Planet Linux Australia
The way Fedora does automatic software updates has changed with the replacement of yum(8) with dnf(8).
Start by disabling yum's automatic updates, if installed:# dnf remove yum-cron yum-cron-daily
Then install the dnf automatic update software:# dnf install dnf-automatic
Alter /etc/dnf/automatic.conf to change the "apply_updates" line:apply_updates = yes
Instruct systemd to run the updates periodically:# systemctl enable dnf-automatic.timer # systemctl start dnf-automatic.timer
PyCon Australia 2015 is pleased to announce that its Call for Proposals is now open!
The conference this year will be held on Saturday 1st and Sunday 2nd August 2015 in Brisbane. We’ll also be featuring a day of Miniconfs on Friday 31st July.
The deadline for proposal submission is Friday 8th May, 2015.
PyCon Australia attracts professional developers from all walks of life, including industry, government, and science, as well as enthusiast and student developers. We’re looking for proposals for presentations and tutorials on any aspect of Python programming, at all skill levels from novice to advanced.
Presentation subjects may range from reports on open source, academic or commercial projects; or even tutorials and case studies. If a presentation is interesting and useful to the Python community, it will be considered for inclusion in the program.
We’re especially interested in short presentations that will teach conference-goers something new and useful. Can you show attendees how to use a module? Explore a Python language feature? Package an application?Miniconfs
Four Miniconfs will be held on Friday 31st July, as a prelude to the main conference. Miniconfs are run by community members and are separate to the main conference. If you are a first time speaker, or your talk is targeted to a particular field, the Miniconfs might be a better fit than the main part of the conference. If your proposal is not selected for the main part of the conference, it may be selected for one of our Miniconfs:
DjangoCon AU is the annual conference of Django users in the Southern Hemisphere. It covers all aspects of web software development, from design to deployment – and, of course, the use of the Django framework itself. It provides an excellent opportunity to discuss the state of the art of web software development with other developers and designers.
The Python in Education Miniconf aims to bring together community workshop organisers, professional Python instructors and professional educators across primary, secondary and tertiary levels to share their experiences and requirements, and identify areas of potential collaboration with each other and also with the broader Python community.
The Science and Data Miniconf is a forum for people using Python to tackle problems in science and data analysis. It aims to cover commercial and research interests in applications of science, engineering, mathematics, finance, and data analysis using Python, including AI and ‘big data’ topics.
The OpenStack Miniconf is dedicated to talks related to the OpenStack project and we welcome proposals of all kinds: technical, community, infrastructure or code talks/discussions; academic or commercial applications; or even tutorials and case studies. If a presentation is interesting and useful to the OpenStack community, it will be considered for inclusion. We also welcome talks that have been given previously in different events.
Full details: http://2015.pycon-au.org/cfp
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For the last few years I have subscribed to the online edition of The Economist magazine. Previously I read it via their website but for the last year or two I have used their mobile app. Both feature the full-text of each week’s magazine. Since I subscribed near 15 years ago I have paid:Launched Jun 1997 US$ 48 Jun 1999 US$ 48 Oct 2002 US$ 69 Oct 2003 US$ 69 Dec 2006 US$ 79 Oct 2009 US$ 79 Oct 2010 US$ 95 Oct 2011 US$ 95 Mar 2014 NZ$ 400 (approx US$ 300)
You will note the steady creep for a few years followed by the huge jump in 2014.
Note: I reviewed by credit card bill for 2012 and 2013 and I didn’t see any payments, it is possible I was getting it for free for two years . Possibly this was due to the transition between using an outside card processor (Worldpay) and doing the subscriptions in-house.
Last year I paid the bill in a bit of a rush and while I was surprised at the amount I didn’t think to hard. This year however I had a closer look. What seems to have happened is that The Economist has changed their online pricing model from “cheap online product” to “discount from the printed price”. This means that instead of online subscribers paying the same everywhere they now pay slightly less than it would cost to get the printed magazine delivered to the home.
Unfortunately the New Zealand price is very high to (I assume) cover the cost of shipping a relatively small number of magazines via air all the way from the nearest printing location.
So readers in New Zealand are now charged NZ$ 736 for a two-year digital subscription while readers in the US are now charged US$ 223 ( NZ$ 293) for the same product. Thus New Zealanders pay 2.5 times as much as Americans.
Fortunately since I am a globe-trotting member of the world elite® I was able to change my subscription address to my US office and save a bunch of cash. However for a magazine that publishes the Big Mac Index comparing prices of products around the world the huge different in prices for the same digital product seems a little weird.
The use of cloud computing as an alternative implementation for high performance computing (HPC) initially seems to be appealing, especially to IT managers and to users who may find the jump from their desktop application to the command line interface challenging. However a careful and nuanced review of metrics should lead to a reconsideration of these assumptions.
Job control is a basic feature of popular UNIX and Linux shells, such as “bash”.
It can be very useful, so I thought I’d make a little tutorial on it…
You can also use fg and bg with a job number, if you have several jobs in the list.
You can start a job in the background: put an &-symbol at the end of the command. This works well for jobs that write to a file, but not for interactive jobs. Things might get messy if you have a background job that writes to the terminal.
If you forget the % with kill, it will try to kill by process-id instead of job number. You don’t want to accidentally kill PID 1!
An example:vi /etc/apache2/vhosts.d/ids.conf ^Z jobs find / >find.out & jobs fg 2 ^Z jobs bg 2 jobs kill %2 fg
I follow a few blog aggregators (or "planets") and it's always a struggle to keep up with the amount of posts that some of these get. The best strategy I have found so far to is to filter them so that I remove the blogs I am not interested in, which is why I wrote PlanetFilter.Other options
In my opinion, the first step in starting a new free software project should be to look for a reason not to do it So I started by looking for another approach and by asking people around me how they dealt with the firehoses that are Planet Debian and Planet Mozilla.
It seems like a lot of people choose to "randomly sample" planet feeds and only read a fraction of the posts that are sent through there. Personally however, I find there are a lot of authors whose posts I never want to miss so this option doesn't work for me.
A better option that other people have suggested is to avoid subscribing to the planet feeds, but rather to subscribe to each of the author feeds separately and prune them as you go. Unfortunately, this whitelist approach is a high maintenance one since planets constantly add and remove feeds. I decided that I wanted to follow a blacklist approach instead.PlanetFilter
PlanetFilter is a local application that you can configure to fetch your favorite planets and filter the posts you see.
You can either:
- add file:///var/cache/planetfilter/planetname.xml to your local feed reader
- serve it locally (e.g. http://localhost/planetname.xml) using a webserver, or
- host it on a server somewhere on the Internet.
The software will fetch new posts every hour and overwrite the local copy of each feed.
A basic configuration file looks like this:[feed] url = http://planet.debian.org/atom.xml [blacklist] Filters
There are currently two ways of filtering posts out. The main one is by author name:[blacklist] authors = Alice Jones John Doe
and the other one is by title:[blacklist] titles = This week in review Wednesday meeting for
In both cases, if a blog entry contains one of the blacklisted authors or titles, it will be discarded from the generated feed.Tor support
Since blog updates happen asynchronously in the background, they can work very well over Tor.
In order to set that up in the Debian version of planetfilter:
- Install the tor and polipo packages.
Set the following in /etc/polipo/config:proxyAddress = "127.0.0.1" proxyPort = 8008 allowedClients = 127.0.0.1 allowedPorts = 1-65535 proxyName = "localhost" cacheIsShared = false socksParentProxy = "localhost:9050" socksProxyType = socks5 chunkHighMark = 67108864 diskCacheRoot = "" localDocumentRoot = "" disableLocalInterface = true disableConfiguration = true dnsQueryIPv6 = no dnsUseGethostbyname = yes disableVia = true censoredHeaders = from,accept-language,x-pad,link censorReferer = maybe
Tell planetfilter to use the polipo proxy by adding the following to /etc/default/planetfilter:export http_proxy="localhost:8008" export https_proxy="localhost:8008"
The source code is available on repo.or.cz.
I've been using this for over a month and it's been working quite well for me. If you give it a go and run into any problems, please file a bug!
I'm also interested in any suggestions you may have.
A guest blog post I wrote on managing git branches when doing devops.
When doing Devops we all know that using source code control is a “good thing” — indeed it would be hard to imagine doing Devops without it. But if you’re using Puppet and R10K for your configuration management you can end up having hundreds of old branches lying around — branches like XYZ-123, XYZ-123.fixed, XYZ-123.fixed.old and so on. Which branches to cleanup, which to keep? How to easily cleanup the old branches? This article demonstrates some git configurations and scripts that make working with hundreds of git branches easier…
Go to Devops and Old Git Branches to read the full article.
The increasing size of datasets acts a critical issue for eResearch, especially given that they are expanding at a rate greater than improvements in desktop application speed, suggesting that HPC knowledge is requisite. However knowledge of such systems is not common.
I didn't realize there had been a flash flood in Canberra in 1971 that killed seven people, probably because I wasn't born then. However, when I ask people who were around then, they don't remember without prompting either, which I think is sad. I only learnt about the flood because of the geocache I found hidden at the (not very well advertised) memorial today.
This was walk inspired by one from Best Bush, Town and Village Walks in and around the ACT by Marion Stuart. I was disappointed that the guide book didn't mention the flash flood however, and skips the memorial.
Interactive map for this route.
Tags for this post: blog pictures 20150323-curtin photo canberra bushwalk
Related posts: Goodwin trig; Big Monks; Geocaching; Confessions of a middle aged orienteering marker; Narrabundah trig and 16 geocaches; Cooleman and Arawang Trigs
- curry powder
- chilli sauce
- soy sauce
- tomato sauce
- chicken, prawns, and/or seafood mix
- egg noodles (any kind)
- lemon juice (optional)
- oyster sauce (optional)
- garlic (optional)
- ginger (optional)
- onion (optional)
- tomatoes (optional)
- tofu (optional)
- vegetables (optional, type is your choice)
Coat chicken with bicarbonate soda if desired (meat tenderiser. This step is not required at all if chicken is diced into small enough pieces and cooked well) and then wash off in cold water. Marinade chicken in fish sauce, sugar, garlic, pepper (optional step). Fry off chicken, tofu, onion, garlic, ginger, etc... in pan. Create sauce by using tomato sauce, soy sauce, chill sauce, curry powder, sugar, etc... Cook sauce and add noodles/rice when ready. Garnish everything with chopped lettuce and fried shallots if desired.
The following is what it looks like.
- 11 facts about the changing face of the Australian workforce http://t.co/5GuEcwtatb 15:33:00, 2015-03-20
- Fact check: Did the Government inherit the ‘worst set of accounts’ in history? http://t.co/gaaxll2Pgi #auspol 13:19:12, 2015-03-20
- Brazilian study of 3,500 newborns over 30 years finds link between breastfeeding and intelligence http://t.co/yHhNOVUDj7 11:20:03, 2015-03-20
- Ten companies directly responsible for third of Australia’s greenhouse gas pollution, report finds http://t.co/j8RJDH0HMB 09:42:01, 2015-03-20
- Australia’s plain packaging laws successful, studies show http://t.co/3VH3EC8iX5 19:32:04, 2015-03-19
- Nestlé: “as a human being you should have no right to water” http://t.co/hEuLTNNhza 19:32:04, 2015-03-17
I really like this area. Its scenic, has nice trails, and you can't tell you're in Canberra unless you really look for it. It seemed lightly used to be honest, I think I saw three other people the entire time I was there. I encountered more dogs off lead than people.
Interactive map for this route.
Tags for this post: blog pictures 20150321-narrabundah photo canberra bushwalk trig_point
Related posts: Goodwin trig; Big Monks; Cooleman and Arawang Trigs; One Tree and Painter; A walk around Mount Stranger; Forster trig
PSA: If you are a web professional, work in a digital agency or build mobile apps, please read this article now: Taking the social model of disability online
"The social model of disability reframes discussion of disability as a problem of the world, rather than of the individual. The stairs at the train station are the problem, rather than using a wheelchair."
El Gibbs has reminded me of question time during Gian Wild's keynote at Drupal Downunder in 2012. Gian asserts that accessibility guidelines are a legal requirement for everyone, not just Government. There was an audible gasp from the audience.
It's true that our physical environment needs to include ramps, lifts, accessible toilets, reserved parking spaces, etc in order to accommodate those with mobility needs. Multi-lingual societies require multi-lingual signage. There are hearing loops - but for some reason, this "social model" of accessibility doesn't seem to have extended online.
Making the digital world accessible, and counteracting the systemic discriminatory impact of failing to do so is something we must take seriously. We must build this in during planning and design, we must make it easy for content editors to maintain WCAG compliance AFTER a site or app is delivered.
Building accessibility features in from the beginning also means it costs less to implement, and delivers a double win of making the whole team more mindful of these issues to begin with. It should be part of the acceptance criteria, it should be part of the definition of done.
I'd like to see us tackle these issues directly in Drupal core. If you're interested in keeping track of accessibility issues in Drupal, you might like to follow drupala11y on twitter, and check out issues on drupal.org that have been tagged with "accessibility".
Accessibility traps might not affect you now, but they will. This is probably affecting people you know right now. People who silently struggle with small font sizes, poor contrast, cognitive load, keyboard traps, video without captions.
My own eyesight and hearing is not what it was. My once able parents now require mobility aids. My cousin requires an electric wheelchair. A friend uses a braille reader, and yet I still forget. It's not front and centre for me, but it should be. Let's all take a moment to think about how we can focus on making our online and digital world more accessible for everyone. It really does benefit us all.
Very much a minor update to the presentation I gave in 2013, this talk provides a definition of supercomputers, high performance computing, and parallel programming, their use and current metrics, the importance and dominance of the Linux operating system in these areas, as well as some practical hands-on examples.
An Introduction to Supercomputers. Presentation to Linux Users of Victoria Beginners Workshop, 21st March, 2015
Interactive map for this route.
Tags for this post: blog pictures 20150320-namadgi photo canberra bushwalk namadgi border
Related posts: Goodwin trig; Big Monks; Geocaching; Confessions of a middle aged orienteering marker; A quick walk through Curtin; Narrabundah trig and 16 geocaches
- 40 Maps that Explain World War One – A bunch of maps from all sorts of sources that explain different aspects of the origins and path of WW1. Huge rang of stuff.
- On Interviewing as a Junior Dev – Liz Rush kept a record of her hunt for a job. Lots of anecdotes, advice and data.
- The Little-Known Story of How The Shawshank Redemption Became One of the Most Beloved Films of All Time – Good long article about the making of the movie with quotes from those involved.
- State of the Art in Microservices by Adrian Cockcroft (video 38min) – A good intro to Microservices and an overview of what is currently happening in the area. Slides are here
While watching another disappointing day in Australian political life unfold, I wondered: How long has it been since Tony Abbott declared, “good government starts today“?
It’s such a great example of Abbott’s hopelessness: He survived as Prime Minister after a failed party room spill motion only to deliver another classic clanger. Good job, Tony.
Then I checked the date and realised it had only been 38 days since the attempted spill. It seems much longer because barely a day goes by without a spectacular cock-up or gaffe by Abbott or one of his ministers.
Laura Tingle wrote yesterday that “we are being governed by idiots and fools“, excoriating the Abbott government for recklessness and incompetence, hinting at a deeper problem in our political system. Jonathan Green picked up where Tingle left off, suggesting Australia’s next great reforms “will be of this stagnant polity itself”. We can only hope.
I don’t want to juggle the date arithmetic next time I ponder how long we’ve been blessed with “good government”. The obvious* solution is a Twitter account to remind everyone*, right?
Thus, an automated, single-serving Twitter account that tweets the number of days since the spill, with a topical news item and photo, neither of which tend to reflect well on the Prime Minister.
— Good job, Tony (@goodjobtony) March 19, 2015Violence Against Women
Late yesterday evening, a wise voice caught me off guard: There’s a lot of men making a lot of noise about data retention today. Where’s that noise when a woman is killed every week by a partner or ex-partner?
If central Sydney can undergo substantial social and commercial upheaval after the deaths of two young men in “king hit” attacks, surely 8 intimate partner homicides (and 22 total suspicious deaths) of women so far this year would elicit some response? History suggests otherwise.
So we must make more noise.
My meagre contribution today is, yes, a single-serving Twitter account. I know it’s silly and practically meaningless, but hopefully people will see it, share it, and support women like Rosie Batty who are doing the really important work.
It will tweet updated figures from two sources:
First, Guardian Australia has a page for women who have died “where police have later laid charges against their partners or ex-partners”. (It’s a mouthful of legalese because they have to be careful about affecting trials.)
Second, Destroy the Joint’s Counting Dead Women Australia team maintains a Facebook post that documents every woman who has died violently, and follows what happens after. It’s based on a UK project of the same name.
38 days since “good government” began. 22 women violently killed in Australia this year. Two very different numbers.
— Counting Dead Women (@WomenKilledAus) March 19, 2015
Shortly after I published the first post on a simple VHF SDR, Brady KC9TPA started making suggestions about optimising the code. So I encouraged him to have a look into the transmit side. How can we take a baseband modem signal (like GMSK) and convert it up to a HF IF frequency like 10.7 MHz using the STM32F4 DAC?
After a busy month (and not much sleep) Brady has done it! The following figures explain how it works:
Normally we would use a baseband DAC, mixer, LO, and crystal filter to generate a signal at HF (top). However Brady has shown it is possible to use a much simpler architecture (bottom).
So with the STM32F4, some clever software, and a buffer amplifier, he has generated a 10.7MHz HF signal. The DAC runs at 2MHz, which creates images (aliases) spaced every 1 MHz. The Band Pass Filter (BPF) selects just the image you want, e.g. 10.7 MHz in our case. The BPF doesn’t have to be very demanding like an Xtal filter, as the other images are 1MHz away. It is possible to tune the exact frequency a few hundred kHz in software.
Compared to a baseband IQ design this architecture doesn’t need two DACs, and doesn’t have have any IQ balance issues.
He used a GMSK modem signal as the baseband signal, however it could have easily been SSB, analog FM, or FreeDV. This is basically a baseband to HF SSB exciter. With a suitable BPF it could easily be tuned to anywhere on the lower HF bands. Software could then be used to tune the tx frequency within that band.
Brady received and sampled the 10.7MHz signal using an off the shelf SDR and it demodulated perfectly. Here are few photos showing his experimental set up, just a STM32F4 Discovery board and a buffer amplifier connected to the DAC. Note the sharp edges on the scope plot – this indicates lots of juicy HF content that we can tune to. He hasn’t added a BPF yet. The last plot is the GMSK signal as received by our demodulator running in Octave.
Our next step will be to mix this signal to VHF and add a PA to produce a 1 Watt 2M signal, to support our VHF FreeDV work. Please contact us if you can help us with a VHF PA design!
This design and the previous post that demonstrated the HF rx side suggests that the SM1000 could be modified to be a HF SDR transceiver. It already has a microphone and speaker amplifier, and even runs FreeDV out of the box! We would need to add a BPF, PA, and some gain on the rx side.
There is still a question over the STM32F4 internal ADC, e.g. it’s inter-modulation performance when used in over-sampled mode (thanks Glen English for pointing this out). Some more work required there. However this architecture is not limited to the STM32F4 – any uC connected to a few M-sample/s DAC and ADC (internal or external) will do. That’s the great thing about radios based on gcc C code and nearly no hardware!