Search Results: "ron"

27 June 2008

Benjamin Mako Hill: One Step Behind

My friend Aaron is moving back to Boston and in the process getting stuff for his apartment from Ikea. A lot of Ikea stuff is secured with hard plastic strapping. Luckily, Ikea also sells scissors to help you cut your way through it! The scissors are secured with hard plastic strapping. If only he'd bought another pair of scissors...

Miriam Ruiz: Glass Ceiling

Katherine Lawrence and Marianne Schreiber, two women at Hewlett-Packard, used the term Glass Ceiling to to refer to invisible barriers that impede the career advancement of females. While on the surface there seems to be a clear path of promotion, in fact women seem to hit a point where there is no way to progress beyond. Carol Hymowitz and Timothy Schellhardt used the term again afterwards in the March 24, 1986 edition of the Wall Street Journal, which is considered by many people the starting point of the usage of that term. Even though the term Glass Ceiling was originally specifically applied to discrimination against women, its meaning has expanded to describe similar situations of other collectives. I was wondering whether there might be a Glass Ceiling in Debian too. I know some of you will be tempted to answer “no way!” or “yeah! of course!” without even thinking about it. Please don’t. Keep in mind that a Glass Ceiling situation is referred to as a “ceiling” as there is a limitation blocking upward advancement, and “glass” (transparent) because the limitation is not immediately apparent and is normally an unwritten and unofficial policy. Give a serious and deep thought about it before commenting. It’s quite likely that if you are too sure about what the answer might be, one way or the other, that you might be wrong. I just wanted to make us think a bit about it.

Pierre Habouzit: Re: SSL...

Steve,
If you don't like seeing cumbersome security warnings for insecure https connections, how about not using https when what you really want is http in the first place?
Because I don't necessarily have the choice. When I'm reporting a bug on a given open source Trac, they often put https on them because they think it's better for them (and for them it is because they generated the certificate and so on), and there is no http version. Note that when I use https for myself, I import my CA in firefox, so I don't have a single warning, so I kind of know how to avoid them when I care about https. But there isn't always a plain HTTP alternative, and that is what makes it a real PITA. Okay, you want to warn the user the https isn't secure, there are plenty of ways that don't require you to add an exception on a certificate. I spoke of the little lock, because that's what is even on IE, but please remember than when you browse trusted https, the URL bar is in this kind of yellow. Well, if the https is unsecure, just don't put that background. If you really want, you can add some kind of rosa color to mark that it's "bad" but it in a not too terrible way (in opposition to a broken/invalid certificate and where the URL bar should be blinking red with an air-raid like siren). I repeat, the fact that the HTTPS certificate is self-signed never changes the fact that when a given user goes on this kind of https site, he wants to be there, and HE WILL click on the 5 silly steps of the SSL exception thing. So why bother ? It serve one single purpose: pissing users off. And for what it's worth, I disagree with you, most of the people that are not computer related I know absolutely don't know they could think that http_s_ is more secure than http. Each time I give them an URL without the http:// part they ask, is this https or http ?, because they absolutely don't get the difference, and I don't try to explain it to them, because this would lead them to think https is better. Those kind of people only rely on visual helpers from the browser part. They really do. PS: yes I also believe that bad security is worse than no security because it gives the illusion for people to be safe, and then they have bad behavior. When your condom is broken, things can go really wrong. But you missed my point, in the sense, probably because I'm too annoyed to make it clear inbetween rants. My point really was what I tried to explain, namely that if people don't know they should think there is security in the first place, your remark is moot, and for the other you can activate the different URL background, it's just fine. Of course, invalid certificates must remain a pain to go through, this whole thing is only about the untrusted ones.

26 June 2008

Steve Langasek: bad security is worse than no security

Pierre, "Why on earth is https with an untrusted certificate less secure than http ?." Apparently you thought this was a rhetorical question. I disagree. https with an untrusted certificate is less secure than http, because whether or not most users understand the meaning of https, there are a significant number of users who do understand what it means, or at least think they do. You can't seriously tell me you that you think all users always look for the lock icon instead of looking at the URL to know whether they're protected, can you? Users, on the whole, are very good at cargo-culting where technology is concerned. Just because many users look for the icon does /not/ mean that there aren't other users who know just enough of the definition of "protocol" to be a danger to themselves. An https URL is a declaration on the part of the server (or the party linking to it) that the resource in question should be secure. This creates an expectation on the part of those users who know what https is that if the connection succeeds, it is secure, which means they'll think it's ok to do the kinds of things that they normally do over secure connections but won't do over unsecured ones. It therefore certainly is important to give users feedback that an https connection has failed. If you try to connect to an https resource, and your browser can't verify the certificate, something is wrong. Either the server operator is a stooge for Intel trying to drive up the client CPU requirements for web connectivity so that they can sell more chips, or the server operator has failed to establish a chain of trust to you in the appropriate manner, or someone really has compromised the connection with a man-in-the-middle attack. Any of these conditions are something that ought to be brought to the user's attention, not ignored. If you don't like seeing cumbersome security warnings for insecure https connections, how about not using https when what you really want is http in the first place?

Robert Collins: 27 Jun 2008

Dear lazyweb number 3. So far, I've asked: high latency net simulations - great answers. python friendly back-end accessible search engines - many answers, none that fit the bill. So I wrote my own :). Today, I shall ask - is there a python-accessible persistent b+tree(or hashtable, or ...) module. Key considerations: - scaling: millions of nodes are needed with low latency access to a nodes value and to determine a nodes absence - indices are write once. (e.g. a group of indices are queried, and data is expired altered by some generational tactic such as combining existing indices into one larger one and discarding the old ones) - reading and writing is suitable for sharply memory constrained environments. ideally only a few 100KB of memory are needed to write a 100K node index, or to read those same 100K nodes back out of a million node index. temporary files during writing are fine. - backend access must either be via a well defined minimal api (e.g. 'needs read, readv, write, rename, delete') or customisable in python - easy installation - if C libraries etc are needed they must be already pervasively available to windows users and Ubuntu/Suse/Redhat/*BSD systems - ideally sorted iteration is available as well, though it could be layered on top - fast, did I mention fast? - stable formats - these indices may last for years unaltered after being written, so any libraries involved need to ensure that the format will be accessible for a long time. (e.g. python's dump/marshal facility fails) sqlite, bdb already fail at this requirements list. snakesql, gadfly, buzhug and rbtree fail too.

Decklin Foster: The data are

So I always knew that my ThinkPad's display sucked. But now I have scientific proof! (Long-winded post about my job follows.) I was running some timing tests at work on the code for a psychology experiment. This involves quickly presenting a stimulus to the subject, then measuring reaction time and synchronizing with EEG readings. Nothing very complicated, but accurate timing is essential; you don't want another variable confounding your results. So I have this photocell device that sends a signal to a Mac through the EEG hardware when there is really actually physical light coming off of the screen, not just when I told the computer to display something. Now CRTs, of course, are actually scanning (with an electron gun) the display at 75 or 85 Hz or something, not constantly pumping out light to the whole screen. This means 12 or 13 (or whatever) ms between refreshes. So if you want something to appear for 100 ms, you have to fudge a little, and make it so that you get maybe 8 or 9 scans. You can synchronize your presentation to the refresh so this is feasible. But how long the subject really perceives it ultimately depends on how "flickery" the monitor is at a given refresh rate. LCDs, on the other hand, do not have this problem. They actually do produce light constantly -- their refresh rate is pretty much always only 60 Hz or less, but you get the same(ish) output over the entire cycle, instead of in blips that give the illusion of a constant image (in fact, as Matthew points out, they can continue to hold the same image for even longer periods between refreshes. Can't wait to try out that patch). And luckily for us, 6 cycles are in theory exactly 100 ms (in practice, it's close enough). Or so I thought. I could not, no matter how many times I banged my head against it, get consistent results between our laptop (also a ThinkPad) and any external display. For reasons I do not entirely understand (probably scheduling issues), on CRTs I was getting one extra cycle, so I had to reduce the time by one to compensate. This was done for published studies years before I arrived at the lab, so (for the sake of not introducing additional variables) there is an extremely large disincentive to go back and fix it the Right Way, whatever that is. Our laptop's internal display was producing results that were skewed like those of a CRT. I thought for a minute I was going nuts from testing all day, but it kept happening. Curious, I swapped out the lab's T60 for my faster T61 and (to rule anything else out) killed all my other processes and wrote a fresh PyEPL script that did nothing but repeatedly blink some text for 100 ms. Here is, on the external VGA port, a cheap old 15" Dell LCD I pulled from the server room: http://www.rupamsunyata.org/~decklin/blogfiles/20080626/vga-lcd.png (These images are from the Mac, which is still using System 9.something. I had to remember Command-Shift-3 to take a screenshot and use StuffIt to get them off of it. Srsly. I can't remember the last time I used StuffIt.) And here is a CRT, showing the refreshes: (The DIN3 line is the actual signal, and the others are integrated over some number of milliseconds to compensate for scanning and attempt to get a usable number. Of course, this is done in hardware, not synchronized to anything else.) http://www.rupamsunyata.org/~decklin/blogfiles/20080626/vga-crt.png Now, this is the one that blew my mind. The ThinkPad's internal LCD: http://www.rupamsunyata.org/~decklin/blogfiles/20080626/lvds-lcd.png You can see that 60 Hz is spaced much farther apart, and that there are 6 cycles as intended, but. It's acting like a CRT! On the refresh, it puts out enough light to trigger the photocell, but inbetween, nothing. I ought to be noticing flicker and/or getting headaches all the time, if this is truly the case. (I guess I did get glasses for and because of staring at computer displays all the time. Should update my hackergotchi.) I have to admit I do not understand what is going on here at all. But it seems like making any assumptions about a display is (as the voice in my head was telling me all along) a very bad idea. Perhaps someone can email me some clue. But at least I have some hard data to validate my subjective opinion of the ThinkPad's internal LCD. Anyway: I still recommend the ThinkPad, even if the display is awful. I have a nice external monitor connected through DVI to the dock at home, and I mainly use a laptop so I can get out of the house and go hack outside or in a coffeeshop (not ideal lighting). The build quality, keyboard/trackpoint, performance, and the fact that Debian (testing or unstable, anyway) Just Works are all higher up on the list for me. I do wish I could afford the new lighter one, though.

Pierre Habouzit: About free software, UI and bad excuses

Okay, following my irritated post I received (sigh) complaints about me being too harsh. So to these people here is what I say, because I'm tired answering the same thing over and over. For starters, the SSL dialog in firefox is badly designed:
  1. My mom doesn't grok it, so it totally fails the "corridor testing" (see JoelOnSoftware if you don't know what it is), stop pretending otherwise;
  2. since it fails with the "average not very computer literate user", I, as an advanced user, believe to be representative of this kind of person, say and affirm that this UI is completely broken and horrible, not to mention counter-intuitive.
That said, I have other things to say on the form. Yeah I've been harsh, and I will continue to be about this issue: this has not been designed with the simplicity in mind, but by geeks (FSVO geek) that believe that it's important to educate people about how nice HTTPS is and that everyone should talk in S3kr3t because its 733t. And I'm sure they tried very hard to make it very painful for users to have to deal with HTTPS and not believe in it to be trusted for bad reasons. Why ? HELLLOOOO PEOPLE this is the wrong way to do it. People are already aware that it is https, because they did typed https in the URL. And again, my mom doesn't know what the s in https stands for and she doesn't care. What she cares about is to see the small lock when she logs on her bank website, not even when she goes on her webmail. You REALLY want to make a simple UI ? Well, please try to explain and justify (with real arguments) Why on earth is https with an untrusted certificate less secure than http ?. Okay I'll let you 3 seconds to think. 1
2
3 What is your answer ? OH see ? it isn't. So now second 1 question, why does it need to be more painful to use https with an untrusted certificate than plain http ?. Well, I don't have 3 seconds to give anymore, so let's jump to the answer: there is absolutely no reason. See, I'm far from an UI expert, and what I use every day for UIs would revulse 99% of the planet: vim as an editor, awesome as a tiling window manager, vimperator for a browser, and I live most of the time in a terminal. But it takes me like 10 minutes to design what I believe to be an excellent UI for https with untrusted certificate: just don't mind the certificate and show it like plain HTTP. YES I'M ANNOYED That brings me to the last point. I see in my comments, and have received the same by mail, that I should not be harsh with people writing such a brilliant piece of software. Well, the fact that firefox is or is not a good piece of software is totally irrelevant. When you claim no less than trying to reinvent the web, well, if you fuck up this big, you deserve it. No matter if it's a free piece of software or not. (or a piece of free software or not). When you request your users to click on FIVE completely counter-intuitive buttons/urls to finally be able to see a webpage they want to see (and my mom doesn't care about the webmail being insecurely hosted, really), with the first screen being almost the same than what you get when a serer timeouts or 404, well, you're just out of your mind. There is absolutely nothing that can excuse such a bad design, and the SSL thing is a failure. I mean everyone is laughing at the vista way of asking you if you really meant to go pee, well I see no difference here, it's as dumb and inefficient. No matter how much firefox did improved (and it did memory wise, believe me, I feel it, and I'm really glad about that), https is part of my everyday's life. Those five clicks are a real PAIN. When I'm reading documentation, browsing some sources, and so on, I go through this dialog about 3 to 10 times in a row. I'm totally unimpressed, and just because a couple of geeks believed that it was GOOD to educate me about how dangerous untrusted certificates are, I have to break my workflow to grab my mouse in the middle of my work. No sorry, I don't really want to be calm. In fact, what annoys me the most, is that I'm a programmer. And as a programmer, the worst thing to me, is regression. Regression is what happens when you're sloppy, and don't test your program enough. It's what happen when you aren't good enough to keep your concentration, and don't see the big picture, and constantly break your program invariants. So when I see a regression that people did on purpose, well, it shocks me beyond what I can explain with words, that's the worst thing you can do to a piece of software. I won't really mind a new feature that only partially works, I won't mind if a feature that is complicated to write isn't there after 5 years dreaming of it, but this ? I do mind. There is no way to consider that ruining a piece of software like that to the name of A Greater Good is excusable. Oh and last words: wanting to educate people this way is a way worst offense that what I will ever say on the subject. Such a condescending approach to what they think of their users reminds me of various journalists that I met, and that when I tried to rephrase some things so that they can write about it to their readers, answered to me oh you know, they're too dumb, they'll never understand. And as a result, articles or interview are always distorted, can't interest the readers that don't care about the subject a lot, because there's nothing captivating in the article, and is totally inexact and uninteresting to people interested in the matter, because it's void from its substance. Well, the SSL dialog gives me the very same impression: it's annoying to me who knows what a SSL certificate is, and my mom won't know a single bit more what an SSL certificate is and why she should care[1].
Notes [1] and actually the whole point guys, is that she should not

Russell Coker: Kernel Security vs Uptime

For best system security you want to apply kernel security patches ASAP. For an attacker gaining root access to a machine is often a two step process, the first step is to exploit a weakness in a non-root daemon or take over a user account, the second step is to compromise the kernel to gain root access. So even if a machine is not used for providing public shell access or any other task which involves giving user access to potential hostile people, having the kernel be secure is an important part of system security. One thing that gets little consideration is the overall effect of applying security updates on overall uptime. Over the last year there have been 14 security related updates (I count a silent data loss along with security issues) to the main Debian Etch kernel package. Of those 14, it seems that if you don’t use DCCP, NAT for CIFS or SNMP, IA64, the dialout group, then you will only need to patch for issues 2, 3 (for SMP machines), 4, 5, 7 (sound drivers get loaded on all machines by default), 9, 10, 11, 12, 13, and 14. This means 11 reboots a year for SMP machines and 10 a year for uni-processor machines. If a reboot takes three minutes (which is an optimistic assumption) then that would be 30 or 33 minutes of downtime a year due to kernel upgrades. In terms of uptime we talk about the number of “nines”, where the ideal is generally regarded as “five nines” or 99.999% uptime. 33 minutes of downtime a year for kernel upgrades means that you get 99.993% uptime (which is “four nines”). If a reboot takes six minutes (which is not uncommon for servers) then it’s 99.987% uptime (”thee nines”). While it doesn’t seem likely to affect the number of “nines” you get, not using SMP has the potential to avoid future security issues. So it seems that when using a Xen (or other virtualisation technology) assigning only one CPU to the DomUs that don’t need any more could improve uptime for them. For Xen Dom0’s which don’t have local users or daemons, don’t use DCCP, NAT for CIFS or SNMP, wireless, CIFS, JFFS2, PPPoE, bluetooth, H.323 or SCTP connection tracking, then only issue 11 applies. However for “five nines” you need to have 5 minutes of downtime a year or less. It seems unlikely that a busy Xen server can be rebooted in 5 minutes as all the DomUs need to have their memory saved to disk (writing out the data to disk and reading it back in after a reboot will probably take at least a couple of minutes) or they need to be shutdown and booted again after the Dom0 is rebooted (which is a good procedure if the security fix affects both Dom0 and DomU use), and such shutdowns and reboots of DomU’s will take a lot of time. Based on the past year, it seems that a system running as a basic server might get “four nines” if configured for a fast boot (it’s surprising that no-one seems to be talking about recent improvements to the speed of booting as high-availability features) and if the boot is slower then you are looking at “three nines”. For a Xen server unless you have some sort of cluster it seems that “five nines” is unattainable due to reboot times if there is one issue a year, but “four nines” should be easy to get. Now while the 14 issues over the last year for the kernel seems likely to be a pattern that will continue, the one issue which affects Xen may not be representative (small numbers are not statistically significant). I feel confident in predicting a need for between 5 and 20 kernel updates next year due to kernel security issues, but I would not be prepared to bet on whether the number of issues affecting Xen will be 0, 1, or 4 (it seems unlikely that there would be 5 or more). I will write a future post about some strategies for mitigating these issues. Here is my summary of the Debian kernel linux-image-2.6.18-6-686 (Etch kernel) security updates according to it’s changelog, they are not in chronological order, it’s the order of the changelog file:


  1. 05 Jun 2008: CVE-2008-2358 for DCCP and CVE-2008-1673 for ASN.1 (NAT for CIFS and SNMP).

  2. 23 May 2008: CVE-2008-2136 memory leak in IPv6 over IPv4 tunnels, CVE-2007-6712 timer related bugs, CVE-2008-1615 ptrace on AMD64 architecture, and CVE-2008-2137 “Validate address ranges regardless of MAP_FIXED”.

  3. 07 May 2008: CVE-2008-1669 SMP race

  4. 11 Apr 2008: CVE-2007-6694 PPC only, CVE-2008-0007 Add VM_DONTEXPAND to vm_flags in drivers that register a fault handler but do not bounds check the offset argument, CVE-2008-1294 prevent user escape from RLIMIT_CPU, and CVE-2008-1375 fix dnotify race.

  5. 10 Feb 2008: CVE-2008-0010 and CVE-2008-0600 Fix missing access check in vmsplice.

  6. 25 Jan 2008: Not a security issue, but silent data loss on IA64.

  7. 22 Jan 2008: CVE-2007-6151 ISDN memory overrun, CVE-2008-0001 something related to checking the access to a directory, CVE-2007-2878 FAT filesystem related, CVE-2007-4571 ALSA bug that allows user to read kernel memory.

  8. 17 Sep 2007: Fix minor DOS attack for slightly privileged users (EG members of dialout group).

  9. 18 Dec 2007: CVE-2007-6063 overflows in ISDN subsystem, CVE-2007-6206 core dumping over an existing file can get the wrong ownership (should be possible to use kernel.core_pattern to work around this [1]), CVE-2007-5966 timer issue, CVE-2006-6058 Minix fs DOS attack via corrupted fs, and CVE-2007-6417 tmpfs memory leak.

  10. 29 Nov 2007: CVE-2007-3104 local kernel DOS attack (Oops), CVE-2007-4997 malicious frame on wireless interface crashes system, CVE-2007-5500 potential system hang, and CVE-2007-5904 CIFS overflows from server sending corrupt data.

  11. 02 Oct 2007: CVE-2007-4573 Xen 64bit with 32bit DomU, CVE-2006-5755 Xen, CVE-2007-4133 memory management DOS, and CVE-2007-5093 DOS when unplugging a webcam that is in use.

  12. 25 Sep 2007: CVE-2007-3731 ptrace causing Oops, CVE-2007-3739 memory management Oops, CVE-2007-3740 CIFS not honoring umask, CVE-2007-4573 ptrace of 32bit process on AMD64 bug, and CVE-2007-4849 JFFS2 (flash media) filesystem bug.

  13. 27 Aug 2007: CVE-2007-2172 IPv4 memory related issue (local DOS or compromise?), CVE-2007-2875 local user can read kernel memory if cpuset filesystem is mounted, CVE-2007-3105 buffer overflow in random number generator, CVE-2007-3843 CIFS, and CVE-2007-4308 AAC RAID.

  14. 11 Aug 2007: CVE-2007-1353 bluetooth, CVE-2007-3513 usblcd, CVE-2007-2525 PPPoE, CVE-2007-3642 H.323 connection tracking, CVE-2007-2172 IPv4 local exploit, CVE-2007-2453 slightly less random numbers, CVE-2007-2876 SCTP connection tracking, CVE-2007-3851 i965 batch buffer usage, and CVE-2007-3848 potential privilege escalation.

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Wouter Verhelst: Firefox sucks. No, really!

Warning: big rant ahead. I received some comments on my previous post, as expected. Most of them were helpful; e.g., the oldbar extension is very useful. One of them was silly.
It depends: If your application is "fullscreened", clicking on the link without having the focus could lead to interesting situation like "Hey, It does nothing?"
Just to make a point here, let me reiterate: There is no excuse whatsoever to steal the focus Sorry for the shouting, but seriously. I have the following in my icewm configuration: 
ClickToFocus = 0
RaiseOnFocus = 0
FocusOnMap = 0
FocusOnAppRaise = 0
FocusOnMapTransient = 0
FocusOnMapTransientActive = 1
RaiseOnClickClient = 0
What this means is that I don't want anything to either get the focus or get on top of anything else all by itself, unless it happens to be a new dialog box created by an application that already has the focus. I also don't want windows to appear on top of anything else just because they received the focus. I also happen to prefer focus-follows-mouse, which you can get by way of the ClickToFocus thing. The reason I prefer it this way, is that often I have several applications open all at once. For instance, when I read RSS feeds, I have my RSS reader open on one virtual desktop, and read through the articles. Since my laptop's processor is much, much faster in certain things than is my network, I also make use of its multitasking abilities to have it preload links in the background (on another virtual desktop, preferably). Unfortunately, somehow, firefox manages to bypass all that configuration and shows up in front, stealing the focus; and in the process, it completely interferes with the way I work. No doubt they do this in order to help some hypothetical "grandma" or other stupid clueless person who's never used a computer before, but let me tell you something: software should be written for people who actually do use software, not for stupid nitwits who can't even read an error message that tells them "you cannot do A, please go ahead and do B instead". But I guess I'm too stupid or something to understand the usability "experts" who know it all best and say that software should be "intuitive" so that those who are 53 and see a computer for the first time in their live can sit right next to it and start emailing. Hah. As if the above wasn't enough, firefox 3 also is a crashing load of shit. I just spent the better part of an hour to try and make a payment using my bank's excellent online payment software which requires nothing more than javascript, SSL, and a digipass 810 that is provided by the bank as part of the online banking contract. Unfortunately firefox insisted on crashing halfway through entering the required information, for six times in a row. You'd think I'd be filing a bug now, but no, it managed to crash in a different location every time. I'd probably have to start debugging firefox to get this done, which is not something I'll do in this life. You know what the problem is? Webbrowser developers think they're developing the most important application for any computer. They're not. It's just a webbrowser, no more important than an xterm or a mail client: a tool to get a job done. Period. Grunt.

Martin F. Krafft: Euro 2008 rage

As some of you may know, the Euro 2008 football championships are on in Austria and Switzerland at the moment. I am not a football fan at all, although I won t mind watching a game between two skilled and fairplaying teams (which is becoming a rarity, I heard). But I don t care much about it, unless it negatively affects those who don t care (which includes myself). For instance, last night, after Germany beat Turkey in the semi-finals, a group of hooligans roamed about in Dresden and vandalised Turkish food shops and hurt the people working there (German only). I can kind of understand fans getting overly excited and driving their cars madly through the city, honking the horns at frequencies directly proportional to their cumulative personality disorders (or inversely proportional to their penis size), but violence in reaction to winning? Fuck you, you low pieces of shit. ! Update: there seems to be no information on whether the attackers were German. A foreigner living in Berlin has written in to complain that my blog post casts a negative light onto Germany in terms of hostility towards foreigners, which he disputes. Germany has had to fight that image for decades, and my blog post puts fresh petrol on the fire. I do not intend that. I leave it up to each individual to make up their own mind, and to me, a group of hooligans is in no way representative of an entire nation. End update Quite clearly, there are people on the street who should be locked up. I won t go there though, at least not in this post. Instead, let s talk more about football and its effects, because encouraging this sort of violence is only one of many consequences, which we are forced to tolerate in the interest of the public. Everyone wants football, right? What follows are somewhat related, but otherwise incoherent rants. Enjoy, or stop reading. I m not a misanthrope, I think. There are many other aspects of this football event which make me want to throw up. One of them is the (sight of the) average organism who participates in the craze. Look at them! Monkeys are more intelligent than that! Has evolution taken a 180 degree turn? Of course, you can t blame the individuals, as their brains have been flooded and effectively shut off, so they don t make any trouble when they trott along the path to dumbification. It s the big companies and the media industry, blinded by short sight, do everything in their power to speed up this decline, fueling the consumerism of the stupified morons making up our the populace, just for the paycheck at the end of the day. The UEFA is primarily a huge money-making machine, and if you want more information on that I suggest that you look a bit into the distribution of media rights for the event. Another instance, which has a little more relevance to the normal person on the street is their ticket distribution: people have to pay hundreds of Euros to UEFA a year before the event for a chance to be given a ticket for any random day. The ticket is made out in their name and cannot be transferred. If you can t make the game, you can return the ticket to get you money back after the event. If you don t get a ticket, you ll also get your money back a year later. Interest-free loans, anyone? But hey, I actually don t care about most of that. Let those who want to consume consume, let those who can t entertain themselves watch television, let the UEFA and media people get rich by making people stupid, and let me go about my daily business. We held a small barbeque party some days ago, and I went out to buy a few kegs of beer from a local brewery. That was my first confrontation with the football circus, as the brewery happens to be about half a kilometre from the stadium where a match was on that night. It took me at least 40 minutes until I had argued successfully with five police officers and could pick up the kegs. Swap brewery for any of the other shops in the area, who did not receive any compensation whatsoever, and you ll note how the football circus takes priority over everyone s everyday life, even if you don t give a single flying food for the sport. I love Zurich, and just like most people, taking a stroll along the lakeside, between Bellevue and the Chinese Garden on a sunny afternoon is one of the more delightful ways to spend time in the city and enjoy its beauty unless they are putting up massive public viewing areas everywhere (and make shitloads of noise in doing so), and even dump elevated VIP platforms into the lake to add noise in the view to the noise in the ear. The official entities of Switzerland surely pushed for the event, as it drives tourism and brings money into the country. But were the people actually considered? Could we have done anything against this craze? I bet noone ever asked. I find it very sad how much garbage these fan monkeys produce. Switzerland is well-organised, and there are plenty of garbage cans around, many of which have been put in place specifically for the event, but it s already too much to ask of these low organisms to put the shit left from their consumption into those bins. And I won t even go near the question of how much energy this entire event wastes. Yay entertainment! Yay stupification of the populace! If you have football to celebrate, you don t have to consider the environment, or poverty, or other such annoying issues. Sunday night, the circus will come to an end, and what ll be left is a few days of cleaning and tearing down all the structures. Then this place will finally retun back to normal, and there ll be a little less idiots on the street, at least in the places I frequent. NP: Dimmer: There My Dear

Russell Coker: Dell PowerEdge T105

Today I received a Dell PowerEDGE T105 for use by a client. My client had some servers for development and testing hosted in a server room at significant expense. They also needed an offsite backup of critical data. So I suggested that they buy a cheap server-class machine, put it on a fast ADSL connection at their home, and use Xen DomU’s on that for development, testing, and backup. My client liked the concept but didn’t like the idea of having a server in his home. So I’m going to run the server from my home. I selected a Dell PowerEDGE tower system because it’s the cheapest server-class machine that can be purchased new. I have a slight preference for HP hardware but HP gear is probably more expensive and they are not a customer focussed company (they couldn’t even give me a price). So exactly a week after placing my order I received my shiny new Dell system, and it didn’t work. I booted a CentOS CD and ran “memtest” and the machine performed a hard reset. When it booted again it informed me that the event log had a message, and the message was “Uncorrectable ECC Error” with extra data of “DIMM 2,2“. While it sucks quite badly to receive a new machine that doesn’t work, that’s about the best result you can hope for when you have a serious error on the motherboard or the RAM. A machine without ECC memory would probably just randomly crash every so often and maybe lose data (see my previous post on the relative merits of ECC RAM and RAID [1]). So I phoned up Dell (it’s a pity that their “Packing Slip” was a low quality photocopy which didn’t allow me to read their phone number and that the shipping box also didn’t include the number so I had to look them up on the web) to get technical support. Once we had established that by removing the DIMMs and reinserting them I had proved that there was a hardware fault they agreed to send out a technician with a replacement motherboard and RAM. I’m now glad that I bought the RAM from Dell. Dell’s business model seems to revolve around low base prices for hardware and then extremely high prices for extras, for example Dell sells 1TB SATA disks for $818.40 while MSY [1] has them for $215 or $233 depending on brand. When I get the machine working I will buy two 1TB disks from MSY (or another company with similar prices). Not only does that save some money but it also means that I can get different brands of disk. I believe that having different brands of hard disk in a RAID-1 array will decrease the probability of having them both fail at the same time. One interesting thing about the PowerEdge T105 is that Dell will only sell two disks for it, but it has four SATA connectors on the motherboard, one is used for a SATA DVD player so it would be easy to support three disks. Four disks could be installed if a PCIe SATA controller was used (one in the space for a FDD and another in the space for a second CD/DVD drive), and if you were prepared to go without a CD/DVD drive then five internal disks could probably work. But without any special hardware the space for a second CD/DVD drive is just begging to be used for a third hard disk, most servers only use the primary CD/DVD drive for installing the OS and I expect that the demand for two CD/DVD drives in a server is extremely low. Personally I would prefer it if servers shipped with external USB DVD drives for installing the OS. Then when I install a server room I could leave one or two drives there in case a system recovery is needed and use the rest for desktop machines. One thing that they seem to have messed up is the lack of a filter for the air intake fan at the front of the case. The Opteron CPU has a fan that’s about 11cm wide which sucks in air from the front of the machine, in front of that fan there is a 4cm gap which would nicely fit a little sponge filter. Either they messed up the design or somehow my air filter got lost in transit. Incidentally if you want to buy from Dell in Australia then you need to configure your OS to not use ECN (Explicit Congestion Notification [2] as the Dell web servers used for sales rejects all connections from hosts with ECN enabled. It’s interesting that the web servers used for providing promotional information work fine with ECN and it’s only if you want to buy that it bites you. But in spite of these issues, I am still happy with Dell overall. Their machine was DOA, that happens sometimes and the next day service is good (NB I didn’t pay extra for better service). I expect that they will fix it tomorrow and I’ll buy more of their gear in future. Update: I forgot to mention that Dell shipped the machine with two power cables. While two power cables is a good thing for the more expensive servers that have redundant PSUs, for a machine with only one PSU it’s a bit of a waste. For some time I’ve been collecting computer power cables faster than I’ve been using them (due to machines dying and due to clients who want machines but already have spare power cables). So I’ve started giving them away at meetings of my local LUG. At the last meeting I gave away a bag of power cables and I plan to keep taking cables to the meetings until people stop accepting them.

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Pierre Habouzit: firefox3 and SSL

Yes Stefano, I too believe that the SSL certificate thingy in Iceweasel 3 is just a bad joke. I mean WHAT THE FUCK WERE THEY THINKING ? At least in the RCs it improved, and the logo isn't the same as 404, it took me 10 refresh the first time I saw it to understand that it was not a 404 but an untrusted self-signed certificate. And the whole "exception" thing is absurd. NO I DON'T WANT TO ADD AN EXCEPTION you morons. Here would be a good UI, that I never saw implemented in any browser but would make sense: It's enough for 99.9% of the users. Then, some of us really care about importing some untrusted certificates (for our own webmails e.g.). Then well, a small button that allows advanced users to check, import, and mark an untrusted certificate as trusted is just what one needs. One can even hide that in some menu, it would be fine. I for example, have only checked the SSL certificate from my webmail and something like 3 or 4 websites. I do NOT want to be bugged for the other. But no, instead we have this completely delirious interface that no-one can sanely call User Interface. They're on crack. Anyways, here is a way to make your pain easier, either in about:config or in your $ HOME /.mozilla/firefox/$ profile-with-name-on-crack-id /user.prefs set the following values this way[1]: 
 user_pref("browser.ssl_override_behavior", 2);
 user_pref("browser.xul.error_pages.expert_bad_cert", true);
It makes validating a certificate two clicks away (one of the settings shows the 'add exception' buttons instead of showing a link to make them visible, the other settings makes firefox download the certificate for you so that you don't have to ASK HIM to do so[2]. And you know the worst thing ? I'm sure the guy(s) who wrote this fucking dialog is(are) very proud of it.
Notes [1] Thanks to glandium for the hints [2] WTF people, WTF do you need us to make you download the certificate. This is nonsensical, the user had already 3 clicks to have the add exception dialog, and you need one to download the certificate ? WTF are you thinking!!!

Simon Richter: Seconded

This. (context)

25 June 2008

Pablo Lorenzzoni: Exciting new World

I ve just tested the improvements in the performance of Javascript in Firefox 3 and WOW! Javascript in FF3 is really fast. While googling about it I just ran across a recent interview with Brendan Eich about the future of Javascript and I got excited about two things about this future. First was what we already have, still in the beginning, but with a lot of potential: HotRuby. Really interesting to script a webpage in Ruby (which is my favorite language) and, while it s not embedded the way Javascript is, it gets compiled in the server side with YARV (the new bytecode compiler for the next version of Ruby, 1.9), and then served to the browser in the form of JSON objects, so it can be interpreted by the Javascript engine in it. All this is transparent and work with XMLHttpRequest. It s not a coincidence that Eich mentions it as being a form of ARAX (changing the J in AJAX for R from Ruby). I already do a lot of coding in Ruby not having to deal with Javascript anymore is surely a plus. ITOH, Eich is talking about improvements in Javascript that would render it as a real programming language Maybe coding in it would not be so painful anymore by then ;-) The whole interview have to do with this Project Tamarin, a high-performance, open source implementation of the ECMAScript 4th edition (ES4) language specification [ ECMAScript 4 is the same thing as Javascript 2 ] by the Mozilla developers. And this is the second thing I got excited for: they ve planned to glue IronRuby (Ruby compiler for argh! .NET) to it via IronMonkey. So exciting news! Either via Tamarin or via HotRuby, we ll get Ruby browser scripting. My free mind tends to favor HotRuby instead of IronRuby/IronMonkey/Tamarin But in the end what matters is that all those people now cursed by Javascript will finally have a taste of what a real programming language feels like.. Who knows! They might even like it ;-D

Gunnar Wolf: Firefox suckyness

I have to agree with Wouter regarding Firefox Iceweasel 3's suckyness. It might be a superior product in many fronts (I prefer it overall to its predecesor), but were it not for the usefulness of its many available extensions (most notably Web Developer, which has become an integral part of my everyday life), I'd have jumped ship for basically any other browser.
I'm just... adding an <AOL>ME TOO!</AOL> on Wouter's comments... WTF, just go to about:config...

So... Are you telling me that Firefox (even if it were the original, Mozilla-blessed version) has a warranty? No? Didn't think so... Go to about:license. You will see the very familiar and expected:
7. Disclaimer of warranty
Covered code is provided under this license on an "as is" basis, without warranty of any kind, either expressed or implied, including, without limitation, warranties that the covered code is free of defects (...)
Other than this downright stupid issue (which by and large goes against the regular Free Software culture), my main gripe is the number of active regions in the location-entry boxes - Yes, I can jump straight to the search box with Ctrl-K and to the location bar with Ctrl-L, but if I happen to try to move between them with good ol' Tab, why must it be inconsistent?
What do I mean? Go to the search field, press Tab. As expected, you are in the Location entry. Now, press Shift-Tab. For 5 points, where are you now? Bzzzt, no, you are not back where you began - You are in a stupid button which looks like your favicon giving you the identity information about the page you are looking at.
Having this button is a great idea - but why does it have to sit in the way of my tabulation? Were it because, in an inspired moment, the Firefox interface designers decided that buttons should be keyboard-accessible, I'd be most happy (it is by far my most mouse-intensive application, and I hate that... But it's just a button embedded in what should be a clean text-entry box.
And for that matter, it is not even a consistent button - Shift-tabbing from the search field will not get you to the search engine selector. And no key combination will lead you to the noisy (and also, mutually inconsistent) iconic buttons at the far right of both fields... Which, again, have no reason to be inside a text entry field!
Oh, and I found another pretty little jewel: Go to any site which has a self-signed SSL certificate. Of course, Firefox will go to great lengths to make sure you understand how unsafe is it for you to trust anybody who didn't pay big bucks to Verisign... But this is enough reason for me to send a bug report:

I am connecting through a crypted HTTPS connection. The site is providing identity information - not certified, right, but it does provide something. And the connection is crypted. Firefox/Iceweasel 2 showed me the URL in a light-yellow background showing the connection was secure - Now it just denies penta.debconf.org the right to call itself secure.
(Yes, I am not an interface designer... But it seems neither are they)
[update]Bug filed. Any comments will be welcome in Bugzilla. The bug with the Debconf site (and I do regard it as a bug) is that Iceweasel displays that Your connection to this web site is not encrypted because some of the elements (i.e. the CSS, images..) are sent in the clear - Even though the real information is crypted. Ever heard of data/visualization decoupling?

Biella Coleman: The Cultural Significance of Free Software

When it comes to research and writing, anthropologists are notorious for being slow as molasses. It takes, on average, 9 years to finish grad school and then another 3-6 years before you write and publish your first book. Such is the sometimes frustrating pace of academia. But sometimes it is worth the wait as this new book, Two Bits, the Cultural Significance of Free Software by the anthropologist of science and technology Chris Kelty, makes clear. I am pretty intimate with the details of the book as ck was one of my dissertation committee members. I have read earlier versions and was fortunate enough to teach the final version to a small group of graduate students last spring. While there have been previous books on the subject of open source or peer-to-peer production more generally, this is the first book to delve deep, analytically and historically, into the cultural significance of free software. And the best part is that ck managed (I am not sure how but he did) to convince Duke University Press to release the whole book under a CC license. So download it to your heart’s delight and if you find it useful, do order a treeware copy (as you can’t beat that for easy and comfortable reading). For the developers out there, I would suggest starting with the introduction, which provides an initial overview of some of the main themes he develops and then I would dig into part two where the historical chapters reside and then loop back to the theoretical chapters in part one or continue to part three. Trust me, these will fascinate and surprise even those geeks with a relatively deep historical sense of this world. In fact, my very favorite academic piece on free software exists in these pages: and is the chapter on the history of the actual conflict between James Gosling and Richard Stallman that led to the creation of the GNU General Public License. Here is a small excerpt to whet your appetite:
In brief the controversy was this: in 1983 James Gosling decided to sell his version of EMACS a version written in C for UNIX called GOSMACS to a commercial software vendor called Unipress. GOSMACS, the second most famous implementation of EMACS (after Stallman s itself ), was written when Gosling was a graduate student at Carnegie Mellon University. For years, Gosling had distributed GOSMACS by himself and had run a mailing list on Usenet, on which he answered queries and discussed extensions. Gosling had explicitly asked people not to redistribute the program, but to come back to him (or send interested parties to him directly) for new versions, making GOSMACS more of a benevolent dictatorship than a commune. Gosling maintained his authority, but graciously accepted revisions and bug-fixes and extensions from users, incorporating them into new releases. Stallman s system, by contrast, allowed users to distribute their extensions themselves, as well as have them included in the official EMACS. By 1983, Gosling had decided he was unable to effectively maintain and support GOSMACS a task he considered the proper role of a corporation.
[ . . .]
Indeed, the general irony of this complicated situation was certainly not as evident as it might have been given the emotional tone of the debates: Stallman was using code from Gosling based on permission Gosling had given to Labalme, but Labalme had written code for Gosling which Gosling had commercialized without telling Labalme conceivably, but not likely, the same code. Furthermore, all of them were creating software that had been originally conceived in large part by Stallman (but based on ideas and work on TECO, an editor written twenty years before EMACS), who was now busy rewriting the very software Gosling had rewritten for UNIX. The once proud hacker ethic that Labalme mentions would thus amount not so much to an explicit belief in sharing so much as a fast-and-loose practice of making contributions and fixes without documenting them, giving oral permission to use and reuse, and losing records that may or may not have existed hardly a noble enterprise.
[. . .]
The story is a lively one, punctuated with some great e-mail “moments,” and gives you a play-by-play sense of how it is that free software become so entangled with the law and how the unwritten norms that guided sharing were violated to then become transformed, explicit, and written. The other chapter that will also fascinate those who want a deeper sense of this history is on UNIX and its role in creating the technical and collaborative conditions necessary to secure the explosion of free software years later. The story of the norms of sharing source code is, not by accident, writes Kelty, also the history of the UNIX operating system. This connection has been made by others but not shown in any historical detail as it is done in this book. For those interested in more anthropological issues, the first few chapters is where this type of more conceptual theorizing is at. Chris Kelty introduces the master trope of his book: the recursive public which is an idea that feeds into a longer academic debate, inaugurated by Jurgen Habermas, on the role of publicity, dialogue, and circulation of ideas and texts in cementing a democratic sphere. Many others, such as Charles Taylor, Michael Warner, and Nancy Fraser have since refigured and rehashed the meaning publics and public debate but there have been few ethnographies on the topic. It is here where Chris Kelty intervenes most forcefully to conceptualize publics in explicitly ethnographic terms and in an arena technology and the Internet which is often left undertheorized by cultural theorists. There is a lot more in the book (the third section examines some of the various political modulations of free software, such as Connexions and Creative Commons) but instead of saying any more, I will just leave you with his definition of a recursive public and again urge you to check out the book for yourself!
A recursive public is a public that is vitally concerned with the material and practical maintenance and modification of the technical, legal, practical, and conceptual means of its own existence as a public; it is a collective independent of other forms of constituted power and is capable of speaking to existing forms of power through the production of actually existing alternatives.

Clint Adams: Relaxation

I was misled. That much is probably true. I certainly had no idea what I was getting myself into. Enough of that though; there's narrative fading away. The part I should take responsibility for is the decision I made to stray off the map. Perhaps it was not so much a decision as a compulsion. I looked at the map. I saw the suspicious unmarked area at the edge, and concluded immediately that there was something good there, something the people wanted to keep hidden from me. I was correct, but I presumed far too much about the terrain. I thought I would make a quick exploration of the secret place, then backtrack to the more mapped area and get back with the program. Enough of that though; I've nearly forgotten the story. First I should point out that, had the map been to scale, it should have taken me an leisurely fifteen minutes to get to my first destination. It should have, assuming the land would be as flat as the map that represented it. Instead, it turned out to be something one could cover in fifteen minutes if one had, say, a jetpack and spring boots. I'm probably wrong; I'd probably injure myself in the process and take longer. Anyway, the average incline was close to 45 , and luckily was mostly uphill. Luckily. When I got to a resting place, I was able to conclude that my supply of fluids was almost certainly insufficient for me to continue. On the other hand, there was probably no way I would return if I went back for more drink. I told myself that there would likely be a beverage-selling shack out in the middle of nowhere around the next bend or so. Having solved this probability problem, I pressed on into the blazing sun. I came to a path leading down to the sea. It was unclear what was down there, but it was clear that it seemed to be a million miles down, and that that path might be the only way back. Given my current state of exhaustion and hydration, I decided to pass on this opportunity. After continuing for a while, the features at the bottom of that path became visible. A very pretty cove was down there, and almost certainly no shack o' drinks. I then came upon a fork. A wide path led downward: to what, I could not see. To its left, a narrow and rough path led straight. Knowing that a descent probably meant climbing four to eight times the altitude back somehow, and assuming the less pleasant-looking path led somewhere better, I went left. After a while, the land began to slope down, ever so slightly. Little clusters of bottles and newspapers were left on the rocks here and there. Then came a sofa under a tent. I began to wonder what hippies were traveling this path. The slope grew greater, and I passed a bench in a tent. Then I came to a giant staircase, almost straight down. It was covered in weeds and insects. Some were vegan, some wanted my flesh. As I got toward the bottom I thought about how glad I was that I had come that way from the top and not the other way around. Oh, I was very glad. At the bottom was something resembling a plastic bottle graveyard and barrels among barrels filled with water. Rubber hoses seemed to run randomly between certain barrels. A kitchen stood at the edge of some barrels. I suddenly got the feeling that I was not supposed to be here. After discovering that a couple of escape routes were actually dead ends, I proceeded to descend a small staircase to a terraced garden. Hoses lay about the rows, presumably for watering the plants. A cot under a tent lay empty, and I hurried past hoping I would not encounter the owner. Then I was at the ocean. The coast was lined with huge boulders, and a wooden bridge led me to the first one, and another wooden bridge took me to the second. Then the bridges stopped. In the distance, I could see that pretty little cove from before. I took stock. I could either return whence I came, up that horrifying staircase, or I could try to traverse the rocky coast over to the cove, then maybe do a faceplant on the beach and let the tide drown me rather than climbing back up. It seemed like a no-brainer, so I began making my way toward the cove. It got harder. Several times I became very afraid, either of falling and smashing my head against a rock or falling into the water below, or some sequential combination thereof. In the end I turned out to be more afraid of going back, at least until I got to what I judged the point of no return. I was reasonably close to where I imagined the sandy beach started, but there was a huge and impassable boulder in the way. Also, if I went further there was no way I would be able to climb back up in case I needed to retreat. I was thinking I would need to retreat, because unless there was some magical hidden toehold, I would be forced to jump into the water and swim around. I did not want to jump into the water. I wanted my phone to stay unfried in the event that I would need to use it to get rescued. I also did not want to call anyone to get rescued, especially since I didn't really know how to explain where I was. With a heavy sigh, I gave up, turned, and went back. This time I moved more quickly, though incurring more damage to my hands and feet. No humans were visible at the crazy farm/garden and makeshift reservoir, but plenty of bugs were visible on the staircase. I made the mistake of trying to lean against the railing to catch my breath. When I finally got to the bench in the tent, I understood exactly what it was for. I sat down, took a sip of my remaining water, ate an apple, and kept going up. When I got to the couch, I sat again. This time I sat and tried to figure out a plan. I still clung to the belief that once I got back to somewhere less wild I'd be able to buy a drink. I noted that I only had a little bit of water left, that I was dehydrated, that I was sunburned, that my pulse was about 180, and that there were no dogs or Russian people wandering past me. I ate a pear and drank my last few drops of water. I kept sitting until my pulse was down to around 150, then I figured I needed to keep moving. I was experiencing most of the effects of caffeine, and for free. Oddly, I passed a dog a few steps later. It was just standing by a rock, looking at me. I decided not to converse. When I had nearly reached the fork again, a couple came my way. I thought about begging them for water. I decided not to be rude. I have no idea what happened to them. I'm betting they wisely decided not to go down the steps. Resolving that the only sane option was to go back all the way to where I absolutely knew I could buy something potable, I headed in that direction. Still, I took two risks. Instead of going up the exact way I had come, or taking a well-travelled path down, I took a narrow and flat dirt path. It was actually a bit of a dilemma. I started down the latter two more than once each. Finally I saw that the down path was rather V shaped, and I concluded correctly that the straight path would bypass that angular-half-pipe-like construct. When I finally got to a point I recognized, it was smooth sailing the rest of the way down. I bought water and a snack, since I had had almost nothing to eat that day. At this point it would have been prudent to call it quits and go off and gorge myself on seafood or something, but no, I was now in the mapped area and surely it would all be roses and manna. Finishing one bottle, I bought two more. Five minutes later I bought another. I had now overcompensated, but I was playing it safe. I continued my explorations. Bicyclists kept nearly running into me, and, aside from the obvious, I viewed this as a good sign. Bicyclists, especially those that can't seem to steer straight for some reason, avoid difficult terrain. This is why they take their bikes on subways, trains, and buses. I don't like bike-riding, but if I had my druthers, I would always go downhill. No up, no flat, just down. Like downhill skiing, just down. It is a good thing I don't ride a bike. Once I got to the point where the bicycles thinned out to nonexistence, I was at an intersection. The way I wanted to go was up. The way I didn't want to go, but was a reasonable option, was only very slightly up. Additional factors complicated this decision point. [elision] This passage has been marked friends-only and you will not be able to view it without logging in. Moving hurriedly away from there, I headed upward. After a couple of turns, I ran into Catholics. First there were dead Catholics. Then there were Catholics pre-occupied with dead Catholics. Then there were Catholics waiting to die. Then there were seminarians. Then there were teens with prayer books. When I reached the next pinnacle, there were more teens with prayer books. There were benches, and there were no teens on them, for the teens were standing or sitting on the ground, quietly contemplating the Word. Unfortunately, they had decided that the benches were more suitable for holding all their bags, so there was nowhere for me to sit. I considered interrupting their reverie, but decided it wouldn't be very Christian of me to disturb them, so I just placed an ancient Drasnian curse on them and plodded down the hill toward a small beach. I really didn't need any more sun, but at least there probably wouldn't be anyone praying there. The water was tempting, but I'm always paranoid about my belongings when swimming alone, and if my phone were taken I wouldn't be able to call anybody to come rescue me at the next crisis point, sure to come. So I skirted the coastline and arrived at a much larger beach, one with facilities and services. Opting to save money but complicate things by using the public changing rooms and showers, I made a discovery. [elision] This passage has been marked friends-only and you will not be able to view it without logging in. Nonetheless, I changed into my swimming trunks, stuffed everything else but my towel, sunglasses, and a disgusting sugary drink I never should have bought into my bag, and went barefoot a few buildings down to rent a locker. The locker was ridiculously large for a single person, which is good to know should I ever want to kidnap a family and torture them at this place. The proprietor informed me that they were closing at some specific time, about an hour from then. I had no timekeeping device outside of the locker, so I had to wing it, and erring heavily on the side of caution, I had a short beach diversion. Given that large swathes of my epidermis were turning bright red, it's probably for the best. Handling the shower, locker, and changing in the other direction was slightly more complicated, but I did it and then I headed inland, figuring I should have a substantial meal for once that day. On my way to find dinner is when things got really crazy. [elision] This passage has been marked friends-only and you will not be able to view it without logging in. I wandered over to a bench to eat my newly-acquired snack, and did not exercise enough caution, because the flimsy paper bag ripped and I got sauce all over my pants and a little on my shirt. Unfortunately I had used my napkin in that earlier episode, and I'm not sure how much it would have helped anyway. Thus I continued on, looking like a slobby retard. Then I made an obviously-poor decision and ended up having a subpar dinner. What happened after that is a story for another time.

Wouter Verhelst: Iceweasel sucks.

I knew this since quite a while, actually—most of the firefox developers seem to developing for something else than what I use; but, well, using something else isn't very appealing to me. Anyway, yesterday the Iceweasel 3.0 update came on my laptop, and I couldn't help but sigh. I hadn't tried anything, hadn't read any reviews, didn't know what would happen; but given their track record, I expected only problems. I wasn't disappointed. Or, well, I was, depending on how you look at it. And that's only after a day. I fear the next few weeks. For the time being, hints on getting the above moronic stupidities gone (apart from the about:config one, which takes a single click) would be helpful. And then of course I'm not even mentioning the fact that most of my add-ons don't work with 3.0 yet—but that is to be expected with a new brouwser, of course. At least flashblock works, which is the most important one.

24 June 2008

Matthew Garrett: Power management design philosphy

One of the traditional problems with power management has been balancing power savings against reduced functionality. The two traditional approaches to this have been to have sane defaults or to let the user tweak them, with a hybrid approach being to have sane defaults and an "advanced" box that lets users set their own parameters.

Both of these options suck.

The problem with sane defaults is that power management is an area where the "sane default" genuinely does differ between users. Usage patterns will determine the appropriate spindown period for a hard drive. AHCI's ALPM will disable hotswap detection, which is fine for home users but a pain if people want to rip out a failed RAID element. ALPM also introduces a small amount of latency (on the order of a seek in the most aggressive mode), which is entirely irrelevant for almost everyone but is a pain if you're trying to offer i/o latency guarantees. PCI-E link power management adds small quantities of latency. Letting the CPU run to full speed whenever it wants to is good for power management but potentially bad for thermal management. Screensaver timeouts vary depending on whether you're watching a movie or not.

The problem with leaving everything tweakable is that you're asking users to make choices about things but not giving them the information they need to make those choices. Whether you get a power saving from hard drive spindown depends on whether the drive is idle for long enough to save the power you'll spend spinning it back up. Get it wrong and you'll be putting your drive under extra load, reducing performance and consuming more power than you were to begin with. If you limit the maximum speed of your CPU to keep it cool, you'll be wasting power and performance even when it's well below the thermal limits. Disabling ALPM because you might want to change a RAID device at some stage means you're consuming power despite generally not needing to use the additional functionality.

But while these options both suck in different ways, they share one fundamental failure. They both imply static configuration. The correct power management policy depends on the way that a machine is being used at a specific instant in time, and no matter how many power management profiles you add there's no way for a user to switch between them fast enough to obtain a decent power/performance ratio.

Adaptive power management adopts a different strategy. Rather than define a static policy (or several static policies), the hardware is monitored to determine the best power management settings. An example of this is the ondemand CPUfreq governor. Rather than attempt to provide a static configuration, the processor frequency is automatically changed to meet demand while also keeping the overall power consumption as low as possible. This patch adds a thermal component to its policy, preventing the machine from overheating. Result? No requirement to provide tunables to userspace.

Something similar is achievable with hard-drive spindown. By simply monitoring how often reads or writes actually hit disk, it's possible to automatically adjust the spindown period to obtain decent power savings while reducing the number of spinups. This approach is imperfect - in an ideal world we'd know to spin the drive up before it's needed, but that simply isn't possible. However, the user is almost certainly unable to make a better guess. It's not realistic for a user to be able to predict whether or not a given page is still in cache or has been evicted. Nothing is lost by providing a dynamic policy, and another unnecessary tunable has vanished.

The difficult part of an adaptive policy comes when roles are switched in ways that don't correspond to changse in hardware status. One of the most common cases is that of screensaver settings when the user is watching a video. It's not practical for the kernel or a system daemon to predict this case, so we have two choices:.One of these choices involves the user having to explicitly state something that's obvious - playing a video automatically implies the desire to adopt a different power management policy, and so asking the user to manually adjust that is ridiculous.

The loss of hotswap notifications when ALPM is enabled? Simply reenable it if SMART starts complaining or the RAID set becomes degraded or a filesystem is unmounted or any of the other things that will have to be done before a drive can be safely removed. Latency an issue? Let userspace tell you what its latency requirements are. When we get down to it, the only settings that we can't infer are things like idle-time-to-suspend, screensaver settings and default brightnesses. Which, curiously, are about the only things that Mac OS exposes[1].

The problem we face is that we don't currently have interfaces to let applications tell us what their requirements are. This is theoretically straightforward, but getting it right is important. Beyond latency and screensaver issues, what constraints do applications want to impose? How can we expose an interface to those constraints? This is the sort of thing we'll be looking at at the Linux Plumbers Conference, so if you have ideas about what they'd need to look like then sign up. Or, even better, submit a paper and be part of the process that gets Linux's power consumption as close to the theoretical minimum as possible.

[1] My Vista system gives me 25 options which can be set for each of AC and battery.

Uwe Hermann: DIY secure pseudo-DDNS setup using ssh

Here's a quick HOWTO for setting up your own secure pseudo-dynamic DNS (DDNS) server. It's not a "real" DDNS service, i.e. you won't be able to use standard DNS tools or protocols to talk to the server, but it covers 98% of all functionality I expect from a service such as DynDNS or similar ones: It tells me the IP address of a certain box which doesn't have a static IP address (e.g. my home-server). Requirements You'll need: Setup On the homeserver: On the publicserver: The script Finally, here's the content of the updateip script: 
  #!/bin/sh
  # Update IP address.
  echo $SSH_CLIENT   cut -d " " -f 1 > /home/user/homeserverip.txt
So to summarize: the homeserver's user simply executes the updateip script on the remote publicserver, which in turn abuses the $SSH_CLIENT environment variable which contains the public IP the ssh connection was coming from (which is exactly what we're looking for). We store that IP in the homeserverip.txt file, which will always contain the latest-known IP address of the homeserver (because of the cronjob). Getting the current homeserver IP address You can now retrieve the current IP address of your homeserver easily from anywhere (i.e. from your laptop when you're in another, possibly hostile network) in order to connect to your homeserver: 
  $ ssh -x user@publicserver cat /home/user/homeserverip.txt
To make this a bit more convenient you can add a shell alias (e.g. into ~/.bashrc): 
  alias homeserverip='ssh -x user@publicserver cat /home/user/homeserverip.txt'
Or, to conveniently login to your homeserver as user: 
  alias homeserverlogin='ssh -x user@ ssh -x user@publicserver cat /home/user/homeserverip.txt '
Conclusion, advantages This may not be the most elegant solution, and it has a number of drawbacks when compared to services such as DynDNS, but it's sufficient for me and it also has some advantages: Personally I'm currently using this mechanism for two things, more might follow: So far it works pretty nicely. Update 2008-06-24: Various fixes and simplifications. SSH key must be password-less. Don't run cronjob once per minute, that's overkill.

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