Search Results: "ed"

27 January 2012

Lior Kaplan: PHP 5.4 @ Zend

As a Linux integration guy at Zend, most of my time is spent in compiling PHP related code or dealing with the variety of Linux distributions we support. With the coming release for PHP 5.4, we (at Zend) had some interesting stuff going on. As part of the RC phase, I got to check the status of the 50-60 PHP extensions we provide, especially the PECL extensions which have different release cycles than the main PHP. With minor versions, this usually doesn t really matter, but for major versions this means that some extensions need a little bit of love and fixes to work well with the new PHP version. This of course with the help of our developers. The changes are usually one-liners due to a variable type change, or finding commits in the extension s SCM and applying/back-porting it to the current versions (e.g. pecl memcache). Our policy regarding the patches we have, is that they should at least be sent to upstream (a core member or a bug report, e.g. #55703). I think I m in the best position to enforce that patch policy, so in a few recent cases, I found myself asking one of our developers if the patch he sent me was already accepted upstream before willing to take it into the build process (in this case they are used temporarily, till we ll work with the next RC or final release).
While most people build PHP as a final and standalone product, we also test it against ZendServer (or the other way around, depends on your POV). This helps to discover problems related to and implications of the changes done in the major version. During the PHP 5.4 RC cycle (which is still not finished), we had, more than a few times, that an internal problem discovered led to debugging, code reviewing and sending feedback (and patches when relevant) to the PHP project. Providing fixes for the issues found, helps having PHP in a better shape for release. At least for me, that s one of the fun parts of work getting the chance to contribute back to the community (or at least making sure others do, as I don t write the patches myself).

Filed under: PHP

26 January 2012

Guido G nther: git-buildpackage in experimental

I've started uploading snapshots of git-buildpackage to experimental recently. Here's a short list of what changed over the version in wheezy and sid: This blog is flattr enabled.

Ondřej Čertík: When double precision is not enough

I was doing some finite element (FE) calculation and I needed the sum of the lowest 7 eigenvalues of a symmetric matrix (that comes from the FE assembly) to converge to at least 1e-8 accuracy (so that I can check calculation done by some other solver of mine, that calculates the same but doesn't use FE). In reality I wanted the rounded value to 8 decimal digits to be correct, so I really needed 1e-9 accuracy (but it's ok if it is let's say 2e-9, but not ok if it is 9e-9). With my FE solver, I couldn't get it to converge more than to roughly 5e-7 no matter how hard I tried. Now what?

When doing the convergence, I take a good mesh and keep increasing "p" (the polynomial order) until it converges. For my particular problem, it is fully converged for about p=25 (the solver supports the order up to 64). Increasing "p" further will not increase the accuracy anymore, and the accuracy stays at the level 5e-7 for the sum of the lowest 7 eigenvalues. For optimal meshes, it converges at p=25, for not optimal meshes, it converges for higher "p", but in all cases, it doesn't get below 5e-7.

I know from experience, that for simpler problems, the FE solver can easily converge to 1e-10 or more using double precision. So I know it is doable, now the question is what the problem is: there
are a few possible reasons:

When using the same solver for simpler potential, it converged nicely to 1e-10. So this suggests there is no bug in the assembly or solver itself. It is possible that the quadrature is not accurate enough, but again, if it converges for simple problem, it's probably not it. So it seems it is the ill conditioned matrix, that causes this. So I printed the residuals (that I simply calculated in Fortran using the matrix and the eigenvectors returned by LAPACK), and it only showed 1e-9. For simpler problems, it can go to 1e-14 easily. So that must be it. How do we fix it?

Obviously by making the matrix less ill conditioned, which is caused by the mesh for the problem (the ratio of the longest/shortest elements is 1e9) but for my problem I really needed such a mesh. So the other option is to increase the real number accuracy.

In Fortran all real variables are defined as real(dp), where dp is an integer defined at a single place in the project. There are several ways to define it, but it's value is 8 for gfortran and it means double precision.So I increased it to 16 (quadruple precision), recompiled. Now the whole program calculates in quadruple precision (more than 30 significant digits). I had to recompile LAPACK using the "-fdefault-real-8" gfortran option, that promotes all double precision numbers to quadruple precision, and I used the "d" versions (double precision, now promoted to quadruple) of LAPACK routines.

I rerun the calculation ---- and suddenly LAPACK residuals are around 1e-13, and the solver converges to 1e-10 easily (for the sum of the lowest 7 eigenvalues). Problem solved.

Turning my Fortran program to quadruple precision is as easy as changing one variable and recompiling. Turning LAPACK to quadruple precision is easy with a single gfortran flag (LAPACK uses the old f77 syntax for double precision, if it used real(dp), then I would simply change it as for my program). The whole calculation got at least 10x slower with quadruple. The reason is that gfortran runtime uses the libquadmath library, that simulates quadruple precision (as current CPUs only support double precision natively).

I actually discovered a few bugs in my program (typically some constants in older code didn't use the "dp" syntax, but had the double precision hardwired). Fortran warns about all such cases, when the real variables have incompatible precision.

It is amazing how easy it is to work with different precision in Fortran (literally just one change and recompile). How could this be done with C++? This wikipedia page suggests, that "long double" is only 80bit in most cases (quadruple is 128bit), but gcc offers __float128, so it seems I would have to manually change all "double" to "__float128" in the whole C++ program (this could be done with a single "sed" command).

Ben Hutchings: Testing backport of the isci driver for Intel C600 SAS/SATA controllers

Phil Kern made a general call for testing of Debian 6.0.4. I would like to more specifically point out that I backported the isci driver for Intel C600 SAS/SATA controllers. Unfortunately I have not yet had any testing results for this. If you have any machines with this hardware not yet in production, please do consider testing the new Linux kernel package, version 2.6.32-41. Updated: I now have a positive test result from the user who requested this driver in the installer.

Michal Čihař: Dictionaries for N9/N950

I was just about to start writing own viewer for StarDict dictionaries for Harmattan, when I noticed that somebody already took the effort and the application is available. It's called DictionaryStar and it's developed on gitorious. With the hard part done, I've adjusted packaging of various dictionaries I've made available for StarDict so that it works fine on Harmattan. For now only English-Czech one is completed, you hopefully be able to get it soon at Nokia store. The reason I've started with only one is that this pretty much does not fit into content guidelines for Nokia store and I expect problems when this will be passing their QA. So I've decided to push only one for now and once I get it through, adding others will be easy.

Filed under: English Meego Stardict 0 comments Flattr this!

Aigars Mahinovs: Zombies. Wait, don t run away, yet

I never got the craze for the zombie this and zombie that. I saw the premise as thinner than vampire storyline which in my book only had a good day with Buffy franchise. But then I got Kindle and run out of stuff to read and decided to pick up something less lively and more shambling. And you know what I found there are a few great books hiding behind the zombie label. I read them in the worng order, so to help you guys out, here is the way I would recommend to check out if the zombie genre is interesting to you: Start with World War Z: An Oral History of the Zombie War. It is written as a historical book documenting the memories of people that have survived the world wide zombie apocalipse is a series of escalating short stories. This is a perfect bathroom or bus reading. Each story focuses on how people react (or fail to react) to a radical change in their environment. Zombies are a tool to expose the human condition for this book. The next you could read (or you could even skip this if it get a bit boring for you) is The Zombie Survival Guide: Complete Protection from the Living Dead this is a problem solving book, it basically takes a problem ( ZOMBIES! ) a goal ( I want to survive! ) and describes the logical steps needed to reach the goal in the context of the problem. It is very educational on the issue of problem solving, especially with unusual problems. But it can get boring for people if so, don t give up, but just skip this book for now and move on the the best of them all The third is a trilogy, two books are already published, the third is coming soon first books is Feed (Newsflesh, Book 1) and the second is Deadline (Newsflesh, Book 2). This is a rare gem of modern literature. Basically this is a book set in the world long time after a zombie outbreak (with a good reason why and how it happened) where people have already lived a few decades with the problema and the kids are very used to it. So the book is written from a perspective of a young woman and her brother, who were born after Rising and are now into one of the most dangerous profession journalism. :) Early on they become the first bloggers to be picked to follow a presidential election campagn (book was written before Obama campaign really took off) and it only get wilder from there. I really liked these books. So much so, that I will now explore the other zombie fiction books to see if there possibly is something good there as well. Any recommendations?

Ian Wienand: pylint and hiding of attributes

I recently came across the pylint error: 
E:  3,4:Foo.foo: An attribute affected in foo line 12 hide this method
in code that boiled down to essentially: 
class Foo:
    def foo(self):
        return True
    def foo_override(self):
        return False
    def __init__(self, override=False):
        if override:
            self.foo = self.foo_override
Unfortunately that message isn't particularly helpful in figuring out what's going on. I still can't claim to be 100% sure what the message is intended to convey, but I can construct something that maybe it's talking about. Consider the following using the above class 
foo = Foo()
moo = Foo(override=True)
print "expect True  : %s" % foo.foo()
print "expect False : %s" % moo.foo()
print "expect True  : %s" % Foo.foo(foo)
print "expect False : %s" % Foo.foo(moo)
which gives output of: 
$ python ./foo.py 
expect True  : True
expect False : False
expect True  : True
expect False : True
Now, if you read just about any Python tutorial, it will say something along the lines of:
... the special thing about methods is that the object is passed as the first argument of the function. In our example, the call x.f() is exactly equivalent to MyClass.f(x). In general, calling a method with a list of n arguments is equivalent to calling the corresponding function with an argument list that is created by inserting the method s object before the first argument. [Official Python Tutorial]
The official tutorial above is careful to say in general; others often don't. The important point to remember is how python internally resolves attribute references as described by the data model. The moo.foo() call is really moo.__dict__["foo"](moo); examining the __dict__ for the moo object we can see that foo has been re-assigned: 
>>> print moo.__dict__
 'foo': <bound method Foo.foo_override of <__main__.Foo instance at 0xb72838ac>>
Our Foo.foo(moo) call is really Foo.__dict__["foo"](moo) -- the fact that we reassigned foo in moo is never noticed. If we were to do something like Foo.foo = Foo.foo_override we would modify the class __dict__, but that doesn't give us the original semantics. So I postulate that the main point of this warning is to suggest to you that you're creating an instance that now behaves differently to its class. Because the symmetry of calling an instance and calling a class is well understood you might end up getting some strange behaviour, especially if you start with heavy-duty introspection of classes. Thinking about various hacks and ways to re-write this construct is kind of interesting. I think I might have found a hook for a decent interview question :)

Russ Allbery: Do symbols files make sense for C++?

I also posted this to debian-devel, which is where the discussion will be, but I wanted to post it on my journal as well so that others who may be interested will see it on Planet Debian. For those not familiar with Debian, this concerns the implications of a new feature for how Debian tracks shared library dependencies. I'm currently working on the Policy modification to document (and recommend) use of symbols instead of shlibs, but I'd only personally used symbols with C libraries. Today I decided that I should try adding a symbols file to a C++ library, particularly if I'm going to recommend everyone do it. I tried this exercise with xml-security-c, which is, I think, a reasonably typical C++ library. Not the sort of core C++ library that would sit at the center of the distribution, but a random software package that's in Debian because other things use it. The experience was rather interesting, and I ended up uploading the new version without a symbols file and continuing to just use shlibs. That's for the following reasons:
  1. The generated symbols file was HUGE. Hundreds of lines. This is a marked difference from the typical C symbols file, which is of quite manageable size. Some of that is that the library provides a lot of different classes, but some of it is that C++ just generates a lot of exported symbols. There's no way that I could do what I would do with a C library and understand those symbols, why they're there, and whether they are likely to have changed between revisions.
  2. Generating a reasonable symbols file was a pain. Generating an unreasonable symbols file that just contains all of the mangled symbols is largely mechanical and uninteresting, but that symbols file doesn't seem to me to convey useful information. So I did some scripting to translate the symbols back with c++filt, and add (c++) tags, and then try to understand what I was looking at and figure out whether I should sort the symbols list because the default sort is by mangled name, which is meaningless. This is a rather unappealing process. It's not particularly difficult, but it's very awkward and feels like it's missing vital tools.
  3. The resulting symbols file is incomprehensible to someone without strong knowledge of C++. It's full of opaque entries that don't make sense to the non-C++ programmer, which I suspect is a substantial number of people who package C++ libraries for Debian. I know enough C++ from school that I can evaluate security fixes, make simple patches, and review upstream changes, and I think that's all that should be needed to package things for Debian. But I'm deeply uncomfortable producing a symbols file on my own that contains entries for things that I know nothing about and cannot evaluate when they've last changed, like "non-virtual thunk to FooClass::~FooClass@Base".
  4. Once I had a symbols file that resulted in a successful build and that I could have uploaded, I started thinking about how I was going to maintain it. With a C program, I would change the symbols file versions when the underlying function implementation changes in a way that may not offer eqiuvalence, similar to bumping shlibs. I realized that I was going to have no idea when that happened, and the only way that I would maintain the symbols file would be to either trust upstream to maintain ABI equivalence and therefore only change the symbols file when upstream changes the SONAME, or not trust upstream to maintain ABI equivalence and therefore change all the versions with each new upstream release. That gives me exactly the same semantics as a shlibs file, so what's the point in having a symbols file?
  5. The exported symbols of the library contained many symbols that obviously weren't really from that library, but instead were artifacts of the C++ compilation process, things like instantiations of std::vector. Do those go into the symbols file? Do they change from architecture to architecture? If they disappear again, is that actually an ABI break? How do I know? It's all very mysterious, and while shlibs provides the same semantics as just ignoring this, at least I'm not then including in the package data, generated by me, things that I'm just blindly ignoring.
I came away from this experience thinking that I should revise the Policy amendment to say that symbols files are really for C libraries and for C++ libraries with either a tightly maintained symbol export list or maintained by a C++ expert, and that most C++ library maintainers should just not bother with this and use shlibs, bumping the shlibs version or not based on their impression of how good upstream is at maintaining ABI equivalence. But that feels like a result contrary to what I had previously thought was the intended direction, so I wanted to ask the Debian development community as a whole: am I missing something? Are these symbols files actually useful? Am I missing some trick to make them useful?

MJ Ray: Phones, Privacy and Co-ops

And now a slightly longer than usual rant: The problem with the o2 network disclosing mobile browsers phone numbers that I repeated 2 days ago (and it appeared on our co-op website) snowballed yesterday to the point that it was on the short bulletins from ITN, BBC, IRN and probably many more. And then o2 fixed it. Good! The reply claims that it s only since 10th January which is rather at odds with other claims that it has been happening since at least March 2010 in some situations. I started buying from o2 in December. I was using Three, but their network where I stay in Norfolk isn t reliable and you can t just buy a device in a shop for The Phone Co-op. The dongle from o2 is a recent Huawei USB device that just worked in debian and was fairly easy for me to get working in Ubuntu. There s space in it for a memory card, so maybe I could boot from it but that s an idea for later. The o2 deal is OK but not great, and the included wifi is nowhere near as good as it looked: when it says it includes BT Openzone that doesn t include any of the BT Openzone-H hotspots that are much more common. You re only allowed to register one device for wifi, so no using your phone, tablet and laptop at different times! I can t believe it s legal to advertise that as unlimited wifi , but o2 is still a better offer than access to BT Openzone-H hotspots at 39/month (yes, that s the price for wifi-only ). Ultimately, I think the problem is that there s a rubbish choice of mobile (wifi or 3G) internet access providers in the UK. It s a completely and utterly failed market, so you need to use Virtual Private Networks and similar tricks to protect yourself from the dysfunctional networks. My VPN meant my mobile number was safe: how about yours? As luck would have it, I had already proposed a resolution about protecting customer privacy to The Phone Co-op (affiliate link) for our AGM on Saturday 4 February (if you re a member, let me know). We were trying to find a compromise wording and I don t think this little o2 scandal has hurt my proposal at all! At least the phone co-op s mobile service is based on Orange s network, which wasn t affected. How does your network perform? There s an Internet Service Provider evilness test which might tell you.

Joey Hess: announcing github-backup

Partly as a followup to a Github survey, and partly because I had a free evening and the need to write more haskell code, any haskell code, I present to you, github-backup. github-backup is a simple tool you run in a git repository you cloned from Github. It backs up everything Github knows about the repository, including other forks, issues, comments, milestones, pull requests, and watchers. This is all stored in the repository, as regular files, on a "github" branch. Available in Cabal now, in Debian maybe if someone packages haskell-github.

Russell Coker: Links January 2012

Cops in Tennessee routinely steal cash from citizens [1]. They are ordered to do so and in some cases their salary is paid from the cash that they take. So they have a good reason to imagine that any large sum of money is drug money and take it. David Frum wrote an insightful article for NY Mag about the problems with the US Republican Party [2]. TreeHugger.com has an interesting article about eco-friendly features on some modern cruise ships [3]. Dan Walsh describes how to get the RSA SecureID PAM module working on a SE Linux system [4]. It s interesting that RSA was telling everyone to turn off SE Linux and shipping a program that was falsely marked as needing an executable stack and which uses netstat instead of /dev/urandom for entropy. Really the only way RSA could do worse could be to fall victim to an Advanced Persistent Attack :-# The Long Now has an interesting summary of a presentation about archive.org [5]. I never realised the range of things that archive.org stores, I will have to explore that if I find some spare time! Jonah Lehrer wrote a detailed and informative article about the way that American high school students receive head injuries playing football[6]. He suggests that it might eventually be the end of the game as we know it. Fran ois Marier wrote an informative article about optimising PNG files [7], optipng is apparently the best option at the moment but it doesn t do everything you might want. Helen Keeble wrote an interesting review of Twilight [8]. The most noteworthy thing about it IMHO is that she tries to understand teenage girls who like the books and movies. Trying to understand young people is quite rare. Jon Masters wrote a critique of the concept of citizen journalism and described how he has two subscriptions to the NYT as a way of donating to support quality journalism [9]. The only comment on his post indicates a desire for biased news (such as Fox) which shows the reason why most US media is failing at journalism. Luis von Ahn gave an interesting TED talk about crowd-sourced translation [10]. He starts by describing CAPTCHAs and the way that his company ReCAPTCHA provides the CAPTCHA service while also using people s time to digitise books. Then he describes his online translation service and language education system DuoLingo which allows people to learn a second language for free while translating text between languages [11]. One of the benefits of this is that people don t have to pay to learn a new language and thus poor people can learn other languages great for people in developing countries that want to learn first-world languages! DuoLingo is in a beta phase at the moment but they are taking some volunteers. Cory Doctorow wrote an insightful article for the Publishers Weekly titles Copyrights vs Human Rights [12] which is primarily about SOPA. Naomi Wolf wrote an insightful article for The Guardian about the Occupy movement, among other things the highest levels of the US government are using the DHS as part of the crackdown [13]. Naomi s claim is that the right-wing and government attacks on the Occupy movement are due to the fact that they want to reform the political process and prevent corruption. John Bohannon gave an interesting and entertaining TED talk about using dance as part of a presentation [14]. He gave an example of using dancerts to illustrate some concepts related to physics and then spoke about the waste of PowerPoint. Joe Sabia gave an amusing and inspiring TED talk about the technology of storytelling [15]. He gave the presentation with live actions on his iPad to match his words, a difficult task to perform successfully. Thomas Koch wrote an informative post about some of the issues related to binary distribution of software [16]. I think the problem is evenm worse than Thomas describes. Related posts:
  1. Links January 2011 Halla Tomasdottir gave an interesting TED talk about her financial...
  2. Links January 2010 Magnus Larsson gave an interesting TED talk about using bacteria...
  3. Links January 2009 Jennifer 8 Lee gave an interesting TED talk about the...

25 January 2012

Phil Hands: The future arrived

... a week ago, in the shape of Alexandra Daphne Scholz, my enchanting daughter. A proud father shows the world his adorable 6 day old daughter She seems to have inherited my hairstyle. Gundemarie Scholz (my wife) and she are both doing remarkably well, to the extent that they both keep surprising medical staff with their rapid progress. For those of you that care about such things: She was 2.9kg (6lb 6oz) at birth, and 49cm (1'7") tall ... or should that be "long", given that she's not doing so much standing up as yet? What she is doing is sleeping, breast feeding, and excreting ... rather a lot. Between times, it's mostly gurgling cheerfully, looking around at the world, and attempting to study her own hands -- I find her completely fascinating. That being the case, don't expect anything very sensible out of me for the foreseeable future (so no change there, eh? ;-) ) and because I cannot resist the urge, here are a few more snaps of her: Alexandra in the Neonatal unit, having a well earned nap when a day old Alexandra in the Neonatal unit, looking around at the world Alexandra snuggled up in bed this morning As you can see, at only one day old, it seems that she'd already managed to get hold of the Amulet of Yendor, and was having a well earned nap ;-)

Bartosz Fe&#324;ski: Sentelic touchpad

With the latest changes in driver for Sentelic touchpad I m eventually able to use two-finger scrolling, and disable touchpad while typing. Middle-button emulation and on pad click & drag doesn t work yet, though. Edge scrolling either. Anyway it starts to be really usable and there is some progress to merge this driver with mainline kernel. I believe last time I was compiling kernel was around 2.4.18 and only because at that time I was maintaining router for some network and needed some special iptables extensions. Happily it hasn t changed too much since then and I can compile 3.2.1 without problem ;)

Christian Perrier: Nine years after...

...I closed the oldest bug report I ever reported that is^W was still opened.

Petter Reinholdtsen: Setting up a new school with Debian Edu/Squeeze

The next version of Debian Edu / Skolelinux will include a new tool sitesummary2ldapdhcp, which can be used to quickly set up all the computers in a school without much manual labour. Here is a short summary on how to use it to set up a new school. First, install a combined Main Server and Thin Client Server as the central server in the network. Next, PXE boot all the client machines as thin clients and wait 5 minutes after the last client booted to allow the clients to report their existence to the central server. When this is done, log on to the central server and run sitesummary2ldapdhcp -a in the konsole to use the collected information to generate system objects in LDAP. The output will look similar to this: 
% sitesummary2ldapdhcp -a
info: Updating machine tjener.intern [10.0.2.2] id ether-00:01:02:03:04:05.
info: Create GOsa machine for auto-mac-00-01-02-03-04-06 [10.0.16.20] id ether-00:01:02:03:04:06.
Enter password if you want to activate these changes, and ^c to abort.
Connecting to LDAP as cn=admin,ou=ldap-access,dc=skole,dc=skolelinux,dc=no
enter password: *******
%
After providing the LDAP administrative password (the same as the root password set during installation), the LDAP database will be populated with system objects for each PXE booted machine with automatically generated names. The final step to set up the school is then to log into GOsa, the web based user, group and system administration system to change system names, add systems to the correct host groups and finally enable DHCP and DNS for the systems. All clients that should be used as diskless workstations should be added to the workstation-hosts group. After this is done, all computers can be booted again via PXE and get their assigned names and group based configuration automatically. We plan to release beta3 with the updated version of this feature enabled this weekend. You might want to give it a try. Update 2012-01-28: When calling sitesummary2ldapdhcp to add new hosts, one need to add the option -a. I forgot to mention this in my original text, and have added it to the text now.

Bartosz Fe&#324;ski: Cracow against ACTA

Wow that s really big demonstration.
I ve just uploaded video with people walking near Wawel castle plenty of people during almost 20 minutes.
I suppose there was more than 50k people and wonder what s going to be shown in TV ;) I really like it.

Pietro Abate: new thinkpad x220

This summer my beloved thinkpad x301 died in a cloud of smoke. It was exactly 3 years and 20 days old while my warranty was valid only for 3 years. Now, don't tell me this is a coincidence. Anyway. After about 5 months, I finally managed to convince my employer to get me a new thinkpad, the x220. My specs includes a 128G SSD , 4G of RAM, 2.4Gz processor, camera and fingerprint reader. It's a pity that the x300 series is not in production anymore. They were light, with a solid battery and a large screen. The X1 just don't cut it. Even though it can be consider the successor of the x300, its battery life is just not enough for my needs. On the other hand, the x220 is a very nice machine : the screen is a bit smaller then the X300, but it is light, with a very powerful processor, good battery and it feels very solid. In my opinion lenovo should have packed the new hw of the x220 in the chassis of the x300, maybe with small compromise on the battery life (I got the big battery and I can squeeze almost 7 hs with a single charge) but clearly this was not a good business choice... Installing debian on this laptop is not immediate because none of the official debian installers are shipped with a recent kernel (as in 3.x series). Since with the official debian installer I cannot have neither the driver for the Ethernet card or the driver for the wirelles card, I opted to use a custom installer built by kmuto (http://kmuto.jp/debian/d-i/ ) . Using this installer the ethernet card is recognized immediately and it's easy to proceed with the installation as usual. Another option would have been to add the binary blog for the wireless chip, but apparently the deb installer supports only WEP auth, while all my access point are WPA. I didn't spend too much time on the wireless setup, so it might well be that is indeed possible to install using a WPA access point. Last time I installed a laptop, I used the automatic partition option to have lvm on top of a lucks encrypted partition, only to discover later that the default dimensions of the partitions were a bit too small for me. For example, by default the boot partition is only 256Mb. This is plenty if you want to have only one kernel image installed at each given time, but if you want more then one kernel, memtest and for example a grml rescue iso, it's easy to run out of space. So I proceed to manually partition the disc creating a boot partition of 512M, and using the rest as a luks encrypted device with lvm on top and 3 logical volumes : sys (15G), swap (4G) and home (the rest). For my daily use having 15G on my laptop for /usr, /var, etc should more the enough... Next step was to install the system. Since in recent times I got extremely pissed off with gnome 3, I've decided to dump it completely and go back to awesome. But since awesome all by itself is a bit sad, I paired it up with xfce. Everything works, except the automount, and I'm still trying to figure out how to make it work. Apparently is a consolkit problem... I'll write another post about the xfce4 + awsome setup soon... Today I've also started playing with the finger print reader. It seems working, but I haven't managed yet to use it in conjunction with pam for authentication ... more to come. And... On last closing remark : during the last 5 months I've used a dell latitude e6410 ... Gosh. I feel I'm on anther planet. The keyboard of a thinkpad give you pleasure, not pain, from 2 to 4G of RAM is a big jump and from a conventional HD to a SSD ... well... it seems I'm flyinggggg :) I've the impression my productivity just went up 50% !!! If you work with your laptop everyday get a good laptop. It is well worth the investment ...

Russell Coker: SE Linux Status in Debian 2012-01

Since my last SE Linux in Debian status report [1] there have been some significant changes. Policy Last year I reported that the policy wasn t very usable, on the 18th of January I uploaded version 2:2.20110726-2 of the policy packages that fixes many bugs. The policy should now be usable by most people for desktop operations and as a server. Part of the delay was that I wanted to include support for systemd, but as my work on systemd proceeded slowly and others didn t contribute policy I could use I gave up and just released it. Systemd is still a priority for me and I plan to use it on all my systems when Wheezy is released. Kernel Some time between Debian kernel 3.0.0-2 and 3.1.0-1 support for an upstream change to the security module configuration was incorporated. Instead of using selinux=1 on the kernel command line to enable SE Linux support the kernel option is security=selinux. This change allows people to boot with security=tomoyo or security=apparmor if they wish. No support for Smack though. As the kernel silently ignores command line parameters that it doesn t understand so there is no harm in having both selinux=1 and security=selinux on both older and newer kernels. So version 0.5.0 of selinux-basics now adds both kernel command-line options to GRUB configuration when selinux-activate is run. Also when the package is upgraded it will search for selinux=1 in the GRUB configuration and if it s there it will add security=selinux. This will give users the functionality that they expect, systems which have SE Linux activated will keep running SE Linux after a kernel upgrade or downgrade! Prior to updating selinux-basics systems running Debian/Unstable won t work with SE Linux. As an aside the postinst file for selinux-basics was last changed in 2006 (thanks Erich Schubert). This package is part of the new design of SE Linux in Debian and some bits of it haven t needed to be changed for 6 years! SE Linux isn t a new thing, it s been in production for a long time. Audit While the audit daemon isn t strictly a part of SE Linux (each can be used without the other) it seems that most of the time they are used together (in Debian at least). I have prepared a NMU of the new upstream version of audit and uploaded it to delayed/7. I want to get everything related to SE Linux up to date or at least with comparable versions to Fedora. Also I sent some of the Debian patches for the auditd upstream which should reduce the maintenance effort in future. Libraries There have been some NMUs of libraries that are part of SE Linux. Due to a combination of having confidence in the people doing the NMUs and not having much spare time I have let them go through without review. I m sure that I will notice soon enough if they don t work, my test systems exercise enough SE Linux functionality that it would be difficult to break things without me noticing. Play Machine I am now preparing a new SE Linux Play Machine running Debian/Unstable. I wore my Play Machine shirt at LCA so I ve got to get one going again soon. This is a good exercise of the strict features of SE Linux policy, I ve found some bugs which need to be fixed. Running Play Machines really helps improve the overall quality of SE Linux. Related posts:
  1. Status of SE Linux in Debian LCA 2009 This morning I gave a talk at the Security mini-conf...
  2. SE Linux in Debian I have now got a Debian Xen domU running the...
  3. Debian SE Linux Status At the moment I ve got more time to work on...

Jon Dowland: Music for Our Future

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In 2010, a collaboration between the SyFy channel, Create Digital Music, XLR8R and Pitchfork created "Music for our Future": a compilation album of free music inspired by the TV show "Caprica". XLR8R hosted it but their page for the release has subsequently disappeared. A few people here and there on the 'net have been asking for a copy, so here it is on archive.org: http://www.archive.org/details/MusicForOurFuture. Some background info, photos etc. via CDM.

24 January 2012

James Morrison: Appengine

I've been working with appengine for a few months now. I've managed to find out the hard way that appcfg.py rollback is useless. I've learned to create a git branch for each refactoring I start on. The git branch also includes a new app version for the branch. When push all my changes to my live site, I upload one last time to the new app. Merge my branch into the master then change the live version from the old one to the new one.

I haven't learned how this work flow translates to having multiple developers. Hopefully, it is simple enough that other people can follow.

I also use make since it's an easy way to automate tasks. I hear redo is good, but for python, I'm not really compiling anything, I'm simply writing shell scripts and make is a great shell script dispatcher.

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