Its the close of September. And just a week ago I turned 16: in hex, that is. Although I do distinctly remember how I wished coming back to being a 16-decimal-year-old then… So, how does it feel being one? I’ve barely begun to feel it. There has been a lot of distractions to keep me from contemplating too much about $age:

• School: Its almost out. Today we’re supposed to have our finals, but due to the wake of the super-typhoon that hit Manila a couple of days ago, the admins moved the exams to next Saturday. Yay!!!
• Work: Since the beginning of September, I have taken up work as a guest Software Engineer for Orange & Bronze Software Labs. Their mightly SABDFL, Calen Legaspi, has been working me up to join his company since he first heard of me last June (I think,) thanks to Charo and Ealden who at the time were regulars at #ubuntu-ph. Last August, I got a call from Dean, and getting me interested in doing a C++ project for the company. Well, needless to say, after learning lots about Perl and software development in general playing Sendpage on the SoC, I decided to jump in for a 3-month stint: now that my first month’s up, and we’re in a bit of a jam thanks to some force majeure, I hope we do kick out something by the first week of October (and have an Oktoberfest even…)
• Play: Also at the start of the month did I get my very own laptop, thanks to Google from my SoC work: an MSI MegaBook S262, which looks so much like a MacBook, but really much powerful than what Apple’s offering: Core Duo processor, 1 GB DDR2, 80GB PATA, SuperMulti DVD, WiFi and LAN, all of which work wonderfully in Kubuntu and Sarge. And the hardware’s mighty upgradeable, too… Now, I am finding myself mall-hoping Metro Manila in hopes of finding decent free WiFi, hehe…
• Politics: There’s some mighty talk going on in the PLUG mailing list about the FOSS bill proposed by a allegedly-communist party in the House of Representatives. While I think its quite laudable to have Free Software finally getting some real legislative attention, my apprehensions about the trustworthiness of the current administration is getting the better of me. That, as well as my fears about the pushing party’s own agenda about the matter, have been keeping me on a rather cautionary stance, since being a FOSS developer myself, a lot of what the current draft presents will directly affect how FOSS will grow here in the Philippines. Hopefully, once this passes, the FOSS bill ought to be a stimulator for Philippine growth, and not become just another fancy way for congressmen to get more pork…

That’s just the tip of the iceberg. Moving back to Manila again has its own issues; I still have to look for a better place to stay (not that I’m complaining about my Tita’s place in Malate, but hey, we’re already overcrowded… I suppose I’ll get my own flat once I think I can stay out beyond the 3 months,) and I have to get better internet connectivity (all the better for my chroots to keep updated, and finally get back on the Debian/Ubuntu packaging scene.) I also have to find some time to get a passport, a haircut, some nice pair of sneakers, and a Wii. I’ve yet to know what this being 0×16 business is all about, but this I have to say: Thanks $DEITY for all the fish.

Today I reached another milestone in the development of upstart, the packages in universe can now replace the existing sysvinit package. Before trying this, make sure your installation is up to date as we’ve had to split out some parts of sysvinit into a new sysvutils package. If you’re up to date, and want to try it out, install the upstart and upstart-compat-sysv packages from universe. Note that the first reboot after you’ve installed the packages (from sysvinit to upstart) will be a little tricky … use reboot -f. If your system boots and shuts down normally, everything’s working just fine. Note that both will be somewhat more quiet than you’re used to, unless you have usplash running. Throughout the rest of this entry, I’ll try to answer some of the questions and comments that I’ve received since the last post. Events As I talked about previously, upstart is an event-based init daemon. Events are the primary force for having your services and tasks started and stopped at the appropriate time and in the appropriate order. So what are events and where do they come from? (Note that this part is under development, so may change in later releases). Events are just simple strings that may be sent by any process when something it is tracking the state of changes. They have no state or longevity, and if, when queued, they do not cause any job state changes, then they have no effect unless they are sent again. Jobs can list which events cause them to be started if they are not already running and which events cause them to be stopped if they are running. Multiple start and stop events may be listed, in which case the first to occur changes the job until the next one occurs. upstart itself generates the following system events:

• “startup”, on system boot.
• “shutdown”, when the system is about to be shut down.
• “stalled”, when there are no jobs running and no events in the queue.

The shutdown tool included in the package also causes one of the following events to be sent once the “shutdown” event has been handled:

• “reboot”,
• “halt”,
• “poweroff”,
• “maintenance” (aka. going into “single user” mode),
• any user-defined event with shutdown -e event.

Jobs also generate events whenever they change state, this is the primary source of events for ordering:

• “jobname/start”, when the job is first started.
• “jobname/started”, once the job is running.
• “jobname/stop”, when the job is first stopped.
• “jobname/stopped”, once the job has stopped.
• “jobname”, for services this is generated once it is running; for tasks this is generated once it has finished.

And as mentioned, any other process on the system may send events through the control socket or just by using initctl trigger EVENT. For now this is just the event string, however it’s intended that the event may include other details including environment variables and even file descriptors. Typical example To clarify how it all hangs together, here’s an example (using fictional names) of how the tasks and events can be arranged to provide race-free mounting of filesystems.

• “udev” service started on the “startup” event.
• udev daemon is configured to send a “new-block-device” event whenever a new block device is added to the system.
• “checkfs” task is started on the “new-block-device” event to check the filesystem.
• “mountfs” task is started when the “checkfs” task has finished and mounts the filesystem if listed in /etc/fstab
• “filesystem-mounted” event is generated whenever a filesystem is mounted.
• “fstab” task is started on the “filesystem-mounted” event, it checks the list of mounted filesystems against /etc/fstab and if all are mounted, generates the “writable-filesystem” event.
• other services and tasks would be started on the “writable-filesystem” event.

By breaking this job into these small tasks, we can see how the pieces fit together. Because everything is now done on events, there are no race conditions; we know that any filesystem listed in /etc/fstab will be checked and mounted. The only reason they wouldn’t be is if there’s an error of some kind, and that means you have larger problems anyway and the system administrator would have a shell to fix it. Of course, the moment they finish checking the filesystem and mount it, the boot process would carry on. There’s no reason that any of these events need to be generated by the upstart daemon itself, it can receive them from any other daemon on the system such as udev, acpid, etc. This keeps the focus of the init daemon narrow. A large part of the future development will be working out exactly what kinds of events we want init itself to generate, what kinds we want to come from elsewhere, and what the contents of an event can be. Getting Involved If you want to get involved with trying to nudge the direction of upstart development, you can join the upstart-devel mailing list at http://lists.netsplit.com/ Or if you just want to grab the source code, tarballs are published at http://people.ubuntu.com/\_{scott/software/upstart/ and the bzr archive is at http://bazaar.launchpad.net/\}keybuk/upstart/main

upstart is a replacement for the init daemon, the process spawned by the kernel that is responsible for starting, supervising and stopping all other processes on the system. The existing daemon is based on the one found in UNIX System V, and is thus known as sysvinit. It separates jobs into different “run levels” and can either run a job when particular run levels are entered (e.g. /etc/init.d/rc 2) or continually during a particular run level (e.g. /sbin/getty). The /etc/init.d/rc script is also based on the System V one (and is in the sysv-rc package), it simply executes the stop then start scripts found in /etc/rcN.d (where N is the run level) in numerical order. Why change it? Running a fixed set of scripts, one after the other, in a particular order has served us reasonably well until now. However as Linux has got better and better at dealing with modern computing (arguably Linux’s removable device support is better than Windows’ now) this approach has begun to have problems. The old approach works as long as you can guarantee when in the boot sequence things are available, so you can place your init script after that point and know that it will work. Typical ordering requirements are:

• Hard drive devices must have been discovered, initialised and partitions detected before we try and mount from /etc/fstab.

• Network devices must have been discovered and initialised before we try and start networking.

This worked ten years ago, why doesn’t it work now? The simple answer is that our computer has become far more flexible:

• Drives can be plugged in and removed at any point, e.g. USB drives.

• Storage buses allow more than a fixed number of drives, so they must be scanned for; this operation frequently does not block.

• To reduce power consumption, the drive may not actually be spun up until the bus scan so will not appear for an even longer time.

• Network devices can be plugged in and removed at any point.

• Firmware may need to be loaded after the device has been detected, but before it is usable by the system.

• Mounting a partition in /etc/fstab may require tools in /usr which is a network filesystem that cannot be mounted until after networking has been brought up.

We’ve been able to hack the existing system to make much of this possible, however the result is chock-full of race conditions and bugs. It was time to design a new system that can cope with all of these things without any problems. What we needed was an init system that could dynamically order the start up sequence based on the configuration and hardware found as it went along. Design of upstart upstart is an event-based init daemon; events generated by the system cause jobs to be started and running jobs to be stopped. Events can include things such as:

• the system has started,

• the root filesystem is now writable,

• a block device has been added to the system,

• a filesystem has been mounted,

• at a certain time or repeated time period,

• another job has begun running or has finished,

• a file on the disk has been modified,

• there are files in a queue directory,

• a network device has been detected,

• the default route has been added or removed.

In fact, any process on the system may send events to the init daemon over its control socket (subject to security restrictions, of course) so there is no limit. Each job has a life-cycle which is shown in the graph below: The two states shown in red (“waiting” and “running”) are rest states, normally we expect the job to remain in these states until an event comes in, at which point we need to take actual to get the job into the next state. The other states are temporary states; these allow a job to run shell script to prepare for the job itself to be run (“starting”) and clean up afterwards (“stopping”). For services that should be respawned if they terminate before an event that stops them is received, they may run shell script before the process is started again (“respawning”). Jobs leave a state because the process associated with them terminates (or gets killed) and move to the next appropriate state, following the green arrow if the job is to be started or the red arrow if it is to be stopped. When a script returns a non-zero exit status, or is killed, the job will always be stoped. When the main process terminates and the job should not be respawned, the job will also always be stopped. As already covered, events generated by the init daemon or received from other processes cause jobs to be started or stopped; also manual requests to start or stop a job may be received. The communication between the init daemon and other processes is bi-directional, so the status of jobs may be queries and even changes of state to all jobs be received. How does it differ from launchd? launchd is the replacement init system used in MacOS X developed as an “Open Source” project by Apple. For much of its life so far, the licence has actually been entirely non-free and thus it has only become recently interesting with the licence change. Much of the goal of both systems appears initially to be the same; they both start jobs based on system events, however the launchd system severly limits the events to only the following:

• system startup,

• file modified or placed in queue directory,

• particular time (cron replacement),

• connection on a particular port (inetd replacement).

Therefore it does not actually allow us to directly solve the problems we currently have; we couldn’t mount filesystems once the “filesystem checked” event has been recived, we couldn’t check filesystems when the block device is added and we certainly couldn’t start daemons once the complete filesystem (as described by /etc/fstab) is available and writable. The launchd model expects the job to “sit and wait” if it is unable to start, rather than provide a mechanism for the job to only be started when it doesn’t need to wait. Jobs that need /usr to be mounted would need to spin in a loop waiting for /usr to be available before continuing (or use a file in a tmpfs to indicate it’s available, and use that modification as the event). This is not especially surprising given that Apple have a high degree of control over both their hardware and the actual underlying operating system; they don’t need to deal with the wide array of different configurations that we have in the Linux world. Had the licence been sufficiently free at the point we began development of our own system, we would probably have extended launchd rather than implement our own. At the point Apple changed the licence, our own system was already more suitable for our purposes. How does it differ from initng? Initng by Jimmy Wennlund is another replacement init daemon intended to replace the sysvinit system used by Linux. It is a dependency-based system, where upstart is an event-based system. The notion of a dependency-based system is interesting to talk about at this point. Jobs declare dependencies on other jobs that need to happen before the job itself can be started. Starting the job causes its dependencies to be started first, and their dependencies, and so on. When jobs are stopped, if running jobs have no dependencies, they themselves can be stopped. It’s a neat solution to the problem of ordering a fixed boot sequence and the problem of keeping the number of running processes to a minimum needed. However this means that you need to have goals in mind when you boot the system, you need to have decided that you want gdm to be started in order for it, and its dependencies, to be started. Initng uses run levels to ensure this happens, where a run level is a list of goal jobs that should be running in that run level. It’s also not clear how the dependencies interact with the different types of job, a dependency on Apache would need the daemon to be running where a dependency on “checkroot” would need the script to have finished running. Upstart handles this by using different events (“apache running” vs. “checkroot stopping”). Again while interesting, Initng does not solve the problems that we wanted to solve. It can reorder a fixed set of jobs, but cannot dynamically determine the set of jobs needed for that particular boot. A typical example would be that if the only dependency on the job that configures networking is the mount network filesystems job, then should that job fail or notbe a goal (e.g. because there are no network filesystems to be mounted) the result is that network devices themselves will not be configured. You could make everything a goal, and just use the dependencies to determine the order, however this is less efficient than just ordering the existing sysv-rc scripts (which can be done at install time). Another example is that often you simply don’t know whether something is a dependency or not without reading other configuration, for example the mount network filesystems may be a dependency of everything under /usr or may just be a dependency of anything allowing the user to login if it just mounts /home. The difference in model can be summed up as “initng starts with a list of goals and works out how to get there, upstart starts with nothing and finds out where it gets to.” How does it differ from Solaris SMF? SMF is another approach to replacing init developed by Sun for the Solaris operating system. Like initng it’s a dependency-based system, so see above for the differences between those systems and upstart. SMF’s main focus is serive management; making sure that once services are running, they stay running, and allowing the system administrator to query and modify the states of jobs on the system. Upstart provides the same set of functionality in this regard, services are respawned when they fail and system administrators can at any time query the state of running services and adjust the state to their liking. Will it replace cron, inetd, etc? The goal of upstart is to replace those daemons, so that there is only one place (/etc/event.d) where system administrators need to configure when and how jobs should be run. In fact, the goal is that upstart should also replace the “run event scripts” functionality of any daemon on the system. Daemons such as acpid, apmd and Network Manager would send events to init instead of running scripts themselves with their own perculiar configuration and semantics. A system administrator who only wanted a particular daemon to be run while the computer was on AC power would simply need to edit /etc/event.d/daemon and change “on startup” to “on ac power”. What about compatibility? There’s a lot of systems administrators out there who have learned how Linux works already and will not want to learn again immediately, there’s also a large number of books that cover the existing software and won’t cover upstart for at least a couple of years. For this reason, compatibility is very important. upstart will continue to run the existing scripts for the forseeable future so that packages will not need to be updated until the author wants. Compatibility command-line tools that behave like their existing equivalents will also be implemented, a system administrator would never need to know that crontab -e is actually changing upstart jobs. Does it use D-BUS?

“To D-BUS people, every problem seems like a D-BUS problem.” —Erik Troan

The UNIX philosophy is that something should do just one job, and do it very well. upstart’s one job is starting, supervising and stopping other jobs; D-BUS’s one job is passing messages between other jobs. D-BUS does provide a mechanism for services to be activated when the first message is sent to them, thereby starting other jobs. Some people have taken this idea and extended it to suggest that all a replacement init system need do is register jobs with D-BUS and turn booting into a simple matter of message parsing. This seems wrong to me, D-BUS would need to be extended to supervise these services, provide means for them to be restarted and stopped; as well as deal with being process #1 which means cleaning up after children whose parent’s have died, etc. It seems far simpler to arrange for D-BUS to send an event to init when it needs a service to be started, and focus on being a very good message passing system. The IPC mechanism used by upstart is not currently D-BUS because of various problems, however it’s always been expected that even if init itself doesn’t communicate with D-BUS directly, there would be a D-BUS proxy that would ensure messages about all init jobs and events would be given to D-BUS and D-BUS clients could send messages to init to query and change the state of jobs. What is the implementation plan? Because this is process #1 we are changing, we want to make sure that we get it right. Therefore instead of releasing a fully-featured daemon and configuration to the world, we’re developing it in the following stages:

1. Principal development; at the end of this stage the daemon has been implemented and can manage jobs as described.
2. Replacement of /sbin/init while running the existing sysv-rc scripts. This is the shake-down test of the daemon, can it perform the same job as the existing sysvinit daemon without any regressions?
3. /etc/rcS.d scripts replaced by upstart jobs. These consitute the majority of tasks for booting the system into at least single-user mode, and contain many of the current ordering problems and race conditions. If the daemon solves the problems here, it will be a success.
4. Other daemon’s scripts replaced by upstart jobs on a package-by-package basis; this will be an ongoing effort during which upstart will continue running the existing sysv-rc scripts as well as its own jobs. During this time the event system may be tweaked to ensure it truly solves the problems we need.
5. Replcement of cron, atd, anacron and inetd. This will happen alongside the above and result in a single place to configure system jobs.
6. Modification of other daemons and processes to send events to init instead of trying to run things themselves.

The current plan is that we will be at least part of the way into stage #3 by the time edgy is released, with that release shipping with upstart as the init daemon and the most critical rcS scripts being run by it to correct the major problems For edgy+1 we hope to have completed stage #5 and be at least part of the way into the implementation of stage #6. From the start of development of edgy+2, no new packages will be accepted unless they provide upstart jobs instead of init scripts and init scripts will be considered deprecated. What state is it in now? The init daemon has been written and is able to manage jobs as described above, receiving events on the control socket to start and stop them. This has now been uploaded to the Ubuntu universe component in the upstart package for testing before it becomes the init daemon. We welcome any experienced users who want to help test this; install the package and follow the instructions in /usr/share/doc/upstart/README.Debian to add a boot option that will use upstart instead of init. If your system boots and shut downs normally (other than a slightly more verbose boot without usplash running) then it is working correctly. Other types of events will be added as required during development and testing. Currently only a basic client tool (initctl) has been written, compatibility tools such as shutdown will be written over the next week or two before it replaces our sysvinit package.

It’s been over a year now since my last proper upload to Debian, and nine months since I announced my intent to put aside working on Debian for a while. With Matthew Garrett’s resignation from Debian, several people have compared it to my own “resignation” from Debian. It has got my thinking about whether I currently intend to ever end my “Sabbatical” and return as an active Debian Developer. I think that the end of my love-affair with Debian started at Debconf last year where several developers treated those of us who also worked on Ubuntu quite rudely. Someone was attacked for wearing an Ubuntu t-shirt at the conference, while someone else was applauded for wearing a “Fuck Ubuntu” t-shirt. That’s where I realised that maybe I didn’t have as much in common with these people as I thought I did. I still don’t understand why Debian singles Ubuntu out for this kind of treatment, we’re still the only derviative distribution that makes all of our patches to Debian available, yet Ubuntu is claimed to not do anything at all. Another example is that Ubuntu is being asked to change the Maintainer field of every package, something no other derivative is being asked to do or has ever been asked to do. Martin Krafft has had some interesting things to say about this strange relationship in the past. If that was the start of my falling out with Debian, I think that Debian considering removing documentation and firmware from the distribution, especially the documentation, was another point I started wondering whether I shared anything in common with the project anymore. Call me strange, but I think that one of the fundamental purposes of a Linux distribution is to be useful to its users. If nobody can use the distribution because it doesn’t support their hardware, and even if it did, all the documentation has been stripped out; I started to wonder what it’s aims are. It became increasingly apparent that the only users Debian was considering a priority were its own developer. And the third thing is simply a matter of Fun. Fun for me, at the moment at least, has been to build a system that fits together extremely nicely with each component doing the right thing. For Ubuntu this has meant being a driving force for it being Linux 2.6 only, with reliance on udev for hardware, etc. Upstart is just a continuation of these goals, getting a system which all “just works”, even if it means throwing out a few things people were previously fond of. All of these things would have been impossible to do in Debian itself. Getting upstart installable required changes to twelve different packages, including sysvinit itself; at a worst case, this would have required the agreement of twelve different maintainers in Debian. It’s often exhausting just persuading one of the reason for the change, persuading a dozen would have been a herculian effort. Perhaps Matthew is right, what Debian lacks is a single leadership. There’s nobody in Debian I could have gone to for approval over the changes I wanted to make, whose decision developers cannot overrule. Ubuntu has such people (the Technical Board and sabdfl), which gives the project an obvious direction instead of a couple of hundred people all pulling in different directions. In a way, I don’t feel that I’ve left Debian. I feel like I was happily going along, only to realise the mob had gone in a different direction and with no easy way of rejoining the group.

Here at Canonical Towers we have several staff who worship at the altar of Extreme Programming, and as such many of the methodologies and rituals prescribed by that religion find their way into our day-to-day working practices. A few of these came together in an interesting way a few weeks ago, and it was suggested by a cow-orker that I blog about it so he could give the URL to people. The first ritual is that of the sprint, I don’t think this is orthodox XP but rather something inspired from it that we picked up from the Python community. With all of the Canonical developers scattered across the globe mostly working from their own homes, it’s become a useful tool; particularly for the Launchpad team. The basic idea for those that haven’t heard of it is simple, and perhaps obvious; you get a selection of the team together in one place, sit them around the same table with particular goals to complete. In effect it’s highly compressed facetime and high bandwidth interaction to nail those tasks that need it, before you head off again and work at a more sedate pace. The second is directly from XP doctrine and is that peculiar observance known as pair programming, something that is often coupled with sprints. For anybody who hasn’t encountered this before, it’s something I’ve always found rather odd. You get two programmers together, both itching to code, and you take one of them’s laptop away; and you don’t just force them to fight over the keyboard either, the laptop-less soul isn’t allowed to touch it. The theory here is that it frees the deprived individual of the hassle of coding and allows them to direct the programmer in ways that may not be immediately obbious, or alternately think about the next bit of work that needs doing. Another interesting side-effect is it can be an interesting way to learn code you’ve not worked with before, if you’re the one doing the coding and you’re being guided what to do by a sage who already knows it. I have a funny story here, so I’m going to digress from the main stream for a moment to tell it. A few months ago I was working in the London office, Mark had been up all night coding and had then given me responsibility to get his changes landed onto the Launchpad mainline. I’m not that hot on quite a bit of Launchpad, and fade to utterly clueless the nearer the code gets to the web application itself; and when trying to merge the two there were conflicts which I needed Mark’s help to resolve. Now as anybody who’s met Mark knows, he’s a pretty good example of a Type-A personality, yet he suggested that we do a spot of pair programming to get the code in and I’d be the one with the laptop as it’d help me get to grips with the affected parts. This hilighted something I’ve always seen as a problem with pair programming, dealing with it when the a person with the keyboard has a totally different way of working to you. In particular, I’m an emacs user, whereas Mark is a die-hard vim user; but also right down to the working directory I would work from, how I test results, etc. When you’re the one without the laptop, this can be quite infuriating, as you know exactly how to solve a problem and the idiot with the keyboard is dithering about doing things you don’t understand just to get there. If you’re a Type-A personality, you generally snatch the laptop away at this point and do it yourself; or at least you would, if you could drive the strange editor the other person uses. I swear Mark was sulking as he gave the laptop back and let me do it. Anyway, there is some relevance to that and we’ll come to it in a moment. The third and final methodology is the concept of unit tests and more specifically test driven development. For anyone who hasn’t come across this before, I highly recommend it; I was suspicious too when Robert Collins took it upon himself to teach me the true way, but now I’m sold. Simply the idea is that if you have any code that doesn’t have another piece of code in a test suite that checks that it’s working correctly, that code is broken. More particularly unit testing involves checking just one feature or requirement at a time, and stacking them together to test all of the code paths. I’ve actually found that this improves the APIs I design, as I write the code in small blocks and functions to make them easier to test. Test driven development takes it even further, you write the unit tests first, before you write the code they’re supposed to test; usually one or two at a time. Obviously these tests will fail at first, it’s then your job to write as little code as possible to make them pass. If your code isn’t right, you add a unit test that will fail, and modify the code to make it pass. This really comes into its own when you’re fixing bugs later, once you’ve identified the bug you write a test case or two that cause the problem; these will of course fail. You can then modify the code to make them pass, and at the same time be sure you’ve not broken other functionality because of the existing test suite. I’ve also found it really useful for particularly complicated or tricky pieces of code, especially those intricate algorithms that do particularly heavy lifting. So onto the event itself, this was a sprint in our London office to indoctrinate Gustavo Niemeyer with the various projects he’d be working on. The goal for this sprint was decided to start the conversion of HCT to Bazaar-NG, and to do this Gustavo and I would pair program. Now my last experience of pair programming had been that story with Mark (see, it had some relevance) and I knew I’d be just as bad if I wasn’t allowed to have the keyboard. I was also acutely aware that if Gustavo was just sitting by and watching, he wouldn’t get much benefit from it either, so he needed to be actively involved in the coding so he could learn the things he’d be working on. I came to what I thought was a pretty neat, and obvious, solution to these problems. We set up my laptop with the code we’d be working on, and on my display were two side-by-side terminals both running screen sessions. Gustavo then set up two same-sized terminals on his, ssh’d into my laptop from both of them and joined the screen sessions. In the left-hand one he ran vi, and in the right-hand one I ran emacs. Thus we both had keyboards, and both had editors, yet could see each other working and even steal the keyboard without danger of violence. We didn’t just sit side-by-side and code on different things though, that’s not pair programming and is just ordinary programming with a bit of a voyeuristic twist. What we did was: in my terminal I started writing the test cases for the code we needed, it was Gustavo’s job to write the code that would make them pass. We actually added a third terminal in which we could run the test cases themselves; so I could run them when I’d added something that would fail, and Gustavo could run them when he thought he’d made them pass again. This turned out to be a rather fun way to work, and at one point I was almost able to try and convince myself that the code was writing itself to pass the test cases I was writing. It also got me thinking that it’d be really neat to use genetic algorithms to breed code to pass test cases.

Last saturday around 2100 (UTC-0400) some people started joining the #debian-ve IRC channel at OFTC, in order to participate on the very first Venezuelan Bugsquashing Party. We had a lot of people interested not only in squashing but also developing for Debian and other topics. Some DD’s were around, specially An bal Monsalve Salazar (anibal) who has been very helpful on testing and uploading packages. Both me and Jos Luis Rivas (ghostbar) made a couple of NMU’s (in his case, xfe and divine; in mine, sdr and orca), fixing six RC bugs. Jos Luis is like 17 or 18 years old and has proven to be a very energetic Debian collaborator. Other maintainers from Debian Venezuela (actually, we’re eleven persons as of last week) were around but couldn’t make a NMU at the time of the event. Others weren’t even present. It was a very small BSP indeed, but we learned lots of things and hopefully our work will help improving the quality in Debian a little bit. It also settles our desires as a group to improve our knowledge and work together to improve the Project without disrupting the overall ecosystem. By the way, the Venezuelan Debconf is definitely going to happen between October 17th. and 21st. Hopefully we’ll have Benjamin Mako Hill, Enrico Zini, Alvaro Lopez Ortega (OMG! Cherokee!) and Randal Schwartz sharing a nice time with people from all parts of Venezuela and the rest of South America. Some local Debian maintainers will set up some nice workshops and demonstrations, ranging from Xen and LTSP in Debian to QA and the local GNU/Linux distribution projects. This local Debconf is part of a larger event, the World Forum on Free Knowledge, which some people at Debian Venezuela help to make. Returning to the BSP topic, I was looking out at a couple of bugs out there, but I lack the hardware and the experience to handle them. One of this is #333915 and other orca bugs, and other one is #385078 regarding a Debconf script in xserver-xorg. The morning before the BTS I was testing the MBONE tools with a friend of mine, and we were quite unhappy by the fact that sdr was almost unusable (passing the mouse cursor over some buttons resulted in annoying notices). So, if you use sdr, please test the last NMU I sent, which fixes two bugs. Just for reference, the webpage where I keep my Debian-related work is here. The case where I learned most was #386938, regarding xserver’s FTBFS in s390. Events like BSP are a great way to motivate people to participate in the Project: while trying to learn anything about this bug I ended reading documentation from IBM, asking advice from someone with an S/390, sending a couple of emails to debian-s390@lists.d.o, browsing at a DD patch in upstream, looking at buildd logs, searching the Web for opcodes lists… usually trying to explain how all this pieces join in a sane way (most times; well, some times, well, seldomly) is quite difficult for someone who tries to promote Debian, but technical events like the BSP provide a really accurate way to see how things work in and around Debian.

One of the single most useful packages when it comes to PDFs in Linux is pdfjam. From the website:

• pdfnup, which allows PDF files to be "n-upped" in roughly the way that psnup does for PostScript files.
• pdfjoin, which concatenates the pages of multiple PDF files together into a single file.
• pdf90, which rotates the pages of one or more PDF files through 90 degrees (anti-clockwise).

The installation is easy as always: apt-get install pdfjam PDF is not exactly the most easily editable format out there, but these tools can save you lots of time and trouble. Just recently I needed to merge two PDFs into one (and I didn't have any source format of the files). A simple pdfjoin foo1.pdf foo2.pdf --outfile bar.pdf does the job in a few seconds. Equally useful when you need to print huge documents is pdfnup --nup 2x2 foo.pdf, which sticks four PDF pages into one (thus drastically reducing the amount of pages you have to print)... Update 2006-09-20: As was noted by several people, pdftk is very cool, too. It can do some other things such as split PDFs, encrypt/decrypt them, manipulate metadata and more...

One of the best part of Rhythm and Roots is that all of downtown Bristol is open, and accessible on a whim. This is the only time of year I can go into the Cameo and enjoy the balcony of this rundown ex-theater turned Christian radio station, with no worse effects than listening to a little Gospel music. The gorgeous Paramount is open to explore (and leech off its wifi), and so many stores up and down have musicians in them providing an excuse to go in and look around without feeling any commercial pressure. It's also nice to walk down the middle of the state line on State St. My other favorite thing is the jam sessions that spring up here and there later in the day with so many bands in one place. Passing a bassist and fiddler on the sidewalk, or six-seven people from two or three bands sitting off playing quietly for themselves and a small, happy audience. As for the actual performances, this year I most enjoyed the Cajun/jazz/swing/innovative mix of The Red Stick Ramblers. It was good to see the divineMAGees in person, but the outdoor sound system wasn't good enough for their sound and I missed the indoor gig. I also appreciated nice bluegrass from Chatham Cty. Line, and old-timey Piedmont music of the Carolina Chocolate Drops. And bits and peices from a dozen or so other bands.

One thing that has always appealed to me about Debian is the strength of the community behind it. A somewhat recent incident has reminded me of how strong this community really is. When several members of the Debian community became concerned about a situation in the life of another member, they immediately tried to contact that member, and that member’s friends and family to insure that person would be ok. Phone calls were made halfway across the world in the middle of the night (in various timezones) to insure the well-being of a member of our community. It is a strong reminder that even though the Debian community may have vigorous arguements about technical and social issues, we still take care of our own.

A lot of people outside Germany, including here in Ghana, can't pronounce my name right (whereas right is what I'm used to...). So I looked through the German wikipedia and tried to figure out how to write my name in the IPA. The result is:If you don't have unicode available, this will probably look strange to you. All these sounds have strange names, here they are:

• j: palatal approximant / Stimmhafter palataler Approximant
• : open-mid back rounded vowel / Gerundeter halboffener Hinterzungenvokal
• a: open front unrounded vowel / Ungerundeter offener Vorderzungenvokal
• : voiceless uvular fricative / Stimmloser uvularer Frikativ
• : near-close near-front unrounded vowel / Ungerundeter zentralisierter fast geschlossener Vorderzungenvokal
• m: bilabial nasal / Stimmhafter bilabialer Nasal

And yes, it is the same letter as in Te , but not the same pronounciation, which is t x. Update: I had to convert my serendipity blog to UTF8 to make this entry right. Did so by mysqladmin dump'ing the whole database and running it through iconv, and then re-inputting it. Sorry to any planets that had a broken entry for a while. Maybe this update paragraph makes these planets update the entry :-)Update 2: As I'm already showing of with unicode characters: The name Joachim is derived from Jehoiakim (Jojakim in German), which is Hebrew and looks like this:

Decorators in Python are just fantastic. Here are a few I've used in Postr. Update: the wonderful James Hensbridge expanded the decorators, so I've updated this post.

def threaded(f):
    def wrapper(*args, **kwargs):
        t = threading.Thread(target=f, args=args, kwargs=kwargs)
        t.setDaemon(True)
        t.start()
    wrapper.__name__ = f.__name__
    return wrapper

This decorator (stolen from O'Reilly) calls the method in a new thread, so execution returns straight away. I use this for long-running tasks that cannot be handled in an asynchronous manner (such as the photo uploading in Postr, which currently uses urllib). The main thread returns straight away so the interface doesn't block, and the uploads continue in the background. Of course this new thread cannot just call GTK+ methods, as GTK+ itself isn't threadsafe. So, I have another decorator that causes a method to be always executed in the main loop by scheduling an idle handler that calls it.

def as_idle(f):
    def wrapper(*args, **kwargs):
        event = threading.Event()
        ret = []
        def task():
            ret.append(f(*args, **kwargs))
            event.set()
            return False
        gobject.idle_add(task)
        event.wait()
        return ret[0]
    wrapper.__name__ = f.__name__
    return wrapper

Erich Schubert requested return values, so James added those too. The calling function will block until the idle handler has called the decorated function. I've split the decorators out into a separate file in Postr, so you can view the latest version online. Magic stuff!

On Friday afternoon I'll be arriving in Oldenburg, Germany, for the eleventh annual Linux developers' conference. Historically, this conference has had a strong focus on non-x86 ports of the Linux kernel, boot loader development, the GNU toolchain, and so forth. At long last, it looks like this may be my opportunity to get my Macintosh Quadra 840AV out of mothballs and back into commission, thanks to Wouter Verhelst. I should be able to fit it into my luggage if I don't bring many clothes... :-) This year, however, in addition to that, a couple of mini-conferences are being piggybacked onto the Oldenburg meeting. These include the GNU Classpath and Debian Java DevJam and the Debian Security Summit. The Java programming language is a divisive issue in the Free Software community, and has a degree of controversy that sets it apart from the usual language wars. The dominant factor in this controversy stems from what Richard Stallman refers to as the Java trap; with the specifications controlled, and the reference implementation kept unavailable on DFSG-free terms by, an industry consortium dominated by large corporations, a Free Software hacker might fear that using Java will consign them to either having to compromise their principles by using non-free class libraries (for example), or being doomed to chase the taillights of standards that could conceivably be tailored to disadvantage competitors. (Java is not alone in this respect; many people fear that Microsoft's .NET, despite being openly standardized through ISO/IEC, will in actuality be completely controlled by Microsoft.) Despite this peril, Java is attractive to GNU/Linux-using organizations. The Free Standards Group, developers of the Linux Standard Base, has received inquiries about a Free Java standard and implementation from organizations already committed to GNU/Linux. In my job, I've encountered an interest in Java from several customers and prospects. Intriguingly, these institutions are, by and large, very much aware of the Java Trap. They like the language, and are not strong advocates of Free Software, but they too are worried about vendor lock-in. They've seen the success of community-driven development as GNU/Linux moves from strength to strength, claiming territory formerly held by Microsoft and proprietary versions of Unix. Even if I can't persuade a customer to adopt a Free Java stack, I can exhort them to only code against Java standards that have seen a free implementation. That way, their development bets are hedged against any "madman theory" of the controlling vendor. Furthermore, this way they only code to standards that are seeing independent implementations, and they leave their engineers free to switch between varieties of development kit. Engineers like flexibility because it enables them to work more efficiently; sales people, marketing personnel, and strategists like efficient engineers because they make a firm more nimble. That's where the GNU Classpath and Debian Java DevJam comes in. Free Software Java enthusiasts want to see their implementations fully mature, and are working hard to make it so. The Free Software community has the opportunity to make its Java implementation not just an available alternative, but a compelling alternative to the proprietary ones on technical as well as licensing grounds. The recent release of GNU Classpath 0.18 shows just how vigorously this opportunity is being seized. Having mature software is only half the battle, however; that software has to be coherently put together and easy for the user and developer to manipulate. For many of these folks, it's not enough just to have good, Free Java virtual machines (like Kaffe and SableVM), class libraries (GNU Classpath), compilers and interpreters (gcj and gij, respectively, from the GNU Compiler Collection), and application servers (Jakarta Tomcat, JBoss, and JOnAS, among others). They also want these technologies to be mutually integrated and easy to install and use. Good software and good packaging complement each other to drive adoption of the technology, and that's what the DevJam is all about. I'm glad to see that representatives of Debian's Java packaging team will be joining not just upstream authors, but their counterparts at Fedora, Ubuntu, and Gentoo in furtherance of this goal. I've approved a budget of EUR 2000, which Petter Reinholdtsen will administrate, to support the expenses of Debian's participation in the DevJam. We've received 1500 USD in sponsorship of this event from a corporate sponsor that chooses to remain anonymous. The other mini-conference I'll be attending is the Debian Security Summit. We're bringing together the heads of our Stable Security and Testing Security teams — the two Joeys, Joey Schulze and Joey Hess, as well as a bevy of other security-minded people, with the goal of revitalizing and streamlining our security processes. Several members of the Stable Security Team have gone dormant over the past several months (or longer), leaving an increasingly small number people to handle, as of Sarge's release, not one but two stable releases. This is because we do not terminate security support for our previous stable release (in this case, Woody), until some time has passed. We've had other challenges on the security front. We had what amounted to a security support hiatus for about three weeks in June, which caused much consternation. More recently, klecker.debian.org, which provides the security.debian.org has suffered some occasional availability problems, and it hasn't always been clear what's caused them. It's my understanding that we have new hardware in place that can serve in a backup, supplemental, or failover capacity. The general feeling at DebConf 5 was that our security apparatus was in need of attention to make sure it keep pace with the demands being placed on it. I've been in fruitful contact with Joey Schulze, Steve Kemp, and others over the past several weeks, and I look forward to a productive few days.