Search Results: "ed"

2 July 2015

Norbert Preining: An amusing lintian error Lenna

Well, there we are, trying to build another round of TeX Live packages for Debian, just to realize that the lintian error that should have been downgraded to warning (or removed) is still around, due to doubts about the license. Ok. Well, anyway, but what I found is even more funny: 
E: texlive-extra source: license-problem-non-free-img-lenna texmf-dist/doc/latex/reflectgraphics/lenna.jpg
which is about one of the most used images in images processing courses, Lenna: who-is-lenna
Without comments, I just quote the lintian error it is a whole lot of fun to read.
Ref: https://en.wikipedia.org/wiki/Lenna, https://www.debian.org/vote/2012/vote_002, #771191
Info: The given source file is cropped from playboy centerfold. This image is a picture of Lena S derberg, shot by photographer Dwight Hooker, cropped from the centerfold of the November 1972 issue of Playboy magazine. According to Hutchison, Jamie (May June 2001). Culture, Communication, and an Information Age Madonna (PDF). IEEE Professional Communication Society Newsletter 45 (3). (page 5 second column second paragraph), this image is distributable but not free. Moreover, Lenna photo has been pointed to as an example of sexism in the sciences, reinforcing gender stereotypes. Please use well known and free test image. Please also submit md5sum, sha1sum, and sha256 of this file as a bug report for lintian.
How fortunate our generation is that we don t have anything else to care about Anyway, back to rebuilding orig.tars, source packages, and binary packages!

Lars Wirzenius: Obnam 1.10 released (backup software)

I have just released version 1.10 of Obnam, my backup program. See the website at http://obnam.org for details on what it does. The new version is available from git (see http://git.liw.fi) and as Debian packages from http://code.liw.fi/debian, and uploaded to Debian, hopefully soon in unstable. The NEWS file extract below gives the highlights of what's new in this version. Version 1.10, released 2015-07-01 Major bug fixes: Minor new features: Minor fixes:

1 July 2015

Daniel Silverstone: Be careful what you ask for

Date: Wed, 01 Jul 2015 06:13:16 -0000
From: 123-reg <noreply@123-reg.co.uk>
To: dsilvers@digital-scurf.org
Subject: Tell us what you think for your chance to win
X-Mailer: MIME::Lite 3.027 (F2.74; T1.28; A2.04; B3.13; Q3.13)
Tell us what you think of 123-reg!
<!--
.style1  color: #1996d8 
-->
Well 123-reg mostly I think you don't know how to do email.

Christian Perrier: [LIFE] Running activities

Hello dear readers, It has been quite some time since I blogged on Planet Debian,so today, I just want to give some news to fellow Debian pals. My involvment in Debian is still there. I'm probably less visible nowadays, but I'm still actively working on some packages, monotiring some i18n activities and doing work on D-I. But, as you know, running has taken precedence nowadays and is still becoming a growing part of my life (along with my family, of course). This year, I had a first "summit" running the "Vulcain" trail race in French "Massif Central" (mountains in Central France), which was 80km and 3000m positive climb race. It was run mostly in snow and with quite bad weather conditions, a good training for more difficult races. I completed it in about more than 12 hours, for a race that finally had less than 60% finishers. Later on, most races were preparation races for the summer moutain races : I mostly ran three 50km trail races in the Paris and neighbourhood area. All of them were very good results with a good feeling. Some were run along with friends from the Kikourou.net web community, where I am now very active. My training was also strongly increased wrt former years (yes that *is* possible), peaking at more than 500km during May, where I was mostly on holidays all month long (lucky man). And now, the first Great Great Thing of the year is coming : La Montagn'hard, 110 kilometers, about 9000 meters positive climb, around Les Contamines, close to Mont-Blanc in French Alps. That is a Big One, indeed. Technically more difficult than the TDS race I ran last August, during DebConf (120km, but "only" 7000 meters climb). Montagn'hard is indeed known as one of the most difficult moutain trail races in France. I plan to complete it in about 29 hours....but that can indeed be 30, 32 or even 35, who knows what can happen? Given the very high temperatures over Europe this week (they'll peak at about 38 C on Saturday in the Alps), that will be an incredibly difficult challenge and we expect about only 40% finishers. A live tracking will be available for thos who care at http://chrono.geofp.com/montagnhard2015/v3/. Wish me luck ! Next challenge will be end of August, with the "Echappee Belle" race : 144km and 10.000 meters positive climb, still in French Alps (Belledonne range, this time). About 48 hours, or even up to 55, two nights out.....harder and hopefully better, faster, stronger...:-)

Steve McIntyre: Quick trip to Sweden

Jo and I spent a few days in Sweden and had an awesome time! The main reason for being there was Leif and Maria's wedding way up north in Skellefte . They cunningly organised their ceremony for the Midsummer weekend, which was an excellent plan - we had a full weekend of partying while we were there. :-) the happy couple We had some time to ourselves while we were there, so we wandered about a little and got to see some of the beautiful coastal countryside. Trund n Then on the way home we stopped off in Ume to visit Mattias Wadenstein (maswan) and his wife Melanie, and he showed me around some of the machines that he's been admining on behalf of Debian. Maybe I'm a sad geek, but I feel quite a bond with one of the machines there, pettersson.debian.org. It's the official CD build machine for Debian, and I've been responsible for thrashing it really hard for the last 5 years or so... :-) Pettersson and friends Massive thanks to the University of Ume and their Academic Computer Club for hosting Debian machines and serving all the CD images for us! maswan and a lot of disks The only downsides from the trip were the massive tiredness (midnight sun is pretty, but notconducive to sleep!) the mosquito bites and the nasty plague^Wcold that we picked up while we were there... Ah well. :-)

29 June 2015

Jonathan McDowell: What Jonathan Did Next

While I mentioned last September that I had failed to be selected for an H-1B and had been having discussions at DebConf about alternative employment, I never got around to elaborating on what I d ended up doing. Short answer: I ended up becoming a law student, studying for a Masters in Legal Science at Queen s University Belfast. I ve just completed my first year of the 2 year course and have managed to do well enough in the 6 modules so far to convince myself it wasn t a crazy choice. Longer answer: After Vello went under in June I decided to take a couple of months before fully investigating what to do next, largely because I figured I d either find something that wanted me to start ASAP or fail to find anything and stress about it. During this period a friend happened to mention to me that the applications for the Queen s law course were still open. He happened to know that it was something I d considered before a few times. Various discussions (some of them over gin, I ll admit) ensued and I eventually decided to submit an application. This was towards the end of August, and I figured I d also talk to people at DebConf to see if there was anything out there tech-wise that I could get excited about. It turned out that I was feeling a bit jaded about the whole tech scene. Another friend is of the strong opinion that you should take a break at least every 10 years. Heeding her advice I decided to go ahead with the law course. I haven t regretted it at all. My initial interest was largely driven by a belief that there are too few people who understand both tech and law. I started with interests around intellectual property and contract law as well as issues that arise from trying to legislate for the global nature of most tech these days. However the course is a complete UK qualifying degree (I can go on to do the professional qualification in NI or England & Wales) and the first year has been about public law. Which has been much more interesting than I was expecting (even, would you believe it, EU law). Especially given the potential changing constitutional landscape of the UK after the recent general election, with regard to talk of repeal of the Human Rights Act and a referendum on exit from the EU. Next year will concentrate more on private law, and I m hoping to be able to tie that in better to what initially drove me to pursue this path. I m still not exactly sure which direction I ll go once I complete the course, but whatever happens I want to keep a linkage between my skill sets. That could be either leaning towards the legal side but with the appreciation of tech, returning to tech but with the appreciation of the legal side of things or perhaps specialising further down an academic path that links both. I guess I ll see what the next year brings. :)

Lunar: Reproducible builds: week 9 in Stretch cycle

What happened about the reproducible builds effort this week: Toolchain fixes Norbert Preining uploaded texinfo/6.0.0.dfsg.1-2 which makes texinfo indices reproducible. Original patch by Chris Lamb. Lunar submitted recently rebased patches to make the file order of files inside .deb stable. akira filled #789843 to make tex4ht stop printing timestamps in its HTML output by default. Dhole wrote a patch for xutils-dev to prevent timestamps when creating gzip compresed files. Reiner Herrmann sent a follow-up patch for wheel to use UTC as timezone when outputing timestamps. Mattia Rizzolo started a discussion regarding the failure to build from source of subversion when -Wdate-time is added to CPPFLAGS which happens when asking dpkg-buildflags to use the reproducible profile. SWIG errors out because it doesn't recognize the aforementioned flag. Trying to get the .buildinfo specification to more definitive state, Lunar started a discussion on storing the checksums of the binary package used in dpkg status database. akira discovered while proposing a fix for simgrid that CMake internal command to create tarballs would record a timestamp in the gzip header. A way to prevent it is to use the GZIP environment variable to ask gzip not to store timestamps, but this will soon become unsupported. It's up for discussion if the best place to fix the problem would be to fix it for all CMake users at once. Infrastructure-related work Andreas Henriksson did a delayed NMU upload of pbuilder which adds minimal support for build profiles and includes several fixes from Mattia Rizzolo affecting reproducibility tests. Neils Thykier uploaded lintian which both raises the severity of package-contains-timestamped-gzip and avoids false positives for this tag (thanks to Tomasz Buchert). Petter Reinholdtsen filled #789761 suggesting that how-can-i-help should prompt its users about fixing reproducibility issues. Packages fixed The following packages became reproducible due to changes in their build dependencies: autorun4linuxcd, libwildmagic, lifelines, plexus-i18n, texlive-base, texlive-extra, texlive-lang. The following packages became reproducible after getting fixed: Some uploads fixed some reproducibility issues but not all of them: Untested uploaded as they are not in main: Patches submitted which have not made their way to the archive yet: debbindiff development debbindiff/23 includes a few bugfixes by Helmut Grohne that result in a significant speedup (especially on larger files). It used to exhibit the quadratic time string concatenation antipattern. Version 24 was released on June 23rd in a hurry to fix an undefined variable introduced in the previous version. (Reiner Herrmann) debbindiff now has a test suite! It is written using the PyTest framework (thanks Isis Lovecruft for the suggestion). The current focus has been on the comparators, and we are now at 93% of code coverage for these modules. Several problems were identified and fixed in the process: paths appearing in output of javap, readelf, objdump, zipinfo, unsqusahfs; useless MD5 checksum and last modified date in javap output; bad handling of charsets in PO files; the destination path for gzip compressed files not ending in .gz; only metadata of cpio archives were actually compared. stat output was further trimmed to make directory comparison more useful. Having the test suite enabled a refactoring of how comparators were written, switching from a forest of differences to a single tree. This helped removing dust from the oldest parts of the code. Together with some other small changes, version 25 was released on June 27th. A follow up release was made the next day to fix a hole in the test suite and the resulting unidentified leftover from the comparator refactoring. (Lunar) Documentation update Ximin Luo improved code examples for some proposed environment variables for reference timestamps. Dhole added an example on how to fix timestamps C pre-processor macros by adding a way to set the build date externally. akira documented her fix for tex4ht timestamps. Package reviews 94 obsolete reviews have been removed, 330 added and 153 updated this week. Hats off for Chris West (Faux) who investigated many fail to build from source issues and reported the relevant bugs. Slight improvements were made to the scripts for editing the review database, edit-notes and clean-notes. (Mattia Rizzolo) Meetings A meeting was held on June 23rd. Minutes are available. The next meeting will happen on Tuesday 2015-07-07 at 17:00 UTC. Misc. The Linux Foundation announced that it was funding the work of Lunar and h01ger on reproducible builds in Debian and other distributions. This was further relayed in a Bits from Debian blog post.

Paul Wise: The aliens are amongst us!

Don't worry, they can't cope with our atmosphere. Alien on the ground Perhaps they are just playing dead. Don't turn your back if you see one. Folks may want to use this alien in free software. The original photo is available on request. To the extent possible under law, I have waived all copyright and related or neighboring rights to this work. The alien has signed a model release. An email or a link to this page would be appreciated though.

Norbert Preining: The Talos Principle Solving puzzles using SAT solvers

After my last post on Portal, there was a sale of The Talos Principle, so I got it and started playing. And soon I got stuck at these kind of puzzles where one has to fit in pieces into a frame. As a logician I hate to solve something by trial and error, so I decided I write a solver for these kind of puzzles, based on a propositional logic encoding and satisfiability solver. Sometimes it is good to be logician! Talos-Puzzles In the Talos Principle, access to new worlds and specific items is often blocked by gates that open by putting Sigils into the frame. Of course, collecting the sigils is the most challenging part, but that is often solvable by logical thinking. On the other hand, solving these fitting puzzles drove me crazy, so let us solve them with a SAT solver. Encoding I used a propositional encoding that for each combination of cells and sigils assigns a propositional variable, which is true if the specific sigil rests in on that cell in the final solution. That is, we have variable (encoded as x_i_j_n) where runs over the cells of the frame, and over the (numbered) sigils. Setup I have written a perl program that for a definition of a puzzle (see later), outputs SMT2 code, which then is checked for satisfiability and generation of model with the z3 solver (which is available in Debian). Necessary assertions We have to state relations between these propositional variables to obtain a proper solution, in particular we have added the following statements: Let us go through them one by one: Every field has at least on sigil on it That is an easy part by asserting

In the SMT2 code it would look like 
(assert (or x_i_j_1 x_i_j_2 ... x_i_j_n))
Every field has at most one sigil on it This can be achieved by asserting for each tile and each pair of different sigil (numbers), that not both of the two hold:

and in SMT2 code: 
(assert (and
  (not (and x_1_1_1 x_1_1_2))
  (not (and x_1_1_1 x_1_1_3))
...
(assert (and
  (not (and x_1_2_1 x_1_2_2))
  (not (and x_1_2_1 x_1_2_3))
...
Every sigil is used at least once This was a bit a tricky one. First I thought I want to express that every sigil is used exactly once by excluding that for one sigil there are more fields assigned to it then the sigil contains parts. So if a sigil occupies 4 tiles, then every combination of 5 tiles needs to evaluate to false. But with 8 8 or so frames, the number of combinations simply explodes to above several million, which brings my harddrive size and z3 to an end. The better idea was to say that every sigil was used at least once. Since all sigils together exactly fill the frame, this is enough. This can be done easily by assuming that for each sigil, at least one of the tiles is assigned to it:

or in SMT code for a 6 6 frame and the first sigil: 
(assert (or x_1_1_n x_1_2_n ...  x_6_6_1))
Defining equations for the sigil s form Of course the most important part are the defining equations for the various sigils. Here I choose the following path: So for example for the top-most sigil in the above photo, I choose the anchor point to be the center, and if that was in , I need to assume that for the upright position

holds. In the same way, when rotated right, we need

All these options have to be disjunctively connected, in SMT code for the case where the anchor lies at (4,2). 
(assert (or
  ...
  (and x_3_2_n x_4_2_n x_5_2_n x_4_3_n)
  (and x_3_3_n x_3_2_n x_3_1_n x_4_2_n)
  (and x_3_2_n x_4_2_n x_5_2_n x_4_1_n)
...
When generating these equations one has to be careful not to include rotated sigils that stick out of the frame, though. Although the above might not be the optimal encoding, the given assertions suffice to check for SAT and produce a model, which allows me to solve the riddles. Implementation in Perl To generate the SMT2 code, I used a Perl script, which is very quickly hacked together. The principle function is (already coded for the above riddle): 
create_smt2_def(8,6,'a','a','b','cl','cl','cr','cr','cr','q','q','sl','sl');
where the first two arguments define the size of the frame, and the rest are codes for sigil types: This function first sets up the header of the smt2 file, followed by shipping out all the necessary variable definitions, in SMT these are defined as Boolean functions, and the other assertions (please see the Perl code linked below for details). The most interesting part are the definitions of the sigils: 
  # for each piece, call the defining assertions
  for my $n (1..$nn)  
    my $p = $pieces[$n-1];
    print "(assert (or\n";
    for my $i (1..$xx)  
      for my $j (1..$yy)  
        if ($p eq 'q')   
          type_square($xx,$yy,$i,$j,$n); 
          elsif ($p eq 'a')  
          type_potest($xx,$yy,$i,$j,$n);
    ....
Every sigil type has its own definiton, in case of the a podest, the type_podest function: 
sub type_potest  
  my ($xx,$yy,$i,$j,$n) = @_;
  my ($il, $jl, $ir, $jr, $iu, $ju);
  $il = $i - 1; $ir = $i + 1; $iu = $i;
  $jl = $jr = $j; $ju = $j + 1;
  do_rotate_shipout($xx,$yy, $i, $j, $n, $il, $jl, $ir, $jr, $iu, $ju);
This function is prototypical, one defines the tiles a sigil occupies if the anchor is placed on (i,j) for an arbitrary orientation of the sigil, and then calls do_rotate_shipout on the list of occupied tiles. This function in turn is very simple: 
sub do_rotate_shipout  
  my ($xx,$yy, $i, $j, $n, @pairs) = @_ ;
  for my $g (0..3)  
    @pairs = rotate90($i, $j, @pairs);
    check_and_shipout($xx,$yy, $n, $i, $j, @pairs);
as it only rotates four times by 90 degrees, and then checks whether the rotated sigil is completely within the frame, and if yes ships out the assertion code. The rotation is done by multiplying the vector from (i,j) to the tile position with the (0 -1 1 0) matrix and adding it again to (i,j): 
sub rotate90  
  my ($i, $j, @pairs) = @_ ;
  my @ret;
  while (@pairs)  
    my $ii = shift @pairs;
    my $jj = shift @pairs;
    my $ni = $i - ($jj - $j);
    my $nj = $j + ($ii - $i);
    push @ret, $ni, $nj;
   
  return @ret;
There are a few more functions, for those interested, the full Perl code is here: tangram.pl. There is no user interface or any config file reading done, I just edit the source code if I need to solve a riddle. Massaging the output Last but not least, the output of the z3 solver is a bit noisy, so I run the output through a few Unix commands to get only the true assignments, which gives me the location of the tiles. That is, I run the following pipeline: 
perl tangram.pl   z3 -in   egrep 'define-fun true false'    sed -e 'h;s/.*//;G;N;s/\n//g'   grep true   sort
which produces a list like the following as output: 
  (define-fun x_1_1_10 () Bool    true)
  (define-fun x_1_2_10 () Bool    true)
  (define-fun x_1_3_5 () Bool    true)
  (define-fun x_1_4_6 () Bool    true)
  (define-fun x_1_5_6 () Bool    true)
  (define-fun x_1_6_6 () Bool    true)
  (define-fun x_2_1_10 () Bool    true)
  (define-fun x_2_2_10 () Bool    true)
  (define-fun x_2_3_5 () Bool    true)
  ...
from which I can read up the solution that puts the tenth sigil (a square) in the lower left corner:
Talos-Puzzle-solved

28 June 2015

Ben Armstrong: Bluff Trail Early Summer 2015

Here s a photo journal of a walk I just completed around the Pot Lake loop of the Bluff Wilderness Hiking Trail. Hope you enjoy it! I was dissatisfied with my initial post, so have reduced the size to improve load time, changed the gallery software and have rewritten many of the captions. [slb_group]
My favourite stunted tamarack, clinging to the rocks.Click this photo to start the slideshow.
The Bluff Wilderness Hiking Trail is a series of four loops. Today I ll tackle only the first in order to get as many pictures as possible, and because when hiking solo, I prefer to stay on the more heavily traveled part. In late summer, I ll probably do all four loops with my friend Ryan again. Meanwhile, I ll stay in shape coming out here when I can for shorter walks. The trail starts here. Right away, even before heading between the marker stones, there s a pretty view of Cranberry Lake off to the right. Pink lady slippers have been plentiful this year! All along the trail, you can find hundreds, if not thousands of these. Boardwalks provide dry passage across the boggy bits. The pitcher plants are thriving, too. The vines with tiny, round leaves are wintergreen. Tasty! I ve not seen anything larger than a deer out here. Roots and rocks are a recurring theme. Many feet beating down on the first loop have packed the earth hard and have exposed more roots than you ll see deeper into the trail system where fewer hikers travel. Step carefully. Sheep laurel is an eye-catcher. To me, they look like little, pink jewels. Yellow markers clearly mark the Pot Lake loop. At crucial junctures there are some signs to point you the right way. If you re looking only at your feet, you may see black circles marked with arrows on some of the rocks, also pointing the way. The vegetation varies from scraggly and clinging to the rocks, to lush and green. The path is wet in parts. Nothing impassible, though. On the first loop in particular, and even within only the first kilometre, there are some pretty stunning views of the lake. Very quickly, you ll find yourself perched up top on the rocks. On this stretch, you need to hop a bit from one rock to the next. Just as quickly as you ascended, you descend back down to the lake again. A good place to stop and have a snack. The start of the first loop, itself. I chide myself for not having discovered this trail until about 2007, even though we moved out here in 2005. It s a treasure we re indebted to the WRWEO for preserving. Leave some comments in the box, if you like. You ll find these maps along the way to track your progress. Remember to follow proper trail etiquette. A particularly steep climb! Despite the best trail maintenance efforts, water still goes where it wants! Good to have boots. Another steep climb. This tree is chattering at me. Raising quite a racket. What s in the hole? I patiently wait with my camera to get a good shot of the tree s occupants. Mother woodpecker, feeding her babies! As the feeding continues, the chirping intensifies! Up on top of a big rock with a view over the lake is another favourite stopping place for a snack. The view at my snack break rock. I never get tired of it. There are some pretty big boulders. Next time I ll bring a friend to stand under it for scale. Another terrific view. A stream just before the first portage. This portage connects Cranberry Lake with Pot Lake. The portage is clearly marked. The Pot Lake end of the portage. One of several upturned trees, with the roots now forming a wall along one side of the trail. The spiral of the roots mimics the spiral split in this boulder which you can walk all of the way into until you reach the centre. Rocks and trees and trees and rocks White pine catkins. Suddenly the close forest opens up into a wide view all around. My favourite stunted tamarack, clinging to the rocks. Last year s cones. This year s aren t out yet on this tree. I love the tamarack s delicate new needles. These blueberries have a head start. Can t wait until it s time to harvest them. Nearly at the top of the Pot Lake loop. This is Pot Lake, itself. I was struck by this one little blighted berry, showing a blush of distress-induced colour amongst the green ones. Another view, nearly at the top. A sign beneath the map: Rare Plant Species: Mountain Sandwort Arenaria groenlandica. Use caution and stay on designated trails. Avoid disturbing habitat. Finally, the top. A map to mark your progress. Apparently the Mountain Sandwort, right at the base of the sign. The mountain sandwort is a pretty, delicate little thing. After passing the sign, the view from the top over Cranberry Lake, indeed both lakes, is a reward worth climbing all of the way up to see. Some other hiker has left a cairn. The descent is not too steep at first. The approach down to the back side of Pot Lake from the top is marked by exposed bedrock and scrubby plants. Finally back to some cover, which is welcome on hotter days. A ferny fairyland. It s not all abrupt ups and downs. Here s an easy, winding stretch of trail. Cinnamon ferns. Ambling along. Rounding the end of Pot Lake. Not very long after reaching the lake, the path climbs several metres up above it. There are some nice, rootless bits on this side of the loop, giving your ankles and knees a break. This guy seemed extremely agitated to see me. A new tamarack cone! Did I mention I like tamaracks? The steep descent back to Cranberry Lake again. Finally back where the loop starts.
[/slb_group]

Sven Hoexter: moto g GPS reset when it is not working with CM 12.1

There seems to be an issue with the moto g, CM 12.1 (nightlies) and the GPS. My GPS receiver stopped to work as well and I could recover it with the following steps in fastboot mode as described on xda-developers. 
fastboot erase modemst1
fastboot erase modemst2
fastboot reboot
That even works with the 4.2.2 fastboot packaged in anroid-tools-fastboot.

Russell Coker: RAID Pain

One of my clients has a NAS device. Last week they tried to do what should have been a routine RAID operation, they added a new larger disk as a hot-spare and told the RAID array to replace one of the active disks with the hot-spare. The aim was to replace the disks one at a time to grow the array. But one of the other disks had an error during the rebuild and things fell apart. I was called in after the NAS had been rebooted when it was refusing to recognise the RAID. The first thing that occurred to me is that maybe RAID-5 isn t a good choice for the RAID. While it s theoretically possible for a RAID rebuild to not fail in such a situation (the data that couldn t be read from the disk with an error could have been regenerated from the disk that was being replaced) it seems that the RAID implementation in question couldn t do it. As the NAS is running Linux I presume that at least older versions of Linux have the same problem. Of course if you have a RAID array that has 7 disks running RAID-6 with a hot-spare then you only get the capacity of 4 disks. But RAID-6 with no hot-spare should be at least as reliable as RAID-5 with a hot-spare. Whenever you recover from disk problems the first thing you want to do is to make a read-only copy of the data. Then you can t make things worse. This is a problem when you are dealing with 7 disks, fortunately they were only 3TB disks and only each had 2TB in use. So I found some space on a ZFS pool and bought a few 6TB disks which I formatted as BTRFS filesystems. For this task I only wanted filesystems that support snapshots so I could work on snapshots not on the original copy. I expect that at some future time I will be called in when an array of 6+ disks of the largest available size fails. This will be a more difficult problem to solve as I don t own any system that can handle so many disks. I copied a few of the disks to a ZFS filesystem on a Dell PowerEdge T110 running kernel 3.2.68. Unfortunately that system seems to have a problem with USB, when copying from 4 disks at once each disk was reading about 10MB/s and when copying from 3 disks each disk was reading about 13MB/s. It seems that the system has an aggregate USB bandwidth of 40MB/s slightly greater than USB 2.0 speed. This made the process take longer than expected. One of the disks had a read error, this was presumably the cause of the original RAID failure. dd has the option conv=noerror to make it continue after a read error. This initially seemed good but the resulting file was smaller than the source partition. It seems that conv=noerror doesn t seek the output file to maintain input and output alignment. If I had a hard drive filled with plain ASCII that MIGHT even be useful, but for a filesystem image it s worse than useless. The only option was to repeatedly run dd with matching skip and seek options incrementing by 1K until it had passed the section with errors. for n in /dev/loop[0-6] ; do echo $n ; mdadm examine -v -v scan $n grep Events ; done Once I had all the images I had to assemble them. The Linux Software RAID didn t like the array because not all the devices had the same event count. The way Linux Software RAID (and probably most RAID implementations) work is that each member of the array has an event counter that is incremented when disks are added, removed, and when data is written. If there is an error then after a reboot only disks with matching event counts will be used. The above command shows the Events count for all the disks. Fortunately different event numbers aren t going to stop us. After assembling the array (which failed to run) I ran mdadm -R /dev/md1 which kicked some members out. I then added them back manually and forced the array to run. Unfortunately attempts to write to the array failed (presumably due to mismatched event counts). Now my next problem is that I can make a 10TB degraded RAID-5 array which is read-only but I can t mount the XFS filesystem because XFS wants to replay the journal. So my next step is to buy another 2*6TB disks to make a RAID-0 array to contain an image of that XFS filesystem. Finally backups are a really good thing
Related posts:
  1. RAID and Bus Bandwidth As correctly pointed out by cmot [1] my previous post...
  2. Some RAID Issues I just read an interesting paper titled An Analysis of...
  3. Reliability of RAID ZDNet has an insightful article by Robin Harris predicting the...

27 June 2015

Christian Perrier: Bugs #780000 - 790000

Thorsten Glaser reported Debian bug #780000 on Saturday March 7th 2015, against the gcc-4.9 package. Bug #770000 was reported as of November 18th so there have been 10,000 bugs in about 3.5 months, which was significantly slower than earlier. Matthew Vernon reported Debian bug #790000 on Friday June 26th 2015, against the pcre3 package. Thus, there have been 10,000 bugs in 3.5 months again. It seems that the bug report rate stabilized again. Sorry for missing bug #780000 annoucement. I'm doing this since....November 2007 for bug #450000 and it seems that this lack of attention is somehow significant wrt my involvment in Debian. Still, this involvment is still here and I'll try to "survive" in the project until we reach bug #1000000...:-) See you for bug #800000 annoucement and the result of the bets we placed on the date it would happen.

25 June 2015

Norbert Preining: TeX Live 2015 hits Debian/unstable

Here we go, I just uploaded 15 packages to the Debian archive that brings TeX Live in Debian up to the 2015 release (and a bit newer)! Debian - TeX Live 2015 Uploaded packages are asymptote, biber, context, context-modules, jadetex, musixtex, pmx, tex-common, texinfo, texinfo-doc-nonfree, texlive-base, texlive-bin, texlive-extra, texlive-lang, xmltex. The packages are basically what has been in experimental for quite some time, plus a checkout of tlnet from yesterday. For details on the changes and the new packaging, please consult this post. So, now let the flood of bug reports begin, but in the mean time, enjoy!

24 June 2015

Norbert Preining: TeX Live Manager News June 2015

TeX Live 2015 has been released, and normal operation with daily updates has started. During the freeze time and afterwards I have made a few changes to the TeX Live Manager (tlmgr) that I want to highlight here. texlive-tlmgr The main changes are better error and return code handling (which should be hardly visible for the users), and more more informative output of the tlmgr info action, incorporating more data from the TeX Catalogue. Error handling With a program that started as an experiment that has grown into the central configuration and management program, there are lots of old code pieces that did not do proper error signaling via return values. That meant that the return value of a tlmgr run didn t have any meaning, mostly because it was 0 (success) most of the times. I have now tried to do proper return code handling throughout the tlmgr code base, that is the tlmgr.pl and the necessary Perl modules. While this should not be a user visible changes, it turned out that the MacOS TeX Live Utility by Adam Maxwell (btw, a great program, it would be nice to have something similar written for Unix replacing the bit clumsy tlmgr gui), got broken for paper configuration, due to forgotten return value fixes in the TLPaper.pm module. That is fixed now in our repository. All in all we do hope that the return value of a tlmgr run now gives proper information about success or error. I might add a bit more semantics by returning bit-values in case of errors, but this is in early stages of thinking. TeX Catalogue data in tlmgr info Since more or less the very beginning we incorporated information from the TeX Catalogue into our database. In particular did we carry over the license information, version, CTAN directory, and date of last change of information in the Catalogue. ctan-page-asana-mathRecently (or not so recently, I actually don t know), CTAN has enriched their package view with more information, in particular a list of topics, and a list of related packages. Take for example the Asana-math package. It s CTAN page now displays besides the previously available information also a list of topics and a list of related packages. The topic index can also be browsed directly when searching for a specific package. I have now added functionality in the TeX Live Manager that tlmgr info also prints out the topic names and related packages. In the case of Asana Math fonts, that would look like: 
$ tlmgr info Asana-Math
package:     Asana-Math
category:    Package
shortdesc:   A font to typeset maths in Xe(La)TeX and Lua(La)TeX.
longdesc:    The Asana-Math font is an OpenType font that includes almost all mathematical Unicode symbols and it can be used to typeset mathematical text with any software that can understand the MATH OpenType table (e.g., XeTeX 0.997 and Microsoft Word 2007). The font is beta software. Typesetting support for use with LaTeX is provided by the fontspec and unicode-math packages.
installed:   Yes
revision:    37556
sizes:       doc: 9k, run: 1177k
relocatable: No
cat-version: 000.955
cat-date:    2015-06-02 20:04:19 +0200
cat-license: ofl
cat-topics:  font font-maths font-otf font-ttf
cat-related: stix xits
collection:  collection-fontsextra
GUIs could use the topic names and related packages to link directly to the CTAN page. At the moment the related packages are named according to CTAN standards, which are a bit different from what we use in TeX Live. I am not sure whether I will change that, or ship out both names. We will see.
The changes are currently in testing, see section about Test version here, and will be pushed out in due time, probably in the next week. As usual, in case of any problems or bugs, please contact us at the TeX Live mailing list. Enjoy.

Russell Coker: Smart Phones Should Measure Charge Speed

My first mobile phone lasted for days between charges. I never really found out how long it s battery would last because there was no way that I could use it to deplete the charge in any time that I could spend awake. Even if I had managed to run the battery out the phone was designed to accept 4*AA batteries (it s rechargeable battery pack was exactly that size) so I could buy spare batteries at any store. Modern phones are quite different in physical phone design (phones that weigh less than 4*AA batteries aren t uncommon), functionality (fast CPUs and big screens suck power), and use (games really drain your phone battery). This requires much more effective chargers, when some phones are intensively used (EG playing an action game with Wifi enabled) they can t be charged as they use more power than the plug-pack supplies. I ve previously blogged some calculations about resistance and thickness of wires for phone chargers [1], it s obvious that there are some technical limitations to phone charging based on the decision to use a long cable at ~5V. My calculations about phone charge rate were based on the theoretical resistance of wires based on their estimated cross-sectional area. One problem with such analysis is that it s difficult to determine how thick the insulation is without destroying the wire. Another problem is that after repeated use of a charging cable some conductors break due to excessive bending. This can significantly increase the resistance and therefore increase the charging time. Recently a charging cable that used to be really good suddenly became almost useless. My Galaxy Note 2 would claim that it was being charged even though the reported level of charge in the battery was not increasing, it seems that the cable only supplied enough power to keep the phone running not enough to actually charge the battery. I recently bought a USB current measurement device which is really useful. I have used it to diagnose power supplies and USB cables that didn t work correctly. But one significant way in which it fails is in the case of problems with the USB connector. Sometimes a cable performs differently when connected via the USB current measurement device. The CurrentWidget program [2] on my Galaxy Note 2 told me that all of the dedicated USB chargers (the 12V one in my car and all the mains powered ones) supply 1698mA (including the ones rated at 1A) while a PC USB port supplies ~400mA. I don t think that the Note 2 measurement is particularly reliable. On my Galaxy Note 3 it always says 0mA, I guess that feature isn t implemented. An old Galaxy S3 reports 999mA of charging even when the USB current measurement device says ~500mA. It seems to me that method the CurrentWidget uses to get the current isn t accurate if it even works at all. Android 5 on the Nexus 4/5 phones will tell the amount of time until the phone is charged in some situations (on the Nexus 4 and Nexus 5 that I used for testing it didn t always display it and I don t know why). This is an useful but it s still not good enough. I think that what we need is to have the phone measure the current that s being supplied and report it to the user. Then when a phone charges slowly because apps are using some power that won t be mistaken for a phone charging slowly due to a defective cable or connector.
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23 June 2015

Sandro Tosi: CFEngine: upgrade Debian packages

say you use CFEngine to install Debian packages on your server, so it's likely you'll have a bundle looking like this:

bundle agent agentname

vars:

 "packages" slist =>
"pkg1",
"pkg2",
"pkg3"
;

 packages:

 "$(packages)"
package_policy => "addupdate",
package_method => apt_get;

this works great to guarantee those packages are installed, but if a newer version is available in the repositories, that wont be installed. If you want CFEngine to do that too, then the web suggests this trick:

packages:

 "$(packages)"
package_policy => "addupdate",
package_version => "999999999",
package_method => apt_get;

which tweak the install system declaring that you want to install version 999999999 of each package, so if you have available a higher version than the one installed, CFEngine will happily upgrade it for you. It works great.. but sometimes it doesn't. why oh why?

That's because Debian versions can have a epoch: every plain version (like 1.0-1) has an implicit epoch of 0, and same goes for the 999999999 above, that means if any of the installed packages has an epoch, that version will sort higher than 999999999 and the package wont be upgraded. If you want to be sure to upgrade every package, then the right solution is:

packages:

 "$(packages)"
package_policy => "addupdate",
package_version => "9:999999999",
package_method => apt_get;

Bits from Debian: Reproducible Builds get funded by the Core Infrastructure Initiative

The Core Infrastructure Initiative announced today that they will support two Debian Developers, Holger Levsen and J r my Bobbio, with $200,000 to advance their Debian work in reproducible builds and to collaborate more closely with other distributions such as Fedora, Ubuntu, OpenWrt to benefit from this effort. The Core Infrastructure Initiative (CII) was established in 2014 to fortify the security of key open source projects. This initiative is funded by more than 20 companies and managed by The Linux Foundation. The reproducible builds initiative aims to enable anyone to reproduce bit by bit identical binary packages from a given source, thus enabling anyone to independently verify that a binary matches the source code from which it was said it was derived. For example, this allow the users of Debian to rebuild packages and obtain exactly identical packages to the ones provided by the Debian repositories.

Ben Armstrong: Debian Live Rescue needs some love

You may have noticed that Jessie no longer includes the useful rescue flavour of live image, formerly included in Wheezy and earlier releases, and neither will Stretch unless you take action. This is my second public call for help this year to revive it. So if you care about rescue, here s how you can help: If you have any questions not answered in this post, please feel free to leave a comment on this blog, talk to the Debian Live team on irc I m SynrG, and hang out with the team at #debian-live @ irc.oftc.net) or drop us an email at debian-live@lists.debian.org.

Russell Coker: One Android Phone Per Child

I was asked for advice on whether children should have access to smart phones, it s an issue that many people are discussing and seems worthy of a blog post. Claimed Problems with Smart Phones The first thing that I think people should read is this XKCD post with quotes about the demise of letter writing from 99+ years ago [1]. Given the lack of evidence cited by people who oppose phone use I think we should consider to what extent the current concerns about smart phone use are just reactions to changes in society. I ve done some web searching for reasons that people give for opposing smart phone use by kids and addressed the issues below. Some people claim that children shouldn t get a phone when they are so young that it will just be a toy. That s interesting given the dramatic increase in the amount of money spent on toys for children in recent times. It s particularly interesting when parents buy game consoles for their children but refuse mobile phone toys (I know someone who did this). I think this is more of a social issue regarding what is a suitable toy than any real objection to phones used as toys. Obviously the educational potential of a mobile phone is much greater than that of a game console. It s often claimed that kids should spend their time reading books instead of using phones. When visiting libraries I ve observed kids using phones to store lists of books that they want to read, this seems to discredit that theory. Also some libraries have Android and iOS apps for searching their catalogs. There are a variety of apps for reading eBooks, some of which have access to many free books but I don t expect many people to read novels on a phone. Cyber-bullying is the subject of a lot of anxiety in the media. At least with cyber-bullying there s an electronic trail, anyone who suspects that their child is being cyber-bullied can check that while old-fashioned bullying is more difficult to track down. Also while cyber-bullying can happen faster on smart phones the victim can also be harassed on a PC. I don t think that waiting to use a PC and learn what nasty thing people are saying about you is going to be much better than getting an instant notification on a smart phone. It seems to me that the main disadvantage of smart phones in regard to cyber-bullying is that it s easier for a child to participate in bullying if they have such a device. As most parents don t seem concerned that their child might be a bully (unfortunately many parents think it s a good thing) this doesn t seem like a logical objection. Fear of missing out (FOMO) is claimed to be a problem, apparently if a child has a phone then they will want to take it to bed with them and that would be a bad thing. But parents could have a policy about when phones may be used and insist that a phone not be taken into the bedroom. If it s impossible for a child to own a phone without taking it to bed then the parents are probably dealing with other problems. I m not convinced that a phone in bed is necessarily a bad thing anyway, a phone can be used as an alarm clock and instant-message notifications can be turned off at night. When I was young I used to wait until my parents were asleep before getting out of bed to use my PC, so if smart-phones were available when I was young it wouldn t have changed my night-time computer use. Some people complain that kids might use phones to play games too much or talk to their friends too much. What do people expect kids to do? In recent times the fear of abduction has led to children doing playing outside a lot less, it used to be that 6yos would play with other kids in their street and 9yos would be allowed to walk to the local park. Now people aren t allowing 14yo kids walk to the nearest park alone. Playing games and socialising with other kids has to be done over the Internet because kids aren t often allowed out of the house. Play and socialising are important learning experiences that have to happen online if they can t happen offline. Apps can be expensive. But it s optional to sign up for a credit card with the Google Play store and the range of free apps is really good. Also the default configuration of the app store is to require a password entry before every purchase. Finally it is possible to give kids pre-paid credit cards and let them pay for their own stuff, such pre-paid cards are sold at Australian post offices and I m sure that most first-world countries have similar facilities. Electronic communication is claimed to be somehow different and lesser than old-fashioned communication. I presume that people made the same claims about the telephone when it first became popular. The only real difference between email and posted letters is that email tends to be shorter because the reply time is smaller, you can reply to any questions in the same day not wait a week for a response so it makes sense to expect questions rather than covering all possibilities in the first email. If it s a good thing to have longer forms of communication then a smart phone with a big screen would be a better option than a feature phone , and if face to face communication is preferred then a smart phone with video-call access would be the way to go (better even than old fashioned telephony). Real Problems with Smart Phones The majority opinion among everyone who matters (parents, teachers, and police) seems to be that crime at school isn t important. Many crimes that would result in jail sentences if committed by adults receive either no punishment or something trivial (such as lunchtime detention) if committed by school kids. Introducing items that are both intrinsically valuable and which have personal value due to the data storage into a typical school environment is probably going to increase the amount of crime. The best options to deal with this problem are to prevent kids from taking phones to school or to home-school kids. Fixing the crime problem at typical schools isn t a viable option. Bills can potentially be unexpectedly large due to kids inability to restrain their usage and telcos deliberately making their plans tricky to profit from excess usage fees. The solution is to only use pre-paid plans, fortunately many companies offer good deals for pre-paid use. In Australia Aldi sells pre-paid credit in $15 increments that lasts a year [2]. So it s possible to pay $15 per year for a child s phone use, have them use Wifi for data access and pay from their own money if they make excessive calls. For older kids who need data access when they aren t at home or near their parents there are other pre-paid phone companies that offer good deals, I ve previously compared prices of telcos in Australia, some of those telcos should do [3]. It s expensive to buy phones. The solution to this is to not buy new phones for kids, give them an old phone that was used by an older relative or buy an old phone on ebay. Also let kids petition wealthy relatives for a phone as a birthday present. If grandparents want to buy the latest smart-phone for a 7yo then there s no reason to stop them IMHO (this isn t a hypothetical situation). Kids can be irresponsible and lose or break their phone. But the way kids learn to act responsibly is by practice. If they break a good phone and get a lesser phone as a replacement or have to keep using a broken phone then it s a learning experience. A friend s son head-butted his phone and cracked the screen he used it for 6 months after that, I think he learned from that experience. I think that kids should learn to be responsible with a phone several years before they are allowed to get a learner s permit to drive a car on public roads, which means that they should have their own phone when they are 12. I ve seen an article about a school finding that tablets didn t work as well as laptops which was touted as news. Laptops or desktop PCs obviously work best for typing. Tablets are for situations where a laptop isn t convenient and when the usage involves mostly reading/watching, I ve seen school kids using tablets on excursions which seems like a good use of them. Phones are even less suited to writing than tablets. This isn t a problem for phone use, you just need to use the right device for each task. Phones vs Tablets Some people think that a tablet is somehow different from a phone. I ve just read an article by a parent who proudly described their policy of buying feature phones for their children and tablets for them to do homework etc. Really a phone is just a smaller tablet, once you have decided to buy a tablet the choice to buy a smart phone is just about whether you want a smaller version of what you have already got. The iPad doesn t appear to be able to make phone calls (but it supports many different VOIP and video-conferencing apps) so that could technically be described as a difference. AFAIK all Android tablets that support 3G networking also support making and receiving phone calls if you have a SIM installed. It is awkward to use a tablet to make phone calls but most usage of a modern phone is as an ultra portable computer not as a telephone. The phone vs tablet issue doesn t seem to be about the capabilities of the device. It s about how portable the device should be and the image of the device. I think that if a tablet is good then a more portable computing device can only be better (at least when you need greater portability). Recently I ve been carrying a 10 tablet around a lot for work, sometimes a tablet will do for emergency work when a phone is too small and a laptop is too heavy. Even though tablets are thin and light it s still inconvenient to carry, the issue of size and weight is a greater problem for kids. 7 tablets are a lot smaller and lighter, but that s getting close to a 5 phone. Benefits of Smart Phones Using a smart phone is good for teaching children dexterity. It can also be used for teaching art in situations where more traditional art forms such as finger painting aren t possible (I have met a professional artist who has used a Samsung Galaxy Note phone for creating art work). There is a huge range of educational apps for smart phones. The Wikireader (that I reviewed 4 years ago) [4] has obvious educational benefits. But a phone with Internet access (either 3G or Wifi) gives Wikipedia access including all pictures and is a better fit for most pockets. There are lots of educational web sites and random web sites that can be used for education (Googling the answer to random questions). When it comes to preparing kids for the real world or the work environment people often claim that kids need to use Microsoft software because most companies do (regardless of the fact that most companies will be using radically different versions of MS software by the time current school kids graduate from university). In my typical work environment I m expected to be able to find the answer to all sorts of random work-related questions at any time and I think that many careers have similar expectations. Being able to quickly look things up on a phone is a real work skill, and a skill that s going to last a lot longer than knowing today s version of MS-Office. There are a variety of apps for tracking phones. There are non-creepy ways of using such apps for monitoring kids. Also with two-way monitoring kids will know when their parents are about to collect them from an event and can stay inside until their parents are in the area. This combined with the phone/SMS functionality that is available on feature-phones provides some benefits for child safety. iOS vs Android Rumour has it that iOS is better than Android for kids diagnosed with Low Functioning Autism. There are apparently apps that help non-verbal kids communicate with icons and for arranging schedules for kids who have difficulty with changes to plans. I don t know anyone who has a LFA child so I haven t had any reason to investigate such things. Anyone can visit an Apple store and a Samsung Experience store as they have phones and tablets you can use to test out the apps (at least the ones with free versions). As an aside the money the Australian government provides to assist Autistic children can be used to purchase a phone or tablet if a registered therapist signs a document declaring that it has a therapeutic benefit. I think that Android devices are generally better for educational purposes than iOS devices because Android is a less restrictive platform. On an Android device you can install apps downloaded from a web site or from a 3rd party app download service. Even if you stick to the Google Play store there s a wider range of apps to choose from because Google is apparently less restrictive. Android devices usually allow installation of a replacement OS. The Nexus devices are always unlocked and have a wide range of alternate OS images and the other commonly used devices can usually have an alternate OS installed. This allows kids who have the interest and technical skill to extensively customise their device and learn all about it s operation. iOS devices are designed to be sealed against the user. Admittedly there probably aren t many kids with the skill and desire to replace the OS on their phone, but I think it s good to have option. Android phones have a range of sizes and features while Apple only makes a few devices at any time and there s usually only a couple of different phones on sale. iPhones are also a lot smaller than most Android phones, according to my previous estimates of hand size the iPhone 5 would be a good tablet for a 3yo or good for side-grasp phone use for a 10yo [5]. The main benefits of a phone are for things other than making phone calls so generally the biggest phone that will fit in a pocket is the best choice. The tiny iPhones don t seem very suitable. Also buying one of each is a viable option. Conclusion I think that mobile phone ownership is good for almost all kids even from a very young age (there are many reports of kids learning to use phones and tablets before they learn to read). There are no real down-sides that I can find. I think that Android devices are generally a better option than iOS devices. But in the case of special needs kids there may be advantages to iOS.
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