I ve just been asked for advice on buying a digital camera. I m not an expert on cameras but I have a good general knowledge of technology and I m sure that the readers of my blog will correct me rapidly if I make any serious mistakes. ;)Types of CameraThe Wikipedia Page about Digital Cameras is worth reading [1].Here are the types of camera that are useful as a stand-alone camera (IE not camera phones or industrial cameras):

• Digital SLR large, very capable, and very expensive. They have detachable lenses and a prism to split the light between a viewfinder and the CCD that records the digital photo. Such a split provides much less benefit now that you can have an LCD display for the viewfinder. In Australia they seem to start at about $1500.
• Bridge Cameras they are of a similar size and shape to a Digital SLR, but the lens is permanently attached and the price is a lot lower. Typically between $400 and $800.
• Mirrorless Interchangeable Lens Cameras they allow changing lenses like a DSLR but don t have the prism for an optical viewfinder. This makes the optics simpler and cheaper. Andre Pang wrote a good review of one [2] which sells for about $700.
• Compact cameras small and cheap. Between $60 and $400 depending on features.

I suggest that people not start out a hobby of digital photography with a DSLR or other interchangeable lens camera. I think that it s best to start out with simple gear that s cheap if you decide that digital photography is not your thing then you have wasted less money, and if you really get into it then you ll be able to make a more informed choice about an expensive camera after getting some experience.A spare cheap compact camera can be useful even if you own a more expensive camera. There are times when you don t want the bulk of a DSLR or Bridge Camera and when you have a risk of theft or accidental damage such that you don t want to take an expensive camera. People who are really serious about photography apparently take a camera everywhere, you could have a compact camera in your front pocket for fast pictures and a bulky camera in your backpack for when you have time to prepare a quality shot. So buying a cheap camera and then buying an expensive one a few months later would not be wasting money!As the person who asked for advice has never owned a digital camera before I ll focus on cheap compact cameras for the rest of this post.Pixels and LensesCameras are typically advertised with the resolution in Megapixels described in bold. Presumably most people search for the camera with the highest resolution. The first thing to beware of is cameras that don t have hardware which is capable of taking a picture of the stated resolution, they use interpolation to generate a higher resolution image. There are probably some cameras with interpolation that are OK and provide a decent picture at a low price, but generally I recommend avoiding all cameras that do interpolation.Optical zoom is a very important feature. Often pictures have to be cropped to remove unwanted background, if you zoom in appropriately you can avoid cropping and make better use of the available resolution. Beware of cameras that advertise things such as advanced zoom , anything that doesn t exactly say optical zoom is using digital zoom IE interpolation. I suggest not considering a compact camera unless it can do at least 4* optical zoom, with 5* or better being preferable.The physical size of the lens is important. A bigger lens allows better pictures in adverse lighting and also allows a faster shutter speed to give better photos of moving objects and better photos when you are moving. Generally you can get a rough idea of the potential that a camera has by just glancing at the lens, if it s the size of a lens in a mobile phone then the pictures won t be that great. If it is on a telescopic mount and it s wide then the result will be better. When buying a lens for a DSLR or other detachable lens camera you should be able to read specifications of the lens which indicate it s size. For compact cameras the specifications of the lens are usually available from the vendor and often available from review sites but generally aren t included in adverts by retailers. If you are comparing cameras in the store looking at them seems like the best option.The ratio of the lens area to the number of pixels determines how much light is received by the sensors for each pixel. So when there are two cameras that are essentially identical apart from the number of megapixels the one with the highest number isn t necessarily better in all situations. A 12MP camera might not give a better result than a 10MP camera, a monitor described as Full HD has a resolution of 1920*1080 which is 2MP. A 5MP camera is useful to allow cropping but if the aim is to display pictures on current monitors then anything much bigger than 5MP is probably wasted at this time and 10MP will provide pictures that can use the capabilities of monitors that are developed for a while.PrintingSome printers that are affordable for home use might require something like a 7MP camera to print a picture at A4 or Letter size at the highest quality. Professional printing will probably require something even greater. But if your intended use of a digital camera doesn t involve printing the pictures, or only rarely involves printing them at A4 or Letter size then you don t need a high resolution for printing. I expect that there are some available printers that can use paper at sizes such as B3 which might require a 20MP camera for best quality. But if the aim of the printing is to put a picture on your wall (the most common case) then even if it s not at the ideal resolution then probably no-one will notice the difference you can t see the pixels from a few meters away.If the aim of the camera is to photograph professional artwork for the purpose of selling it on the Internet then a high resolution camera really isn t desired. You want to offer pictures on the Internet which aren t good enough to be usefully printed.VideoThe capabilities for recording video can vary significantly between different cameras in the same range. If you don t care about video then that s fine, but if video matters to you then you have to read the specs. It s also worth considering digital video cameras, I have previously summarised the available digital video cameras although I m sure that there have been some new models since then [3]. A good (expensive) digital camera will have video functionality that compares well to most digital video cameras but it will cost a lot more.Choosing a Compact CameraThere are many compact cameras in the $100 to $150 price range. Ted s has the Samsung Digimax ES65 for $99.95 which has 10MP and 5* optical zoom. This seems like a good deal. Practice with a cheap camera could easily allow you to make a better choice when buying a more expensive camera that saves you more than $100 so it seems unlikely that you will have any great regrets about buying a $100 camera.Buying from the specs is a bad idea, I recommend testing a camera in the store before buying every store that you want to buy from allows this. But don t expect that quality pictures in the store means much, the people who run the camera stores usually set them up with good lighting so that pictures will tend to turn out well. The aim of an in-store test is not to discover what the camera does well, but to discover what (if anything) it does badly. Also it s useful to test the ergonomics of the camera before buying, discover whether you would be happy to hold the camera for an hour.It s a good idea to ask the staff at a camera store for advice, but don t rely on such advice. My experience is that they tend not to ask what the prospective customer plans to do with the camera and this significantly limits the quality of their recommendations.ConclusionMake your first digital camera a cheap compact camera that doesn t cost much more than $100. Make sure it has at least 4* optical zoom with 5* being preferred. Don t worry too much about the number of megapixels, anything more than 5 will do. Test the camera in the store to look for any obvious reasons that make it unsuitable for your use. If you want video then be prepared to pay a little more as the cheapest cameras have a low resolution for video.

• [1] http://en.wikipedia.org/wiki/Digital_camera
• [2] http://algorithm.com.au/blog/files/gf1.php
• [3] http://etbe.coker.com.au/2010/07/20/digital-video-cameras/

Everybody already heard about Ironman triathlons: 3.8km swimming, 180km cycling and a marathon. these are everywhere around the world now. But, have you ever heard about what's currently happening in Monterrey, MX? Yes, the double deca world challenge. Deca what? Deca Iron man. So, TEN times an Ironman triathlon. And some of these crazy folks are doing it TWICE. 76km swimming, 3600km cycling, 843.9km running. Doh.

In our first few years, Ubuntu experienced explosive growth, from zero to millions of users. Because Ubuntu is an open project, these people don t just use Ubuntu, but can see what s happening next and influence it through suggestions and contributions. The volume of suggestions quickly became unmanageable through ad hoc discussion, because the volume of feedback overwhelmed the relatively few people who were actively developing Ubuntu.

In order to better manage user feedback at this scale, Ubuntu Brainstorm was created in 2008. It s a collaborative filtering engine which allows anyone to contribute an idea, and have it voted on by others. Since then, it s been available to Ubuntu developers and leaders as an information source, which has been used in various ways. The top ideas are printed in the Ubuntu Weekly Newsletter each week. We experimented with producing a report each release cycle and sharing it with the developer community. People have been encouraged to take these suggestions to the Ubuntu Developer Summits. We continue to look for new and better ways to process the feedback provided by the user community. Most recently, I asked my colleagues on the Ubuntu Technical Board in a meeting whether we should take responsibility for responding to the feedback available in Ubuntu Brainstorm. They agreed that this was worth exploring, and I put forward a proposal for how it might work. The proposal was unanimously accepted at a later meeting, and I m working on the first feedback cycle now. In short, the Technical Board will ensure that, every three months, the highest voted topics on Ubuntu Brainstorm receive an official response from the Ubuntu project. The Technical Board won t respond to all of them personally, but will identify subject matter experts within the project, ask them to write a short response, and compile these responses for publication. My hope is that this approach will bring more visibility to common user concerns, help users understand what we re doing with their feedback, and generally improve transparency in Ubuntu. We ve already selected the topics for the first iteration based on the most popular items of the past six months, and are organizing responses now. Please visit brainstorm.ubuntu.com and cast your votes for next time!

I use ratpoison as window manager on my ASUS EeePC netbook nemo for more than two years now. But although I m very happy with ratpoison in the EeePC, there are two feature wishes which have been refused by upstream: One is more flexibel window name matching for the unmanage command. The other one is focus follows mouse between ratpoison frames. Well, I always guessed that it was possible, but it took until now to find outhow to implement focus follows mouse for ratpoison. There s an ancient but still useful tool called Not a Window Manager (nawm) which is a small awk-like interpreter offering mostly window handling functions. The following .nawmrc implements focus follows mouse in nawm:

window newwin;  # stores window to raise
window lastwin; # stores previous window to prevent race conditions
leave  
    lastwin = currentwindow;
 
enter  
    newwin = pointerwindow();
    if (name(newwin) != "" && newwin != lastwin)  
        raise newwin;
        sync;
     
 

The leave hook is necessary to prevent flapping between two windows if switched between them via ratpoison s commands. I also had to add the following hook to my .ratpoisonrc to work around some cases where ratpoison s own window switching didn t work anymore. Only happened with more than one frame with one frame banishing the mouse cursor was annoying, so I filtered that case:

addhook switchwin exec if [  ratpoison -c fdump fgrep -o frame wc -l  -gt 1 ]; then ratpoison -c banish; fi

Unfortunately nawm has been removed from Debian Sid about a year ago due to being buggy and orphaned. There was not upstream development for seven years or so either. So for the moment you can get nawm either from Debian Lenny or from snapshot.debian.org. But I had to fix a segfault in nawm when calling name() on a window without name to be able to use it at all, so you will probably have to rebuild it anyway with the following patch:

diff -u nawm-0.0.20030130/builtins.c nawm-0.0.20030130-patched/builtins.c
--- nawm-0.0.20030130/builtins.c        2010-10-25 06:00:02.000000000 +0200
+++ nawm-0.0.20030130-patched/builtins.c        2010-10-25 04:15:25.000000000 +0200
@@ -546,8 +546,12 @@
     *name = gcstrdup("");
   else
      
-      *name = gcstrdup((char *)nm);
-      XFree(nm);
+      if ((char *)nm)  
+        *name = gcstrdup((char *)nm);
+        XFree(nm);
+        else  
+        *name = gcstrdup("");
+       
      
  

And yes, I m thinking about adopting and reintroducing the nawm package into Debian Sid. But I d prefer if anyone could give me a hint how to do this with more current and still maintained tools (or a patch against ratpoison :-). I looked into suckless-tools, but I haven t found anything in there which provides hooks on X events. And the Perl module Tk seems to be able to set X event hooks, but only within the application being written itself.

#593401

I'm using Twitter plugin for Contacts and Conversations to twitter on my N900.

Twitter recently moved to OAuth. Problem is the Maemo package is outdated and seems to be unmaintained.

I did some research and came across a blog entry about exploring OAuth-protected APIs and some code. Nice idea but not usable for me.

I ended up sitting down and writing a small python script that will re-route your HTTP requests to api.twitter.com after adding all the OAuth bills and whistles, read the reply from twitter and send it back. Neat ? :-)

There's also supertweet.net which I've discovered after I finished writing my script but seems they don't support all of the twitter API call while my script does that.

The script is simple without much error checking but it's been working for me for a few days already.

Last thing, I'm not interested in running a service like supertweet. I'll not be implementing the full OAuth protocol. Need to use it ? Register your own application.

Get the code while hot!

Next step: Thinking of maintaining the twitter plugin for Maemo. I already compiled the latest code and it sort of works fine :-) read more

Debian and Ubuntu have a set of official membership roles that can be granted to regular contributors. Those roles come with rights that enable the contributors to do their work and to participate in the project governance (elections and other official decision-making processes). It s also a way for the distributions to acknowledge the work done: most contributors are proud of the status they reached. The membership structure plays an important role in the development of a distribution: it defines the kind of contributors that are welcome in the project, it sets expectations of the project towards its contributors and defines their rights. In the end, this shapes the project s ability to recruit new contributors to keep the project alive and kicking. This article introduces the existing statuses in Debian and Ubuntu, and defines the sometimes confusing jargon associated with them. The Debian Case Debian only has two types of official members: Debian Developers (DD) and Debian Maintainers (DM). The rights of the developers are codified in the Debian Constitution while those of the maintainers have been defined in a general resolution of 2007. The Debian Maintainer status is still mostly documented in a wiki page. The integration of this new status in Debian s official processes has been slow to come largely because it was introduced at that time without enough negotiation with the involved parties. Nowadays, it is preferred that people get the DM status before applying for DD. DM is a very limited role: maintainers can only upload packages that already have their name on them (either in the Maintainer or Uploaders field) and a specific flag (DM-Upload-Allowed: yes) that only Debian Developers can add. They have no other rights and limited access to Debian s resources. Besides those official roles, there are also maintainers of packages that have no official status within Debian except that they are listed in the Maintainer field of the package. They are doing the maintenance work but all uploads are done by a Debian Developer after verification of the work done (this is called sponsorship and is the only way to start with official packaging work). Once the DD trusts the maintainer, the developer will typically ask the maintainer to apply for DM status in order to be relieved from the sponsorship work. In the end, that makes three different kind of package maintainers and a lot of confusion when you discuss membership issues in particular when the New Maintainer process is the path that you follow to become a Debian Developer. Don t be fooled by the names when reading Debian s documentation! The Ubuntu Case Ubuntu had, from the start, an official Ubuntu Member status that includes all contributors: developers of course, but also documentation writers, artists, translators, etc. This status notably grants the right to vote in elections of the Community Council, the right to participate on Planet Ubuntu, and the @ubuntu.com email alias. For developers, the situation is more complicated: the wiki page lists no less than five different statuses. Initially, developers were split between Ubuntu Core Developers and the MOTU (Masters Of The Universe). The latter were responsible of the universe/multiverse sections of the archive while the former also had upload rights for the main/restricted sections. But, inspired by the Debian Maintainers concept and facing concrete problems in terms of archive management, they changed their infrastructure to offer more fine-grained control on package uploads. Ubuntu can now grant upload permissions on a package-per-package basis, but it can also delegate the right to grant upload permissions with the same granularity. This lead to the new Per-Package Uploader status which is simply an Ubuntu Member with upload rights on a limited set of packages where they have a specific expertise. The more generic Ubuntu Developers status now encompasses members of various development teams that have been delegated the right to manage upload permissions on a (usually large) package set (the current teams are Ubuntu Desktop, Mythubuntu, Kubuntu, and Edubuntu). Those teams can define their own policy to add new members provided they follow the basic rules defined by the Developer Membership Board (see this wiki page). Ubuntu Contributing Developer is an intermediate status for someone who is not yet ready for one of the other developer statuses but who has still shown enough commitment to be an Ubuntu Member. All those statuses can be obtained in a similar way: you prepare a wiki page listing your past contributions, you collect testimonials from existing members that you have worked with, you add yourself in the agenda of the next meeting of the board (or council) that grants the status that you seek, and you attend the meeting. The members of the board will decide whether you are ready for the status (or not) based on what you provided in the wiki, based on your answers during the meeting (and on a mailing-list for developers), and based on what others have to say about you. The most important boards are usually elected by the community while others are commonly appointed by the community council. Those governance bodies include Canonical employees but not as many as one would expect: two out of eight in the Developer Membership Board, two out of eight in the Community Council, but all six members of the Technical Board. The last figure, while not intended, is not surprising given the high expectations set on potential members of the technical board. Mark, as the founder, is the only person to have a permanent seat on both the Community Council and the Technical Board. Comparison of the Statuses Between Debian and Ubuntu The following table summarizes the rights given to each developer role in the two projects (Put the mouse over the abbreviations to know what they are referring to).

Rights	Debian		Ubuntu
	DM	DD	UM	PPU/UD	MOTU	UCD
Package maintenance via sponsorship	Y	N/A	Y	Y	Y	N/A
Official email alias	-	Y	Y	Y	Y	Y
Participate in votes for members	-	Y	Y	Y	Y	Y
Participate in votes for developers	-	Y	-	Y	Y	Y
Upload rights restricted to pre-approved packages	Y	-	-	Y	-	-
Upload rights restricted to a section of the archive	-	-	-	-	Y	-
Unlimited upload rights	-	Y	-	-	-	Y
Number of contributors (as of 2010-07-27)	117	904	462	27	85	63

Please note that the number of contributors are not 100% accurate for Ubuntu. A contributor can have multiple statuses (direct membership to a launchpad group) granted over time (while gaining experience). The problem has been mostly avoided by calculating differences between number of members of the various groups but it s not perfect and it can t be: some MOTU are also PPU for packages in main and it s legitimate (but I only counted them as MOTU and not as PPU). Another limitation is that members of some administrative teams are included indirectly in many teams and thus appear in the count while they should not. Anyway, this simple table makes it obvious that Ubuntu s structure offers a broader choice of statuses. They acknowledge the work of all contributors from the start while still giving the most critical rights only to those who have proven that they deserve them. Despite this difference, Debian still has a significant advantage in terms of number of developers. That number does not tell the whole story though: the Ubuntu contributors include many Canonical employees (e.g. 36 out of 63 core developers have a @canonical.com email registered on their launchpad account) that are likely to spend more time working on the distribution than the average Debian member. But even if comparing person-hours would be a challenging thought experiment, in practice it s of not much interest if both projects continue to cooperate and if more and more of the contributions flow in both directions. Debian is aware of the shortcomings of its structure. Changes to better accommodate non-packagers have been discussed several times already. The last efforts in that direction were unfortunately perceived as a solution ready to go rather than a proposal to be discussed, and the project got quickly buried by a general resolution (GR). Even if that resolution invited for further discussion and a new proposal, the truth is that when someone s initiative is corrected by way of GR, it usually kills any motivation to go forward. Possible Evolution? On the Ubuntu side, the infrastructural changes were completed recently and they don t expect any further change in the near future. They do plan, however, to expand usage of those new features so that more teams benefit from the possibility to control upload rights on packages that are relevant to them, and so that more individuals developers apply to become Per-Package Uploaders on packages that they know very well. On the Debian side, a recent discussion on the debian-project list brought back the topic of the bad terminology and it was agreed that the New Maintainer process should be renamed into something else ( New Developer process has been suggested). But Christoph Berg Debian Account Manager and hence heavily involved in the New Maintainer Team suggested that Debian would be better off implementing the long-awaited membership changes before trying to update all the documentation. It would certainly imply some more vocabulary updates. Later in the discussion, he confirmed that membership reform is on the top of the TODO list of the new maintainer team (just after the rewrite of the nm.debian.org website). What can be expected from this reform? The following answers are my own guesses based on my experience of Debian, but the project hasn t decided anything yet.

• First of all: a new status for contributors that are not packagers. The tricky part will be defining the process to follow and the rights granted.
• Changes to the technical implementation of the DM status. The current implementation does not allow to give upload rights to a single DM if two are listed in the Uploaders field of a package (and both might not have the same experience for that package). Furthermore, it suffers from annoying restrictions like the inability to upload new binary packages.
• A change of the Debian constitution to integrate those new statuses is almost unavoidable.
• Other more invasive changes have been proposed like replacing the NM process by a simple designation by other DD, but it s unlikely to happen. The NM process can already be greatly simplified by the application manager if the applicant can show good testimonials from other developers and if he has a track record of real contributions (e.g. as witnessed by changelog entries in Debian packages).

Almost two years have elapsed since the previous efforts in that direction, the new maintainer team has recruited new members and is in a general better shape. Hopefully, the next episode of this saga will have a better outcome.

This article was first published in Linux Weekly News. In a comment, Mark Shuttleworth tried to explain how the Ubuntu community is being setup.

10 comments Support my work

Well, FrOSCon is over and it s time to sum up the event a bit. First of all: it was great! But it was also hot (I heard the air-condition is off during week-ends ) and busy. And still, it was great! :) Why? Mostly because of the people of course! It was esp nice to meet Rhonda in person (almost all other people [except the grml ones] in the Debian-and-Friends corner were the usual suspects who you see at every (big) FOSS/Linux event). I had some nice chats with Enrico (about Geany and Xfce) and Leo (about bley), besides of the usual when will Squeeze be released? and how does X work in Debian? with random people. When there are a lot of people, a key signing party isn t too far away. Thanks formorer for the orga! You still owe me a sig from FrOSCon 2008 ;) And if someone wonders why he/she got a sign-mail from me even when he/she wasn t at the FrOSCon KSP: I used the fact that I have to sign a lot of keys to sign even more (from the OpenRheinRuhr 2009 KSP and the BSP in M nchengladbach at the beginning of this year [yes tg, I even signed yours, hope you liked the MIME]). As usual I missed almost every talk I wanted to hear and end up with just one (the one about RegEx), which sadly wasn t good at all. I guess that s all I have to say about FrOSCon. Oh wait, no, there was a questionnaire which included the question whether I ll visit future FrOSCons. Of course! Hope to see ya all at MRMCD, OpenRheinRuhr, 27C3 etc So Long, and Thanks for All the Frogs!

My project. This post assumes that the reader has read my last post. I ve been trying to find a reasonable method (which computer to use, single user or multi user) to benchmark for some time, and now an e-mail from Simon Marlow calmed me down. He suggests that in this stage it s not necessary to run a long benchmark, but only a short one, that will be enought to have an idea about what each change is causing to performance. For some time I was struggling with the benchmarks to get a reasonable result. I ve started more than once to write a blog post analysing the results I ve got, until in the middle of the post I notice the results are not consistent. This usually happens when there s a big distortion in benchmarks that shouldn t present no change. For instance, in a patch that only changes code that is executed with +RTS -w -RTS, there was a difference of 50% on execution time in default mode, that is, without +RTS -w -RTS. I think that only disabling CPU scaling and running a small number of tests, which make it easier to reproduce a possibly inconsistent result, will be enough to get a good data. I ve made a stack of patches, splitting each part of my work. The stack does not reflect my preferences between the patches, that is, the complete stack applied is not what I think that is the best change to GHC. It s only a set of patches applied linearly, in a way that it s easy to see the impact in performance of each change. The patches are: Don t check for swept blocks in -DS.

The checkHeap function assumed the allocated part of the block contained only alive objects and slops. This was not true for blocks that are collected using mark sweep. The code in this patch skip the test for this kind of blocks.

This patch is only needed to make it possible to run the binary with the parameters +RTS -w -DS -RTS. I ve already explained this patch. I didn t measure the difference in performance before this patch, since it only changes code that is not going to be executed in the benchmarks, since none of them are runned with -DS. Immix: allocate and free memory on lines. This is the main patch with the initial implementation of Immix. As it is the initial implementation, it has it s problems, that will be treated in the following patches. The comparison was done using 3 programs from nofib/gc: fibheaps, fulsom and constraints, as suggested by Simon Marlow. Two tests were made for each version of the compiler code: one using the default GC strategie (copy-collection with mark-compact if there s few heap space left), another one using mark-sweep (or Immix after my changes). When comparing the default GC strategie between before and after this change, the program got 0.4% slower, with the collection of the generation 0 being 0.1% slower and the collection of the generation 1 0.4% slower. Comparing the mark-sweep with Immix, it got 13.7% slower, 15% in GC0 and 7.2% in GC1. The change in memory used is irrelevant. Chose between allocating in line or blocks in todo_block_full The first improvement I ve made is to change the place where the allocation was searching for free lines. Most of the changes were done in the function alloc_for_copy(), in rts/sm/Evac.c. This is bad because this function is called a lot of times, and should be kept fast. So I moved them to ctodo_block_full() in rts/sm/GCUtils.c. It got about 9.9% and 9.6% faster in default and sweep, which makes it 1% faster and 2.8% slower than in the original code. Improvements in sweep() I was bothered that the code I ve written to free memory in lines was messy, and I thought it could be simplified and maybe even turn faster. The general execution time increased 0.4%, but the GC1 time, which is the only one that should be affected, was reduced by 0.6%. In the default GC strategie, there was also a 0.2% increase in time, so I guess this is inside the margin of change. I have to investigate better on this one, but it seems to have improved slightly the performance. Line before inscresing block size. In a conversatio with Simon Marlow, we thought about these two options: one is to search for a line after trying to increase the block size, and that s what I did in Chose between allocating in line or blocks in todo_block_full; the other is trying to search a line first, and just increase the block size if a block (and not a line) was being used for allocation and there is no line available. With this patch I ve changed it to use the second one. Using sweep, the GC time got 0.5% slower, and with default it got 0.1%. rts/sm/Sweep.c: Mark all BF_MEDIUM blocks as BF_FRAGMENTED In my first implementation, the blocks that contain objects bigger than a line (of medium size) are marked with BF_MEDIUM, and are treated as the usual block in mark-sweep: if the block is empty, it s freed; if it s very fragmented, it s marked to be collected using copy-collection. In this patch, instead of making it use the rules of mark-sweep, I just mark it as fragmented and make it be collected by copy-collection. This made the GC0 time be reduced by 3%, but caused an increase of 509.7% in the GC1 time. This was also the first time the memory used was reduced, by 25.4%. The results in the default mode are insignificant. What it seems to me is that the copy-collection code is more efficient with memory usage, but also more slow. Marking objects as BF_FRAGMENTED make this algorithm be used even for full objects. rts/sm/Sweep.c: Don t use 3/4 heuristics to mark as BF_FRAGMENTED The mark-sweep algorithm considered that an object was fragmented if more than 1/4 of the word groups are completely unmarked. I kept using this heuristic, and this change removes it, making more use of the Immix, and less use of copy-collection. This didn t change the memory used, and made the code 10.4% slower in sweep. In default GC mode, there was no relevant difference, as expected. Allocate in lines in minor GCs. In the initial implementation I was only allocating on lines only in major GCs, because I needed the mark stack, which was only available in these kind of allocations. In this change, I created the mark stack on all GCs, and used the allocation on lines. The results for the default mode are insignificant, and the code got 9.0% faster in sweep, using the same memory. Selection I ve made a selection with the presumably better patches, which are: Don t check for swept blocks in -DS, Immix: allocate and free memory on lines, Chose between allocating in line or blocks in todo_block_full, Improvements in sweep() and Allocate in lines in minor GCs. This is an attempt to achieve the best set of patches possible, to see how it improved the original code. Comparing the default strategie for this selection and the original code, it got 3.7% slower. Comparing both sweep, it got 3.9% slower. Comparing the original default with the final sweep, it got 4.2% slower and uses 4.7% more memory. There s a lot of room for improvement, and I m willing to hear suggestions of what I could change in the code to achieve this improvement.

---

The results are available. Every time I had doubt about a comparison, I d run both versions again to check. This is way there are some backup files. The data presented here is not from all the most recent versions of each measurement, but from the ones that I thought were more similar in conditions.

Back in 2009, I did some analysis of the number of developers per country. Apparently, some people at DebConf remember this and asked if I could update this data. So, here we are with the 2010 version, sorted by the ratio of *active* developers per million population for each country.

Act: number of active developers
Dev: total number of developers
A/M: number of active devels per million pop.
D/M: number of devels per million pop.
2009: rank in 2009
2010: rank in 2010
Code	Name		Population	Act	Dev	A/M	D/M	2009	2010
fi	Finland		5359538		21	32	3,92	5,97	1	1
ch	Switzerland	7782900		22	26	2,83	3,34	2	2
nz	New Zealand	4386207		11	15	2,51	3,42	4	3
no	Norway		4895500		11	14	2,25	2,86	5	4
lu	Luxemburg	502202		1	1	1,99	1,99	8	5
se	Sweden		9354462		18	34	1,92	3,63	3	6
de	Germany		81757600	148	212	1,81	2,59	7	7
at	Austria		8356707		14	23	1,68	2,75	6	8
ie	Ireland		6197100		9	12	1,45	1,94	13	9
au	Australia	22413132	32	56	1,43	2,5	9	10
be	Belgium		10827519	14	16	1,29	1,48	10	11
fr	France		65447374	84	112	1,28	1,71	12	12
nl	Netherlands	16607943	20	38	1,2	2,29	11	13
uk	United-Kingdom	62041708	64	102	1,03	1,64	14	14
ca	Canada		34199000	27	56	0,79	1,64	15	15
es	Spain		46030109	34	52	0,74	1,13	16	16
dk	Denmark		5540241		4	8	0,72	1,44	17	17
hr	Croatia		4489409		3	3	0,67	0,67	20	18
lt	Lithuania	3341966		2	2	0,6	0,6	28	19
cz	Czech Rep	10506813	6	6	0,57	0,57	21	20
us	USA		309913000	165	360	0,53	1,16	19	21
it	Italy		60231214	32	46	0,53	0,76	23	22
bg	Bulgaria	7563710		4	4	0,53	0,53	25	23
il	Israel		7602400		4	6	0,53	0,79	24	24
hu	Hungary		10005000	5	11	0,5	1,1	18	25
lv	Latvia		2217969		1	2	0,45	0,9	26	26
uy	Uruguay		3494382		1	2	0,29	0,57	22	27
jp	Japan		127420000	32	45	0,25	0,35	30	28
pl	Poland		38192000	9	13	0,24	0,34	29	29
cr	Costa Rica	4253897		1	1	0,24	0,24	31	30
sk	Slovakia	5379455		1	1	0,19	0,19	32	31
pt	Portugal	11317192	2	4	0,18	0,35	27	32
ar	Argentina	40134425	6	8	0,15	0,2	34	33
tw	Taiwan		23119772	3	3	0,13	0,13	37	34
br	Brazil		192272890	20	21	0,1	0,11	36	35
by	Belarus		9648533		1	1	0,1	0,1	35	36
mg	Madagascar	20653556	2	2	0,1	0,1	44	37
gr	Greece		11306183	1	3	0,09	0,27	33	38
kr	South Korea	48758000	4	6	0,08	0,12	39	39
ec	Ecuador		14790608	1	1	0,07	0,07		40
cl	Chile		17063000	1	2	0,06	0,12	42	41
ru	Russia		141927297	7	8	0,05	0,06	43	42
ro	Romania		22215421	1	2	0,05	0,09	45	43
co	Colombia	45393050	2	3	0,04	0,07	41	44
ve	Venezuela	26814843	1	1	0,04	0,04	40	45
pe	Peru		29461933	1	1	0,03	0,03	46	46
tr	Turkey		72561312	2	2	0,03	0,03	47	47
za	South Africa	49991300	1	8	0,02	0,16	38	48
mx	Mexico		111211789	2	2	0,02	0,02	49	49
th	Thailand	66404688	1	2	0,02	0,03	50	50
eg	Egypt		78737000	1	2	0,01	0,03	51	51
in	India		1184344000	7	7	0,01	0,01	52	52
cn	China		1338612968	6	10	0	0,01	53	53
ua	Ukraine		45888000	0	0	0	0	48	54
								
								
					873	1410	61,91%			

A few interesting facts:

• We now have 62% of active DDs while we had 73% last year. This year's campaign of MIA work has been somehow "successful", apparently
• No earthquake happened in Finland and there hasn't been a huge increase in DD birth in Switzerland, so the first two stay the same. And Luxembourg didn't have a second DD to beat this.
• Sweden lost many active DDs and is no longer close to Switzerland.
• New Zealand made its way in the top 3. I want them to make a special haka for this
• Ireland won 4 places and is now in the top 10. Thanks for their 3 new active DDs
• And France still hasn't kicked Belgium's ass. Maybe will we win when the country splits out?

David Byrne gave an interesting TED talk about how changes to architecture drove changes to musical styles [1]. I think he does stretch the point a little. To a certain extent people develop the most complex instruments and the largest music halls that can be supported by the level of technology in their society people with a hunter-gatherer civilisation play drums because they can build them and can carry them. The NY Times has an interesting article about paternity leave in Sweden [2]. The Swedish government pays for a total of 13 months leave that can be split between parents for every child. Of those 13 months 2 months can only be taken by the father and that is likely to increase to a minimum of 4 months of paternity leave after the next election. Dan Meyer gave an interesting TEDX talk about how the current math curriculum in the US (as well as Australia and lots of other countries that do the same thing) is totally wrong [3]. His main point is that maths problems should be based on real-world use cases where not all needed data is immediately available and there is also useless data that must be discarded. He believes that the most important thing is developing mathematical problem solving skills basically the things that I did for fun when I was in primary school are skills that need to be taught to high-school students The Atlantic magazine has an amusing article by Daniel Byman and Christine Fair about the incompetent Islamic terrorists [4]. In Afghanistan half the suicide bombers kill only themselves and the US government has a lot of evidence of Taliban soldiers practicing bestiality and collecting porn. Islamic extremist groups are staffed by people who are bad soldiers and bad Muslims. Jon Masters wrote an interesting post titled What Would Jesus Buy about ethical purchasing decisions [5]. Jon references The Church of Stop Shopping which isn t a real religious organisation but a street theatre activist group. ZeroHedga has an insightful article comparing corporations and the US government to street gangs [6]. The conclusion is that when gangs take over a neighbourhood everyone has to join a gang for their own protection. Hillel Cooperman gave an interesting TED talk about being obsessed with Lego [7]. He compares Lego fans to Furries and makes a good case for this comparison. Marian Bantjes gave an interesting TED talk about her graphic art / graphic design work [8]. I ve never seen anything quite like this. Business Insider has an interesting article about oil cleanup, it seems that most people who worked on the Exxon Valdez disaster are now dead [9], s opposed to most people who worked in almost every other occupation at that time who are either still working or enjoying their retirement. The current gulf disaster is bigger, will require more workers for the cleanup, and can be expected to have a higher death toll. Some people claim that measures to reduce oil efficiency will impact the economy, how will millions of people who are chronically ill for the rest of their lives impact the economy? The NY Times has an interesting article on circle lenses [10], contact lenses designed to make the eyes look larger. It s illegal to sell contact lenses in the US without a prescription, but the latest trend is for women to buy them online in a variety of colors. The FDA should probably approve them, it would be better to have the quality controls you expect from a medical supply company instead of having people rely on Malaysian mail-order companies for the safety of their eyes. Don Marti has written an interesting article about the economic decline in the US, he suggests making pension funds invest in local jobs [11]. Companies are supposed to act on behalf of their stock-holders, but US companies often have the majority of their stock owned by the pension funds of workers but they act on behalf of a small number of rich people who own a minority of the stock. Don s article was inspired by Andy Grove s article in Bloomberg about the stagnation in technological development that has been caused by off-shoring the manufacturing [12]. Neil Brown has completed a test release of a new Linux software RAID feature for arrays with multiple redundancy that have bad sectors [13]. When a disk gets a bad sector the current behavior is to kick it out of the array, if you have two such errors on a 3 disk RAID-1 or a RAID-6 array then you lose all redundancy and are at risk of catastrophic failure even though in most cases both disks will still mostly work. With this patch some regions of the disk may be excluded but it can provide redundancy for other stripes. Thanks Neil for your great work here, and all your previous work over the last 10+ years! The RSPCA has a new campaign titled Close the Puppy Factories [14]. Dogs are kept in very poor conditions and forced to churn out puppies for their entire lives to supply pet stores. The RSPCA recommends that people buy puppies from registered dog breeders (not registered dog breeding companies ) and ask to see the dog s parents. They also recommend not buying from classified adverts or pet stores. Animal shelters have to euthenise huge numbers of unwanted animals, you can buy a pet dog or cat from an animal shelter for a small fee that covers the expenses related to housing and spaying it and save that animal from being euthenised! Maureen Dowd criticises the Catholic Church properly in an article for the New York Times [15]. The Catholic Church officially regards ordaining a woman and raping a child to be equally bad offenses. Frank Rich wrote an interesting column for the New York Times about Mel Gibson [16]. He describes the destruction of Mel Gibson s reputation as a symptom of changes in the culture in the US and also links it to the fall of Ted Haggard (who supported Gibson s most notorious movie The Passion of the Christ).

• [1] http://www.ted.com/talks/david_byrne_how_architecture_helped_music_evolve.html
• [2] http://www.nytimes.com/2010/06/10/world/europe/10iht-sweden.html
• [3] http://www.ted.com/talks/dan_meyer_math_curriculum_makeover.html
• [4] http://www.theatlantic.com/magazine/archive/2010/05/the-case-for-calling-them-nitwits/8130/
• [5] http://www.jonmasters.org/blog/2010/06/27/what-would-jesus-buy/
• [6] http://www.zerohedge.com/article/guest-post-corporate-entities-modern-day-street-gangs
• [7] http://www.ted.com/talks/hillel_cooperman_legos_for_grownups.html
• [8] http://www.ted.com/talks/marian_bantjes_intricate_beauty_by_design.html
• [9] http://www.businessinsider.com/warning-to-gulf-cleanup-workers-almost-every-crew-member-from-the-1989-exxon-valdez-disaster-is-now-dead-2010-6
• [10] http://www.nytimes.com/2010/07/04/fashion/04lenses.html
• [11] http://zgp.org/~dmarti/business/grove-on-jobs/
• [12] http://www.bloomberg.com/news/2010-07-01/how-to-make-an-american-job-before-it-s-too-late-andy-grove.html
• [13] http://lwn.net/Articles/391208/
• [14] http://www.closepuppyfactories.org/
• [15] http://www.nytimes.com/2010/07/18/opinion/18dowd.html
• [16] http://www.nytimes.com/2010/07/18/opinion/18rich.html

Landau, L. D.; Lifshitz, E. M. (1976). Course of Theoretical Physics is still the most interesting and solid base that is to be considered as a reference and inspiration in Theoretical Physics. The reference for "Classical Electrodynamics" is the book by J.D. Jackson. "Advanced Quantum Mechanics" by J.J. Sakurai is a popular student choice. Compendium of Relations contains various formulas and relations of the Standard Model. The Lecture Notes on General Relativity by S. Carroll are a solid introduction for an initiate relativist. "Quantum Field Theory in a Nutshell" by A. Zee is amazing. Quantum electrodynamics can be explored in the books by "The Quantum Theory of Fields" by S. Weinberg or "Quantum field theory" by L.H. Ryder or Quantum Chromodynamics in M.E. Peskin & D.V. Schroeder "An Introduction to Quantum Field Theory". The lecture notes on Quantum Chromodynamics (QCD) might be interesting for people diving into the particle physics standard model. "Finite-temperature field theory: Principles and Application" discusses systems in equilibrium but at finite temperatures and chemical potentials and thus connects to cosmology of the early universe. The field of Statistical Field Theory has the classic "Quantum Many-Particle Systems" by J.W. Negele and H. Orland or the more recent "Quantum Field Theory of Many-Body Systems" by X-G. Wen or "Ultracold Quantum Fields" by H.T.C Stoof, D.B.M. Dickerscheid, K. Gubbels. String Theory is so diverse that you'll find lots of different approaches, recommendations are Graduate Course in String Theory by A. Uranga, Applied Conformal Field Theory by P. Ginsparg, Lectures on String Theory by D. Tong or more introductory the book "A First Course in String Theory " by B. Zwiebach or the dense "Superstring Theory" by M. Green, J. Schwarz and E. Witten, "String Theory" by J. Polchinski. "Quantum Field Theory of Point Particles and Strings" by B. Hatfield assumes no previous stringy background and is known for excellent explanation of the path integral formalism. M. Nakahara wrote the wonderfull bridge to maths: "Geometry, Topology and Physics". So please when looking for "references" in theoretical physics venture on solid grounds and don't get distracted by sketchy notes. Update: Peter West pointed out that the The Feynman Lectures on Physics are missing as a timeless reference.

I have noticed that when I am reading, I cannot simultaneously understand spoken words. If someone speaks to me while I am reading, I can pay attention to their voice, or to the text, but not both. It s as if these two functions share the same cognitive facility, and this facility can only handle one task at a time. If someone is talking on the phone nearby, I find it very difficult to focus on reading (or writing). If I m having a conversation with someone about a document, I sometimes have to ask them to pause the conversation for a moment while I read. This phenomenon isn t unique to me. In Richard Feynman s What Do You Care what Other People Think?, there is a chapter entitled It s as Simple as One, Two, Three where he describes his experiments with keeping time in his head. He practiced counting at a steady rate while simultaneously performing various actions, such as running up and down the stairs, reading, writing, even counting objects. He discovered that he could do anything while counting to [himself] except talk out loud . What s interesting is that the pattern varies from person to person. Feynman shared his discovery with a group of people, one of whom (John Tukey) had a curiously different experience: while counting steadily, he could easily speak aloud, but could not read. Through experimenting and comparing their experiences, it seemed to them that they were using different cognitive processes to accomplish the task of counting time. Feynman was hearing the numbers in his head, while Tukey was seeing the numbers go by. Analogously, I ve met people who seem to be able to read and listen to speech at the same time. I attributed this to a similar cognitive effect: presumably some people speak the words to themselves, while others watch them. Feynman found that, although he could write and count at the same time, his counting would be interrupted when he had to stop and search for the right word. Perhaps he used a different mental faculty for that. Some people seem to be able to listen to more than one person talking at the same time, and I wonder if that s related. I was reminded of this years later, when I came across this video on speed reading. In it, the speaker explains that most people read by silently voicing words, which they can do at a rate of only 120-250 words per minute. However, people can learn to read visually instead, and thereby read much more quickly. He describes a training technique which involves reading while continuously voicing arbitrary sounds, like the vowels A-E-I-O-U. The interesting part, for me, was the possibility of learning. I realized that different people read in different ways, but hadn t thought much about whether one could change this. Having learned a cognitive skill, like reading or counting time, apparently one can re-learn it a different way. Visual reading would seem, at first glance, to be superior: not only is it faster, but I have to use my eyes to read anyway, so why tie up my listening facility as well? Perhaps I could use it for something else at the same time. So, I tried the simple technique in the video, and it had a definite effect. I could feel that I wasn t reading in the same way that I had been before. I didn t measure whether I was going any faster or slower, because I quickly noticed something more significant: my reading comprehension was completely shot. I couldn t remember what I had read, as the memory of it faded within seconds. Before reaching the end of a paragraph, I would forget the beginning. It was as if my ability to comprehend the meaning of the text was linked to my reading technique. I found this very unsettling, and it ruined my enjoyment of the book I was reading. I ll probably need to separate this practice from my pleasure reading in order to stick with it. Presumably, over time, my comprehension will improve. I m curious about what net effect this will have, though. Will I still comprehend it in the same way? Will it mean the same thing to me? Will I still feel the same way about it? The many levels of meaning are connected to our senses as well, and the same idea, depending on whether it was read or heard, may not have the same meaning to an individual. Even our tactile senses can influence our judgments and decisions. I also wonder whether, if I learn to read visually, I ll lose the ability to read any other way. When I retrained myself to type using a Dvorak keyboard layout, rather than QWERTY, I lost the ability to type on QWERTY at high speed. I think this has been a good tradeoff for me, but raises interesting questions about how my mind works: Why did this happen? What else changed in the process that might have been less obvious? Have you tried re-training yourself in this way? What kind of cognitive side effects did you notice, if any? If you lost something, do you still miss it? (As a sidenote, I am impressed by Feynman s exuberance and persistence in his personal experiments, as described in his books for laypeople. Although I consider myself a very curious person, I rarely invest that kind of physical and intellectual energy in first-hand experiments. I m much more likely to research what other people have done, and skim the surface of the subject.)

Many people run Debian testing or unstable or some mix thereof. This works pretty well for a development system or a general desktop system if you know a bit about what you're doing (note: nonetheless officially not recommended). Sometimes you throw packages from experimental into the mix, if you want to get the latest stuff that isn't yet fully integrated into the rest of Debian.

The default APT priority of the Debian experimental release is 1, which ensures that it is never automatically installed or upgraded. This is not always ideal, in my experience. Of course, you don't want a package from experimental to take precedence over a package from stable, testing, or unstable by default. But I think when you have in the past installed a package from experimental, you probably want to pull in upgrades to that package from experimental as well. Otherwise, you will end up with completely unmaintained packages on your system. That is because in practice many packages in experimental are not actually experimental or broken or unmaintained, but just an advance branch of some software that is just for some reason not ready to go down the unstable-testing-stable road.

To make this work better, I have set the priority of experimental to 101 in my /etc/apt/preferences:

Package: *
Pin: release experimental
Pin-Priority: 101

Now the following will happen: If you just apt-get install a package, it will come from whatever "normal" release you have in your sources.list, say stable or testing. You can override that using -t experimental as usual. If you install a package from experimental and later an upgrade is available in experimental, apt-get upgrade will install that automatically. Also, if an upgrade in a "normal" release appears that has a higher version number, that version will be installed.

Of course, caveats apply. Some software in experimental is really experimental and should only be installed under close supervision. If a package is available only in experimental, this setup will install it when you ask for the package, even if you might not have actually wanted it if you had known that it was in experimental. Figure it out yourself. :)

Similar considerations apply to backports. I use

Package: *
Pin: release a=lenny-backports
Pin-Priority: 102

On the system I have in mind here, the standard distribution is stable, testing is 101, and backports is 102, taking precedence over testing. Because for some architecture-independent packages you don't need backports, so you can pull them directly from testing that way.

In general, the APT priority business is relatively powerful and often a good alternative to, say, manually downloading packages from various distributions, installing them manually, forgetting where they came from, and never upgrading them.

The last few days I have been looking into the status of the LDAP directory in Debian Edu, and in the process I started to miss a GUI tool to browse the LDAP tree. The only one I was able to find in Debian/Squeeze and Lenny is LUMA, which has proved to be a great tool to get a overview of the current LDAP directory populated by default in Skolelinux. Thanks to it, I have been able to find empty and obsolete subtrees, misplaced objects and duplicate objects. It will be installed by default in Debian/Squeeze. If you are working with LDAP, give it a go. :) I did notice one problem with it I have not had time to report to the BTS yet. There is no .desktop file in the package, so the tool do not show up in the Gnome and KDE menus, but only deep down in in the Debian submenu in KDE. I hope that can be fixed before Squeeze is released. I have not yet been able to get it to modify the tree yet. I would like to move objects and remove subtrees directly in the GUI, but have not found a way to do that with LUMA yet. So in the mean time, I use ldapvi for that. If you have tips on other GUI tools for LDAP that might be useful in Debian Edu, please contact us on debian-edu@lists.debian.org. Update 2010-06-29: Ross Reedstrom tipped us about the gq package as a useful GUI alternative. It seem like a good tool, but is unmaintained in Debian and got a RC bug keeping it out of Squeeze. Unless that changes, it will not be an option for Debian Edu based on Squeeze.

A couple of months ago, Steve McIntyre introduced the notion of Developer Certification. In essence, if you are (or have been) a Debian Developer, you can ask for a certificate of that status of yours; that might be useful in case you need to "prove" it to anyone (more precisely: to anyone who would care about / believe in a certificate ...). Some people has asked me to provide such certificates and at the n-th iteration I took the chance to streamline a bit the process (yes, I'm lazy). In case you're interested, please check the DDCertificate wiki page and follow the instructions there.
While you are at it, join me in thanking Agnieszka Cicha-Cisek and Patryk Cisek, as they have prepared the LaTeX template. Some other people were interested in being certified, but missed the announcement, so I'm blogging about it mainly to spread the news. Paul Wise has already submitted a request for proper documentation of this possibility. We currently don't have a template for Debian Maintainers, but it should be straightforward to add: patches are welcome!

Hello Currently Config::Model can upgrade /etc/ssh/sshd_config file because Sshd model is complete. All 80 parameters mentioned in sshd_config man pages are described there. The whole model (including doc is about 1000 lines long). If one just want configuration upgrade capability, requiring a complete model is too much work. The aim of this GSoC project is to find a way to provide upgrades at a reasonable cost. Ep 01 focused on what feature was missing from Config::Model to provide a model that could handle unknown parameters in most cases to enable upgrades without a complete model. This covered the use case of an unmaintained model facing software evolution. Now, let s go on with the OpenSsh example and let s see what would be the minimal model that would enable upgrades from older sshd_config version to a more recent one. (Note that this blog is based on upgrade requirements mentioned in sshd_config man page). This will cover the use case of a maintained model targeted for upgrades. From last blog, we know that this minimal model must feature:

• structural information (i.e. Match parameter)
• upgrade information (KeepAlive to TCPKeepAlive)

Let s tackle the structure of this minimal model by re-using the current model structure. We will need 2 classes:

1. Sshd: to handle all leaf parameters a the the Match parameter
2. Sshd::MatchElement: to handle parameters within a Match block

Sshd::MatchElement will need to handle unknown leaf parameters (exceptd Match parameters), so its declaration should be like: 'Sshd::MatchElement' =>
accept =>
match_not => '/Match/i'' ,
type => 'leaf',
value_type => 'string'


Note that there s no element declaration. The accept structure means that Config::Model will accept any parameter that does not contain match in its name and will handle it as a string parameter. (Note that this feature is not yet implemented in Config::Model) Now, we must declare the main class: Sshd. It will feature the a wider accept statement and element declarations for the following parameters:

• Match (the only structural element)
• KeepAlive (obsolete parameter)
• TCPKeepAlive (value migrated from KeepAlive)

Here we go: Any unknown parameter will be accepted by Sshd configuration class: accept =>
type => 'leaf',
value_type => 'string'
, Here are the element that require a special treatment: Match just refer to the class declared above
Match =>
type => 'hash',
index_type => 'uniline',
cargo =>
type => 'node',
config_class_name => 'Sshd::MatchElement'
, KeepAlive is the obsolete parameter. Parameter with status 'deprecated' are handled by Config::Model but will not be written back in the configuration file. Hence re-using the deprecated information elsewhere is more than recommended.
KeepAlive =>
type => 'leaf',
value_type => 'enum',
status => 'deprecated',
choice => [ 'no', 'yes' ]
, Here's the new parameter. It's value is computed from KeepAlive.
TCPKeepAlive =>
type => 'leaf',
value_type => 'enum',
choice => [ 'no', 'yes' ],
migrate_from =>
formula => '$keep_alive',
variables => keep_alive => '- KeepAlive'
,
,
Now that we have the model, we must figure out how to read and write value with minimal coding efforts. Due to the mismatch between the syntax of the file (flat structure) and the actual structure (special Match parameter), a dumb parser/writer cannot be used. A parser that takes into account Match is required. Either dedicated Perl code (like the parser/writer delivered with Config::Model::OpenSsh) or use Augeas and its sshd lenses. In summary, we ve seen that the model required to perform upgrades is about 30 lines instead of the 1000 lines required for a complete model. On the other hand, the syntax of sshd_config makes the parser and writer harder to write. But, normally, this parser/writer should not evolve during the life of OpenSsh project. Now the question that I cannot answer is: Can a packager handle the extra work to maintain this minimal model ? Feedback is welcome here Next episode will study how upgrades based on Config::Model can be applied on files with other syntaxes. All the best

on DMs and the packages they maintain The notion of Debian Maintainer (DM) has been with Debian for about 3 years. As of now, Debian has approximately 120 DMs, which maintain a significant part of the packages in the archive. I'm hereby happy to evilly spoil that Enrico Zini has just set up an index of Debian Maintainers and of the packages they maintain. The index is linked from the people section of our website as a symbolic step in giving more credit to DMs. Now, if anyone would like to setup a nice graph for the statistics page, which monitors the evolution of DMs (and DDs?), that would be useful.
Any idea on how to do that retroactively too?

Conference Management systems are web applications designed to make the lives of conference organisers easier. They usually include features such as registration, payment, paper submission and review, scheduling and publishing of announcements.

Since Wikipedia is apparently not a place for such a "spammy list," I figured I should at least post this here:

Name	Used by	License	Programming Language
A Conference Toolkit	YAPC::Eu	Artistic License	Perl
ConMan	Utah Open Source Conference, Texax Linux Fest	GPL	Python (Django)
Open Conference Systems	various academic conferences	GPL	PHP
OpenConferenceWare	Open Source Bridge	MIT	Ruby on Rails
Pentabarf	DebConf, FOSDEM, CCC	GPL	Ruby on Rails
SCALEreg	SCALE	GPL	Python (Django)
Zookeepr	linux.conf.au	GPL	Python (Pylons)

If you know of any other Open Source systems, please leave a comment!

Face it: technology fails. Sometimes. Sooner or later.Statistics are a nice way to fool people, because they can't interpret the numbers properly. And usually this is done to make things sound less risky than they really are. But it's just too easy to lie with numbers. Say, they risk of a major incident at a plant is less than 1% (per year). Sounds good, doesn't it? But if you have 100 plants, that means it will happen about once a year. Make that 1000. Or even more.There are currently around 440 nuclear reactors in use for electricity. Probably some more the IAEA doesn't know about. There are definitely extra reactors in various military vehicles including unmaintained russian submarines. So make that 500. So looking forward to the next 200 years, we want to make sure things are not likely to happen at a rate of 0.001%. Unless our atomic plants are way more than 99.999% secure, we're likely to see a major nuclear accident sooner or later.Which brings us to a totally differnt scale when we look at photovoltaics or wind power. There are just so many more of these plants, that you can bet on some of them failing completely every day. The good news about these plants is that their damage potential is just so much lower. They might be as much as thousandfold more likely to fail than a nuclear plant. And there are probably a thousand more, too. But even if we completely underestimate the risk they just don't do as much damage even in the worst case. Much unlike a nuclear meltdown or such an oil spill. I bet noone would have thought of oil drilling being this risky. After all, it has been done for years.So how is your risk assessment of nuclear power? Is it less risky than oil drilling?