For those who haven't done seen it, linux.conf.au now has its CFP open, till 7th Aug. It was quite a tight window this time around, but if you already knew about the conference, you probably already have something to pitch to the call :)
IMHO it would be nice to see RDF/Nepomuk folk(s) and some maemo/moblin/i-rebrand mobile hackers too. So please excuse the dual syndication on the premise that some hackers might not have noticed the CFP but have cool stuff which just might be made cooler by chatting over a few beers in 30C summery weather.
Monday, July 26, 2010
Tuesday, July 20, 2010
Winning the West...
This morning I discovered that the UPS had played games during the night and my server was thus off. Turns out the machine endured a hard power drop complements to the APC 1500 UPS. I must say, less than impressed is a euphemistic rating for that particular rack mount UPS. On the other hand, the little 620VA APC unit I have works fine.
Anyway, so the server didn't want to boot, one of the XFS filesystems was wedged. Setting aside the fsck.xfs == nothing glory, at times you do need to xfs_repair. I've hit this once before, having to repair and zero the metadata log to regain mount ability. No log zeroing was needed this time it turned out.
The trick here is that during booting of a Fedora machine, if a local filesystem complains during fsck -A loud enough then you get offered a root shell assuming you have the password. Unfortunately, every character typed seemed to be taken as the password, so if root has a password of length > 1 char then you can't login this way. And with 20 local filesystems and no indication of which was the problem this makes for hours of bliss. Forget rides in the mountains, nice scotch, or a good book, Russian roulette with fsck is the edge of the seat fun way to spend a few hours.
Anyways, having a 4gb live Fedora USB stick helped. Having access to rpms for XFS helped too, and those were extracted and installed on the USB stick should the need arise again. For those finding this through the libferris internet searches, the command you are after is
rpm2cpio foo.rpm | cpio -id
to extract the foo.rpm to paths relative to the current directory. Though if that command escapes you then having a wedged ext? or XFS not permitting you to boot up would likely be an epic problem. FWIW I also managed to wedge btrfs into a charming state recently due to a non UPS backed power failure. This is not a slur on any of these filesystems. Trying to get performance and durability in the face of arbitrary hardware and firmware paths is not hard, its rock hard^TM. There is no substitute for a good UPS if you care about your byteses.
Anyway, so the server didn't want to boot, one of the XFS filesystems was wedged. Setting aside the fsck.xfs == nothing glory, at times you do need to xfs_repair. I've hit this once before, having to repair and zero the metadata log to regain mount ability. No log zeroing was needed this time it turned out.
The trick here is that during booting of a Fedora machine, if a local filesystem complains during fsck -A loud enough then you get offered a root shell assuming you have the password. Unfortunately, every character typed seemed to be taken as the password, so if root has a password of length > 1 char then you can't login this way. And with 20 local filesystems and no indication of which was the problem this makes for hours of bliss. Forget rides in the mountains, nice scotch, or a good book, Russian roulette with fsck is the edge of the seat fun way to spend a few hours.
Anyways, having a 4gb live Fedora USB stick helped. Having access to rpms for XFS helped too, and those were extracted and installed on the USB stick should the need arise again. For those finding this through the libferris internet searches, the command you are after is
rpm2cpio foo.rpm | cpio -id
to extract the foo.rpm to paths relative to the current directory. Though if that command escapes you then having a wedged ext? or XFS not permitting you to boot up would likely be an epic problem. FWIW I also managed to wedge btrfs into a charming state recently due to a non UPS backed power failure. This is not a slur on any of these filesystems. Trying to get performance and durability in the face of arbitrary hardware and firmware paths is not hard, its rock hard^TM. There is no substitute for a good UPS if you care about your byteses.
Saturday, July 10, 2010
Take the Wrather With You...
If anyone in the maemo world knows of recent plasma packages for the n810, please drop a line or leave a comment linking to it from here.. The post is about Abomination, my perl/KDE4 code to grab and log data from the Australian Bureau of Meteorology and present it in an interesting way.
I notice that doppler wind is now available from the Australian Bureau of Meteorology. Also, I didn't notice the up to 512km composite rain maps before. The plan is to include support for both of these radar types into my KDE plasmoiods. I think having the doppler wind as a transparent overlay above the rainfall overlay would be quite telling, being able to see why clouds burst at given points.
Though this doesn't solve the deeper, more interesting question of if the system that is causing the interesting wind trend will remain for the next 2 hours while you are outside performing activity-Y and wanting to remain dry.
I notice that doppler wind is now available from the Australian Bureau of Meteorology. Also, I didn't notice the up to 512km composite rain maps before. The plan is to include support for both of these radar types into my KDE plasmoiods. I think having the doppler wind as a transparent overlay above the rainfall overlay would be quite telling, being able to see why clouds burst at given points.
Though this doesn't solve the deeper, more interesting question of if the system that is causing the interesting wind trend will remain for the next 2 hours while you are outside performing activity-Y and wanting to remain dry.
Sunday, July 4, 2010
Perl io::all, REST, and libferris, wagging the dog
A feature that I've had planned to add to libferris since the UKUUG spring conference earlier this year is Perl io::all support. I've syndicated this because adding an io:all interface to KDE kio stuff would also be very cool IMHO.
I'm digging around for others who think io:all is cool and perhaps that libferris is "plus neutral" and might have some time to help out with the creation of a CPAN module to let the two things work together. In libferris there is a single shot interface to get metadata or file content as a single std::string or an std::iostream based interface allowing seeks, streaming and all that jazz. Ultimately I'd like to make the streaming stuff meet perl::io and also have a fake hash there to allow EA to get read on demand. The C++ and to a fairly large extent the Perl binding side I have knowledge of. But I admit to mostly being a Perl user rather than developer of the language or CPAN modules.
If anyone has pointers to stuff that would help out doing this stuff (tutorials and the like) or would like to support the feature in other ways please drop me a line or comment here. Otherwise, I'll probably dig into this later this year, time permitting.
I'm also thinking about making a REST server for CRUDing libferris. This should make Web clients much simpler to create, for example file managers in Yahoo widget UI. Once again, if this interests you, feel free to jump on in ;-p I'll have a survey of existing REST apis for this sort of stuff, obviously providing a similar interface will help other clients to interface. Luckily I can reuse some of the knowledge I gained when mounting web services as filesystems in the creation of the libferris web service server.
I'm digging around for others who think io:all is cool and perhaps that libferris is "plus neutral" and might have some time to help out with the creation of a CPAN module to let the two things work together. In libferris there is a single shot interface to get metadata or file content as a single std::string or an std::iostream based interface allowing seeks, streaming and all that jazz. Ultimately I'd like to make the streaming stuff meet perl::io and also have a fake hash there to allow EA to get read on demand. The C++ and to a fairly large extent the Perl binding side I have knowledge of. But I admit to mostly being a Perl user rather than developer of the language or CPAN modules.
If anyone has pointers to stuff that would help out doing this stuff (tutorials and the like) or would like to support the feature in other ways please drop me a line or comment here. Otherwise, I'll probably dig into this later this year, time permitting.
I'm also thinking about making a REST server for CRUDing libferris. This should make Web clients much simpler to create, for example file managers in Yahoo widget UI. Once again, if this interests you, feel free to jump on in ;-p I'll have a survey of existing REST apis for this sort of stuff, obviously providing a similar interface will help other clients to interface. Luckily I can reuse some of the knowledge I gained when mounting web services as filesystems in the creation of the libferris web service server.
Saturday, June 26, 2010
Meritocracy, Fate Or Anarchy
Many folks on a higher pay grade than mine tout that open source thrives as a Meritocracy. In this model, folks who are interested enough create a project and release the source under GPL/Whatever and if the project is "good" or "gooder" than other ones it has more merit and will advance to become more widely used etc. One interesting counter point to this made by Alain de Botton in his TED talk where if this rise due to merit, then things also sink due to it. Alain is not talking open source, but if we switch to that context, then if your project is not becoming successful, or you are struggling, then the Meritocracy eye balls would see that since you created the project, by implication you are scum.
During such talks of open source, I have to remove myself from the direct discussion. My hubris is not quite up to the task to extrapolate my situation, be it good or bad, to the larger context.
However, I have seen other people who have single handedly created fairly complex projects over many years only to have large corporate sponsorship arrive for other offshoot or fairly recently created projects. In this case I often wonder that it really doesn't seem that merit has much input into the funding decision. Of course, some will say that to talk about open source and funding is crass, if you like to do it then you will regardless of the open fingered gloves and dynamo powered netbook. But seriously, if a project gets 5-10 full time paid developers, are you confident you can "compete" with that, for 6 months, 3 years, 10 years? Or is it the case that more or less your project has been swept under the bridge by a corporate funding decision you were not even aware was happening?
Another good example of this is the Linux distributions who want a project for "Y" and decide to create a solution themselves rather than trying to adopt something that a committed developer has been working on for years. In some cases the "owning" the code can be more important than reuse, and most often the code is released under and open source license. But this be a fairly vicious demotivator for folks who were writing the existing "Y" solutions.
The specific examples of these sorts of things that I've seen over the years have led me to wonder what sort of model open source really follows. It does seem that Fate or Anarchy are most close to the process at times. Fate particularly coming into play when a developer is at a conference and happens to bump into the guy who works at a company who might be funding a project in a similar area soon. This angle has implications for open source conferences and CFPs in general. If you are not living in Europe or the USA then you will have a lesser exposure to conferences in those spheres and to some degree your project will have less chance of success, no matter what the code does or how well. While many conferences have a travel budget, where you are living will be a factor in whether your project Y or somebody else doing Y2 will get to talk.
Unfortunately these thoughts do not really have a strong conclusion. I thought I'd throw it out there a long with a few TED links to try to brighten up some a few folks who might have read about open source as a meritocracy and started to feel gloomy. Another interesting and related TED is by Dan Pink.
And all ya'll might like the metated which lets you grab talks from a single link source. Its really just an XML file with direct links and metadata, so if your downloader doesn't like it, emacs and wget are your friend.
During such talks of open source, I have to remove myself from the direct discussion. My hubris is not quite up to the task to extrapolate my situation, be it good or bad, to the larger context.
However, I have seen other people who have single handedly created fairly complex projects over many years only to have large corporate sponsorship arrive for other offshoot or fairly recently created projects. In this case I often wonder that it really doesn't seem that merit has much input into the funding decision. Of course, some will say that to talk about open source and funding is crass, if you like to do it then you will regardless of the open fingered gloves and dynamo powered netbook. But seriously, if a project gets 5-10 full time paid developers, are you confident you can "compete" with that, for 6 months, 3 years, 10 years? Or is it the case that more or less your project has been swept under the bridge by a corporate funding decision you were not even aware was happening?
Another good example of this is the Linux distributions who want a project for "Y" and decide to create a solution themselves rather than trying to adopt something that a committed developer has been working on for years. In some cases the "owning" the code can be more important than reuse, and most often the code is released under and open source license. But this be a fairly vicious demotivator for folks who were writing the existing "Y" solutions.
The specific examples of these sorts of things that I've seen over the years have led me to wonder what sort of model open source really follows. It does seem that Fate or Anarchy are most close to the process at times. Fate particularly coming into play when a developer is at a conference and happens to bump into the guy who works at a company who might be funding a project in a similar area soon. This angle has implications for open source conferences and CFPs in general. If you are not living in Europe or the USA then you will have a lesser exposure to conferences in those spheres and to some degree your project will have less chance of success, no matter what the code does or how well. While many conferences have a travel budget, where you are living will be a factor in whether your project Y or somebody else doing Y2 will get to talk.
Unfortunately these thoughts do not really have a strong conclusion. I thought I'd throw it out there a long with a few TED links to try to brighten up some a few folks who might have read about open source as a meritocracy and started to feel gloomy. Another interesting and related TED is by Dan Pink.
And all ya'll might like the metated which lets you grab talks from a single link source. Its really just an XML file with direct links and metadata, so if your downloader doesn't like it, emacs and wget are your friend.
Monday, May 31, 2010
redrum a distro: rm -rf /Fedora13
Some discussion recently came up as to what the outcome of a "rm -rf /" would be on a Linux machine. It's been ages since I last tested, and at the time there was no LVM in use, and /dev was actual nodes instead of a virtual filesystem. So, I was installing Fedora 13 64bit to test some hardware out and couldn't resist "seeing what happens". Needless to say, its not going to be an outcome that is pleasant, but academically interesting perhaps. If you don't know what the command does, don't execute it! And probably, don't even if you know what it does ;)
Also, I ran this from a gnome-terminal under a normal graphical session.
The filesystem layout was:
The home partition still contained /home/whiteele/.gvfs and the root lvm had var/lib/nfs/rpc_pipefs and empty boot, dev, home, proc, selinux, sys directories. But other than that everything else was eaten by the rmrf. Oh yes, and you have to supply the --no-preserve-root option to ensure the rm command that you know you are being silly.
Also, I ran this from a gnome-terminal under a normal graphical session.
The filesystem layout was:
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/vg_test-lv_root
51606140 3111784 45872916 7% /
tmpfs 769704 548 769156 1% /dev/shm
/dev/sda1 495844 28538 441706 7% /boot
/dev/mapper/vg_test-lv_home
560152184 203192 531494900 1% /home
The home partition still contained /home/whiteele/.gvfs and the root lvm had var/lib/nfs/rpc_pipefs and empty boot, dev, home, proc, selinux, sys directories. But other than that everything else was eaten by the rmrf. Oh yes, and you have to supply the --no-preserve-root option to ensure the rm command that you know you are being silly.
Friday, May 28, 2010
Libferris and flickr, vimeo, facebook etc.
If you don't read Linux Format, issue 133 and 132 have some good material on how to mount web services as filesystems using libferris.
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