a point
628 where it become possible to set up RPi3 based GSM sniffers? I tried
629 using Raspbian instead of Debian, but there seem to be something wrong
630 with GNU Radio on raspbian, causing glibc to abort().
</p
>
635 <title>Datalagringsdirektivet kaster skygger over Høyre og Arbeiderpartiet
</title>
636 <link>http://people.skolelinux.org/pere/blog/Datalagringsdirektivet_kaster_skygger_over_H_yre_og_Arbeiderpartiet.html
</link>
637 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/Datalagringsdirektivet_kaster_skygger_over_H_yre_og_Arbeiderpartiet.html
</guid>
638 <pubDate>Thu,
7 Sep
2017 21:
35:
00 +
0200</pubDate>
639 <description><p
>For noen dager siden publiserte Jon Wessel-Aas en bloggpost om
640 «
<a href=
"http://www.uhuru.biz/?p=
1821">Konklusjonen om datalagring som
641 EU-kommisjonen ikke ville at vi skulle få se
</a
>». Det er en
642 interessant gjennomgang av EU-domstolens syn på snurpenotovervåkning
643 av befolkningen, som er klar på at det er i strid med
644 EU-lovgivingen.
</p
>
646 <p
>Valgkampen går for fullt i Norge, og om noen få dager er siste
647 frist for å avgi stemme. En ting er sikkert, Høyre og Arbeiderpartiet
649 <a href=
"http://people.skolelinux.org/pere/blog/Datalagringsdirektivet_gj_r_at_Oslo_H_yre_og_Arbeiderparti_ikke_f_r_min_stemme_i__r.html
">denne
650 gangen heller
</a
>. Jeg har ikke glemt at de tvang igjennom loven som
651 skulle pålegge alle data- og teletjenesteleverandører å overvåke alle
652 sine kunder. En lov som er vedtatt, og aldri opphevet igjen.
</p
>
654 <p
>Det er tydelig fra diskusjonen rundt grenseløs digital overvåkning
655 (eller
"Digital Grenseforsvar
" som det kalles i Orvellisk nytale) at
656 hverken Høyre og Arbeiderpartiet har noen prinsipielle sperrer mot å
657 overvåke hele befolkningen, og diskusjonen så langt tyder på at flere
658 av de andre partiene heller ikke har det. Mange av
659 <a href=
"https://data.holderdeord.no/votes/
1301946411e
">de som stemte
660 for Datalagringsdirektivet i Stortinget
</a
> (
64 fra Arbeiderpartiet,
661 25 fra Høyre) er fortsatt aktive og argumenterer fortsatt for å radere
662 vekk mer av innbyggernes privatsfære.
</p
>
664 <p
>Når myndighetene demonstrerer sin mistillit til folket, tror jeg
665 folket selv bør legge litt innsats i å verne sitt privatliv, ved å ta
666 i bruk ende-til-ende-kryptert kommunikasjon med sine kjente og kjære,
667 og begrense hvor mye privat informasjon som deles med uvedkommende.
668 Det er jo ingenting som tyder på at myndighetene kommer til å være vår
670 <a href=
"http://people.skolelinux.org/pere/blog/How_to_talk_with_your_loved_ones_in_private.html
">Det
671 er mange muligheter
</a
>. Selv har jeg litt sans for
672 <a href=
"https://ring.cx/
">Ring
</a
>, som er basert på p2p-teknologi
673 uten sentral kontroll, er fri programvare, og støtter meldinger, tale
674 og video. Systemet er tilgjengelig ut av boksen fra
675 <a href=
"https://tracker.debian.org/pkg/ring
">Debian
</a
> og
676 <a href=
"https://launchpad.net/ubuntu/+source/ring
">Ubuntu
</a
>, og det
677 finnes pakker for Android, MacOSX og Windows. Foreløpig er det få
678 brukere med Ring, slik at jeg også bruker
679 <a href=
"https://signal.org/
">Signal
</a
> som nettleserutvidelse.
</p
>
684 <title>Simpler recipe on how to make a simple $
7 IMSI Catcher using Debian
</title>
685 <link>http://people.skolelinux.org/pere/blog/Simpler_recipe_on_how_to_make_a_simple__7_IMSI_Catcher_using_Debian.html
</link>
686 <guid isPermaLink=
"true">http://people.skolelinux.org/pere/blog/Simpler_recipe_on_how_to_make_a_simple__7_IMSI_Catcher_using_Debian.html
</guid>
687 <pubDate>Wed,
9 Aug
2017 23:
59:
00 +
0200</pubDate>
688 <description><p
>On friday, I came across an interesting article in the Norwegian
689 web based ICT news magazine digi.no on
690 <a href=
"https://www.digi.no/artikler/sikkerhetsforsker-lagde-enkel-imsi-catcher-for-
60-kroner-na-kan-mobiler-kartlegges-av-alle/
398588">how
691 to collect the IMSI numbers of nearby cell phones
</a
> using the cheap
692 DVB-T software defined radios. The article refered to instructions
693 and
<a href=
"https://www.youtube.com/watch?v=UjwgNd_as30
">a recipe by
694 Keld Norman on Youtube on how to make a simple $
7 IMSI Catcher
</a
>, and I decided to test them out.
</p
>
696 <p
>The instructions said to use Ubuntu, install pip using apt (to
697 bypass apt), use pip to install pybombs (to bypass both apt and pip),
698 and the ask pybombs to fetch and build everything you need from
699 scratch. I wanted to see if I could do the same on the most recent
700 Debian packages, but this did not work because pybombs tried to build
701 stuff that no longer build with the most recent openssl library or
702 some other version skew problem. While trying to get this recipe
703 working, I learned that the apt-
>pip-
>pybombs route was a long detour,
704 and the only piece of software dependency missing in Debian was the
705 gr-gsm package. I also found out that the lead upstream developer of
706 gr-gsm (the name stand for GNU Radio GSM) project already had a set of
707 Debian packages provided in an Ubuntu PPA repository. All I needed to
708 do was to dget the Debian source package and built it.
</p
>
710 <p
>The IMSI collector is a python script listening for packages on the
711 loopback network device and printing to the terminal some specific GSM
712 packages with IMSI numbers in them. The code is fairly short and easy
713 to understand. The reason this work is because gr-gsm include a tool
714 to read GSM data from a software defined radio like a DVB-T USB stick
715 and other software defined radios, decode them and inject them into a
716 network device on your Linux machine (using the loopback device by
717 default). This proved to work just fine, and I
've been testing the
718 collector for a few days now.
</p
>
720 <p
>The updated and simpler recipe is thus to
</p
>
724 <li
>start with a Debian machine running Stretch or newer,
</li
>
726 <li
>build and install the gr-gsm package available from
727 <a href=
"http://ppa.launchpad.net/ptrkrysik/gr-gsm/ubuntu/pool/main/g/gr-gsm/
">http://ppa.launchpad.net/ptrkrysik/gr-gsm/ubuntu/pool/main/g/gr-gsm/
</a
>,
</li
>
729 <li
>clone the git repostory from
<a href=
"https://github.com/Oros42/IMSI-catcher
">https://github.com/Oros42/IMSI-catcher
</a
>,
</li
>
731 <li
>run grgsm_livemon and adjust the frequency until the terminal
732 where it was started is filled with a stream of text (meaning you
733 found a GSM station).
</li
>
735 <li
>go into the IMSI-catcher directory and run
'sudo python simple_IMSI-catcher.py
' to extract the IMSI numbers.
</li
>
739 <p
>To make it even easier in the future to get this sniffer up and
740 running, I decided to package
741 <a href=
"https://github.com/ptrkrysik/gr-gsm/
">the gr-gsm project
</a
>
742 for Debian (
<a href=
"https://bugs.debian.org/
871055">WNPP
743 #
871055</a
>), and the package was uploaded into the NEW queue today.
744 Luckily the gnuradio maintainer has promised to help me, as I do not
745 know much about gnuradio stuff yet.
</p
>
747 <p
>I doubt this
"IMSI cacher
" is anywhere near as powerfull as
748 commercial tools like
749 <a href=
"https://www.thespyphone.com/portable-imsi-imei-catcher/
">The
750 Spy Phone Portable IMSI / IMEI Catcher
</a
> or the
751 <a href=
"https://en.wikipedia.org/wiki/Stingray_phone_tracker
">Harris
752 Stingray
</a
>, but I hope the existance of cheap alternatives can make
753 more people realise how their whereabouts when carrying a cell phone
754 is easily tracked. Seeing the data flow on the screen, realizing that
755 I live close to a police station and knowing that the police is also
756 wearing cell phones, I wonder how hard it would be for criminals to
757 track the position of the police officers to discover when there are
758 police near by, or for foreign military forces to track the location
759 of the Norwegian military forces, or for anyone to track the location
760 of government officials...
</p
>
762 <p
>It is worth noting that the data reported by the IMSI-catcher
763 script mentioned above is only a fraction of the data broadcasted on
764 the GSM network. It will only collect one frequency at the time,
765 while a typical phone will be using several frequencies, and not all
766 phones will be using the frequencies tracked by the grgsm_livemod
767 program. Also, there is a lot of radio chatter being ignored by the
768 simple_IMSI-catcher script, which would be collected by extending the
769 parser code. I wonder if gr-gsm can be set up to listen to more than
770 one frequency?
</p
>