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15 June 2016

Russ Allbery: Review: Matter

Review: Matter, by Iain M. Banks
Publisher: Orbit
Copyright: February 2008
ISBN: 0-316-00536-3
Format: Hardcover
Pages: 593
Sursamen is an Arithmetic, Mottled, Disputed, Multiply Inhabited, Multi-million Year Safe, and Godded Shellworld. It's a constructed world with multiple inhabitable levels, each lit by thermonuclear "suns" on tracks, each level supported above the last by giant pillars. Before the recorded history of the current Involved Species, a culture called the Veil created the shellworlds with still-obscure technology for some unknown purpose, and then disappeared. Now, they're inhabited by various transplants and watched over by a hierarchy of mentor and client species. In the case of Sursamen, both the Aultridia and the Oct claim jurisdiction (hence "Disputed"), and are forced into an uneasy truce by the Nariscene, a more sophisticated species that oversees them both. On Sursamen, on level eight to be precise, are the Sarl, a culture with an early industrial level of technology in the middle of a war of conquest to unite their level (and, they hope, the next level down). Their mentors are the Oct, who claim descendance from the mysterious Veil. The Deldeyn, the next level down, are mentored by the Aultridia, a species that evolved from a parasite on Xinthian Tensile Aranothaurs. Since a Xinthian, treated by the Sarl as a god, lives in the heart of Sursamen (hence "Godded"), tensions between the Sarl and the Aultridians run understandably high. The ruler of the Sarl had three sons and a daughter. The oldest was killed by the people he is conquering as Matter starts. The middle son is a womanizer and a fop who, as the book opens, watches a betrayal that he's entirely unprepared to deal with. The youngest is a thoughtful, bookish youth pressed into a position that he also is not well-prepared for. His daughter left the Sarl, and Sursamen itself, fifteen years previously. Now, she's a Special Circumstances agent for the Culture. Matter is the eighth Culture novel, although (like most of the series) there's little need to read the books in any particular order. The introduction to the Culture here is a bit scanty, so you'll have more background and understanding if you've read the previous novels, but it doesn't matter a great deal for the story. Sharp differences in technology levels have turned up in previous Culture novels (although the most notable example is a minor spoiler), but this is the first Culture novel I recall where those technological differences were given a structure. Usually, Culture novels have Special Circumstances meddling in, from their perspective, "inferior" cultures. But Sursamen is not in Culture space or directly the Culture's business. The Involved Species that governs Sursamen space is the Morthanveld: an aquatic species roughly on a technology level with the Culture themselves. The Nariscene are their client species; the Oct and Aultridia are, in turn, client species (well, mostly) of the Nariscene, while meddling with the Sarl and Deldeyn. That part of this book reminded me of Brin's Uplift universe. Banks's Involved Species aren't the obnoxious tyrants of Brin's universe, and mentoring doesn't involve the slavery of the Uplift universe. But some of the politics are a bit similar. And, as with Uplift, all the characters are aware, at least vaguely, of the larger shape of galactic politics. Even the Sarl, who themselves have no more than early industrial technology. When Ferbin flees the betrayal to try to get help, he ascends out of the shellworld to try to get assistance from an Involved species, or perhaps his sister (which turns out to be the same thing). Banks spends some time here, mostly through Ferbin and his servant (who is one of the better characters in this book), trying to imagine what it would be like to live in a society that just invented railroads while being aware of interstellar powers that can do practically anything. The plot, like the world on which it's set, proceeds on multiple levels. There is court intrigue within the Sarl, war on their level and the level below, and Ferbin's search for support and then justice. But the Sarl live in an artifact with some very mysterious places, including the best set piece in the book: an enormous waterfall that's gradually uncovering a lost city on the level below the Sarl, and an archaeological dig that proceeds under the Deldeyn and Sarl alike. Djan Seriy decides to return home when she learns of events in Sarl, originally for reasons of family loyalty and obligation, but she's a bit more in touch with the broader affairs of the galaxy, including the fact that the Oct are acting very strangely. There's something much greater at stake on Sursamen than tedious infighting between non-Involved cultures. As always with Banks, the set pieces and world building are amazing, the scenery is jaw-dropping, and I have some trouble warming to the characters. Dramatic flights across tower-studded landscapes seeking access to forbidden world-spanning towers largely, but don't entirely, make up for not caring about most of the characters for most of the book. This did change, though: although I never particularly warmed to Ferbin, I started to like his younger brother, and I really liked his sister and his servant by the end of the book. Unfortunately, the end of Matter is, if not awful, at least exceedingly abrupt. As is typical of Banks, we get a lot of sense of wonder but not much actual explanation, and the denouement is essentially nonexistent. (There is a coy epilogue hiding after the appendices, but it mostly annoyed me and provides only material for extrapolation about the characters.) Another SF author would have written a book about the Xinthian, the Veil, the purpose of the shellworlds, and the deep history of the galaxy. I should have known going in that Banks isn't that sort of SF author, but it was still frustrating. Still, Banks is an excellent writer and this is a meaty, complex, enjoyable story with some amazing moments of wonder and awe. If you like Culture novels in general, you will like this. If you like set-piece-heavy SF on a grand scale, such as Alastair Reynolds or Kim Stanley Robinson, you probably like this. Recommended. Rating: 8 out of 10

14 June 2016

Simon McVittie: GTK versioning and distributions

Allison Lortie has provoked a lot of comment with her blog post on a new proposal for how GTK is versioned. Here's some more context from the discussion at the GTK hackfest that prompted that proposal: there's actually quite a close analogy in how new Debian versions are developed. The problem we're trying to address here is the two sides of a trade-off: Historically, GTK has aimed to keep compatible within a major version, where major versions are rather far apart (GTK 1 in 1998, GTK 2 in 2002, GTK 3 in 2011, GTK 4 somewhere in the future). Meanwhile, fixing bugs, improving performance and introducing new features sometimes results in major changes behind the scenes. In an ideal world, these behind-the-scenes changes would never break applications; however, the world isn't ideal. (The Debian analogy here is that as much as we aspire to having the upgrade from one stable release to the next not break anything at all, I don't think we've ever achieved that in practice - we still ask users to read the release notes, even though ideally that wouldn't be necessary.) In particular, the perceived cost of doing a proper ABI break (a fully parallel-installable GTK 4) means there's a strong temptation to make changes that don't actually remove or change C symbols, but are clearly an ABI break, in the sense that an application that previously worked and was considered correct no longer works. A prominent recent example is the theming changes in GTK 3.20: the ABI in terms of functions available didn't change, but what happens when you call those functions changed in an incompatible way. This makes GTK hard to rely on for applications outside the GNOME release cycle, which is a problem that needs to be fixed (without stopping development from continuing). The goal of the plan we discussed today is to decouple the latest branch of development, which moves fast and sometimes breaks API, from the API-stable branches, which only get bug fixes. This model should look quite familiar to Debian contributors, because it's a lot like the way we release Debian and Ubuntu. In Debian, at any given time we have a development branch (testing/unstable) - currently "stretch", the future Debian 9. We also have some stable branches, of which the most recent are Debian 8 "jessie" and Debian 7 "wheezy". Different users of Debian have different trade-offs that lead them to choose one or the other of these. Users who value stability and want to avoid unexpected changes, even at a cost in terms of features and fixes for non-critical bugs, choose to use a stable release, preferably the most recent; they only need to change what they run on top of Debian for OS API changes (for instance webapps, local scripts, or the way they interact with the GUI) approximately every 2 years, or perhaps less often than that with the Debian-LTS project supporting non-current stable releases. Meanwhile, users who value the latest versions and are willing to work with a "moving target" as a result choose to use testing/unstable. The GTK analogy here is really quite close. In the new versioning model, library users who value stability over new things would prefer to use a stable-branch, ideally the latest; library users who want the latest features, the latest bug-fixes and the latest new bugs would use the branch that's the current focus of development. In practice we expect that the latter would be mostly GNOME projects. There's been some discussion at the hackfest about how often we'd have a new stable-branch: the fastest rate that's been considered is a stable-branch every 2 years, similar to Ubuntu LTS and Debian, but there's no consensus yet on whether they will be that frequent in practice. How many stable versions of GTK would end up shipped in Debian depends on how rapidly projects move from "old-stable" to "new-stable" upstream, how much those projects' Debian maintainers are willing to patch them to move between branches, and how many versions the release team will tolerate. Once we reach a steady state, I'd hope that we might have 1 or 2 stable-branched versions active at a time, packaged as separate parallel-installable source packages (a lot like how we handle Qt). GTK 2 might well stay around as an additional active version just from historical inertia. The stable versions are intended to be fully parallel-installable, just like the situation with GTK 1.2, GTK 2 and GTK 3 or with the major versions of Qt. For the "current development" version, I'd anticipate that we'd probably only ship one source package, and do ABI transitions for one version active at a time, a lot like how we deal with libgnome-desktop and the evolution-data-server family of libraries. Those versions would have parallel-installable runtime libraries but non-parallel-installable development files, again similar to libgnome-desktop. At the risk of stretching the Debian/Ubuntu analogy too far, the intermediate "current development" GTK releases that would accompany a GNOME release are like Ubuntu's non-LTS suites: they're more up to date than the fully stable releases (Ubuntu LTS, which has a release schedule similar to Debian stable), but less stable and not supported for as long. Hopefully this plan can meet both of its goals: minimize breakage for applications, while not holding back the development of new APIs.

13 June 2016

Satyam Zode: GSoC 2016 Week 2 and 3: Reproducible Builds in Debian

This is report on my previous week activities with Debian Reproducible-Builds. In last 10 days, I had build different Debain packages at my own using prebuilder to experience the reproducibility issues. I am thankful to deki and Lunar for suggesting me to do that task. Based on this experience, I managed to find more use cases for hide=profiles specification. I also researched differences of different unreproducible Debian packages on http://tests.reproducible-builds.org . There are many packages available for examination. In brief I did following tasks: Upcoming week will be an important as well as fun week because I will be implementing the use cases. Right now, I am currently looking at different softwares which ignores stuff and taking notes of it. So that, it will help me during implementing solution of use cases. I am also looking forward to feedback from community on use cases and CLI interfaces. Have a great week :)

Raphaël Hertzog: Freexian s report about Debian Long Term Support, May 2016

A Debian LTS logoLike each month, here comes a report about the work of paid contributors to Debian LTS. Individual reports In May, 166 work hours have been dispatched among 9 paid contributors. Their reports are available: Evolution of the situation The number of sponsored hours stayed the same over May but will likely increase a little bit the next month as we have two new Bronze sponsors being processed. The security tracker currently lists 36 packages with a known CVE and the dla-needed.txt file lists 36 packages awaiting an update. Despite the higher than usual number of work hours dispatched in May, we still have more open CVE than we used to have at the end of the squeeze LTS period. So more support is always needed Thanks to our sponsors New sponsors are in bold.

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Keerthana Krishnan: A beginner s guide to Debian Source Packages

Source packages have a very different process of installation and handling while compared to the traditional executable packages which are handled by the sudo apt-get install command. Source packages provide source for a software. These are used to build other packages. Source code can be studied or errors can be fixed in this by downloading these to your system. To access these you have to add deb-src lines sources.list in /etc/apt/sources.list If you had followed my earlier article on setting up Jessie, this means you have to remove the # in front of the deb-src lines. First, find the required source package online in the debian packages list here. Be sure to select the Source Package Names option while searching. When you find a package it will have a list of binary packages that are built from this source package. Make sure you have all the dependencies to build the package by running:
     $ apt-get build-dep packagename
Then, download the source package, using the following command:
     $ apt-get source packagename
This will download three files: a .orig.tar.gz, a .dsc and a .diff.gz. In the case of packages made specifically for Debian, the last of these is not downloaded and the first usually won t have orig in the name. The .dsc file is used by dpkg-source for unpacking the source package into the directory packagename-version. Within each downloaded source package there is a debian/ directory that contains the files needed for creating the .deb package. To auto-build the package when it s been downloaded, just add -b to the command line, like this:
     $ apt-get -b source packagename
If you decide not to create the .deb at the time of the download, you can create it later by running:
     $ dpkg-buildpackage -rfakeroot -uc -b
from within the directory that was created for the package after downloading. To install the package built by the commands above one must use the package manager directly, like this:
     # dpkg -i file.deb
There s a difference between apt-get s source method and its other methods. The source method can be used by normal users, without needing special root powers. The files are downloaded to the directory from which the apt-get source package command was called. Tip : If you are a developer testing software, you may need to run the make command after this. Be sure to run make check as well later to make sure there are no errors and everything is alright. Most of the commands I ve used here was by following the APT How To documentation which is marked as obsolete for some reason but turned out to be pretty useful. Hope it works for you too!

12 June 2016

Iustin Pop: Elsa Bike Trophy 2016 my first bike race!

Elsa Bike Trophy 2016 my first bike race! So today, after two months of intermittent training using Zwift and some actual outside rides, I did my first bike race. Not of 2016, not of 2000+, but like ever. Which is strange, as I learned biking very young, and I did like to bike. But as it turned out, even though I didn't like running as a child, I did participate in a number of running events over the years, but no biking ones. The event Elsa Bike Trophy is a mountain bike event cross-country, not downhill or anything crazy; it takes part in Estavayer-le-Lac, and has two courses - one 60Km with 1'791m altitude gain, and a smaller one of 30Km with 845m altitude gain. I went, of course, for the latter. 845m is more than I ever did in a single ride, so it was good enough for a first try. The web page says that this smaller course est nerveux, technique et ne laisse que peu de r pit . I choose to think that's a bit of an exaggeration, and that it will be relatively easy (as I'm not too skilled technically). The atmosphere there was like for the running races, with the exception of bike stuff being sold, and people on very noisy rollers. I'm glad for my trainer which sounds many decibels quieter The long race started at 12:00, and the shorter one at 12:20. While waiting for the start I had to concerns in mind: whether I'm able to do the whole course (endurance), and whether it will be too cold (the weather kept moving towards rain). I had a small concern about the state of the course, as it was not very nice weather recently, but a small one. And then, after one hour plus of waiting, go! Racing, with a bit of "swimming" At first thing went as expected. Starting on paved roads, moving towards the small town exit, a couple of 14% climbs, then more flat roads, then a nice and hard 18% short climb (I'll never again complain about < 10%!), then entering the woods. It became quickly apparent that the ground in the forest was in much worse state than I feared. Much worse as in a few orders of magnitude. In about 5 minutes after entering the tree cover, my reasonably clean, reasonably light bike became a muddy, heavy monster. And the pace that until then went quite OK became walking pace, as the first rider that didn't manage to keep going up because the wheel turned out of the track blocked the one behind him, which had to stop, and repeat until we were one line (or two, depending on how wide the trail was) of riders walking their bikes up. While on dry ground walking your bike up is no problem, or hiking through mud with good hiking shoes is also no problem, walking up with biking shoes is a pain. Your foot slides and you waste half of your energy "swimming" in the mud. Once the climb is over, you get on the bike, and of course the pedals and cleats are full of heavy mud, so it takes a while until you can actually clip in. Here the trail version of SPD was really useful, as I could pedal reasonably well without being clipped-in, just had to be careful and push too hard. Then maybe you exit the trail and get on paved road, but the wheels are so full of mud that you still are very slow (and accelerate very slowly), until the shed enough of the mud to become somewhat more "normal". After a bit of this "up through mud, flat and shedding mud", I came upon the first real downhill section. I would have been somewhat confident in dry ground, but I got scared and got off my bike. Better safe than sorry was the thing for now. And after this is was a repetition of the above: climb, sometimes (rarely) on the bike, most times pushing the bike, fast flat sections through muddy terrain where any mistake of controlling the bike can send the front wheel flying due to the mud being highly viscous, slow flat sections through very liquid mud where it definitely felt like swimming, or any dry sections. My biggest fear, uphill/endurance, was unfounded. The most gains I made were on the dry uphills, where I had enough stamina to overtake. On flat ground I mostly kept order (i.e. neither being overtaken nor overtaking), but on downhill sections, I lost lots of time, and was overtaken a lot. Still, it was a good run. And then, after about 20 kilometres out of the 30, I got tired enough of getting off the bike, on the bike, and also tired mentally and not being careful enough, that I stopped getting off the bike on downhills. And the feeling was awesome! It was actually much much easier to flow through the mud and rocks and roots on downhill, even when it was difficult (for me) like 40cm drops (estimated), than doing it on foot, where you slide without control and the bike can come crashing down on you. It was a liberating feel, like finally having overcome the mud. I was soo glad to have done a one-day training course with Swiss Alpine Adventure, as it really helped. Thanks Dave! Of course, people were still overtaking me, but I also overtook some people (who were on foot; he he, I wasn't the only one it seems). And being easier, I had some more energy so I was able to push a bit harder on the flats and dry uphill sections. And then the remaining distance started shrinking, and the last downhill was over, I entered through familiar roads the small town, a passer-by cries "one kilometre left", I push hard (I mean, hard as I could after all the effort), and I reach the finish. Oh, and my other concern, the rain? Yes it did rain somewhat, and I was glad for it (I keep overheating); there was a single moment I felt cold, when exiting a nice cosy forest into a field where the wind was very strong headwind, of course. Lessons learned I did learn a lot in this first event. Results So, how did I do after all? As soon as I reached the finish and recovered my items, among which the phone, I checked the datasport page: I was rank 59/68 in my category. Damn, I hoped (and thought) I would do better. Similar % in the overall ranking for this distance. That aside, it was mighty fun. So much fun I'd do it again tomorrow! I forgot the awesome atmosphere of such events, even in the back of the rankings. And then, after I reach drive home and open on my workstation the datasport page, I get very confused: the overall number of participants was different. And the I realised: not everybody finished the race when I first checked (d'oh)! Final ranking: 59 out of 84 in my category, and 247/364 in the overall 30km rankings. That makes it 70% and 67% respectively, which matches somewhat with my usual running results a few years back (but a bit worse). It is in any case better than what I thought originally, yay! Also, Strava activity for some more statistics (note that my Garmin says it was not 800+ meters of altitude ): I'd embed a Veloviewer nice 3D-map but I can't seem to get the embed option, hmm TODO: train more endurance, train more technique, train in more various conditions!

Sune Vuorela: Randa day 0

Sitting on Lake Zurich and reflecting over things was a great way to get started. http://manifesta.org/2015/11/pavillon-of-reflections-for-zurich-in-2016/ After spending a bit of time in a train, I climbed part of a mountain together with Adriaan up to the snow where I could throw a snowball at him. We also designed a couple of new frameworks on our climbing trip. Maybe they will be presented later.

Mario Lang: A Raspberry Pi Zero in a Handy Tech Active Star 40 Braille Display

TL;DR: I put a $5 Raspberry Pi Zero, a Bluetooth USB dongle, and the required adapter cable into my new Handy Tech Active Star 40 braille display. An internal USB port provides the power. This has transformed my braille display into an ARM-based, monitorless, Linux laptop that has a keyboard and a braille display. It can be charged/powered via USB so it can also be run from a power bank or a solar charger, thus potentially being able to run for days, rather than just hours, without needing a standard wall-jack. [picture: a Raspberry Pi Zero embedded within an Active Star 40] [picture: a braille display with a keyboard on top and a Raspberry Pi Zero inside]
Some Background on Braille Display Form Factors Braille displays come in various sizes. There are models tailored for desktop use (with 60 cells or more), models tailored for portable use with a laptop (usually with 40 cells), and, nowadays, there are even models tailored for on-the-go use with a smartphone or similar (with something like 14 or 18 cells). Back in the old days, braille displays were rather massive. A 40-cell braille display was typically about the size of a 13" laptop. In modern times, manufacturers have managed to reduce the size of the internals such that a 40-cell display can be placed in front of a laptop or keyboard instead of placing the laptop on top of the braille display. While this is a nice achievement, I personally haven't found it to be very convenient because you now have to place two physically separate devices on your lap. It's OK if you have a real desk, but, at least in my opinion, if you try to use your laptop as its name suggests, it's actually inconvenient to use a small form factor, 40-cell display. For this reason, I've been waiting for a long-promised new model in the Handy Tech Star series. In 2002, they released the Handy Tech Braille Star 40, which is a 40-cell braille display with enough space to put a laptop directly on top of it. To accommodate larger laptop models, they even built in a little platform at the back that can be pulled out to effectively enlarge the top surface. Handy Tech has now released a new model, the Active Star 40, that has essentially the same layout but modernized internals. [picture: a plain Active Star 40] You can still pull out the little platform to increase the space that can be used to put something on top. [picture: an Active Star 40 with extended platform and a laptop on top] But, most conveniently, they've designed in an empty compartment, roughly the size of a modern smartphone, beneath the platform. The original idea was to actually put a smartphone inside, but this has turned out (at least to me) to not be very feasible. Fortunately, they thought about the need for electricity and added a Micro USB cable terminating within the newly created, empty compartment. My first idea was to put a conventional Raspberry Pi inside. When I received the braille display, however, we immediately noticed that a standard-sized rpi is roughly 3mm too high to fit into the empty compartment. Fortunately, though, a co-worker noticed that the Raspberry Pi Zero was available for order. The Raspberry Pi Zero is a lot thinner, and fits perfectly inside (actually, I think there's enough space for two, or even three, of them). So we ordered one, along with some accessories like a 64GB SDHC card, a Bluetooth dongle, and a Micro USB adapter cable. The hardware arrived a few days later, and was immediately bootstrapped with the assistance of very helpful friends. It works like a charm!
Technical Details The backside of the Handy Tech Active Star 40 features two USB host ports that can be used to connect devices such as a keyboard. A small form-factor, USB keyboard with a magnetic clip-on is included. When a USB keyboard is connected, and when the display is used via Bluetooth, the braille display firmware additionally offers the Bluetooth HID profile, and key press/release events received via the USB port are passed through to it. I use the Bluetooth dongle for all my communication needs. Most importantly, BRLTTY is used as a console screen reader. It talks to the braille display via Bluetooth (more precisely, via an RFCOMM channel). The keyboard connects through to Linux via the Bluetooth HID profile. Now, all that is left is network connectivity. To keep the energy consumption as low as possible, I decided to go for Bluetooth PAN. It appears that the tethering mode of my mobile phone works (albeit with a quirk), so I can actually access the internet as long as I have cell phone reception. Additionally, I configured a Bluetooth PAN access point on my desktop machines at home and at work, so I can easily (and somewhat more reliably) get IP connectivity for the rpi when I'm near one of these machines. I plan to configure a classic Raspberry Pi as a mobile Bluetooth access point. It would essentially function as a Bluetooth to ethernet adapter, and should allow me to have network connectivity in places where I don't want to use my phone.
BlueZ 5 and PAN It was a bit challenging to figure out how to actually configure Bluetooth PAN with BlueZ 5. I found the bt-pan python script (see below) to be the only way so far to configure PAN without a GUI. It handles both ends of a PAN network, configuring a server and a client. Once instructed to do so (via D-Bus) in client mode, BlueZ will create a new network device - bnep0 - once a connection to a server has been established. Typically, DHCP is used to assign IP addresses for these interfaces. In server mode, BlueZ needs to know the name of a bridge device to which it can add a slave device for each incoming client connection. Configuring an address for the bridge device, as well as running a DHCP server + IP Masquerading on the bridge, is usually all you need to do.
A Bluetooth PAN Access Point with Systemd I'm using systemd-networkd to configure the bridge device. /etc/systemd/network/pan.netdev:
[NetDev]
Name=pan
Kind=bridge
ForwardDelaySec=0
/etc/systemd/network/pan.network:
[Match]
Name=pan
[Network]
Address=0.0.0.0/24
DHCPServer=yes
IPMasquerade=yes
Now, BlueZ needs to be told to configure a NAP profile. To my surprise, there seems to be no way to do this with stock BlueZ 5.36 utilities. Please correct me if I'm wrong. Luckily, I found a very nice blog post, as well as an accommodating Python script that performs the required D-Bus calls. For convenience, I use a Systemd service to invoke the script and to ensure that its dependencies are met. /etc/systemd/system/pan.service:
[Unit]
Description=Bluetooth Personal Area Network
After=bluetooth.service systemd-networkd.service
Requires=systemd-networkd.service
PartOf=bluetooth.service
[Service]
Type=notify
ExecStart=/usr/local/sbin/pan
[Install]
WantedBy=bluetooth.target
/usr/local/sbin/pan:
#!/bin/sh
# Ugly hack to work around #787480
iptables -F
iptables -t nat -F
iptables -t mangle -F
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
exec /usr/local/sbin/bt-pan --systemd --debug server pan
This last file wouldn't be necessary if IPMasquerade= were supported in Debian right now (see #787480). After the obligatory systemctl daemon-reload and systemctl restart systemd-networkd, you can start your Bluetooth Personal Area Network with systemctl start pan.
Bluetooth PAN Client with Systemd Configuring the client is also quite easy to do with Systemd. /etc/systemd/network/pan-client.network:
[Match]
Name=bnep*
[Network]
DHCP=yes
/etc/systemd/system/pan@.service:
[Unit]
Description=Bluetooth Personal Area Network client
[Service]
Type=notify
ExecStart=/usr/local/sbin/bt-pan --debug --systemd client %I --wait
Now, after the usual configuration reloading, you should be able to connect to a specific Bluetooth access point with:
systemctl start pan@00:11:22:33:44:55
Pairing via the Command Line Of course, the server and client-side service configuration require a pre-existing pairing between the server and each of its clients. On the server, start bluetoothctl and issue the following commands:
power on
agent on
default-agent
scan on
scan off
pair XX:XX:XX:XX:XX:XX
trust XX:XX:XX:XX:XX:XX
Once you've set scan mode to on, wait a few seconds until you see the device you're looking for scroll by. Note its device address, and use it for the pair and (optional) trust commands. On the client, the sequence is essentially the same except that you don't need to issue the trust command. The server needs to trust a client in order to accept NAP profile connections from it without waiting for manual confirmation by the user. I'm actually not sure if this is the optimal sequence of commands. It might be enough to just pair the client with the server and issue the trust command on the server, but I haven't tried this yet.
Enabling Use of the Bluetooth HID Profile Essentially the same as above also needs to be done in order to use the Bluetooth HID profile of the Active Star 40 on Linux. However, instead of agent on, you need to issue the command agent KeyboardOnly. This explicitly tells bluetoothctl that you're specifically looking for a HID profile.
Configuring Bluetooth via the Command Line Feels Vague While I'm very happy that I actually managed to set all of this up, I must admit that the command-line interface to BlueZ feels a bit incomplete and confusing. I initially thought that agents were only for PIN code entry. Now that I've discovered that "agent KeyboardOnly" is used to enable the HID profile, I'm not sure anymore. I'm surprised that I needed to grab a script from a random git repository in order to be able to set up PAN. I remember, with earlier version of BlueZ, that there was a tool called pand that you could use to do all of this from the command-line. I don't seem to see anything like that for BlueZ 5 anymore. Maybe I'm missing something obvious?
Performance The data rate is roughly 120kB/s, which I consider acceptable for such a low power solution. The 1GHz ARM CPU actually feels sufficiently fast for a console/text-mode person like me. I'll rarely be using much more than ssh and emacs on it anyway.
Console fonts and screen dimensions The default dimensions of the framebuffer on the Raspberry Pi Zero are a bit unexpectedly strange. fbset reports that the screen dimension is 656x416 pixels (of course, no monitor connected). With a typical console font of 8x16, I got 82 columns and 26 lines. With a 40 cell braille display, the 82 columns are very inconvenient. Additionally, as a braille user, I would like to be able to view Unicode braille characters in addition to the normal charset on the console. Fortunately, Linux supports 512 glyphs, while most console fonts do only provide 256. console-setup can load and combine two 256-glyph fonts at once. So I added the following to /etc/default/console-setup to make the text console a lot more friendly to braille users:
SCREEN_WIDTH=80
SCREEN_HEIGHT=25
FONT="Lat15-Terminus16.psf.gz brl-16x8.psf"

Note

You need console-braille installed for brl-16x8.psf to be available.

Further Projects There's a 3.5mm audio jack inside the braille display as well. Unfortunately, there are no converters from Mini-HDMI to 3.5mm audio that I know of. It would be very nice to be able to use the sound card that is already built into the Raspberry Pi Zero, but, unfortunately, this doesn't seem possible at the moment. Alternatively, I'm looking at using a Micro USB OTG hub and an additional USB audio adapter to get sound from the Raspberry Pi Zero to the braille display's speakers. Unfortunately, the two USB audio adapters I've tried so far have run hot for some unknown reason. So I have to find some other chipset to see if the problem goes away. A little nuisance, currently, is that you need to manually power off the Raspberry, wait a few seconds, and then power down the braille display. Turning the braille display off cuts power delivery via the internal USB port. If this is accidentally done too soon then the Raspberry Pi Zero is shut down ungracefully (which is probably not the best way to do it). We're looking into connecting a small, buffering battery to the GPIO pins of the rpi, and into notifying the rpi when external power has dropped. A graceful, software-initiated shutdown can then be performed. You can think of it as being like a mini UPS for Micro USB.
The image If you are a happy owner of a Handy Tech Active Star 40 and would like to do something similar, I am happy to share my current (Raspbian Stretch based) image. In fact, if there is enough interest by other blind users, we might even consider putting a kit together that makes it as easy as possible for you to get started. Let me know if this could be of interest to you.
Thanks Thanks to Dave Mielke for reviewing the text of this posting. Thanks to Simon Kainz for making the photos for this article. And I owe a big thank you to my co-workers at Graz University of Technology who have helped me a lot to bootstrap really quickly into the rpi world.
P.S. My first tweet about this topic is just five days ago, and apart from the soundcard not working yet, I feel like the project is already almost complete! By the way, I am editing the final version of this blog posting from my newly created monitorless ARM-based Linux laptop via an ssh connection to my home machine.

11 June 2016

Francois Marier: Cleaning up obsolete config files on Debian and Ubuntu

As part of regular operating system hygiene, I run a cron job which updates package metadata and looks for obsolete packages and configuration files. While there is already some easily available information on how to purge unneeded or obsolete packages and how to clean up config files properly in maintainer scripts, the guidance on how to delete obsolete config files is not easy to find and somewhat incomplete. These are the obsolete conffiles I started with:
$ dpkg-query -W -f='$ Conffiles \n'   grep 'obsolete$'
 /etc/apparmor.d/abstractions/evince ae2a1e8cf5a7577239e89435a6ceb469 obsolete
 /etc/apparmor.d/tunables/ntpd 5519e4c01535818cb26f2ef9e527f191 obsolete
 /etc/apparmor.d/usr.bin.evince 08a12a7e468e1a70a86555e0070a7167 obsolete
 /etc/apparmor.d/usr.sbin.ntpd a00aa055d1a5feff414bacc89b8c9f6e obsolete
 /etc/bash_completion.d/initramfs-tools 7eeb7184772f3658e7cf446945c096b1 obsolete
 /etc/bash_completion.d/insserv 32975fe14795d6fce1408d5fd22747fd obsolete
 /etc/dbus-1/system.d/com.redhat.NewPrinterNotification.conf 8df3896101328880517f530c11fff877 obsolete
 /etc/dbus-1/system.d/com.redhat.PrinterDriversInstaller.conf d81013f5bfeece9858706aed938e16bb obsolete
To get rid of the /etc/bash_completion.d/ files, I first determined what packages they were registered to:
$ dpkg -S /etc/bash_completion.d/initramfs-tools
initramfs-tools: /etc/bash_completion.d/initramfs-tools
$ dpkg -S /etc/bash_completion.d/insserv
initramfs-tools: /etc/bash_completion.d/insserv
and then followed Paul Wise's instructions:
$ rm /etc/bash_completion.d/initramfs-tools /etc/bash_completion.d/insserv
$ apt install --reinstall initramfs-tools insserv
For some reason that didn't work for the /etc/dbus-1/system.d/ files and I had to purge and reinstall the relevant package:
$ dpkg -S /etc/dbus-1/system.d/com.redhat.NewPrinterNotification.conf
system-config-printer-common: /etc/dbus-1/system.d/com.redhat.NewPrinterNotification.conf
$ dpkg -S /etc/dbus-1/system.d/com.redhat.PrinterDriversInstaller.conf
system-config-printer-common: /etc/dbus-1/system.d/com.redhat.PrinterDriversInstaller.conf
$ apt purge system-config-printer-common
$ apt install system-config-printer
The files in /etc/apparmor.d/ were even more complicated to deal with because purging the packages that they come from didn't help:
$ dpkg -S /etc/apparmor.d/abstractions/evince
evince: /etc/apparmor.d/abstractions/evince
$ apt purge evince
$ dpkg-query -W -f='$ Conffiles \n'   grep 'obsolete$'
 /etc/apparmor.d/abstractions/evince ae2a1e8cf5a7577239e89435a6ceb469 obsolete
 /etc/apparmor.d/usr.bin.evince 08a12a7e468e1a70a86555e0070a7167 obsolete
I was however able to get rid of them by also purging the apparmor profile packages that are installed on my machine:
$ apt purge apparmor-profiles apparmor-profiles-extra evince ntp
$ apt install apparmor-profiles apparmor-profiles-extra evince ntp
Not sure why I had to do this but I suspect that these files used to be shipped by one of the apparmor packages and then eventually migrated to the evince and ntp packages directly and dpkg got confused. If you're in a similar circumstance, you want want to search for the file you're trying to get rid of on Google and then you might end up on http://apt-browse.org/ which could lead you to the old package that used to own this file.

Shirish Agarwal: The road to debconf 2016, tourism and arts.

A longish blog post, please bear, a second part of the blog post would be published in few days from now. My fixed visa finally arrived, yeah:) But this story doesn t start here, it starts about a year back. While I have been contributing to Debian in my free time over the years, and sometimes paid time as well, I had never thought of going overseas as the experiences I knew from friends and relatives, it isn t easy to get all the permissions and paperwork done to say the least (bureaucracy @ work). But last year, when Debconf 15 was being launched, there are/were 2-3 friends of mine who are studying, doing their Ph.D. in some computer/web stuff, living in Germany currently that they goaded me to apply. The first few times I gave some standard excuses, but when they kept on for a while, just to shut them up I applied to the debconf team applying for food, accommodation and travel sponsorship. I didn t have high hopes as there obviously are many more talented peers around me who understand FOSS and Debian at a much more fundamental, philosophical as well as technical level than me. Much to my surprise though, about a month (and around two or three weeks just before the event was about to take place) I got the bursary/sponsorships for food, accommodation as well as travel. I was unsure that the remaining time was enough to get a visa hence declined that time around. That whole episode gave me the confidence that perhaps my application would be accepted if I applied again. Using my previous years understanding, decided to give it a shot again as this would also enable me to get a feel of visa bureaucracy as well as gain a bit of novice understanding about what factors go in choosing a flight and believe me the latter part proved to be pretty confusing. While the visa business seems easy, the form at least is easy and what they ask, it can be troublesome as far as visa-processing process is concerned. It took a better part of the month to get the visa which I needed. The in-between time is and can be a bit stressful as you have committed funds for travel i.e. the airline tickets and are in a limbo as you didn t know that if the visa is cancelled for some reason, your tickets would be refunded or not. A little history is needed and hopefully is helpful for anybody who s applying for a short-stay Visa in South Africa. Exactly, A month and day back I had applied for visa. The visa I had applied for is 17 days as the flights within my budget was for those days only. The visa I got was for 10 days only which was ending in the middle of the conference. I tried many avenues to get information and was told that I needed to write a correction letter telling/sharing the information about the correct time period and dates in BOLD with a heavier weight/point which is what I did and gave to VFS office without any further payment on my part. It took a bit more time than the first time around but the consulate co-operated. While I can understand the oversight as they probably get more visas requests along with special and urgent requests so such occurrences can happen. I am and was happy that there was a recourse rather than starting from scratch which probably would have made me more anxious due to the first experience . Apparently I was lucky that I had done with Qatar Airways as later came to know that there are other airways which don t refund money even after visa rejection . This information I got to know pretty late in the game otherwise I wouldn t have been much stressed. As had committed knew had to go the whole hog and whatever barriers are there, have overcome at least as far as the visa part/process is concerned. Now after few days, will probably start to worry about the actual travel, part nervousness, part excitement, nervousness as it will be an alien land, am obese so traveling economy on 787-8 and 777-300 ER will be tricky. The 787-8 will probably be a rough ride as it s a 9 hr. journey and the seat are a mere 18 , the cattle class as shared by one of our esteemed politicians. This blame has to do with Boeing 787 rather than anybody else. Hopefully, if there is a next time, would make better choices. Anyways,have selected an aisle seat so that will be able to walk every hr. or so to get the circulation in legs going as leg room in economy is not much from my domestic air travel experiences. If I do survive the travel, then will see South Africa and try to get some free time and explore South Africa and try to figure out how are they able to get one and half time tourists while we get around half figure for a whole year even though we are bigger (area-wise) to South Africa. I did find something positive for us as well, it s not all doldrums all around. Now, I had been thinking about if I know any South African music and movies. I had explored djembe while growing up in teens but other than that, not much. The only music I have heard is Harry Belafonte . So I hope to bring some Indian movies and music with me so that people if they have not explored Bollywood as well as Indian classical music could explore some of it, of course it will be pale imitation of what Sawai Gandharva Music Festival for instance gives. I also hope to hear and get some music and movies to learn more about South Africa.
Filed under: Miscellenous Tagged: #bollywood, #Debconf Germany 2015, #Debconf South Africa 2016, #Debconf15, #Debconf16, #djembe, #South-African consulate, music, tourism, visa

Paul Tagliamonte: It's all relative

As nearly anyone who's worked with me will attest to, I've long since touted nedbat's talk Pragmatic Unicode, or, How do I stop the pain? as one of the most foundational talks, and required watching for all programmers. The reason is because netbat hits on something bigger - something more fundamental than how to handle Unicode -- it's how to handle data which is relative. For those who want the TL;DR, the argument is as follows: Facts of Life:
  1. Computers work with Bytes. Bytes go in, Bytes go out.
  2. The world needs more than 256 symbols.
  3. You need both Bytes and Unicode
  4. You cannot infer the encoding of bytes.
  5. Declared encodings can be Wrong
Now, to fix it, the following protips:
  1. Unicode sandwich
  2. Know what you have
  3. TEST
Relative Data I've started to think more about why we do the things we do when we write code, and one thing that continues to be a source of morbid schadenfreude is watching code break by failing to handle Unicode right. It's hard! However, watching what breaks lets you gain a bit of insight into how the author thinks, and what assumptions they make. When you send someone Unicode, there are a lot of assumptions that have to be made. Your computer has to trust what you (yes, you!) entered into your web browser, your web browser has to pass that on over the network (most of the time without encoding information), to a server which reads that bytestream, and makes a wild guess at what it should be. That server might save it to a database, and interpolate it into an HTML template in a different encoding (called Mojibake), resulting in a bad time for everyone involved. Everything's awful, and the fact our computers can continue to display text to us is a goddamn miracle. Never forget that. When it comes down to it, when I see a byte sitting on a page, I don't know (and can't know!) if it's Windows-1252, UTF-8, Latin-1, or EBCDIC. What's a poem to me is terminal garbage to you. Over the years, hacks have evolved. We have magic numbers, and plain ole' hacks to just guess based on the content. Of course, like all good computer programs, this has lead to its fair share of hilarious bugs, and there's nothing stopping files from (validly!) being multiple things at the same time. Like many things, it's all in the eye of the beholder. Timezones Just like Unicode, this is a word that can put your friendly neighborhood programmer into a series of profanity laden tirades. Go find one in the wild, and ask them about what they think about timezone handling bugs they've seen. I'll wait. Go ahead. Rants are funny things. They're fun to watch. Hilarious to give. Sometimes just getting it all out can help. They can tell you a lot about the true nature of problems. It's funny to consider the isomorphic nature of Unicode rants and Timezone rants. I don't think this is an accident. U n i c o d e timezone Sandwich Ned's Unicode Sandwich applies -- As early as we can, in the lowest level we can (reading from the database, filesystem, wherever!), all datetimes must be timezone qualified with their correct timezone. Always. If you mean UTC, say it's in UTC. Treat any unqualified datetimes as "bytes". They're not to be trusted. Never, never, never trust 'em. Don't process any datetimes until you're sure they're in the right timezone. This lets the delicious inside of your datetime sandwich handle timezones with grace, and finally, as late as you can, turn it back into bytes (if at all!). Treat locations as tzdb entries, and qualify datetime objects into their absolute timezone (EST, EDT, PST, PDT) It's not until you want to show the datetime to the user again should you consider how to re-encode your datetime to bytes. You should think about what flavor of bytes, what encoding -- what timezone -- should I be encoding into? TEST Just like Unicode, testing that your code works with datetimes is important. Every time I think about how to go about doing this, I think about that one time that mjg59 couldn't book a flight starting Tuesday from AKL, landing in HNL on Monday night, because United couldn't book the last leg to SFO. Do you ever assume dates only go forward as time goes on? Remember timezones. Construct test data, make sure someone in New Zealand's +13:45 can correctly talk with their friends in Baker Island's -12:00, and that the events sort right. Just because it's Noon on New Years Eve in England doesn't mean it's not 1 AM the next year in New Zealand. Places a few miles apart may go on Daylight savings different days. Indian Standard Time is not even aligned on the hour to GMT (+05:30)! Test early, and test often. Memorize a few timezones, and challenge your assumptions when writing code that has to do with time. Don't use wall clocks to mean monotonic time. Remember there's a whole world out there, and we only deal with part of it. It's also worth remembering, as Andrew Pendleton pointed out to me, that it's possible that a datetime isn't even unique for a place, since you can never know if 2016-11-06 01:00:00 in America/New_York (in the tzdb) is the first one, or second one. Storing EST or EDT along with your datetime may help, though! Pitfalls Improper handling of timezones can lead to some interesting things, and failing to be explicit (or at least, very rigid) in what you expect will lead to an unholy class of bugs we've all come to hate. At best, you have confused users doing math, at worst, someone misses a critical event, or our security code fails. I recently found what I regard to be a pretty bad bug in apt (which David has prepared a fix for and is pending upload, yay! Thank you!), which boiled down to documentation and code expecting datetimes in a timezone, but accepting any timezone, and silently treating it as UTC. The solution is to hard-fail, which is an interesting choice to me (as a vocal fan of timezone aware code), but at the least it won't fail by misunderstanding what the server is trying to communicate, and I do understand and empathize with the situation the apt maintainers are in. Final Thoughts Overall, my main point is although most modern developers know how to deal with Unicode pain, I think there is a more general lesson to learn -- namely, you should always know what data you have, and always remember what it is. Understand assumptions as early as you can, and always store them with the data.

10 June 2016

Valerie Young: Week 1 on Reproducible Builds

In this post I m reviewing what I ve done the last 6 days of Outreachy-funded reproducible builds work, outline what I plan to do the next two weeks, and speculate on long term goals. For those of you involved in the Debian reproducible builds project, please provide feedback about future plans and work! Week One review One week of Outreachy completed! What have I done? The change that broke everything was the addition of a directory: tests.reproducible-builds.org/debian The directory was added to contain all Debian-specific pages, in line with the other project s reproducible builds status pages: arch linux, fedora, coreboot, etcs. Previously, all Debian pages we simply served directly out of the DocumentRoot. To fix all the broken things, I m pretty sure I had to find, inspect, and add /debian or change global variables within every file pointer in the entire tests website. Sometime tedious, but chasing down bugs and complaints was mostly fun  I also learned (everything I now know) about Apache websites, redirects, the website/navigation/directory structure of tests.reproducible-builds.org, and the roles of many of the reproducible scripts in jenkins.debian.net/bin. Week Two plan What will or should I do next? In the short term, over the next two weeks, I hope to make useful improvements to the tests website and backend while continuing to get up to speed (as well as learn Python). Have other thoughts about minor improvements to tests.reproducible-builds.org? Please let me know! The above list is not internally prioritized, feel free to ask for things to be bubbled up. Longer-term goals My long term summer goal is to make the Debian test code more easily extensible to show the reproducible results from other projects. This will lower the barrier for new projects to keep track of the reproducibility of their code, for great good. This starts with the reproducible.db database, which presently only tracks reproducible testing results for the Debian project. The reproducible builds project s needs have outgrown the original SQLight database, so this redesigning includes a migration to Postgre. Goals of the redesign include ease of querying/comparing packages across distributions, as well as generalization to include results from projects other than Debian. I ll start on this work in two weeks, when I get to DebCamp!  Redesigning the database will also lead to updating the python script which use that data to produce the Debian tests website. Other project scripts (like Fedora, RedHat and Coreboot) can then be updated to track results in the database as well, instead simply directly producing their own test websites. update: as an intermediate step before redesigned the reproducible.db database to handle multiple projects h01ger recommended I help the FreeBSD project recorded tests to a FreeBSD specific database.

Guido G nther: Debian Fun in May 2016

Debian LTS May marked the thirteenth month I contributed to Debian LTS under the Freexian umbrella. I spent the 17.25 hours working on these LTS things: Other Debian stuff

Jaminy Prabaharan: Weekly Report for GSoC16-week 1 and week2

After introducing ourselves to the community, we start contributing to the open and free source software. Since this is the first week, I have went through theories which would help me in coding. Before coding it is always safer to refer to theories so that we don t need to spare time in debugging. The following were my week 1-4 plans:

These two weeks I have completed my first two tasks in the list.I have committed and pushed my works in GitHub.https://github.com/Jaminy/GSoC

Successfully logged into the email account using IMAP and examined each folders.Examined inbox to extract To , From and CC of the last message received.Trying to extract all message details to put in CSV file.


Ben Hutchings: Debian LTS work, May 2016

I was assigned another 15 hours of work by Freexian's Debian LTS initiative, but only worked a total of 10 hours. I intend to make up for this in June. I began preparing the next stable update for Linux 3.2 on kernel.org, but haven't yet sent it out for review. I rebased the wheezy-security branch onto Linux 3.2.80, and added fixes for one more security issue and one data corruption issue affecting aufs. I started a week in the front desk, triaging new issues for wheezy.

9 June 2016

Patrick Schoenfeld: Ansible: Indenting in Templates

When using ansible to configure systems and services, templates can reach a significant complexity. Proper indenting can help to improve the readability of the templates, which is very important for further maintenance. Unfortunately the default settings for the jinja2 template engine in ansible do enable trim_blocks only, while a combination with lstrip_blocks would be better. But here comes the good news: It s possible to enable that setting on a per-template base. The secret is to add a special comment to the very first line of a template:
#jinja2: lstrip_blocks: True
This setting does the following: If enabled, leading spaces and tabs are stripped from the start of a line to a block . So a resulting template could look like this:
global
 % for setting in global_settings % 
     % if setting ... % 
    option   setting  
     % endif % 
 % endfor % 
Unfortunately (or fortunately, if you want to see it this way  this does not strip leading spaces and tabs where the indentation is followed by pure text, e.g. the whitespaces in line 4 are preserved. So as a matter of fact, if you care for the indentation in the resulting target file, you need to indent those lines according to the indentation wanted in the target file instead, like it is done in the example. In less simple cases, with more deep nesting, this may seem odd, but hey: it s the best compromise between a good, readable template and a consistently indented output file.

8 June 2016

Daniel Pocock: Working to pass GSoC

GSoC students have officially been coding since 23 May (about 2.5 weeks) and are almost half-way to the mid-summer evaluation (20 - 27 June). Students who haven't completed some meaningful work before that deadline don't receive payment and in such a large program, there is no possibility to give students extensions or let them try and catch up later. Every project and every student are different, some are still getting to know their environment while others have already done enough to pass the mid-summer evaluation. I'd like to share a few tips to help students ensure they don't inadvertently fail the mid-summer evaluation Kill electronic distractions As a developer of real-time communications projects, many people will find it ironic or hypocritical that this is at the top of my list. Switch off the mobile phone or put it in silent mode so it doesn't even vibrate. Research has suggested that physically turning it off and putting it out of sight has significant benefits. Disabling the voicemail service can be an effective way of making sure no time is lost listening to a bunch of messages later. Some people may grumble at first but if they respect you, they'll get into the habit of emailing you and waiting for you to respond when you are not working. Get out a piece of paper and make a list of all the desktop notifications on your computer, whether they are from incoming emails, social media, automatic updates, security alerts or whatever else. Then figure out how to disable them all one-by-one. Use email to schedule fixed times for meetings with mentors. Some teams/projects also have fixed daily or weekly times for IRC chat. For a development project like GSoC, it is not necessary or productive to be constantly on call for 3 straight months. Commit every day Habits are a powerful thing. Successful students have a habit of making at least one commit every day. The "C" in GSoC is for Code and commits are a good way to prove that coding is taking place. GSoC is not a job, it is like a freelance project. There is no safety-net for students who get sick or have an accident and mentors are not bosses, each student is expected to be their own boss. Although Google has started recommending students work full time, 40 hours per week, it is unlikely any mentors have any way to validate these hours. Mentors can look for a commit log, however, and simply won't be able to pass a student if there isn't code. There may be one day per week where a student writes a blog or investigates a particularly difficult bug and puts a detailed report in the bug tracker but by the time we reach the second or third week of GSoC, most students are making at least one commit in 3 days out of every 5. Consider working away from home/family/friends Can you work without anybody interrupting you for at least five or six hours every day? Do you feel pressure to help with housework, cooking, siblings or other relatives? Even if there is no pressure to do these things, do you find yourself wandering away from the computer to deal with them anyway? Do family, friends or housemates engage in social activities, games or other things in close proximity to where you work? All these things can make a difference between passing and failing. Maybe these things were tolerable during high school or university. GSoC, however, is a stepping stone into professional life and that means making a conscious decision to shut those things out and focus. Some students have the ability to manage these distractions well, but it is not for everybody. Think about how leading sports stars or musicians find a time and space to be "in the zone" when training or rehearsing, this is where great developers need to be too. Some students find the right space in a public library or campus computer lab. Some students have been working in hacker spaces or at empty desks in local IT companies. These environments can also provide great networking opportunities. Managing another summer job concurrently with GSoC It is no secret that some GSoC students have another job as well. Sometimes the mentor is aware of it, sometimes it has not been disclosed. The fact is, some students have passed GSoC while doing a summer job or internship concurrently but some have also failed badly in both GSoC and their summer job. Choosing one or the other is the best way to succeed, get the best results and maximize the quality of learning and community interaction. For students in this situation, now it is not too late to make the decision to withdraw from GSoC or the other job. If doing a summer job concurrently with GSoC is unavoidable, the chance of success can be greatly increased by doing the GSoC work in the mornings, before starting the other job. Some students have found that they actually finish more quickly and produce better work when GSoC is constrained to a period of 4 or 5 hours each morning and their other job is only in the afternoon. On the other hand, if a student doesn't have the motivation or energy to get up and work on GSoC before the other job then this is a strong sign that it is better to withdraw from GSoC now.

Gunnar Wolf: University degrees and sysadmin skills

I'll tune in to the post-based conversation being held on Planet Debian: Russell Coker wonders about what's needed to get university graduates with enough skills for a sysadmin job, to which Lucas Nussbaum responds with his viewpoints. They present a very contrasting view of what's needed for students And for a good reason, I'd say: Lucas is an academician; I don't know for sure about Russell, but he seems to be a down-to-the-earth, dirty-handed, proficient sysadmin working on the field. They both contact newcomers to their fields, and will notice different shortcomings. I tend to side with Lucas' view. That does not come as a surprise, as I've been working for over 15 years in an university, and in the last few years I started walking from a mostly-operative sysadmin in an academic setting towards becoming an academician that spends most of his time sysadmining. Subtle but important distinction. I teach at the BSc level at UNAM, and am a Masters student at IPN (respectively, Mexico's largest and second-largest universities). And yes, the lack of sysadmin abilities in both is surprising. But so is a good understanding of programming. And I'm sure that, were I to dig into several different fields, I'd feel the same: Student formation is very basic at each of those fields. But I see that as natural. Of course, if I were to judge people as geneticists as they graduate from Biology, or were I to judge them as topologists as they graduate from Mathematics, or any other discipline in which I'm not an expert, I'd surely not know where to start Given I have about 20 years of professional life on my shoulders, I'm quite skewed as to what is basic for a computing professional. And of course, there are severe holes in my formation, in areas I never used. I know next to nothing of electronics, my mathematical basis is quite flaky, and I'm a poor excuse when talking about artificial intelligence. Where am I going with this? An university degree (BSc in English, would amount to "licenciatura" in Spanish) is not for specialization. It is to have a sufficiently broad panorama of the field, and all of the needed tools to start digging deeper and specializing either by yourself, working on a given field and learning its details as you go, or going through a postgraduate program (Specialization, Masters, Doctorate). Even most of my colleagues at the Masters in Engineering in Security and Information Technology lack of a good formation in fields I consider essential. However, what does information security mean? Many among them are working on legal implications of several laws that touch our field. Many other are working on authenticity issues in images, audios and other such media. Many other are trying to come up with mathematical ways to cheapen the enormous burden of crypto operations (say, "shaving" CPU cycles off a very large exponentiation). Others are designing autonomous learning mechanisms to characterize malware. Were I as a computing professional to start talking about their research, I'd surely reveal I know nothing about it and get laughed at. That's because I haven't specialized in those fields. University education should give a broad universal basis to enter a professional field. It should not focus on teaching tools or specific procedures (although some should surely be presented as examples or case studies). Although I'd surely be happy if my university's graduates were to know everything about administering a Debian system, that would be wrong for a university to aim at; I'd criticize it the same way I currently criticize programs that mix together university formation and industry certification as if they were related.

Reproducible builds folks: Reproducible builds: week 58 in Stretch cycle

What happened in the Reproducible Builds effort between May 29th and June 4th 2016: Media coverage Ed Maste will present Reproducible Builds in FreeBSD at BDSCan 2016 in Ottawa, Canada on June 11th. GSoC and Outreachy updates Toolchain fixes Other upstream fixes Packages fixed The following 53 packages have become reproducible due to changes in their build-dependencies: angband blktrace code-saturne coinor-symphony device-tree-compiler mpich rtslib ruby-bcrypt ruby-bson-ext ruby-byebug ruby-cairo ruby-charlock-holmes ruby-curb ruby-dataobjects-sqlite3 ruby-escape-utils ruby-ferret ruby-ffi ruby-fusefs ruby-github-markdown ruby-god ruby-gsl ruby-hdfeos5 ruby-hiredis ruby-hitimes ruby-hpricot ruby-kgio ruby-lapack ruby-ldap ruby-libvirt ruby-libxml ruby-msgpack ruby-ncurses ruby-nfc ruby-nio4r ruby-nokogiri ruby-odbc ruby-oj ruby-ox ruby-raindrops ruby-rdiscount ruby-redcarpet ruby-redcloth ruby-rinku ruby-rjb ruby-rmagick ruby-rugged ruby-sdl ruby-serialport ruby-sqlite3 ruby-unicode ruby-yajl ruby-zoom thin The following packages have become reproducible after being fixed: Some uploads have addressed some reproducibility issues, but not all of them: Uploads with an unknown result because they fail to build: Patches submitted that have not made their way to the archive yet: Package reviews 45 reviews have been added, 25 have been updated and 25 have been removed in this week. 12 FTBFS bugs have been reported by Chris Lamb and Niko Tyni. diffoscope development strip-nondeterminism development Mattia uploaded strip-nondeterminism 0.018-1 which improved support for *.epub files. tests.reproducible-builds.org Misc. Last week we also learned about progress of reproducible builds in FreeBSD. Ed Maste announced a change to record the build timestamp during ports building, which is required for later reproduction. This week's edition was written by Reiner Herrman, Holger Levsen and Chris Lamb and reviewed by a bunch of Reproducible builds folks on IRC.

Lucas Nussbaum: Re: Sysadmin Skills and University Degrees

Russell Coker wrote about Sysadmin Skills and University Degrees. I couldn t agree more that a major deficiency in Computer Science degrees is the lack of sysadmin training. It seems like most sysadmins learned most of what they know from experience. It s very hard to recruit young engineers (freshly out of university) for sysadmin jobs, and the job interviews are often a bit depressing. Sysadmins jobs are also not very popular with this public, probably because university curriculums fail to emphasize what s exciting about those jobs. However, I think I disagree rather deeply with Russell s detailed analysis. First, Version Control. Well, I think that it s pretty well covered in university curriculums nowadays. From my point of view, teaching CS in Universit de Lorraine (France), mostly in Licence Professionnelle Administration de Syst mes, R seaux et Applications base de Logiciels Libres (warning: french), a BSc degree focusing on Linux systems administration, it s not usual to see student projects with a mandatory use of Git. And it doesn t seem to be a major problem for students (which always surprises me). However, I wouldn t rate Version Control as the most important thing that is required for a sysadmin. Similarly Dependencies and Backups are things that should be covered, but probably not as first class citizens. I think that there are several pillars in the typical sysadmin knowledge. First and foremost, sysadmins need a good understanding of the inner workings of an operating system. I sometimes feel that many Operating Systems Design courses are a bit too much focused on the Design side of things. Yes, it s useful to understand the low-level mechanisms, and be able to (mentally) recreate an OS from scratch. But it s also interesting to know how real systems are actually built, and what are the trade-off involved. I very much enjoyed reading Branden Gregg s Systems Performance: Enterprise and the Cloud because each chapter starts with a great overview of how things are in the real world, with a very good level of detail. Also, addressing OS design from the point of view of performance could be a way to turn those courses into something more attractive for students: many people like to measure, benchmark, optimize things, and it s quite easy to demonstrate how different designs, or different configurations, make a big difference in terms of performance in the context of OS design. It s possible to be a sysadmin and ignore, say, the existence of the VFS, but there s a large class of problems that you will never be able to solve. It can be a good trade-off for a curriculum (e.g. at the BSc level) to decide to ignore most of the low-level stuff, but it s important to be aware of it. Students also need to learn how to design a proper infrastructure (that meets requirements in terms of scalability, availability, security, and maybe elasticity). Yes, backups are important. But monitoring is, too. As well as high availability. In order to scale, it s important to be able to automatize stuff. Russell writes that Sysadmins need some programming skills, but that s mostly scripting and basic debugging. Well, when you design an infrastructure, or when you use configuration management tools such as Puppet, in some sense, you are programming, and in terms of needs to abstract things, it s actually similar to doing object-oriented programming, with similar choices (should I use that off-the-shelf puppet module, or re-develop my own? How should everything fit together?). Also, when debugging, it s often useful to be able to dig into code, understand what the developer was trying to do, and if the expected behavior actually matches what you are seeing. It often results in spending a lot of time to create a one-line fix, and it requires very advanced programming skills. Again, it s possible to be a sysadmin with only limited software development knowledge, but there s a large class of things that you are unlikely to address properly. I think that what makes sysadmins jobs both very interesting and very challenging is that they require a very wide range of knowledge. There s often the ability to learn about new stuff (much more than in software development jobs). Of course, the difficult question is where to draw the line. What is the sysadmin knowledge that every CS graduate should have, even in curriculums not targeting sysadmin jobs? What is the sysadmin knowledge for a sysadmin BSc degree? for a sysadmin MSc degree?

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