Shallow Thoughts : tags : lca2009
Akkana's Musings on Open Source Computing and Technology, Science, and Nature.
Fri, 01 Apr 2011
The LA Times had a great article last weekend about
Tasmanian devils,
the mysterious facial cancer which is threatening to wipe them out,
and the Bonorong wildlife preserve
in Hobart which is involved in trying to rescue them.
The disease, called
devil
facial tumour disease, is terrible.
It causes tumours on the devils' face and mouth, which eventually grow
so large and painful that the animal starves to death.
It's a cancer, but a very unusual one: it's transmissible and can pass
from one devil to another, one of only three such cancers known.
That means that unlike most cancers, tumour cells aren't from the
infected animal itself; they're usually contracted from a bite from
another devil.
Almost no Tasmanian devils are immune to DFTD. Being isolated for so
long on such a small island, devils have little genetic diversity,
so a disease that affects one devil is likely to affect all of them.
It can wipe out a regional population within a year.
A few individuals seem to have partial immunity, and scientists
are desperately hunting for the secret before the disease wipes out
the rest of the devil population. Organizations like Bonorong are
breeding Tasmanian devils in captivity in case the answer comes too
late to save the wild population.
When I was in Hobart in 2009 for Linux.conf.au (which, aside from being
a great Linux conference, also raised over $35,000 to help
save the devils),
I had the chance to visit Bonorong. I was glad I did: it's fabulous.
You can wander around and feed kangaroos, wallabees and the ever-greedy
emus, see all sorts of rarer Australian wildlife like echidnas, quolls
and sugar gliders, and pet a koala (not as soft as they look).
But surprisingly, the best part was the tour. I'm usually not much for
guided tours, and Dave normally hates 'em. But this one was given by
Greg Irons, the director of the park who's featured in the Times
article, and he's fantastic. He obviously loves the animals and he knows
everything about them -- Dave called him an "animal nerd" (that's a
compliment, really!) And he's a great showman, with a lively and
fact-filled presentation that shows each animal at its best while
keping all ages entertained. If you didn't love marsupials, and
particularly devils and wombats, before you come to Bonorong,
I guarantee you will by the time you leave.
A lot of the accounts of devil facial tumour disease talk about devils
fighting with each other and spreading the disease, but watching them
feed at Bonorong showed that fighting isn't necessary. Tasmanian devils
feed in groups, helping each other tear apart the carcass by all
latching onto it at once and pulling. With this style of feeding,
it's easy to get bitten in the mouth accidentally.
Of course, I have a lot more photos from Bonorong:
Bonorong
Wildlife Park photos.
Tags: travel, lca2009, linux.conf.au, australia, nature
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10:48 Apr 01, 2011
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Fri, 06 Feb 2009
I've written before about how I'd like to get a netbook like an Asus Eee,
except that the screen resolution puts me off: no one makes a netbook
with vertical resolution of more than 600. Since most projectors prefer
1024x768, I'm wary of buying a laptop that can't display that resolution.
(What was wrong with my beloved old Vaio? Nothing, really, except that
the continued march of software bloat means that a machine that can't
use more than 256M RAM is hurting when trying to run programs
(*cough* Firefox *cough) that start life by grabbing about 90M and
goes steadily up from there. I can find lightweight alternatives for
nearly everything else, but not for the browser -- Dillo just doesn't
cut it.)
Ebay turned out to be the answer: there are lots of subnotebooks
there, nice used machines with full displays at netbook prices.
And so a month before LCA I landed a nice Vaio TX650 with 1.5G RAM,
Pentium M, Intel 915GM graphics and Centrino networking.
All nice Linux-supported hardware.
But that raised another issue: how do widescreen laptops
(the TX650 is 1366x768) talk to a projector?
I knew it was possible -- I see people presenting from widescreen
machines all the time -- but nobody ever writes about how it works.
The first step was to get it talking to an external monitor at all.
I ran a VGA cable to my monitor, plugged the other end into the Vaio
(it's so nice not to need a video dongle!) and booted. Nothing. Hmm.
But after some poking and googling, I learned that
with Intel graphics, xrandr is the answer:
xrandr --output VGA --mode 1024x768
switches the external VGA signal on, and
xrandr --auto
switches it back off.
Update, April 2010: With Ubuntu Lucid, this has changed and now it's
xrandr --output VGA1 --mode 1024x768
-- in other words, VGA changed to VGA1. You can run xrandr
with no arguments to get a list of possible output devices and find
out whether X sees the external projector or screen correctly.
Well, mostly. Sometimes it doesn't work -- like, unfortunately,
at the lightning talk session, so I had to give my
talk without visuals. I haven't figured that out yet.
Does the projector have to be connected before I run xrandr?
Should it not be connected until after I've already run xrandr?
Once it's failed, it doesn't help to run xrandr again ... but
a lot of fiddling and re-plugging the cable and power cycling the
projector can sometimes fix the problem, which obviously isn't helpful
in a lightning talk situation.
Eventually I'll figure that out and blog it (ideas, anyone?)
but the real point of today's article is resolution. What I
wanted to know was: what happened to that wide 1366-pixel screen when
I was projecting 1024 pixels? Would it show me some horrible elongated
interpolated screen? Would it display on the left part of the laptop
screen, or the middle part?
The answer, I was happy to learn, is that it does the best thing
possible: it sends the leftmost 1024 pixels to the projector, while
still showing me all 1366 pixels on the laptop screen.
Why ... that means ... I can write notes for myself, to display in
the rightmost 342 screen pixels!
All it took was a little bit of
CSS hacking
in my
HTML slide
presentation package, and it worked fine.
Now I have notes just like my Mac friends with their Powerpoint and
their dual-head video cards, only I get to use Linux and HTML.
How marvellous! I could get used to this widescreen stuff.
Tags: laptop, X11, linux, speaking, projector, lca2009, linux.conf.au
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22:12 Feb 06, 2009
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Wed, 04 Feb 2009
I still haven't finished writing up a couple of blog entries from
bumming around Tasmania after LCA2009, but I did get some photos
uploaded:
Tasmania
photos. Way too many photos of cute Tassie devils and other
animals at the Bonorong wildlife park, as well as the usual
collection of scenics and silly travel photos.
Tags: travel, tasmania, lca2009, nature, photo
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15:49 Feb 04, 2009
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Fri, 23 Jan 2009
The conference is over! Amazing how quickly a week passes.
Simon Phipps warmed us up with a very good keynote, full of inside
jokes and knowledgeable quips indicating he knows the community even
if he is a Sun guy.
Matthew Wilcox had some good tips on improving performance on solid
state disks that I know will keep Dave busy for a while (I got him a
small laptop SSD for his birthday and he's been enjoying it quite a
bit -- it's hugely less power intensive and much faster for most
operations than the regular disk it replaced). Apparently a lot of
his advice will only work on snazzy high-end IBM SSDs, not the cheap
ones like netbooks have or like Dave has, but some of them may be
helpful anyway. Dave is trying the suggestion of using no I/O
scheduler, echo "noop" > /sys/block/sda/queue/scheduler
--
apparently there's a lot of crap the scheduler has to traverse that
isn't noticable when the drive is seeking all the time, but on an SSD
that doesn't need to seek, it can make a big difference. Also,
apparently ext4 or btrfs (still under development) have some
enhancements that help with SSD performance.
I went to Paul Fenwick's talk (Awesome Things You've Missed in
Perl) even though I'm not a Perl hacker ... I know by now that
Paul will always have something fun, and indeed he did,
including a live demo of a bot that plays Minesweeper.
The "awesome things" were indeed pretty cool, and I even found
myself tempted to check out Perl again, especially for the new
smart regular expression and grammar syntax (you can name parts
of regular expressions then define grammars based on them -- very nice!)
Matthew Garrett had entertaining stories on power management, though
not a lot of practical advice. Summary: power management sucks, maybe
it'll get better some day; users shouldn't be forced to predict their
use patterns in order to optimize power usage; video wastes a ton of
power, like higher-than-necessary refresh rates when the user is
merely viewing static images on an LCD that doesn't need much
refreshing.
Then it was lunchtime -- time for the Great Shaving, where Linus
shaved Bdale's beard as part of the enormous charity deal (something
between $35,000 and $40,000 -- the count still isn't finished yet)
toward saving the Tasmanian Devil.
Bdale shared some of the emails from his wife (with her permission)
and they were pretty funny, as was
"Geek My Ride" (Jonathan Oxer and Jared Herbohn or "Flame") had an
entertaining presentation full of successful and impressive demos (we
didn't see the actual cars -- those will be at Open Day tomorrow,
apparently). I didn't see the whole presentation because I was
fiddling around with an idea for a lightning talk, but I saw enough
to get the idea.
Kevin Pulo's "Fun with LD_PRELOAD" was indeed fun. He had quite a few
examples of existing LD_PRELOAD hacks as well as a detailed example of
how to make a custom preloaded library. It's quite a bit more
elaborate than I realized, but certainly do-able and something I've
been meaning to experiment with for quite a while.
Then, sadly, it was time for the closing ceremonies, including
lightning talks (I worked up the nerve and participated, though my
laptop didn't behave and wouldn't talk to the projector -- weird how
xrandr sometimes works and sometimes doesn't).
And then the closing announcements:
next year's LCA will be in Wellington, NZ.
The Great Shaving had made the Hobart afternoon news, and someone
brought in a tape of it. The funniest thing was that they focused
on Bdale and the donation but never mentioned the guy who was doing
the shaving (some unassuming guy named Linus).
Tags: lca2009, linux.conf.au
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Thu, 22 Jan 2009
The highlight of Thursday morning was a filler: one of the speakers
had to cancel, so Paul Fenwick filled in with a combination of two
short talks: "The Art of Klingon Programming" and "What's new in Perl
5.10?" I'm not a Perl programmer (at least not when I have a choice)
but his talks were entertaining and even educational. What struck me
most was that showmanship and humor don't have to detract from
technical content. I'd had a discussion the previous day about the
balance of offering lots of technical content versus entertaining the
audience and not overwhelming them. Most technical talks are either
dry, content heavy and so jam packed with information that you can't
possibly remember everything, or lighter weight and glitzy but with
not much real technical content and a "watered down" feeling.
Paul's Klingon talk was one of the most content-full presentations
I've seen at a conference, with lots of code examples, yet it kept
the audence laughing, listening and grokking (to mix SF metaphors)
all the way through. Showmanship can make it easier, not harder,
to remember technical content.
In the afternoon, I'd been very much looking forward to the Arduino
tutorial (Jonathan Oxer and Hugh Blemings) but it was a bit of a
disappointment.
The acoustics of the room and the handheld microphone, combined with
the interactive nature of the presentation, meant that I could barely
understand a word High Blemings said, and only some of what Jon Oxer
said. (I've heard Jon Oxer talk before and never had trouble, so
I primarily blame the room.)
Partway through, I skipped out to go check Donna Benjamin's "The Joy
of Inkscape." It had been moved from its original lecture hall to a
much smaller room with tables. The smaller room was Standing Room
Only, a raucous and enthusiastic bunch who (the sitting ones, at
least) were nearly all tapping away on laptops exploring either the
demo Donna was showing or other Inkscape projects.
It was clearly a
hugely successful and fun tutorial and I wanted to stay, but I
couldn't find a place to sit where I could both see the screen and
hear Donna, so I made my way back to Arduino.
The second half, when they
demoed various interesting sensors and a few unusual Arduino
applications, was better than the first. But talking to folks later,
a number of us were surprised because we expected a more interactive
tutorial (the prep had encouraged us to bring or buy Arduino hardware).
The hot talk of the day was one I missed, after the tea break.
I went to a talk on Spring, a robotics library (Clinton Roy),
which was interesting
enough and certainly popular (lots of people sitting by the door
because all the seats were full) but afterward all I heard
was people enthusing about Jeff Arnold's amazing Ksplice talk.
He demonstrated a system of updating kernels in place, with no
reboot required. People couldn't say enough about the talk,
and I'm looking forward to downloading the video and seeing what I missed.
Tags: lca2009, linux.conf.au, speaking, arduino
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Wed, 21 Jan 2009
Wednesday started with a keynote by Tom Limoncelli that was, frankly,
disappointing. A lot of it was specific to enterprise sysadmins
(including a set of "homework" for all the new directives you're
going to implement in your IT department) and the rest was, well,
nothing special.
The first regular talk I heard was Keith Packard, describing advances
in X (and related graphical desktop software) over the past year.
Surprisingly, there actually have been a lot of advances.
Chief among them is GEM, a system for sharing data efficiently
between X and the kernel to avoid all the horribly inefficient copying
that's always happened in the past. It all sounded very promising
except that if I understand him correctly, none of this works on
graphics cards, only on integrated Intel graphics. A nice step, but
until it works everywhere I'm not sure it's really a solution.
But Keith was overshadowed by his coworker, Carl Worth, who spoke
next, giving a lively and interesting discussion of the architecture
of graphics on Linux, including the many ways control might flow
depending on which libraries are in use and the capabilities
of the graphics card/chipset are. Better, he enumerated the many
ways of tracing the execution of the various graphics layers --
gtk, cairo, X, mesa etc. -- and I'm looking forward to downloading
his slides to get the list of debugging commands. This may also be
the first talk I've seen to use GIMP as a presentation system.
(He only used it for one slide, where he drew and labelled new
codepaths people have proposed to get around graphics bottlenecks.
My tutorial (on Firefox/Mozilla hacking) was after lunch. I was fairly
happy with it. The audience had a lot of questions, the slides I had
hoped were funny got laughs, and the time worked out -- I had to rush
through the last handful of slides because of the amount of audience
questions and discussion, which is much better than ending early
because no one was interested.
Jonathan Corbet's talk on the Linux Development Process mostly
fairly basic details I already knew (what the difference kernel trees
mean, how subsystem maintainers act as gatekeepers, why it's better
to maintain code in the mainline kernel tree than separate code)
but his talks always have nuggets of interest and relevant stories,
with Linus sitting in the audience to add another perspective.
The talk ended with some good advice on how to get started in kernel
development: review code, and (in a quote from Andrew Morton) "try to
make the kernel work well on every machine you have access to."
Wednesday night's Penguin Dinner was spectacular. The dinner was fairly
spectacular itself (a huge and varied buffet), but the really
impressive part was after dinner. We saw a short presentation on the
plight
of the Tasmanian devil (the largest marsupial
carnivore after the extinction of the Tasmanian "tiger", or thylacine,
in the early 1900s). The devil is threatened
due to a transmissible cancer that causes horrible facial tumors
which are invariably fatal. Then the charity auction began, led by
Rusty Russell.
At auction was one item: a large format numbered print of a
beautiful, award winning
waterfall
photograph by Karen Garbee. Bidding was spirited and rose very
quickly into the thousands of dollars, at which point things got
complicated, with coalitions of multiple people bidding, other people
offering matching offers under certain conditions, other items (such
as a GEEK license plate registered in Queensland) being added to the
photograph. In the end the winning bid was $10,500 (which amounts to
something over $36,000 when various matching funds are included)
on condition that Linus shave Bdale's beard.
Poor Bdale! The beard suits him and he's had it since 1982.
But it will come back, and the Tasmanian devils won't if the cancer
drives them to extinction.
Tags: linuc.conf.au, lca2009
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Tue, 20 Jan 2009
I missed a lot of the miniconf talks on Tuesday because I wanted to
make some last-minute changes to my talk. But I do want to comment
on one: Simon Greener's talk on "A Review of Australian Geodata
Providers." Of course, I'm not in Australia, but it was quite
interesting to hear how similar Australia's problematic geodata
siguation is to the situation in the US. His presentation was
entertaining, animated and I learned some interesting facts about
GPS and geodata in general.
And Dave and I got another good astronomy opportunity with the dark
skies at Peppermint Bay at the Speakers' Dinner. Despite occasional
intrusive clouds we managed to get a great view of the Large
Magellanic Cloud and a decent view of the small one, as well as
eta Carinae and the star clouds between Crux and Carina. Pity
I'd forgotten to bring my thumpin' travel optics that I'd been using
the previous evening: a 6x20 monocular.
Tags: lca2009, linux.conf.au, astronomy, mapping, GIS
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Mon, 19 Jan 2009
On day one of LCA 2009, I divided my time between the LinuxChix and
Kernel miniconfs.
In the morning,
Paul McKenney, in "Why is parallel Programming Hard?", discussed
some of the background of parallel programming research, then gave an
entertaining demonstration of instruction overhead using a roll of
toilet paper. Each square represented one clock cycle -- he estimated
there were a few hundred clock cycles in the full roll -- and he had
audience members unroll the roll carefully, passing it from one
person to the next. It took a long time.
Over at the LinuxChix miniconf, Jacinta Richardson gave a wonderfully
entertaining (and useful) talk "On Speaking".
She explained how to hack audience members' brains, particularly the
corpus callosum and the hippcampus, by using emotion, visual images
and suspenseful stories to give your audience whole-brain entertainment.
After Jacinta's talk we spent some time going around the room
introducing ourselves, and speakers got a chance to plug their
upcoming talks.
I skipped the panel on Geek Parenting (not being a parent)
to go back to the kernel miniconf's "Problem Solving Hour".
Questions involved network performance, solid state disk performance,
how to debug crashes, tracing (the moderator commented that if you're
thinking of getting involved in the kernel effort but aren't quite
sure what to do, there's a huge need for better tracing and
performance analysis tools), solid-state disks (someone plugged
the talk on that subject on Friday) and similar interesting topics.
I asked about an overheating problem I've been having with
my laptop. I mentioned that even in single-user mode, the CPU
temperature keeps going up, so I was pretty sure it was a kernel
and not userspace issue. Matthew Garrett said that a lot of drivers
are optimized for a normal use case -- meaning X -- and may work very
poorly in text mode. You can have something that's overheating in
single-user mode, then you start X and a bunch of power management
systems kick in and the temperature actually goes down. So how do
you figure out what's causing a temperature problem? Open up the
laptop when it's hot, poke around then figure out what's hot.
Then debug that component.
Lunch was a lovely BBQ provided by Google.
After lunch,
Matthew Garrett, in "How I learned to stop worrying and love ACPI",
was entertaining, as all his talks are. I'm not sure I actually
learned much in the way of practical advice for helping ACPI work
better on my machines, but at least I learned lots of new ways in
which ACPI sucks more than I ever realized.
Then it was back to LinuxChix for a workshop on getting schoolgirls
more interested in IT. We saw short presentations from the four
workshop leaders, then split into groups -- our group went outside
and sat in the hazy sunshine and talked about how to get girls,
teachers, parents and school IT staff on board.
After tea, all the LinuxChix groups reported back on the discussions
and there was a full-room discussion on how to get involved with
educational programs like that. Then we ended with lightning talks;
I got roped into giving one, so I didn't take notes on the rest,
but they were all fun and interesting.
Then in the evening, after dinner, we found a spot somewhat sheltered
from the lights of the hotel for some quick astronomy before bed.
The sky was hazy and picking up lots of sky glow from a light beam
shining from the hotel, but fortunately the sky around the Southern
Cross was clear.
We found both the Large and Small Magellanic clouds, as well as
Eta Carina and some other clusters around the Southern Cross.
A lovely view, unmatched by anything I saw from around Sydney or
Melbourne. Tasmania definitely wins for stargazing!
Tags: lca2009, linux.conf.au, astronomy
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Sat, 17 Jan 2009
I'm in Tasmania! I still love the sound of that -- it sounds so exotic.
But this is just a short entry, partly to make sure my feed is working
for the LCA 2009 planet, and partly to write about an experience on
the outbound flight.
Planes never seem to leave the gate on time. There's always something.
This time, the problem was that some of the reading lights in First
and Business classes weren't working properly. So they fiddled with
them for a while. Dave joked "They'll probably have to reboot the
Windows computer that's running the lighting system." "Ha ha," I
laughed.
Then came the next announcement:
Uh, ladies and gentlemen, we've determined that it's not the lights
themselves that are causing the problem. It seems to be a software
problem with the computer running the system. So we're going to shut
down for about two minutes and see if that fixes the problem.
How do you reboot a lighting controller on a plane?
It turns out, what you do is -- shut down the entire plane.
Shut the engines off, cutting all power to the entire plane --
no lights, no fan, even the emergency lights went out after a few
seconds.
They stayed off for about three and a half minutes (not two) and
then took a bit over half a minute to come back up, bit by bit.
And indeed, that fixed the problem. Dave commented afterward,
"That's like rebooting your PC by cutting the main breaker to the
entire house."
Tags: lca2009, linux.conf.au
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22:54 Jan 17, 2009
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