Search Results: "ron"

4 March 2013

Eddy Petrișor: So, I did the responsible thing and fixed appdirs

In my previous post I expressed my frustration at the way a perfectly nice and fine idea, a portable way to get the standard configuration and data directory/files, was broken for Linux and BSD, because the authors of appdirs thought the XDG standard was "subject to some interpretation".

Although I said I decided not to use appdirs, I realised that wouldn't help anyone, so I fixed the code.

During the coding phase I discovered that the authors of appdirs broke the XDG standard even more, this time, ignoring XDG_DATA_DIRS, and talking about XDG_CONFIG_DIRS. When I found this I became convinced the *nix part of the implementation was subject to continuous irony, since the comment in this newly found breakage said "Perhaps should *use* that envvar", referring to XDG_CONFIG_DIRS, but writing later in code:

/etc/xdg/<appname>

Sweet, isn't it?

If you want a fixed version, you can grab it from my repository, on the linux-fixes branch:

https://github.com/eddyp/appdirs/tree/linux-fixes

2 March 2013

Bastian Blank: LDAP, Insignificant Space and Postfix

For some, LDAP, just like X.500, is black magic. I won't argue against. Sometimes it really shows surprising behavior. It always makes sense, if you think about what LDAP is built for. One surprising behavior is the handling of the "Insignificant Space"
LDAP supports syntax and comparator methods. The syntax specifies how the entry should look. Usually this is some form of text, but numbers or stuff like telephone numbers are supported as well. The comparators specifies how the values are compared. Most of the text comparators are defined to apply the handling of insignificant spaces. Insignificant space handling normalizes the use of spaces. First all leading and trailing spaces are removed. All the internal spaces are normalized to at most two spaces. At the end all strings starts and ends with one space to allow proper sub-string matches. The resulting strings are used for comparisons. This behavior makes sense most of the time. If the user want to find something in the directory, he usually don't cares about spaces, but about content. But I found one occurrence where this produces some grieve. Postfix supports LDAP since some time. And lets say, it does not care about spaces in its queries. This is no problem as e-mail addresses do not contain spaces. Or do they?
Yes, e-mail addresses can contain spaces. This is not widely known, but still allowed. This addresses are quoted and the command looks like RCPT TO:<" test"@example.com>. The local part is quoted and contains a space at the beginning. And this is where the problem starts. Postfix sanitizes the address. It uses a simplified internal representation of the address for all lookups. So the address gets test@example.com. This form is used in all table lookups. The LDAP table uses the internal form of the address. This address is copied verbatim into the query. This query may look this way (mail= test@example.com). It is sent to the server this way. The LDAP server applies the insignificant space modifications. The query is now interpreted and the comparator specified modifications are applied. The query gets effectively changed to (mail=test@example.com). And this is where the fun starts. Postfix accepts undeliverable mails. Depending on the setup, such LDAP queries may be used to check for valid addresses. Because of the space handling, the sender can add spaces to the beginning of the address and it will still be considered valid. In later steps this addresses are not longer valid. Addresses starting with spaces are considered invalid in some locations of Postfix. What surprised me a bit is that virtual alias handling did not map them. The unmodified addressed showed up on the LMTP backend server. That's why they showed up my radar. I would say Postfix is wrong in this case. The LDAP server applies the spec correctly and defines spaces in e-mail addresses as insignificant. Postfix on the other side considers them significant. The easiest fix would be to not allow any spaces in the LDAP table.

Russ Allbery: Review: Asimov's, June 2011

Review: Asimov's Science Fiction, June 2011
Editor: Sheila Williams
Issue: Volume 35, No. 6
ISSN: 1065-2698
Pages: 112
Sheila Williams's editorial is about a new ebook-only anthology of Asimov's stories, with some discussion of electronic sales. This sort of business editorial is what she's best at writing, although in this case I'm far enough in my reading that I'm reading it through a bit of a time machine. Silverberg's essay is about popular bubbles and is mildly interesting, although I've read quite a lot about this at greater length. I think he misses the plot at the end, though, where he brings in the 2008 collapse and works on focusing the blame on speculators rather than those selling the fraudulent investments. James Patrick Kelly has a surprisingly graceful introduction to fanfic that does a better job at conveying the underlying enthusiasm than most mainstream coverage. The review column this month is Peter Heck's workman-like survey of recently released books of interest. "The Cold Step Beyond" by Ian R. MacLeod: Most of MacLeod's writing I've read has focused on lush world-building, usually with a mix of magic and industrial revolution. This felt like a departure: a character study of a heavily-modified warrior and monster hunter against a clearly science-fictional background. The protagonist has no memory of her past beyond her training in a religious institution, and is as much machine as woman. She is on one of her first missions to hunt dangerous monsters. But she's given almost no direction, and rather than encountering a monster, she encounters a feral woman with an ancient ray gun. MacLeod has a very SFnal twist waiting in the wings, but what I liked best were the character dynamics and the interplay of duty and self-determination. (8) "All the News That's Fit" by Carol Emshwiller: This story follows Emshwiller's normal pattern of telling the story of an outsider and representative of outsider culture trying to understand a society, but her protagonist here is both more alone and more proactive than her average protagonist. She lives in a distant mountain village only rarely visited by a traveling reporter who brings news from outside. When he doesn't come, she goes out looking for him, at first to rescue him if he ran into trouble and later to find the news herself. Much of the story has the reader worrying nervously for her as she observes the large city while clearly having no idea how to live there. The ending provides an interesting and (at least for me) unexpected twist on the rural person coming to the big city, but it was marred by a level of anger from the protagonist that I never thought was well-motivated. (6) "Walking Stick Fires" by Alan DeNiro: There is a science fiction subgenre that, for lack of a better term, I'll call post-apocalyptic surrealism. This is an entry in that strange subgenre, featuring two alien bikers having mostly unmotivated adventures with strange objects and even stranger creatures on an Earth that's apparently been invaded and mostly devastated by multiple parties. Like a lot of post-apocalyptic surrealism, it never makes much sense. It reminded me of Rucker but with a bit more characterization and less hand-waving math. (4) "Apocalypse Daily" by Felicity Shoulders: I really liked the premise for this story. The protagonist is a concept designer for a social-oriented MMORPG, but one where only scores and resources carry over rather than the whole world. The goal of the game is survival: the world ends regularly, globally or locally, in a huge variety of ways, and one scores points and earns resources for further iterations by finding ways to survive that catastrophe. The game is structured to encourage cooperation, at least at first. But Katrina gets into a mildly paranoid workplace conflict with someone else on her team, leading to some significant changes in the underlying expectations of the game. Unfortunately, while the background and idea are quite solid, the direction the story goes is predictable pessimism, the conclusion doesn't say much that I found interesting, and I ended up detesting the protagonist. I would have preferred a more unique psychological twist. (6) "The Fighter" by Colin P. Davies: This is a rather short story, essentially an idea study in the context of a police stop of a futuristic entertainment fighter. This is another one of those depressing takes on a common SF trope. I didn't entirely follow the world-building, but it was all dark and pointless enough that I didn't really want to dig further. (4) "Kiss Me Twice" by Mary Robinette Kowal: I've read a few police procedurals featuring AIs before, but this is by far the best one I've read. Huang is a detective, and like all the detectives he makes extensive use of the police department AI. Unlike most of the detectives, though, he treats her as a full partner and close to human, and she reciprocates with a Mae West persona and a closer relationship with him than most of the department. They're in the middle of investigating a murder when there is a raid on the police department and the AI herself is stolen. The rest of the story entangles their investigation with the theft of the AI. The police AI is, of course, restored from backup, but that's the first time that's ever happened to her, and she's shaken by it, and more disturbed by the knowledge that there are two copies of her running. The mystery angle of the story is reasonably satisfying, but the AI characterization and Huang's careful feeling-out of their relationship and appropriate behavior on his part is the best part of the story. This is a great story: long, satisfying, and thoroughly excellent. I'd happily read more fiction in this universe. (8) Rating: 7 out of 10

1 March 2013

Joerg Jaspert: tmux - like screen, just nicer. Replacing clusterssh too.

By now I am a long time happy user of tmux instead of screen. I started using it somewhere in 2011 and by now I only have one usage of screen left over (direct ttyS0 access for one serial). As usual I have a custom config for it, and if you are interested there is a link for you: tmux.conf. But the more interesting part and why I blog is that I also wrote a little helper around tmux. Ingeniously called tm. And a colleague said I should let other people use it too and place it somewhere accessible. So, err, here it is. Or better, the usage output of it, the actual script has a link somewhere below. 
tmux helper by Joerg Jaspert <joerg@ganneff.de>
Call as: tm CMD [host]...
CMD is one of
 ls          List running sessions
 s           Open ssh session to host
 ms          Open multi ssh sessions to hosts, synchronizing input
 $anything   Either plain tmux session with name of $anything or
             session according to TMDIR file
TMDIR file:
Each file in $TMDIR defines a tmux session.
Filename is the commandline option $anything
Content is defined as:
  First line: Session name
  Second line: extra tmux options
  Any following line: A hostname to open a shell with in the normal
  ssh syntax. (ie [user@]hostname)
Environment variables recognized by this script:
TMPDIR - Where tmux stores its session information
         DEFAULT: If unset: /tmp
TMSORT - Should ms sort the hostnames, so it always opens the same
         session, no matter in which order hostnames are presented
         DEFAULT: true
TMOPTS - Extra options to give to the tmux call
         Note that this ONLY affects the final tmux call to attach
         to the session, not to the earlier ones creating it
         DEFAULT: -2
TMDIR  - Where are session information files stored
         DEFAULT: $ HOME /.tmux.d
TMWIN  - Where does your tmux starts numbering its windows?
         This script tries to find the information in your config,
         but as it only checks $HOME/.tmux.conf it might fail.
         So if your window numbers start at anything different to 0,
         like mine do at 1, then you can set TMWIN to 1
It is mainly useful for using tmux as a ssh-multiplexer and replacement for clusterssh though its happy to do any other tmux session too. As the help text may already have told you, you can use it to list existing tmux sessions (oh, wow!). Honestly, that one is there because tm ls is shorter than tmux ls More interestingly, tm s HOSTNAME opens a tmux session with the first window being a ssh shell to HOSTNAME. Should you later type tm s HOSTNAME again, it will attach to the existing session. But the real kicker for me (and colleagues) actually is the ms subcommand of it. ms being short for multi-session, it is my way of no-longer using clusterssh. Basically you type tm ms HOST1 user@HOST2 and it opens a session with one tmux window consisting of two panes. Showing you host1 and host2 at the same time. And the input to both is synchronized, that is - all your input is send to both of them. You aren t limited to just two hosts, do as many as you wish. Actually, I have no idea if tmux has an upper limit, but I did already have more than 100 hosts open at once. The major limitation there is not tmux - but simply the available screenspace, as all hosts are shown in ONE window! (The one advantage of clusterssh, it uses one xterm per host) This is quite helpful in all kinds of administration work involving clusters - imaging installing a package on 5 hosts of a cluster, you usually want it on all of them - or any kind of situations where one wants to run one command on many systems. As I m already said, I m lazy. And so there is a way to easily define multisessions that one uses regulary, by creating files inside the directory behind $TMDIR, usually $ HOME /.tmux.d. They are simple text files and let you easily define sessions you can then (re)open with a simple tm whateveritsname. And if you want the whole script by now: tm

Daniel Pocock: Monitoring JBoss, Tomcat and other application servers with JMXetric

JMXetric 1.0 was finally released in February, let's have a quick look at how conveniently it can be integrated with an application server. A more thorough analysis of gmetric4j and JMXetric can be found in the sections I contributed to the new O'Reilly book Monitoring with Ganglia General comments about JVM instrumentation and the JVM boot classpath Monitoring agents (there are a number of them out there) are loaded at an early stage by the JVM and it needs to have access to any of their dependencies through the boot classpath. JMXetric explicitly declares it's dependencies in MANIFEST.MF:
Boot-Class-Path: oncrpc-1.0.7.jar gmetric4j-1.0.2.jar
 As no absolute path is specified, the JVM will look for those JARs in the same directory where the jmxetric.jar is located. Furthermore, the JVM will expect the exact filenames to match. If other filenames are used (e.g. for a newer version of gmetric), then the JVM command line needs to specify the filenames and locations, for example:
-Xbootclasspath/a:/opt/ganglia/jmxetric/gmetric4j-1.0.3.jar
 Starting JBoss 7 with JMXetric To start with, unpack a vanilla JBoss distribution:
$ mkdir ~/opt
$ cd ~/opt
$ tar xzf ~/Downloads/jboss-as-7.1.0.Final.tar.gz
 Now get the JMXetric code and put it, together with dependencies, in the same directory:
$ mkdir -p ~/opt/ganglia/jmxetric
$ cd ~/opt/ganglia/jmxetric
$ wget http://search.maven.org/remotecontent?filepath=info/ganglia/jmxetric/jmxetric/1.0.2/jmxetric-1.0.2.jar
$ wget http://search.maven.org/remotecontent?filepath=info/ganglia/gmetric4j/gmetric4j/1.0.2/gmetric4j-1.0.2.jar
$ wget http://search.maven.org/remotecontent?filepath=org/acplt/oncrpc/1.0.7/oncrpc-1.0.7.jar
 Set up a config file for JMXetric:
$ mkdir -p ~/opt/ganglia/jmxetric/etc
$ cd ~/opt/ganglia/jmxetric/etc
$ wget https://raw.github.com/ganglia/jmxetric/master/etc/jmxetric.xml
$ cp jmxetric.xml jmxetric-jboss.xml
$ vi jmxetric-jboss.xml
 and insert the following code: 
                <!-- report web server request count -->
		<mbean name="jboss.as:subsystem=web,connector=http" pname="http">
			<attribute name="requestCount" type="int32"/>
		</mbean>
Finally, tell JBoss about the agent:
$ cd ~/opt/jboss-as-7.1.0.Final
$ vi bin/standalone.conf
 and apply the following changes to standalone.conf: 
--- bin/standalone.conf
+++ ../jboss-as-7.1.0.Final.for-jmxetric/bin/standalone.conf
@@ -4,6 +4,7 @@
 ##                                                                          ##
 ##############################################################################
 
+JBOSS_MODULES_SYSTEM_PKGS="org.jboss.logmanager"
 #
 # This file is optional; it may be removed if not needed.
 #
@@ -48,6 +49,8 @@
 #
 if [ "x$JAVA_OPTS" = "x" ]; then
    JAVA_OPTS="-Xms64m -Xmx512m -XX:MaxPermSize=256m -Djava.net.preferIPv4Stack=true -Dorg.jboss.resolver.warning=true -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000"
+   JAVA_OPTS="$JAVA_OPTS -Djava.util.logging.manager=org.jboss.logmanager.LogManager -Xbootclasspath/p:$JBOSS_HOME/modules/org/jboss/logmanager/main/jboss-logmanager-1.2.2.GA.jar -Xbootclasspath/p:$JBOSS_HOME/modules/org/jboss/logmanager/log4j/main/jboss-logmanager-log4j-1.0.0.GA.jar -Xbootclasspath/p:$JBOSS_HOME/modules/org/apache/log4j/main/log4j-1.2.16.jar"
+   JAVA_OPTS="$JAVA_OPTS -javaagent:$HOME/opt/ganglia/jmxetric/jmxetric-1.0.2.jar=host=jboss-host.example.org,port=8649,wireformat31x=true,config=$HOME/opt/ganglia/jmxetric/etc/jmxetric-jboss.xml"
    JAVA_OPTS="$JAVA_OPTS -Djboss.modules.system.pkgs=$JBOSS_MODULES_SYSTEM_PKGS -Djava.awt.headless=true"
    JAVA_OPTS="$JAVA_OPTS -Djboss.server.default.config=standalone.xml"
 else
Note that we are adding some of the core JBoss logging code to the boot classpath - that is because JMXetric depends on the logger, and like many monitoring agents, it is impacted by JBoss bug AS-3681. Adding these extra classpath settings is the workaround. Now go ahead and start JBoss, you should see a log message informing you that JMXetric is operational: 
$ cd ~/opt/jboss-as-7.1.0.Final
$ chmod a+x bin/*.sh
$ bin/standalone.sh
=========================================================================
  JBoss Bootstrap Environment
  JBOSS_HOME: ...
.
.
.
=========================================================================
JMXetricAgent instrumented JVM, see https://github.com/ganglia/jmxetric
12:59:34,395 INFO  [info.ganglia.gmetric4j.GMonitor] Setting up 1 samplers
12:59:34,536 INFO  [org.jboss.modules] JBoss Modules version 1.1.1.GA
12:59:34,617 INFO  [org.jboss.msc] JBoss MSC version 1.0.2.GA
12:59:34,653 INFO  [org.jboss.as] JBAS015899: JBoss AS 7.1.0.Final "Thunder" starting
.
.
.
I hope this example is useful for you. Please feel free to share recipes you develop for collecting useful JVM metrics, and also any custom charts/reports through collaboration with the Ganglia community mailing list, the Ganglia wiki or your own blog.

27 February 2013

Neil McGovern: Let s get physical

Two recent announcements have been made about how it's viewed that people should interact with each other. Both, in my opinion, are misguided. Firstly, Yahoo's chief executive, Marissa Mayer has announced that she's banning staff from remote working. The idea behind this announcement is simple - that "some of the best decisions and insights come from hallway and cafeteria discussions, meeting new people, and impromptu team meetings". This is absolutely spot on, but the next sentence in the leaked internal memo is more problematic: "Speed and quality are often sacrificed when we work from home".
Don't get me wrong, working remotely has some special challenges, but they are by no means insurmountable. There's lots of tips for people working remotely which will turn into a future blog post at some point (I'm running an internal training about how to do it in a couple of weeks), but three simple rules are stay connected, set a routine and take care of yourself. The second decision is one by Ubuntu to move Ubuntu Developer Summits to a purely online meeting, ditching the physical meeting. This misses the point of conferences. If we simply wanted to listen to talks and presentations, why meet up at all? Webcasts have been around for the last 20 years, and yet conferences still exist. The most important part of a conference isn't the talks, it's the "hallway track" - it's the ability for people to meet up, chat and socialise. Be this an impromptu meeting in the corridor, or over a few nice beers. Without this component, why schedule a time at all? Simply publish a list of talks over the coming 3 months, and anyone can pick the best time for them to attend. At Collabora, many of our engineers work remotely. One of the perks we offer is the ability to attend conferences, and to "touch base" and visit and work from one of the offices. It is important to recognise the importance of collaboration physically and it shouldn't be discounted the way Ubuntu has done. But it should not be seen as a silver bullet to an organisation, like Yahoo seem to be implying. Both extremes are wrong, and a balance must be struck to ensure the best outcome for productivity and innovation. (Title from an iconic 80s song)

26 February 2013

Ingo Juergensmann: Xen problems with VMs on 2.6.32-5-xen-amd64?

On Saturday there were some updates for Squeeze/Stable, for example a new/updated version of Xen hypervisor and kernels were downloaded and installed: 
gate:~# dir /var/cache/apt/archives/
base-files_6.0squeeze7_amd64.deb                 libxenstore3.0_4.0.1-5.6_amd64.deb
bind9-host_1%3a9.7.3.dfsg-1~squeeze9_amd64.deb   linux-base_2.6.32-48_all.deb
dbus_1.2.24-4+squeeze2_amd64.deb                 linux-image-2.6.32-5-amd64_2.6.32-48_amd64.deb
dbus-x11_1.2.24-4+squeeze2_amd64.deb             linux-image-2.6.32-5-xen-amd64_2.6.32-48_amd64.deb
firmware-linux-free_2.6.32-48_all.deb            lock
gzip_1.3.12-9+squeeze1_amd64.deb                 openssh-client_1%3a5.5p1-6+squeeze3_amd64.deb
host_1%3a9.7.3.dfsg-1~squeeze9_all.deb           openssh-server_1%3a5.5p1-6+squeeze3_amd64.deb
libbind9-60_1%3a9.7.3.dfsg-1~squeeze9_amd64.deb  openssl_0.9.8o-4squeeze14_amd64.deb
libcups2_1.4.4-7+squeeze3_amd64.deb              partial
libdbus-1-3_1.2.24-4+squeeze2_amd64.deb          perl_5.10.1-17squeeze5_amd64.deb
libdbus-glib-1-2_0.88-2.1+squeeze1_amd64.deb     perl-base_5.10.1-17squeeze5_amd64.deb
libdns69_1%3a9.7.3.dfsg-1~squeeze9_amd64.deb     perl-modules_5.10.1-17squeeze5_all.deb
libisc62_1%3a9.7.3.dfsg-1~squeeze9_amd64.deb     ssh_1%3a5.5p1-6+squeeze3_all.deb
libisccc60_1%3a9.7.3.dfsg-1~squeeze9_amd64.deb   tzdata_2012g-0squeeze1_all.deb
libisccfg62_1%3a9.7.3.dfsg-1~squeeze9_amd64.deb  xen-hypervisor-4.0-amd64_4.0.1-5.6_amd64.deb
libldap-2.4-2_2.4.23-7.3_amd64.deb               xen-linux-system-2.6.32-5-xen-amd64_2.6.32-48_amd64.deb
liblwres60_1%3a9.7.3.dfsg-1~squeeze9_amd64.deb   xenstore-utils_4.0.1-5.6_amd64.deb
libperl5.10_5.10.1-17squeeze5_amd64.deb          xen-utils-4.0_4.0.1-5.6_amd64.deb
libssl0.9.8_0.9.8o-4squeeze14_amd64.deb
Unfortunately this update appears to be problematic on my Xen hosting server. This night it happened the second time that some of the virtual network interfaces disappeared or turned out to be non-working. For example I have two VMs: one running the webserver and one running the databases. Between these two VMs there's a bridge on the dom0 and both VMs have a VIF to that (internal) bridge. What happens is that this bridge becomes inaccessible from within the webserver VM. Sadly there's not much to see in the log files. I just spotted this on dom0:
Feb 26 01:01:29 gate kernel: [12697.907512] vif3.1: Frag is bigger than frame.
Feb 26 01:01:29 gate kernel: [12697.907550] vif3.1: fatal error; disabling device
Feb 26 01:01:29 gate kernel: [12697.919921] xenbr1: port 3(vif3.1) entering disabled state
Feb 26 01:22:00 gate kernel: [13928.644888] vif2.1: Frag is bigger than frame.
Feb 26 01:22:00 gate kernel: [13928.644920] vif2.1: fatal error; disabling device
Feb 26 01:22:00 gate kernel: [13928.663571] xenbr1: port 2(vif2.1) entering disabled state
Feb 26 01:40:44 gate kernel: [15052.629280] vif7.1: Frag is bigger than frame.
Feb 26 01:40:44 gate kernel: [15052.629314] vif7.1: fatal error; disabling device
Feb 26 01:40:44 gate kernel: [15052.641725] xenbr1: port 6(vif7.1) entering disabled state
This corresponds to the number of VMs having lost their internal connection to the bridge. On the webserver VM I see this output:
Feb 26 01:59:01 vserv1 kernel: [16113.539767] IPv6: sending pkt_too_big to self
Feb 26 01:59:01 vserv1 kernel: [16113.539794] IPv6: sending pkt_too_big to self
Feb 26 02:30:54 vserv1 kernel: [18026.407517] IPv6: sending pkt_too_big to self
Feb 26 02:30:54 vserv1 kernel: [18026.407546] IPv6: sending pkt_too_big to self
Feb 26 02:30:54 vserv1 kernel: [18026.434761] IPv6: sending pkt_too_big to self
Feb 26 02:30:54 vserv1 kernel: [18026.434787] IPv6: sending pkt_too_big to self
Feb 26 03:39:16 vserv1 kernel: [22128.768214] IPv6: sending pkt_too_big to self
Feb 26 03:39:16 vserv1 kernel: [22128.768240] IPv6: sending pkt_too_big to self
Feb 26 04:39:51 vserv1 kernel: [25764.250170] IPv6: sending pkt_too_big to self
Feb 26 04:39:51 vserv1 kernel: [25764.250196] IPv6: sending pkt_too_big to self
Rebooting the VMs will result in a non-working VM as it will get paused on creation and Xen scripts complain about not working hotplug scripts and Xen logs shows this: 
[2013-02-25 13:06:34 5470] DEBUG (XendDomainInfo:101)
XendDomainInfo.create(['vm', ['name', 'vserv1'], ['memory', '2048'],
['on_poweroff', 'destroy'], ['on_reboot', 'restart'], ['on_crash',
'restart'], ['on_xend_start', 'ignore'], ['on_xend_stop', 'ignore'],
['vcpus', '2'], ['oos', 1], ['bootloader', '/usr/lib/xen-4.0/bin/pygrub'],
['bootloader_args', ''], ['image', ['linux', ['root', '/dev/xvdb '],
['videoram', 4], ['tsc_mode', 0], ['nomigrate', 0]]], ['s3_integrity', 1],
['device', ['vbd', ['uname', 'phy:/dev/lv/vserv1-boot'], ['dev', 'xvda'],
['mode', 'w']]], ['device', ['vbd', ['uname', 'phy:/dev/lv/vserv1-disk'],
['dev', 'xvdb'], ['mode', 'w']]], ['device', ['vbd', ['uname',
'phy:/dev/lv/vserv1-swap'], ['dev', 'xvdc'], ['mode', 'w']]], ['device',
['vbd', ['uname', 'phy:/dev/lv/vserv1mirror'], ['dev', 'xvdd'], ['mode',
'w']]]])
[2013-02-25 13:06:34 5470] DEBUG (XendDomainInfo:2508)
XendDomainInfo.constructDomain
[2013-02-25 13:06:34 5470] DEBUG (balloon:220) Balloon: 2100000 KiB free;
need 16384; done.
[2013-02-25 13:06:34 5470] DEBUG (XendDomain:464) Adding Domain: 39
[2013-02-25 13:06:34 5470] DEBUG (XendDomainInfo:2818)
XendDomainInfo.initDomain: 39 256
[2013-02-25 13:06:34 5781] DEBUG (XendBootloader:113) Launching bootloader
as ['/usr/lib/xen-4.0/bin/pygrub', '--args=root=/dev/xvdb  ',
'--output=/var/run/xend/boot/xenbl.6040', '/dev/lv/vserv1-boot'].
[2013-02-25 13:06:39 5470] DEBUG (XendDomainInfo:2845)
_initDomain:shadow_memory=0x0, memory_static_max=0x80000000,
memory_static_min=0x0.
[2013-02-25 13:06:39 5470] INFO (image:182) buildDomain os=linux dom=39
vcpus=2
[2013-02-25 13:06:39 5470] DEBUG (image:721) domid	    = 39
[2013-02-25 13:06:39 5470] DEBUG (image:722) memsize	    = 2048
[2013-02-25 13:06:39 5470] DEBUG (image:723) image	    =
/var/run/xend/boot/boot_kernel.xj7W_t
[2013-02-25 13:06:39 5470] DEBUG (image:724) store_evtchn   = 1
[2013-02-25 13:06:39 5470] DEBUG (image:725) console_evtchn = 2
[2013-02-25 13:06:39 5470] DEBUG (image:726) cmdline	    =
root=UUID=ed71a39f-fd2e-4035-8557-493686baa151 ro root=/dev/xvdb
[2013-02-25 13:06:39 5470] DEBUG (image:727) ramdisk	    =
/var/run/xend/boot/boot_ramdisk.QavuAo
[2013-02-25 13:06:39 5470] DEBUG (image:728) vcpus	    = 2
[2013-02-25 13:06:39 5470] DEBUG (image:729) features	    =
[2013-02-25 13:06:39 5470] DEBUG (image:730) flags	    = 0
[2013-02-25 13:06:39 5470] DEBUG (image:731) superpages     = 0
[2013-02-25 13:06:40 5470] INFO (XendDomainInfo:2367) createDevice: vbd :
 'uuid': '04d99772-cf27-aecf-2d1b-c73eaf657410', 'bootable': 1, 'driver':
'paravirtualised', 'dev': 'xvda', 'uname': 'phy:/dev/lv/vserv1-boot',
'mode': 'w' 
[2013-02-25 13:06:40 5470] DEBUG (DevController:95) DevController: writing
 'virtual-device': '51712', 'device-type': 'disk', 'protocol':
'x86_64-abi', 'backend-id': '0', 'state': '1', 'backend':
'/local/domain/0/backend/vbd/39/51712'  to
/local/domain/39/device/vbd/51712.
[2013-02-25 13:06:40 5470] DEBUG (DevController:97) DevController: writing
 'domain': 'vserv1', 'frontend': '/local/domain/39/device/vbd/51712',
'uuid': '04d99772-cf27-aecf-2d1b-c73eaf657410', 'bootable': '1', 'dev':
'xvda', 'state': '1', 'params': '/dev/lv/vserv1-boot', 'mode': 'w',
'online': '1', 'frontend-id': '39', 'type': 'phy'  to
/local/domain/0/backend/vbd/39/51712.
[2013-02-25 13:06:40 5470] INFO (XendDomainInfo:2367) createDevice: vbd :
 'uuid': 'e46cb89f-3e54-41d2-53bd-759ed6c690d2', 'bootable': 0, 'driver':
'paravirtualised', 'dev': 'xvdb', 'uname': 'phy:/dev/lv/vserv1-disk',
'mode': 'w' 
[2013-02-25 13:06:40 5470] DEBUG (DevController:95) DevController: writing
 'virtual-device': '51728', 'device-type': 'disk', 'protocol':
'x86_64-abi', 'backend-id': '0', 'state': '1', 'backend':
'/local/domain/0/backend/vbd/39/51728'  to
/local/domain/39/device/vbd/51728.
[2013-02-25 13:06:40 5470] DEBUG (DevController:97) DevController: writing
 'domain': 'vserv1', 'frontend': '/local/domain/39/device/vbd/51728',
'uuid': 'e46cb89f-3e54-41d2-53bd-759ed6c690d2', 'bootable': '0', 'dev':
'xvdb', 'state': '1', 'params': '/dev/lv/vserv1-disk', 'mode': 'w',
'online': '1', 'frontend-id': '39', 'type': 'phy'  to
/local/domain/0/backend/vbd/39/51728.
[2013-02-25 13:06:40 5470] INFO (XendDomainInfo:2367) createDevice: vbd :
 'uuid': 'e2d61860-7448-1843-3935-6b63c5d2878e', 'bootable': 0, 'driver':
'paravirtualised', 'dev': 'xvdc', 'uname': 'phy:/dev/lv/vserv1-swap',
'mode': 'w' 
[2013-02-25 13:06:40 5470] DEBUG (DevController:95) DevController: writing
 'virtual-device': '51744', 'device-type': 'disk', 'protocol':
'x86_64-abi', 'backend-id': '0', 'state': '1', 'backend':
'/local/domain/0/backend/vbd/39/51744'  to
/local/domain/39/device/vbd/51744.
[2013-02-25 13:06:40 5470] DEBUG (DevController:97) DevController: writing
 'domain': 'vserv1', 'frontend': '/local/domain/39/device/vbd/51744',
'uuid': 'e2d61860-7448-1843-3935-6b63c5d2878e', 'bootable': '0', 'dev':
'xvdc', 'state': '1', 'params': '/dev/lv/vserv1-swap', 'mode': 'w',
'online': '1', 'frontend-id': '39', 'type': 'phy'  to
/local/domain/0/backend/vbd/39/51744.
[2013-02-25 13:06:40 5470] INFO (XendDomainInfo:2367) createDevice: vbd :
 'uuid': 'd314a46e-1ce9-0e8d-b009-3f08e29735f5', 'bootable': 0, 'driver':
'paravirtualised', 'dev': 'xvdd', 'uname': 'phy:/dev/lv/vserv1mirror',
'mode': 'w' 
[2013-02-25 13:06:40 5470] DEBUG (DevController:95) DevController: writing
 'virtual-device': '51760', 'device-type': 'disk', 'protocol':
'x86_64-abi', 'backend-id': '0', 'state': '1', 'backend':
'/local/domain/0/backend/vbd/39/51760'  to
/local/domain/39/device/vbd/51760.
[2013-02-25 13:06:40 5470] DEBUG (DevController:97) DevController: writing
 'domain': 'vserv1', 'frontend': '/local/domain/39/device/vbd/51760',
'uuid': 'd314a46e-1ce9-0e8d-b009-3f08e29735f5', 'bootable': '0', 'dev':
'xvdd', 'state': '1', 'params': '/dev/lv/vserv1mirror', 'mode': 'w',
'online': '1', 'frontend-id': '39', 'type': 'phy'  to
/local/domain/0/backend/vbd/39/51760.
[2013-02-25 13:06:40 5470] DEBUG (XendDomainInfo:3400) Storing VM details:
 'on_xend_stop': 'ignore', 'shadow_memory': '0', 'uuid':
'04541225-6d3c-3cae-a4c4-0b6d4ccfac7a', 'on_reboot': 'restart',
'start_time': '1361794000.37', 'on_poweroff': 'destroy', 'bootloader_args':
'', 'on_xend_start': 'ignore', 'on_crash': 'restart', 'xend/restart_count':
'0', 'vcpus': '2', 'vcpu_avail': '3', 'bootloader':
'/usr/lib/xen-4.0/bin/pygrub', 'image': "(linux (kernel ) (args
'root=/dev/xvdb  ') (superpages 0) (tsc_mode 0) (videoram 4) (pci ())
(nomigrate 0) (notes (HV_START_LOW 18446603336221196288) (FEATURES
'!writable_page_tables pae_pgdir_above_4gb') (VIRT_BASE
18446744071562067968) (GUEST_VERSION 2.6) (PADDR_OFFSET 0) (GUEST_OS linux)
(HYPERCALL_PAGE 18446744071578882048) (LOADER generic) (SUSPEND_CANCEL 1)
(PAE_MODE yes) (ENTRY 18446744071584289280) (XEN_VERSION xen-3.0)))",
'name': 'vserv1' 
[2013-02-25 13:06:40 5470] DEBUG (XendDomainInfo:1804) Storing domain
details:  'console/ring-ref': '2143834', 'image/entry':
'18446744071584289280', 'console/port': '2', 'store/ring-ref': '2143835',
'image/loader': 'generic', 'vm':
'/vm/04541225-6d3c-3cae-a4c4-0b6d4ccfac7a',
'control/platform-feature-multiprocessor-suspend': '1',
'image/hv-start-low': '18446603336221196288', 'image/guest-os': 'linux',
'cpu/1/availability': 'online', 'image/virt-base': '18446744071562067968',
'memory/target': '2097152', 'image/guest-version': '2.6', 'image/pae-mode':
'yes', 'description': '', 'console/limit': '1048576', 'image/paddr-offset':
'0', 'image/hypercall-page': '18446744071578882048',
'image/suspend-cancel': '1', 'cpu/0/availability': 'online',
'image/features/pae-pgdir-above-4gb': '1',
'image/features/writable-page-tables': '0', 'console/type': 'xenconsoled',
'name': 'vserv1', 'domid': '39', 'image/xen-version': 'xen-3.0',
'store/port': '1' 
[2013-02-25 13:06:40 5470] DEBUG (DevController:95) DevController: writing
 'protocol': 'x86_64-abi', 'state': '1', 'backend-id': '0', 'backend':
'/local/domain/0/backend/console/39/0'  to
/local/domain/39/device/console/0.
[2013-02-25 13:06:40 5470] DEBUG (DevController:97) DevController: writing
 'domain': 'vserv1', 'frontend': '/local/domain/39/device/console/0',
'uuid': 'c8819aed-c78f-02b8-0ef7-1600abd15add', 'frontend-id': '39',
'state': '1', 'location': '2', 'online': '1', 'protocol': 'vt100'  to
/local/domain/0/backend/console/39/0.
[2013-02-25 13:06:40 5470] DEBUG (XendDomainInfo:1891)
XendDomainInfo.handleShutdownWatch
[2013-02-25 13:06:40 5470] DEBUG (DevController:139) Waiting for devices
vif2.
[2013-02-25 13:06:40 5470] DEBUG (DevController:139) Waiting for devices
vif.
[2013-02-25 13:06:40 5470] DEBUG (DevController:139) Waiting for devices
vscsi.
[2013-02-25 13:06:40 5470] DEBUG (DevController:139) Waiting for devices
vbd.
[2013-02-25 13:06:40 5470] DEBUG (DevController:144) Waiting for 51712.
[2013-02-25 13:06:40 5470] DEBUG (DevController:628) hotplugStatusCallback
/local/domain/0/backend/vbd/39/51712/hotplug-status.
From my point of view, either Xen hypervisor or the kernel seems to be broken, but it's hard to tell for me. Maybe it would be easier to update the system from Squeeze to Wheezy and get rid off this problem that way? On the other hand this would solve the problem. Are there any other people experiencing problems with that latest update of Xen and kernel? UPDATE: Bug #701744 filed. UPDATE 2: Downgrading kernel and hypervisor on dom0 to the following packages from snapshot.debian.org seems to have solved that problem.
  • xen-hypervisor-4.0-amd64_4.0.1-5.4_amd64.deb
  • linux-image-2.6.32-5-xen-amd64_2.6.32-46_amd64.deb
Note that I haven't tested yet with the newest kernel update from DSA-2632-1. UPDATE 3: After running with older versions of hypervisor and kernel I now have upgraded the hypervisor to xen-hypervisor-4.0-amd64_4.0.1-5.6_amd64.deb and rebooted. Let's see whether it's running stable or not. If not it's the hypervisor, if yes, it's the kernel. UPDATE 4: apparently it's the kernel which is buggy. And the kernel from DSA-2632-1 is affected as well. So, the current workaround is to downgrad to linux-image-2.6.32-5-xen-amd64_2.6.32-46_amd64.deb.
Kategorie:
Debian
Tags:
Xen
Debian
Software
Bug
Server

Russ Allbery: Review: Witches Abroad

Review: Witches Abroad, by Terry Pratchett
Series: Discworld #12
Publisher: Harper
Copyright: 1991
Printing: February 2008
ISBN: 0-06-102061-3
Format: Mass market
Pages: 350
Witches Abroad is the twelfth book in the Discworld series, but there's no strong reason why you couldn't start here. It's the second book about the three witches (Granny Weatherwax, Nanny Ogg, and Magrat Garlick), following Wyrd Sisters, and the third book about Granny Weatherwax, but it doesn't assume any knowledge of the previous books or of Discworld in general. Desiderata Hollow is dying. This is not a surprise; she's known for a long time exactly when she was going to die, and that time has come. She's not particularly bothered by it, but it does pose one difficult problem. She's a fairy godmother, as well as a witch, and she's balancing another fairy godmother because they come in pairs. With her dead, Lilith seems likely to win their long struggle, and that would be a bad thing. She needs to pass her wand on to a successor, but she wasn't the planning sort. At least she claims; this comment of hers turns out to hide an elegant bit of manipulation that leaves her wand in the hands of Magrat and sends the three witches on their way to the city of Genua to confront Lilith. There are two halves to Witches Abroad. The first half is the setup described above and their trip across Discworld. The second half is a sort of retelling of Cinderella, as foreshadowed early on by Desiderata. But the whole book is about stories and story shapes and their head-on collisions with the practical confidence of Nanny Ogg and the endless stubbornness of Granny Weatherwax. I think the three witches are one of Pratchett's best inventions, and Granny Weatherwax the best of the three. She has many of the characteristics that would normally relegate her to a supporting mentor figure: older, very knowledgeable, remarkably good at getting her way and at manipulating situations, and not particularly interested in going on adventures. But Pratchett turns this on end at every opportunity. Granny Weatherwax doesn't act like a mentor at all: she doesn't explain things to Magrat, or anyone else; she's almost constantly bickering with the other witches; and she's a fount of irritated and exasperated opinions about the world. She's one of the best irascibly competent characters in fiction, and she steals every scene she's in, refusing to become a supporting character and staying at the center of the story, despite not being a viewpoint character. (Pratchett wisely keeps her out of the viewpoint role for most of the story, since much of her knowledge and "headology" would be less effective if the reader knew what she was thinking.) The dynamics between the three witches are the best part of this book, and I love all three of them. But I'm also a sucker for fractured fairy tales in general, and Witches Abroad is full of them. Their opponent loves stories and has gathered most of her power from reinforcing and manipulating stories, which means that the density of random stories keeps increasing as they approach Genua. That provides numerous opportunities for the witches to stumble through, analyze, take apart, twist, or untwist numerous familiar stories, ranging from Red Riding Hood to Sleeping Beauty. Pratchett keeps things moving right along, not belaboring connections and not explaining too much, which makes it very easy to keep turning pages. The story does get a bit slower in Genua. There's quite a bit of scene-setting and figuring things out, and while Pratchett maintains the steady stream of humor, it isn't quite as compelling without the ever-changing context. He introduces a bit of voodoo magic, which I found to be the least interesting of the multiple styles of magic that show up here. But there are some absolutely brilliant bits with Nanny Ogg's cat, a wonderfully annoyed Cinderella, and an inversion of the traditional story that kept surprising me. I thought the ending was a bit of an anticlimax, but it does fit the nature of the characters. Despite a few plot short-comings, this is my favorite Discworld book up to this point in the series. Definitely recommended, and not a horrible starting point. Followed by Small Gods in the chronological sense and (later) by Lords and Ladies in the plot sense. Rating: 8 out of 10

25 February 2013

Francesca Ciceri: Three Harry Potter crossovers you want to read

...at least, if you are into fan fictions and Harry Potter. I love fan fictions, and I'll shamelessly admit that I like Harry Potter too, but I usually avoid crossovers. That is because however interesting and exciting is - in theory - to have your favourite characters from different fandoms together, it often ends bad. So, it's a public duty of every fanfic reader to recommend good crossovers, if they stumble upon them. Here are some I found recently (all the quotes are from the stories' summaries). If you read any of these and want to talk about it or if you have more crossovers to recommend, drop me a mail. For more fan fiction recommendations, I suggest you to check this detailed index on tvtropes.org.

Russ Allbery: Review: The Hare with Amber Eyes

Review: The Hare with Amber Eyes, by Edmund de Waal
Publisher: Farrar, Straus and Giroux
Copyright: 2010
ISBN: 0-374-10597-9
Format: Kindle
Pages: 351
A netsuke ( ) is a miniature sculpture, often made from ivory or boxwood, generally rounded and no larger than a matchbox. They were a part of Japanese clothing starting from the 17th century: traditional garments had no pockets, but people needed a way to carry small objects around with them, so they wore pouches or small boxes attached to a cord. The cord could then be passed under the sash of the garment and be held in place there by a netsuke attached to the end of the cord, since the netsuke was too large to slip under the sash. The hare with amber eyes is one of 264 netsuke. It, and all the rest, belonged to Edmund de Waal's uncle Iggie. They sat in a vitrine in his home in Japan, where de Waal went for a two-year scholarship and was working on a book on japonisme: the passionate and creative Western misunderstanding of Japan. When Iggie later died in 1991, de Waal inherited the collection. This book is his attempt to tell their history. The Hare with Amber Eyes falls into the genre of family memoir or biography, but it's one told from an unusual angle. Edmund de Waal is a potter by profession: an artist who creates physical objects that then pass from his studio out into the world. The physicality of the netsuke their occupation of time and space and their passsage through the world fascinates him, and he tries to express that fascination to the reader and uses it as a focal point for the memoir. He tells, here, the story of his own family, but he does so via the netsuke, following them from their purchase in Paris in 1871 through one branch of the family and then another until they reach Iggie and, finally, him. Along the way, he tries to put them into context. At first, the context is primarily artistic, and the early parts of this book are something of a tour of late 19th century artistic culture in Paris. But, as the story continues, the connection becomes more emotional and the context becomes more complicated. Anyone who is a fan of the TV program Antiques Roadshow or any similar effort to trace the history of specific objects will see the immediate appeal in this presentation. Antiques are fascinating in their mute path through lives and history; attempting to reconstruct the rooms they've sat in and the conversations they've witnessed is something I've always found intriguing. But it's also very difficult to do. Most of our objects, and most owners of objects, simply don't have that sort of documentation. I was wondering, at the start of this book, how de Waal was going to manage to construct his history. The answer is that his family is, or at least was, famous enough to have letters, papers, and history in libraries throughout Europe. That's what makes the parts of the book before Iggie's living memory possible. It's a bit disappointing, if unsurprising; de Waal doesn't have any special technique to find hidden history, and most objects could never have this sort of history written about them. The first owner of the netsuke in his family is Charles Ephrussi, a critic, historian, and art historian who was a patron of the Impressionists and who was important enough in Parisian art culture that he is the inspiration of a character in Marcel Proust's Remembrance of Things Past. This means that quite a lot of this book is about people who moved through social circles and lived in ways that I find quite foreign, which made it hard to invest too much in the first part of the book. The Ephrussi family was originally from Odessa and made a fortune as grain merchants some time prior to the start of the history, and by the time de Waal opens their story, they have vast inherited wealth. There is no sign in the book that Charles needs to work in any way. The first part of the book paints a picture of the culture of art patronage partly via descriptions of Charles's rooms and personal collection, to which the netsuke were added during the surge in interest in Japanese art in Europe produced by the opening of Japan during the Meiji period. It's interesting, but for me in a distant and intellectual way. (People with a deeper interest in Impressionist art or other late 19th century art may have a different reaction.) De Waal writes at length at the start of this book about avoiding sentimentality and trying to take an honest and immersive look at the history of the netsuke. The emotional intensity that he brings to this goal seemed a bit odd, since little in the early part of the book seems to tempt towards sentimentality. But then the Dreyfus Affair enters Charles's story, followed by his gift of the vitrine and the netsuke to a cousin in Austria as a marriage gift, and I started to realize the implications of following a possession of a prominent Jewish family in Europe during the first half of the twentieth century. This is the sort of non-fiction book that you can spoil, so I won't give a detailed description of the rest of the book. But there is a specific event in the history of the netsuke that de Waal tells that would be the story most people would start with, and I now understand the sentimentality that de Waal was trying to avoid. It's a great story, but one of the things I like about this book is that de Waal puts it into a broader context and complicates the story. He includes the long periods of time when the netsuke were mostly ignored, he ties them into the history of western obsession with (and exploitation of) Japanese art, and he shows how the sturdy nature of the netsuke, meant for physical handling rather than display, led to them creating the emotional connection that made them important to the family. It's a book that deals with anti-Semitism with accuracy and specifics without being either lurid or overwhelming. It's a book that traces a line through one of the most overwritten and well-trod areas of history and manages to stay on its own path. It's a book that made me angry, and made me cry, and then made me step back and think about those emotions in a broader context and think about the benefits of leaving those emotions behind. I've never read a book quite like this before. It's slow in places (particularly if one is not very interested in art history), utterly compelling in others, and carefully avoids any simple themes or grand stories. It's entangled with some of the darkest events of recent history, but de Waal stays tightly focused on the family through the lens of the netsuke, which is valuable for keeping the story from drifting into well-worn and less unique material. I was not as completely taken by this book as the review that got me to buy it (it's an excellent review, better than this one). But I'm glad that I read it, and I feel like I now know more about the world. Rating: 7 out of 10

24 February 2013

Andrew Pollock: [tech] On owning a Nissan Leaf

I'll soon be disposing of the Nissan Leaf that we leased a few months ago, so I thought it a useful exercise to write about my experiences with it. I am not a car man. I am a gadget man. For me, driving is a means to an end, and I'm much more interested in what I call the "cabin" experience, than the "driving" experience, so this is going to slanted much more that way. That said, I found the Nissan Leaf a fun car to drive, from my limited experiences of having fun driving cars. I liked how responsive it was when you put your foot down. It has two modes of operation, "D" and "Eco". I've actually taken to driving it in "Eco" mode most of the time, as it squeezes more range out of the batteries, but occasionally I'll pop it back into "D" to have a bit of fun. The main difference between the two modes, from a driving perspective, is it seems to limit the responsiveness of the accelerator. In "Eco" mode it feels more like you're driving in molasses, whereas in "D" mode, when you put your foot down, it responses instantly. "D" is great for dragging people off at the lights. It's a very zippy little car in "D" mode. It feels lighter. I've noticed that it has a bit of a penchant for over steering. Or maybe that's just my driving. If I have floored it a bit to take a right turn into oncoming traffic, I've noticed slight over steering. That's about all the driving type "real car stuff" I'll talk about. Now to the driver's "cabin experience". It's absolutely fabulous. I love sitting in the driver's seat of this car. Firstly, the seat itself is heated (in fact all of them are). As is the steering wheel. Nissan has gone to great lengths to allow you to avoid needing to run the car's heating system to heat the car, as doing so immediately drops at least 10 miles off the range. Unfortunately I found the windscreen had a tendency to fog up in the winter rainy periods, so I'd have to intermittently fire up the air conditioning to defog the windscreen. Of course, in the summer months, you're going to want to run the AC to cool down, so the range hit in that situation is unavoidable. I've only had this car from late Autumn until late Winter so far, so that hasn't been an issue I've had to contend with. The dashboard is all digital, and looks relatively high tech, which appeals to my inner geek. It's a dashboard. It tells you stuff. The stuff you'd expect it to tell you. Enough said. The audio system is nice. It supports Bluetooth audio, so one can be streaming Pandora from one's phone, through the sound system, for example. Or listening to audio from the phone. There's also a USB port, and it will play various audio files from USB storage. I found the way it chose to sort the files on a USB stick to be slightly surprising though. I haven't invested the time to figure out how I should be naming files so that they play in the order I expect them to play. The ability to play from USB storage compensates nicely for the fact that it only has a single CD player. (We have a 6 disc stacker in our 2006 Prius). The car also came with a 3 month free trial of Sirius XM satellite radio. This was fun. The only dance music FM station in the Bay Area has a weak signal in Mountain View, and I hate dance music with static, whereas there was an excellent electronic music station that I could listen to in glorious high definition. As long as I wasn't driving under a bridge. There's no way I'd pay money for satellite radio, but it was a fun gimmick to try out. The navigation system is really, really good. I haven't bothered using Google Maps on my phone at all. It gives such good spoken directions, that you don't even need to have the map on the screen. It names all the streets. I couldn't figure out a way to get distances in metric. The telematics service, Carwings, is probably my favourite feature. This is what really makes it feel like a car of the future. Through the companion Android application, I can view the charging status (if it's plugged in) or just check the available range (if it's not plugged in). From a web browser, I can plan a route, and push the route to the vehicle's navigation system. If the car is plugged in, I can also remotely turn on the vehicle's climate control system, pre-warming or cooling the car. It's a little thing, but the door unlocking annoyed me a little bit. I'm used to the Prius, where if you unlock the boot (that's trunk, Americans), or the front passenger door, all the doors unlocked. This was a convenient way of unlocking the car for multiple people as you approached it. With the Leaf, unlocking the boot only unlocks the boot. Unlocking the front passenger door only unlocks that door. It requires a second unlock action to unlock all the doors. I've found this to be slightly cumbersome when trying to unlock the car for everyone all at once, quickly (like when it's raining). Another minor annoyance is the headlights. I've gotten into the habit of driving with the headlights on all the time, because I believe it's safer. In the Prius, one could just leave the headlights switched to the "on" position, and they'd turn off whenever the driver's door was opened after the car was switched off. If you try that in the Leaf, the car beeps at you to warn you you've left the headlights on. It has an "auto" mode, where the car will choose when to turn the headlights on, based on ambient light conditions. In that case, when you turn the car off, it'll leave the headlights on for a configurable period of time and then turn them off. This is actually slightly unsettling, because it makes you think you've left your headlights on. The default timeout was quite long as well, something like 60 seconds. The way multiple Bluetooth phones are handled is just as annoying in the Leaf as it is in the Prius, which disappoints me, given 6 years have passed. The way I'd like to see multiple phones handled is the car chooses to pair with whichever phone is in range, or if multiple phones are in range, it asks or uses the last one it paired with. In reality, it tries to pair with whatever it paired with last time, and one has to press far too many buttons to switch it to one of the other phones it knows about. Range anxiety is definitely something of a concern. It can be managed by using the GPS navigation for long or otherwise anxiety-inducing trips, and then one can compare the "miles remaining" on the GPS with the "miles remaining" on the battery range, and reassure oneself that they will indeed make it to where they're trying to go. The worst case I had was getting to within 5 miles of empty. The car started complaining at me. The charging infrastructure in the Bay Area is pretty good. There are plenty of charging stations in San Francisco and San Jose. I'm spoiled in that I have free charging available at work (including a building at the end of my street, so I never bothered with getting a home charger installed). I've almost never had to pay for charging, so it's been great while gas prices have been on the rise. The car's navigation system knows about some charging stations, so you can plan a route with the charging stations it knows about in mind. The only problem is it doesn't know if the charging stations are in use. If you use the ChargePoint Android app, you can see if the charging stations are in use, but then you have to do this cumbersome dance to find an available charging station and plug the address into the vehicle's navigation system. Of course, what can then happen is in the time you're driving to the charging station, someone else starts using it. I actually got bitten by this yesterday. Would I buy a Leaf again? Not as my sole car. It makes a perfect second/commuter car, but as a primary vehicle, it's too limited by its range. They're also ridiculously expensive in Australia, and Brisbane has absolutely no charging infrastructure.

Gunnar Wolf: International Open Data Day - #OpenData / #DatosAbiertos

I just got this message through my University, and the least I can do (given I'm still, although barely, in time) is to repost it here, hoping it helps to spread the activity we have on this regard in Latin America:
Saturday, February 23 is the International Day of Open Data. Following its policy of promoting free, open and unrestricted access to the results of research funded with public money, CLACSO calls research centers and individual researchers to free their public data so they are available for other researchers and, most importantly, for the community as a whole. That's the reason CLACSO invites researchers and institutions to announce in social networks, mentioning "#DatosAbiertos #OpenData", which are their freed public documents, pointing to the web pages where they can be found. The International Open Data Day is an effort to:
  • Spread the concept of Open Data
  • Debate on the why of Open Data
  • Publish analysis done using open public data
  • Find out how more local and national (not reserved) open data can be published (i.e. Brazil)
  • Call towards using open data in research
  • Find which applications have been developed to handle and visualize open data
  • Organize events for the International Open Data Day (i.e. Monterrey
  • Call towards adding data catalogs in Latin America and the Caribbeanin the Data catalogs directory, in Datacatalogs.org, and in Open data census.
For further information on how to spread research and/or archives in digital repositories and in the CLACSO Digital Repository, please mail biblioteca@clacso.edu.ar We can between all contribute for the Latin American and Caribbean open data community to grow, democratizing access to public data about our societies.
So, what do I consider worthy of adding to a list of resources I can point to?

23 February 2013

Dirk Eddelbuettel: Two papers about RcppEigen and RcppArmadillo published

Two papers got published recently. The first one is Bates and Eddelbuettel (2013). It is titled Fast and Elegant Numerical Linear Algebra Using the RcppEigen Package, and provides a pretty thorough introduction to our RcppEigen package which uses Rcpp to provide access to the Eigen C++ template library from GNU R. The paper is out as Volume 50, Issue 5 at the (all electronic, open, and generally awesome) Journal of Statistical Software. A bibtex entry is available. The second paper is Eddelbuettel and Sanderson (2013). This one is titled RcppArmadillo: Accelerating R with high-performance C++ linear algebra and introduces the RcppArmadillo package which brings Conrad Sanderson's Armadillo C++ template library to GNU R by deploying Rcpp. The paper is currently "in press" at Computational Statistics & Data Analysis but the DOI 10.1016/j.csda.2013.02.005 will remain once a volume and issue is assigned by CSDA. Preprints of both papers are available via my papers page, and as vignettes in the corresponding packages. The upcoming Rcpp class in New York will feature Rcpp, RcppArmadillo and RcppEigen. Space is still available.

Sylvain Le Gall: OUnit 2.0 progress

I have recently started to work on OUnit 2.0. The point of this new version will be to adapt OUnit to improve speed and compatibility with third party system: Only the 3 last point needs to be completed. Here is a screenshot of Jenkins reading JUnit output of an OUnit test: Jenkins, OUnit test results So if you have a long standing issue with OUnit, this is the time to submit a bug. OUnit BTS

Guido G nther: Accelerometer and screen orientation in GNOME3

Following up on using Debian on the WeTab with GNOME Shell I had a look at automatically adjusting the screen orientation when rotating the device. The accelerometer is handled in the asus_laptop module since kernel 3.2, so this shows up in /proc/bus/input/devices: 
I: Bus=0019 Vendor=0000 Product=0000 Version=0000
N: Name="Pegatron Lucid Tablet Accelerometer"
P: Phys=pega_accel/input0
S: Sysfs=/devices/platform/asus_laptop/input/input4
U: Uniq=
H: Handlers=event4 js0 
B: PROP=0
B: EV=9
B: ABS=7
Whenever the screen orientation changes the driver emits a udev event. The helper in /lib/udev/accelerometer processes it thanks to /lib/udev/rules.d/61-accelerometer.rules, determines the orientation and adds the ID_INPUT_ACCELEROMETER_ORIENTATION property to the event which can be checked with udevadm monitor --property: 
UDEV  [5778.534171] change   /devices/platform/asus_laptop/input/input4 (input)
ABS=7
ACTION=change
DEVPATH=/devices/platform/asus_laptop/input/input4
EV=9
ID_FOR_SEAT=input-platform-asus_laptop
ID_INPUT=1
ID_INPUT_ACCELEROMETER=1
ID_INPUT_ACCELEROMETER_ORIENTATION=right-up
ID_PATH=platform-asus_laptop
ID_PATH_TAG=platform-asus_laptop
MODALIAS=input:b0019v0000p0000e0000-e0,3,kra0,1,2,mlsfw
NAME="Pegatron Lucid Tablet Accelerometer"
PHYS="pega_accel/input0"
PRODUCT=19/0/0/0
PROP=0
SEQNUM=1550
SUBSYSTEM=input
TAGS=:seat:
UDEV_LOG=3
USEC_INITIALIZED=6154288
This is captured by gnome-settings-daemon (>=3.2) that adjusts the screen rotation using xrandr2 accordingly. This can be checked by running gnome-settings-daemon with --debug. The old way of using xinput events is no longer supported. Unfortunately Debian's udev has a minor bug that misdetects the input device so this patch is needed to have the screen orientation changed automatically on the WeTab. This blog is flattr enabled.

22 February 2013

Hideki Yamane: Postgresql + GPU / SELinux approach

I've participated an event (18th, Feb), Kohei Kaigai from NEC talked about 3 topics.


  • Places to Visit in Europe
  • PG-Strom: GPU Accelerated AsynchronousSuper-Parallel Query
  • Row-Level Security: DB Security, prevent information leak

I've interested in PG-Strom, it can accelerated query 8 times with $100 GPU card, for more detail, see above link.

This event was hosted in Red Hat office at Yebisu( ), Tokyo. Thanks to Ryo Fujita from Red Hat for his coordination.


Russell Coker: iPhone vs Android

A friend who s a long-time iPhone user just asked for my advice about whether to get a Samsung Galaxy S3, a Samsung Galaxy Note 2, or a iPhone 5. Advantages for Android I think that liberty should be the first consideration, I ve previously written about how Android phones won t necessarily give you as much freedom as you desire if you buy on the basis of price and features [1]. But even the least free Android options are way better than the iOS (iPhone and iPad) environment. This isn t necessarily a big deal for my friend, like most of the population he usually just wants things to work being able to hack them isn t such an issue. However unlike most of the population he does make a reasonable portion of his income from software development and it could be that he will have a contract for developing an app on a mobile device in which case the freedom to tinker on Android will help him. He could use an iPhone for his personal use and develop on an Android platform for his clients, but generally it s more efficient if your personal use of technology is similar to that of your clients. The Nexus devices are very good for liberty and they also have nice hardware at a low price, I ve just got a Nexus 4 for my wife and it s very nice. The next issue is that of hardware standards, I ve previously written about the potential for developing a standard form factor for Android phones [2] although this doesn t seem likely to be implemented in the near future. The wide range of Android hardware means that the range of cases etc on the market is rather small. But the advantage of the wide range is that with an Android phone you can have a device that s bigger, smaller, cheaper, cuter, or faster than an iPhone. There are Android devices which have a higher resolution, more RAM, more storage (if you include SD storage), or has other benefits over an iPhone. For whatever reasonable range of specs appeal to you you can probably find a device to match. I ve previously written about the way the ideal size for devices depends on your hand size and your preferred manner of gripping the device [3], so the lack of size range in Apple devices is not just a limitation on personal choice but also a failure to properly support people with different size hands. Depending on the preferred manner of gripping a phone the iPhone 5 is either too big for an average woman or too small for a tall man. The Google Play store apparently has more applications than the iPhone/iPad App Market. This difference can be expected to increase now that the Samsung Galaxy S3 is outselling the iPhone 5. Comparing the number of unit sales of the iPhone vs Android phones is no longer interesting, comparing Samsung to Apple is the interesting thing. Advantages for the iPhone By all accounts it s quite an easy process to backup and restore all iPhone settings. You can expect that after losing an iPhone you can just connect the new one to your PC and have it work in exactly the same way after all the data is transferred. Trying to do such things on Android is merely difficult if you have root access to your phone and the source and destination phones are of exactly the same make and model. But if you have different versions of the phone or if you don t have root access then it may be impossible. I welcome comments from anyone who knows of good solutions to this problem. The iPhone achieved a reasonable share of the smart-phone market before Android really started going well so there are a lot of people who are used to the iPhone. Simply by being unfamiliar Android will be a more difficult option for people who have used the iPhone such as my friend. But it is possible to learn other systems. Generally I think that this may be a big issue for people who use Macs for all their other computing. But if the only Apple product you use is an iPhone then switching to Android shouldn t be a big deal. Update: One feature of the iPhone that is very important to my friend is the ability to add arbitrary tags in the contacts. In addition to name, address, phone number, etc he wants to add arbitrary notes related to his business. While he could put that sort of thing into the Notes field in Android he would rather have several fields with his own names. Android 4.1.x definitely doesn t have this and I can t test Android 4.2.x at this time. Is there any way of doing such things on Android? Conclusion It seems to me that Android devices are better in every way apart from backup, restore, and general management. If I was about to buy 100 phones then I d probably consider the iPhone (not necessarily buy but definitely consider). But for a single user I definitely recommend Android devices. The Android devices which seem good at the moment are the Galaxy S3 (which I m using now), the Nexus 4 (which is really good apart from being unable to change the battery or add more storage), and the Galaxy Note 2 (which is about the biggest phone available). One of the things that my friend wants to do is to use a phone instead of a tablet or laptop. I think that the Galaxy Note 2 is the only option for him.
Related posts:
  1. My Prediction for the iPhone I have previously written about how I refused an offer...
  2. Standardising Android Don Marti wrote an amusing post about the lack of...
  3. Galaxy S vs Xperia X10 and Android Network Access Galaxy S Review I ve just been given an indefinite loan...

21 February 2013

Biella Coleman: Coding Freedom: The Ethics and Aesthetics of Hacking

Although the book has been out for a number of months, available for purchase and download, Coding Freedom finally has a dedicated home on the Interwebz. Based on my graduate research in anthropology and my dissertation, the book takes an up front and close look at various personal, affective, ethical and political dimensions of free software development. While the book is not on Debian per se, there is one chapter dedicated to the project and a whole lot of Debian developers were interviewed for the book. You can read some reviews and if you like what you see, take a dip.

MJ Ray: In Praise of Consensus

The constitution of the debian operating system project says things like consistent with the consensus of the opinions of the Developers at various points but doesn t say how strong a consensus or how the project will test for consensus. I think those were mistakes, breaking a couple of the conditions for consensus. Wikipedia s understanding of consensus is even worse. Wikipedia seems to treat consensus as a synonym for unanimity. Its testing methods allow an infinite loop to form where the casual observer can t differentiate between a controversial proposal and consensus. I think those were mistakes. These famous-but-imperfect implementations frequently lead to misdirected rants which seem to misunderstand consensus as requiring perpetual bikeshedding. Apache s implementation is rather better and it may surprise you to learn that our co-op is mostly run by consensus. There are two key differences which I feel makes consensus work for us: we ve set limits beforehand on some decisions where we need to act fast where not making a decision would usually be the same as making a bad decision and our methods of testing for consensus are better. We test for consensus with secret-at-vote-time-but-published-after straw polls, or using Crowd Wise by email. I summarise Crowd Wise as follows: gather all ideas plus option 0 (do nothing) if possible, carry out a de Borda (preference) voting round 1, merge/amend/consolidate ideas, voting round 2 if needed. It does still work better if participants put their ego aside a little and co-operate, but it does put limits on non-co-operators. Anyway, as described in Xana/ xana2/ bamamba/ Why Russ is wrong, debian isn t exactly using consensus much at the moment, anyway. Should we try to fix its bugs? Do you know other projects where consensus is working?

20 February 2013

Daniel Pocock: Automatically mirroring SVN repositories to git and github

Updated 21 February 2013: the scripts below have now been adapted to run conveniently from cron and mirror multiple repositories. You can find full scripts and documentation on github There are a number of scripts around, including an earlier blog post of my own, for making a once-off conversion of an SVN repository to a Git repository. However, what if the project team is not yet ready for a full move to git? You may want to start benefiting from git (e.g. using the project as a submodule of another git project, or using Travis-CI.org for automated builds) while development officially continues to take place in SVN. If you don't need to make commits into git just now, you can set up a mirror and refresh it periodically from SVN. This process can be used with various SVN repositories, including Sourceforge and Google Code SVN repositories. Process overview
  • An authors.txt file is created manually before the first run.
  • A git-svn clone of the SVN repository is created. This clone needs to be retained between replication runs.
  • On each run, a temporary git repository is created. The svn-clone is rebased and pushed to the fresh git repository.
  • Fixes (e.g. branch renames and tagging) are made in the temporary git repository.
  • The final results are then pushed from the temporary repository to the real git mirror that is being maintained.
  • Finally, the temporary git repository is deleted, but the svn-clone is kept.
Here is a diagram of the workflow: Config file Here is a sample config file for the script, it mirrors the rather complicated reSIProcate repository with 10,000 commits: 
PROJECT_ROOT=/home/daniel/svn-mirror/resiprocate
AUTHORS_FILE=$ PROJECT_ROOT /authors.txt
SVN_REPO=https://svn.resiprocate.org/rep/resiprocate
SVN_LAYOUT="--trunk=main --branches=branches --tags=tags"
GIT_REPO=git@github.com:resiprocate/resiprocate.git
Of particular note here:
  • The $PROJECT_ROOT is where the svn-clone and the temporary repositories will be created
  • $GIT_REPO is the final destination repository. For testing, it could just be a local directory initialised with git init --bare .
  • In this repository, our trunk is actually called main, hence we have the layout argument --trunk=main. Many projects would just use --trunk=trunk
The script The script itself is below. I'd suggest running it manually a few times first and observing how it behaves, disk space requirements, etc. 
#!/bin/bash
set -e
if [ ! $# -eq 1 ];
then
  echo "Usage:"
  echo "$0 <config-file>"
  exit 1
fi
CONFIG_FILE="$1"
. "$ CONFIG_FILE "   exit 1
SVN_CLONE="$ PROJECT_ROOT /svn-clone"
GIT_BARE="$ PROJECT_ROOT /git-bare-tmp"
if [ ! -d "$ PROJECT_ROOT " ];
then
  mkdir -p "$ PROJECT_ROOT "
fi
cd "$ PROJECT_ROOT "
if [ ! -d "$ SVN_CLONE " ];
then
  git svn clone \
    "$ SVN_REPO " \
    -A "$ AUTHORS_FILE " \
    $ SVN_LAYOUT  \
    "$ SVN_CLONE "
  cd "$ SVN_CLONE "
else
  cd "$ SVN_CLONE "
  git remote rm bare   echo "failed to delete remote:bare, proceeding anyway"
  git svn rebase \
    --fetch-all \
    -A "$ AUTHORS_FILE "
fi
git remote add bare "$ GIT_BARE "
git config remote.bare.push 'refs/remotes/*:refs/heads/*'
if [ -d "$ GIT_BARE " ];
then
  rm -rf "$ GIT_BARE "
fi
mkdir -p "$ GIT_BARE "
cd "$ GIT_BARE "
git init --bare .
git symbolic-ref HEAD refs/heads/trunk
cd "$ SVN_CLONE "
git push bare
cd "$ GIT_BARE "
git branch -m trunk master
git for-each-ref --format='%(refname)' refs/heads/tags   \
   cut -d / -f 4   \
   while read ref;
   do
      git tag "$ref" "refs/heads/tags/$ref"
      git branch -D "tags/$ref"
   done
git remote add origin "$ GIT_REPO "
git config branch.master.remote origin
git config branch.master.merge refs/heads/master
git push --tags origin master
git push --all
rm -rf "$ GIT_BARE "
</config-file>
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