[Notice] Personal content follows. If you got to this post expecting any of the recurring topics I talk about in my blog, feel free to skip it. This is one of the topics I don't like to share as impersonally as a blog post goes But I know I will not be able to meet most of the people I care about that this will reach in person And even if I did, it is not something easy to say. I have failed several times to communicate this to my closest friends. And if you are among the group of people I am thinking of, this will most probably not surprise you, given there is precedent. But in the end, it didn't work out. Nadezhda and I have lived together for practically 14 years. We had a for month long timeout in 2008. And, a couple of weeks ago, decided that we should make the separation definitive while we are in good terms and have hopes to continue having a good relationship. Anyway Life continues. It will take a bit for things to fall in their place. I know that many of you (again, the group of people I am writing this for) know and care for Nadezhda as well as me. We will Try to do things right as much as possible, and keep the many good things that are still there after all. And while life comes back to track, please excuse me for the many oversights I have done and will probably continue doing during the following weeks. (yes, comments closed. As I said ~18 months ago, Want to say something? Just think it hard enough, it will get to its destination)

gnome-doc-utils has a fairly idiosyncratic layout - help/package.pot, help/lang/lang.po - which doesn't suit things like podebconf-report-po that I want to use to call for translations and updates.

This little snippet creates the relevant directory from a gnome-doc-utils Makefile.am:

report-po: Makefile
if [ ! -d po ]; then \
mkdir po/ ; \
fi
cp $(PACKAGE)-help.pot po
cd po ; \
for l in $(DOC_LINGUAS); do \
if [ ! -L $$l.po ]; then \
ln -s ../$$l/$$l.po . ; \
fi; \
echo -n $$l: ; \
msgfmt -c --statistics $$l.po; \
rm -f messages.mo; \
done


Also, I thought gnome-doc-utils updated the PO files automatically but I couldn't get it to do it, so I've got this snippet too:


check: update-po

update-po: Makefile
for l in $(DOC_LINGUAS); do \
xml2po -u $(top_srcdir)/help/$$l/$$l.po $(top_srcdir)/help/C/$(PACKAGE).xml; \
done


Some time ago we decided in phpMyAdmin team to create yet another team meeting (after five years) at FOSDEM 2010. It took some time, but now I should have all travel things arranged (thanks to my employer who sends me there). So if anybody wants to meet there, just drop me an email and I will try to put you on my schedule.

If you use a script to do some customisations run via preseed/late_command then don't do it the following way:
d-i preseed/late_command string cp /hd-media/do-tib-stuff.sh /target/tmp ; in-target /tmp/do-tib-stuff.sh ; rm /target/tp/do-mystuff.sh!
That way you'll never notice, if your script run successfully as its exit code is eaten by the removal. When running several late-commands always use && to chain the commands, so if one command fails the processing will stop and the installer will show you a nice message that indeed something went wrong.

This evening I tested some Noise Canceling Headphones (as described in my previous post [1]). I first tried the ones on sale at Brookstone [2], they were the on the ear type so there was never a chance that I would buy them but they seemed like good ones to test. I wore them for about 10 minutes while I walked around the store looking at all the electronic stuff that s on sale. I noticed that they were much more effective at filtering low frequencies and regular sounds. So for the Christmas music that was playing the music was mostly filtered just leaving the sound of the singing. Also I was able to talk to the guy who worked there and hear him clearly when the noise canceling was turned on this can be considered a bug or a feature depending on your planned use. When I listened to electric fans the sound of the buffeting air was filtered just leaving the high pitched bearing noise. It is well documented that there is a hissing sound from noise canceling headphones and sometimes a feeling of pressure. I didn t hear any hissing but it did feel a little different when I turned on the noise canceling. After 10 minutes I didn t feel in any way uncomfortable, so I could probably survive an entire flight while wearing such headphones. I can highly recommend the customer service at the Brookstone store in Menlo Park. The guy who was working there was totally helpful, even by US standards his customer service was really good. Sometimes when you make an unusual request (such was wanting to try the merchandise for an extended period of time) the staff aren t particularly enthusiastic, but I had no problems at Brookstone! After Brookstone I went to a Bose store and tried the Quiet Comfort 15 noise canceling headphones [3]. The Bose store conveniently had a device configured to emulate the sound of a jet engine to demonstrate how the QC15 stopped that. I was quite impressed with that. I did feel that the QC15 was a little light for my taste, I would rather have something bigger and heavier with thicker padding to improve the passive resistance to sound. But I expect that many people would like it to be small and light as it s designed for travel. I visited a Sony store a couple of times, but no-one seemed able to serve me. I ll go there again some time when they are less busy. Finally I have to note that I have received a significant number of comments suggesting ear-bud type devices. I suggest that anyone who doesn t mind wearing such things should consider ear-bud type devices. But as I can t stand such things I will continue my search for over-ear headphones. I may end up just buying the Bose QC15, they seem to be good enough and not really expensive.

• [1] http://etbe.coker.com.au/2009/12/03/noise-canceling-headphones/
• [2] http://www.brookstone.com/
• [3] http://www.bose.com/controller?url=/shop_online/headphones/noise_cancelling_headphones/index.jsp

Great, I spent a few hours today to set up a nice OpenVPN server. Nice in that I wanted the (Windows) clients to be able to access the company network like they were connected locally. My idea was to use the OpenVPN tap mode and let the DHCP server at work assign IPs to the VPN clients. This turned out to be a dumb idea. After I got everything going, I noticed the following message in syslog (which probably scrolled by previously in the debug drivel):

NOTE: your local LAN uses the extremely common subnet address 192.168.0.x or 192.168.1.x. Be aware that this might create routing conflicts if you connect to the VPN server from public locations such as internet cafes that use the same subnet.

Hmm, sure, I guess that will exclude every second incoming VPN connection. Summary: Think about IP space clashes before setting up a VPN.

My patience with the noise of airlines has run out, on my trip from AU to US I didn t get any sleep due to the cramped seat and the noise of the plane. While I can t do anything about the cramped seat without spending a lot of money it seems that I can do something about the noise with moderate expense. I ve been researching Noise Canceling Headphones [1]. The principle of such devices is that they have a microphone on the outside and a speaker on the inside to generate sound that is 180 degrees out of phase which will then almost cancel out the ambient noise. Apparently such devices are very effective for low frequencies but less effective for high frequencies. High frequencies are more easily blocked by sound insulation, so the ideal seems to be around the ear headphones with lots of padding to passively stop noise with active noise canceling to deal with the lower frequencies. So I m now planning on buying a set of headphones before I leave the US. Choice Magazine (an Australian independent product review organisation) published a review of noise canceling headphones in 2007, it has some interesting information but is not suitable for buying advice today [2]. Choice gave the best results to the Jabra C820s which had just gone out of production when they published the review and by now could only be bought on eBay. The Jabra had an active cancellation of 14.3dB and a passive cancellation of 8.3dB. The best active cancellation of all the reviewed products was 19.5dB for the Bose QuietComfort 3 which incidentally only had a passive cancellation of 4.8dB. Both the Bose and Jabra products got good reviews in a mailing list discussion. It s a pity that Jabra is now only manufacturing products for call centers. I am not considering the headphones that go on top of the ears, they will inherently give less passive protection due to the design and they will annoy me. I am also not considering the ear-buds because I don t like putting things in my ears. I will note that there are some very positive reviews of some of the ear-bud devices. The Etymotic Research devices get very good reviews and are apparently on sale at reasonable prices in Apple stores (among other places) [3]. Anyone who wants noise-canceling headphones and disagrees with me about the desirability of ear-bud type devices should probably consider them. The Bose QuietComfort 15 is selling for $300 (NB for this post all prices will be in US dollars) [4]. It has microphones both inside and outside the ear cup to allow better detection of ambient sound. A single AAA battery is supposed to last 35 hours, it has a detachable audio cable (for use in just blocking noise), and comes with an airline adapter (for the two-port airline sockets). It does require being turned on to listen to audio, some headphones allow you to turn off the noise canceling feature to listen to music without a battery this doesn t matter for my planned use. They have a volume switch (low and high settings) to cope with airlines that set the volume too high. They are specifically designed for passengers in commercial jet aircraft. Surprisingly the Bose web site doesn t mention the number of dB of audio protection and none of the reviews I have read have mentioned it either. The store Brookstone was recommended, they have some unbranded noise canceling headphones, but as they are on the ear and more expensive than comparable Sony products ($130 vs $100) I eliminated them quickly. Sony has a good range of noise-canceling headphones [5]. They have ear-buds starting at $90 and on-ear headphones for as little as $50. They have two models of over the ear headphones that are advertised at $200 and $400. The MDR-NC60 costs $200 and reduces noise by 12dB at 200Hz while the MDR-NC500D costs $400 and reduces noise by 20dB at 160Hz. I don t know why they didn t measure both headphones at the same frequency or give any information on passive sound insulation. They state that the MDR-NC500D was voted as being better than the Bose QC2 and QC3 but made no such claim about the MDR-NC60 presumably the older Bose devices were rated as better than the MDR-NC60, and I have to wonder about how the Bose QC15 would compare to the MDR-NC500D. The MDR-NC500D has an internal Lithium-Ion battery that lasts 16 hours and can take a pair of AA batteries as well for a total of 28 hours. The Sennheiser PXC 350 claims up to 32dB of passive attenuation and up to 18dB of active noise compensation [6]. Their claims about NoiseGuard (TM) cause me to lack confidence in their products. The PXC 350 is advertised at $330 and the reviews that I have read suggest that the Bose might be a better product. Sennheiser also has PXC 450 which offers 23dB of active noise compensation and costs $450. I am not going to pay $450 for headphones. It seems that the choice for over the ear noise canceling headphones comes down to the Sony MDR-NC60 at $200 and the Bose QuietComfort 15 at $300. I have the impression that the Bose product is better, but whether it is $100 better is the question. Also while I haven t forgiven Sony for Rootkitting their customers [7], this is not going to prevent me from buying the headphones that best suit my needs. Does anyone have any suggestions? Did I miss a good brand that I should be considering? Does Sennheiser have some redeeming features that I missed?

• [1] http://en.wikipedia.org/wiki/Noise-cancelling_headphones
• [2] http://www.choice.com.au/Reviews-and-Tests/Technology/Phones-and-mobile-devices/Sound/Noise-cancelling-headphones-review-and-compare.aspx
• [3] http://www.etymotic.com/ephp/hf2.aspx
• [4] http://www.bose.com/controller?url=/shop_online/headphones/noise_cancelling_headphones/index.jsp
• [5] http://www.sonystyle.com/webapp/wcs/stores/servlet/CategoryDisplay?catalogId=10551&storeId=10151&langId=-1&categoryId=3728&N=4294955699
• [6] http://www.sennheiserusa.com/private_headphones_travel-line_500371
• [7] http://en.wikipedia.org/wiki/Sony_rootkit

Until vSphere 4, the only way to add space to an existing VMFS was to add an extent. This means creating a new partition, most of the time on a new LUN, and extend the VMFS there (vSphere 4 is now able to resize a partition on a grown LUN). This is somehow equivalent to adding a physical volume in a volume group under LVM. But contrary to LVM, once you added an extent to a VMFS, it is impossible to remove it. Well, until now, it was. I just pushed my lvm branch of vmfs-tools (get a git snapshot tarball), which includes a new tool named vmfs-lvm, allowing to just do that. For the moment, the tool is not cluster-safe, which means you d better run it on an offline VMFS (i.e. make sure no server is using it). Data should not be at risk because the tool checks the removed extent doesn t contain any data, but it also assumes the filesystem is in a consistent state beforehand. The command line to remove an extent looks like the following:

# vmfs-lvm extent0 extent1 ... extentn remove

This will remove the last extent. Update: There was a bug when setting some values at volume level. The git snapshot link above has been updated accordingly.

Next Saturday a group of more than 20 women that work with Free Software in Argentina and Uruguay will gather to speak at a Free Software event in Buenos Aires, called Software Libre, Pasi n de Mujeres. It's your typical Free Software event, with talks related to the philosophy of Free Software and the Free Culture in general, and also technical talks related to using and developing Free Software. With one important difference: all the speakers will be women. This might sound shocking to some people and normal stuff to some others, but the reaction created by the call for talks of this event was definitely not something I expected. Women from all over the country (and many also from other Latin American countries) have contacted us, to tell us about what they do in their daily lives with Free Software and how they would like to share their work with others. The event is open for both men and women to attend, however, of the more than a 100 people that have already pre-registered, more than half are women. A ratio that is more than amazing when you have been to a Free Software event before. I think that the fact that all the speakers are women is really encouraging for many women to attend, who otherwise wouldn't. Debian will be sponsoring the event, by paying the bus tickets of the speakers that come from the whole country, which is a great help in making this event a big success. I really expect the event to be a fantastic opportunity for the women in our country to finally show all the great work they are doing... I'm very excited about it :) PS: Somehow, I screwed up Planet Debian, filling it with old posts. I'm sorry! :-\

Last year, after many years of peacefully living the whole year in GMT-3, our government decided that Argentina should use DST again. This was done in a rush, but patches were written and applied everywhere to have a correct timezone. Fixing the problem was not enough, tzdata's upstream decided to predict the future:

# From Paul Eggert (2007-12-22):
# For dates after mid-2008, the following rules are my guesses and
# are quite possibly wrong, but are more likely than no DST at all.
Rule    Arg 2007    only    -   Dec 30  0:00    1:00    S
Rule    Arg 2008    max -   Mar Sun>=15 0:00    0   -
Rule    Arg 2008    max -   Oct Sun>=1  0:00    1:00    S

Well, back in December 2007, October 2008 might have seemed like a long time in the future, and they assumed that sometime in the middle the correct date would be announced... But, predictably (knowing Argentina's current government), no DST has yet been announced. However, Paul Eggert's guesses had propagated to almost all UNIX distributions, so that at 0:00 Sunday Oct 5th, all our computers were suddenly one hour ahead of time. Affected systems: Debian, Ubuntu, Gentoo, Red Hat, OpenBSD, FreeBSD, Mac OS. Devices: ipod, maemo, Nokia N95. Websites: Clarin (a major newspaper - still broken 36 hours later), Gmail. And probably many others that I don't know of. I even read that Windows was affected, although I don't know how that might be possible, since as far as I know they don't use tzdata. Anyway, not satisfied with how they mistakenly predicted the future before, a few weeks ago (not enough time in advance to fix almost any systems, only sid had this release), they added this change:

# From Alexander Krivenyshev (2008-09-05):
# As per message from Carlos Alberto Fonseca Arauz (Nicaragua),
# Argentina will start DST on Sunday October 19, 2008.
#
# http://www.worldtimezone.com/dst_news/dst_news_argentina03.html
# http://www.impulsobaires.com.ar/nota.php?id=57832 (in spanish)
Rule    Arg 2007    only    -   Dec 30  0:00    1:00    S
Rule    Arg 2008    max -   Mar Sun>=15 0:00    0   -
Rule    Arg 2008    max -   Oct Sun>=15 0:00    1:00    S

So, they decided to take the word of a guy from Nicaragua (no bad feelings against Nicaragua, but I think that this kind of stuff should be informed by people from the affected country), and from a couple of articles that say that "According to some sources, we might have to change our clocks on the third Sunday of October". Would you change tzdata sources with such information? I definitely wouldn't. Anyway, Aurelien Jarno has already uploaded fixed packages, with no assumption regarding when the DST will happen, which is the sensible thing to do in a case like this. Thanks Aurel!

Reality needs fantasy to render it desirable, just as fantasy needs reality to make it believable. Stephen Duncombe

This fall I have been awash in a few obsessions including book piracy and spam. I recently got to talk about one of these obsessions when I was interviewed about book piracy by Nora Young for her weekly CBC radio and podcast show Spark. I mostly gave a lay of the land panorama with a nod toward some of the conditions, technological and social, that can help us grasp the contemporary explosion of book piracy and also raised some thoughts about what might change the future landscape. What I don t raise is whether a politics built around an explicit embrace of piracy is regressive, progressive, or something else but these ethical questions were posed in the comments left for the full interview. Some of the comments pointed to the pitfalls and shortcoming that can follow the terminology of piracy many of which I share. But what keeps me interested in the politics of piracy is how it can speak the language of spectacle, which can be a powerful tactic and technique for broadcasting a political message. Here I just paraphrasing and cribbing the work of Stephen Duncombe, who has argued, I think quite persuasively, that we cannot rely solely on reasoned debate for building political programs. Duncombe does not argue that we must toss out rationality and truth seeking (these are absolutely necessary) but notes how on their own or if not clothed in some other cloak, they may not be enough to convey and compel, especially in this day of total media saturation. Or to put a but more poetically by him Reality needs fantasy to render it desirable, just as fantasy needs reality to make it believable. Much (though not all) of contemporary digital piracy follows the logic of spectacle. It builds and conveys a fantastical drama of right and wrong, of new possibilities, of freedom from the noose of the law; it signals and speaks to the thrill and fun in twisting, even breaking, existing structures and constraints; and provides a window into another way of acting/behaving. In many cases what it provides is a commons (and I will be exploring it in depth in my class next semester on the commons) and many folks, I imagine, turn to piracy simply for the free stuff, and a number of them come out of the other side transformed into copy fighters willing to engage in a politics beyond sharing stuff and waving the pirate flag. For those of us who believe in greater access and different ways of imagining structures and strategies of re-compensation, piracy on its own is not certainly enough and I understand fully and even to some degree, share the skepticism many feel toward such language. But I am not quite ready to declare a politics of piracy as always politically bankrupt or necessarily backward. I guess what I embrace is a diverse political ecology. For some, the drama of spectacle and thrill of transgression are what turns their political mojo on; for others it is the cool and reasoned debate common to policy and reform; for others, they want to focus on building alternatives as we see with Free Software or radical tech collectives. For some, it is both the reasoned salt and the transgressive pepper that spices their political world. And I would rather have more spice than less, especially in an era where the blandness of political apathy is that which is our most dangerous enemy. Related Links: Here is a wonderful animation by the NZ Book Council that captures what I love about books and renders its materiality wonderfully alive. On the Media has a episode on book publishing and Cory Doctorow has penned some thoughts about the future of book selling. If you want to keep abreast on the politics of liberating books, check out Free our Books. If you are more interested in the technical side of things, check out the book liberator project.

Reality needs fantasy to render it desirable, just as fantasy needs reality to make it believable. Stephen Duncombe

This fall I have been awash in a few obsessions including book piracy and spam. I recently got to talk about one of these obsessions when I was interviewed about book piracy by Nora Young for her weekly CBC radio and podcast show Spark. I mostly gave a lay of the land panorama with a nod toward some of the conditions, technological and social, that can help us grasp the contemporary explosion of book piracy and also raised some thoughts about what might change the future landscape. What I don t raise is whether a politics built around an explicit embrace of piracy is regressive, progressive, or something else but these ethical questions were posed in the comments left for the full interview. Some of the comments pointed to the pitfalls and shortcoming that can follow the terminology of piracy many of which I share. But what keeps me interested in the politics of piracy is how it can speak the language of spectacle, which can be a powerful tactic and technique for broadcasting a political message. Here I just paraphrasing and cribbing the work of Stephen Duncombe, who has argued, I think quite persuasively, that we cannot rely solely on reasoned debate for building political programs. Duncombe does not argue that we must toss out rationality and truth seeking (these are absolutely necessary) but notes how on their own or if not clothed in some other cloak, they may not be enough to convey and compel, especially in this day of total media saturation. Or to put a but more poetically by him Reality needs fantasy to render it desirable, just as fantasy needs reality to make it believable. Much (though not all) of contemporary digital piracy follows the logic of spectacle. It builds and conveys a fantastical drama of right and wrong, of new possibilities, of freedom from the noose of the law; it signals and speaks to the thrill and fun in twisting, even breaking, existing structures and constraints; and provides a window into another way of acting/behaving. In many cases what it provides is a commons (and I will be exploring it in depth in my class next semester on the commons) and many folks, I imagine, turn to piracy simply for the free stuff, and a number of them come out of the other side transformed into copy fighters willing to engage in a politics beyond sharing stuff and waving the pirate flag. For those of us who believe in greater access and different ways of imagining structures and strategies of re-compensation, piracy on its own is not certainly enough and I understand fully and even to some degree, share the skepticism many feel toward such language. But I am not quite ready to declare a politics of piracy as always politically bankrupt or necessarily backward. I guess what I embrace is a diverse political ecology. For some, the drama of spectacle and thrill of transgression are what turns their political mojo on; for others it is the cool and reasoned debate common to policy and reform; for others, they want to focus on building alternatives as we see with Free Software or radical tech collectives. For some, it is both the reasoned salt and the transgressive pepper that spices their political world. And I would rather have more spice than less, especially in an era where the blandness of political apathy is that which is our most dangerous enemy. Related Links: Here is a wonderful animation by the NZ Book Council that captures what I love about books and renders its materiality wonderfully alive. On the Media has a episode on book publishing and Cory Doctorow has penned some thoughts about the future of book selling. If you want to keep abreast on the politics of liberating books, check out Free our Books. If you are more interested in the technical side of things, check out the book liberator project.

Looking at the sorry state of Python in Debian, makes me wonder if we shouldn t enforce team maintainance of packages above a certain popularity/importance/whatever threshold. People worked hard in the last months to fix any bugs that would prevent Python2.6 to land in unstable and yet nothing happens. Time passes by and we will eventually end up with Squeeze having a horribly outdated Python version.

I've been working with Charlie DeTar and the Center for Future Civic Media on a project called Between the Bars which is a blogging platform for prisoners. The current platform is essentially a snail-mail to web gateway: prisoners send letters which semi-automatically scanned and posted to the site; comments are printed and mailed back. As we plan the launch of the project, we are trying to talk to as many stakeholders as possible -- this includes ex-prisoners, families and friends of people who are or have been in prison, non-profits working with prisoners, victims of people in prison, people who work in prisons or in corrections, probation officers, or almost anyone else with a perspective or set of experience that might help us understand the difficult space our project is trying to negotiate and who might be able to help influence the design. At the moment, we're not talking to current prisoners due to rules regulating research involving prisoners, but almost anyone else would be someone we'd love to connect with. We're interested in hearing from people about their experience with prisons or prisoners, about staying connected to families and friends while behind bars, and, ultimately, about how we might design, deploy, and support technology to help folks out. If you or someone you know are stakeholders and would be willing to talk about your experience and opinions with prisons, communication, and technology, please drop us a line at betweenthebars@mit.edu.

1. Response times should dramatically improve on this new server - without flooding planets too. Together with Simon Waters, I've moved from a real (but tired) server to a snazzy virtual one with bytemark. Various other bits will be being updated and the new site will start to host more useful data on translations and string freezes in progress.
   DNS is currently updating, but over the next 24hours the old server should be able to take a rest before being finally powered down.


2. In other news, my house in Plymouth is now on the market - I'm preparing to relocate to Cambridge. No more pharmacy, it's time to work on embedded applications full time. It's going to be a chaotic few months ahead . . .

Biggest, in terms of money involved, piece of equipment is a nice piece of glass to put in front of our camera. Since my wife had been using a Canon SLR since forever (and we stayed with that when moving from the EOS 300 to the current EOS 40D), the choices to upgrade from the kit EF-S 17-85mm f/4-5.6 basically have been:

• EF-S 15-85mm f/3.5-5.6 IS USM: since it's been announced with the 18Mp 7D it should be quite good on the 10Mp 40D. Newest design, certainly one of the best IS on Canon, true wide angle.
• EF 24-70mm f/2.8 L USM: The old trusted one. No IS, but a constant f/2.8. Narrowest zoom range of the lot. A real tank, at almost 1kg.
• EF 24-105mm f/4 L IS USM: The other full frame L lens. Not quite as big, longer, but only f/4.
• EF 24-70mm f/2.8 L IS USM: including waiting for it to be announced and available, of course.

In the end I got the EF 24-70mm f/2.8 L USM, because the EOS 40D is no high ISO monster (we don't plan to upgrade immediately.) Also: I bought the Tokina AT-X 116 PRO DX (11-16mm, f/2.8) a while back and we're quite happy with that so wide-angle is covered. And since we're often shooting indoors (family and other events), f/2.8 is a big plus. On the tele end, there's quite a gap from the 24-70 to the old EF 100-300mm f/4.5-5.6 USM [age of the page to reflect the age of the lens ;-) ] but then the latter is probably the next lens to be replaced anyway. Since I only got 24-70 I can not directly compare these lenses. But after a few early tests I think I'm happy with the 24-70: while it seems to be a bit soft wide open at 24mm and at 70mm, it seems to be very sharp center to edge even at f/2.8 when used in the 35-50mm range. (Note that the 40D is a crop sensor camera, so I'm nicely using the sharp center area of a lens designed for full frame!) Yes, it's huge, so for casual walking around the 17-85mm will probably still get some use. Time will tell. And since it can, potentially at least, be used on a a EOS 5D Mk II, I now have another gadget to covet. Although this would mean giving up the Tokina 11-16mm. Anyway, not for quite some time yet... (The test also included the venerable EF 50mm f/1.8, Mk I, and I must say I'm quite surprised how sharp that one is in the f/4 to f/11 range.)

I ve been investigating the Ext4 filesystem [1]. The main factor that is driving me to Ext4 at the moment is fsck times. I have some systems running Ext3 on large filesystems which I need to extend. In most cases Ext3 filesystems have large numbers of Inodes free because the relationship between the number of Inodes and the filesystem size is set when it is created, enlarging the filesystem increases the number of Inodes and apart from backup/format/restore there is no way of changing this. Some of the filesystems I manage can t be converted because the backup/restore time would involve an unreasonable amount of downtime. Page 11 of the OLS paper by Avantika Mathur et al [2] has a graph of the relationship between the number of Inodes and fsck time. Ext4 also has a number of other features to improve performance, including changes to journaling and block allocation. Now my most important systems are all virtualised. I am using Debian/Lenny and RHEL5 for the Dom0s. Red Hat might back-port Ext4 to the RHEL5 kernel, but there will probably never be a supported kernel for Debian/Lenny with Ext4 and Xen Dom0 support (there may never be a kernel for any Debian release with such support). So this means that in a few months time I will be running some DomUs which have filesystems that can t be mounted in the Dom0. This isn t a problem when everything works well. But when things go wrong it s really convenient to be able to amount a filesystem in the Dom0 to fix things, this option will disappear for some of my systems, so if virtual machine A has a problem then I will have to mount it s filesystems with virtual machine B to fix it. Of course this is a strong incentive to use multiple block devices for the virtual machine so that a small root filesystem can be run with Ext3 and the rest can be Ext4. At the moment only Debian/Unstable and Fedora have support for Ext4 so this isn t a real issue. But Debian/Squeeze will release with Ext4 support and I expect that RHEL6 will also have it. When those releases happen I will be upgrading my virtual machines and will have these support issues. It s a pity that Red Hat never supported XFS, I could have solved some of these problems years ago if XFS was available. Now for non-virtual machines one factor to consider is that the legacy version of GRUB doesn t support Ext4, I discovered this after I used tune2fs to convert all filesystems on my EeePC to Ext4. I think I could have undone that tune2fs option but instead decided to upgrade to the new version of GRUB and copy the kernel and initramfs to a USB device in case it didn t boot. It turns out that the new version of GRUB seems to work well for booting from Ext4. One thing that is not explicitly mentioned in the howto is that the fsck pass needed to convert to Ext4 will not be done automatically by most distributions. So when I converted my EeePC I had to use sulogin to manually fsck the filesystems. This isn t a problem with a laptop, but could be a problem with a co-located server system. For the long term BTRFS may be a better option, I plan to test it on /home on my EeePC. But I will give Ext4 some more testing first. In any case the Ext3 filesystems on big servers are not going to go away in a hurry.

• [1] http://ext4.wiki.kernel.org/index.php/Ext4_Howto
• [2] http://ols.108.redhat.com/2007/Reprints/mathur-Reprint.pdf