Planet Linux Australia

Syndicate content
Planet Linux Australia -
Updated: 5 min 20 sec ago

Clinton Roy: clintonroy

Wed, 2015-03-11 19:28

Awful day.

Sleep was disrupted by neighbours moving their cars around at two thirty am to make way for builders coming. Why two thirty? fucked if I know.

Finally dragged myself out of bed tired and headachy, headed into work.

Did manage to get some stuff done at work before the jack hammering started, and I left immediately in the early afternoon.

Struggling to stay awake till a sensible hour while catching up on a few of these here diary entries.

Filed under: diary

Clinton Roy: clintonroy

Wed, 2015-03-11 19:28

Walked home.

Conference stuff.

Filed under: diary

Clinton Roy: clintonroy

Wed, 2015-03-11 19:28

Walked into work stupidly early.

Home early, straight to bed.

Filed under: diary

Clinton Roy: clintonroy

Wed, 2015-03-11 19:28

Library day.

Filed under: diary

Clinton Roy: clintonroy

Wed, 2015-03-11 19:28

Coder dojo, much to my surprise I was introducing my simplified markov chain generator. It didn’t get much traction, but I felt that was because most of the kids had something they were interested in doing.

Next week I’m apparently talking all about 3D printing…

Filed under: diary

Clinton Roy: clintonroy

Wed, 2015-03-11 19:28

Deliberately didn’t walk to work as I’m giving blood today.

Stuffing myself silly with food and water, and only one coffee. So much water.

Was vindicated when I gave blood in record time with no dramas, and I didn’t get even a minor bruise at the extraction point.

Stuffed myself silly straight after.

Filed under: diary

Clinton Roy: clintonroy

Wed, 2015-03-11 19:28

Walked to walk stupidly early.

Conference work that night.

Filed under: diary

Clinton Roy: clintonroy

Wed, 2015-03-11 19:28

The monthly Python Users group meeting. There was a great talk about calculating statistics, like variances, in a single pass.

Filed under: diary

Clinton Roy: clintonroy

Wed, 2015-03-11 19:28

Walked home.

Conference stuff.

Filed under: diary

Clinton Roy: clintonroy

Wed, 2015-03-11 19:28

Was on the motorbike for the first time in a while today. Riding into work very early is great, riding home at peak hour is silly however.

Filed under: diary

Silvia Pfeiffer: WebVTT Audio Descriptions for Elephants Dream

Tue, 2015-03-10 23:42

When I set out to improve accessibility on the Web and we started developing WebSRT – later to be renamed to WebVTT – I needed an example video to demonstrate captions / subtitles, audio descriptions, transcripts, navigation markers and sign language.

I needed a freely available video with spoken text that either already had such data available or that I could create it for. Naturally I chose “Elephants Dream” by the Orange Open Movie Project , because it was created under the Creative Commons Attribution 2.5 license.

As it turned out, the Blender Foundation had already created a collection of SRT files that would represent the English original as well as the translated languages. I was able to reuse them by merely adding a WEBVTT header.

Then there was a need for a textual audio description. I read up on the plot online and finally wrote up a time-alignd audio description. I’m hereby making that file available under the Create Commons Attribution 4.0 license. I’ve added a few lines to the medadata headers so it doesn’t confuse players. Feel free to reuse at will – I know there are others out there that have a similar need to demonstrate accessibility features.

David Rowe: FreeDV and Codec 2 2015 Road Map

Mon, 2015-03-09 17:30

Last week I had a great chat with Gary Pearce KN4AG from Ham Radio Now:

Which brings me to my plans for 2015……..

2015 Open Digital Voice Road Map

I’m pretty excited about where Open Source Digital Radio is going in 2015. My goals for this year are:

  • A “sub zero” negative SNR FreeDV HF mode.
  • VHF FreeDV mode(s) that demonstrates a TDMA repeater in a 5kHz channel, diversity reception, high bit rate audio/data, and operation at 10dB less C/No than analog FM or 1st generation DV systems.
  • SM1000 speaker-mic and SM2000 VHF radio in production.

This figure shows the work packages we need to execute to make this happen:

The amount of blue shading indicates progress to date. It’s doable, but we could use some help – see below. The custom VHF radio product is the audacious stretch goal, but we need custom hardware to demonstrate the potential of open source VHF DV. In particular decent modems, TDMA, diversity, and variable bit rate (VBR). Sub-carrier VBR is explained in the next section. I’m no Icom, but do have the huge open source advantage of “owning the stack” and a very impressive brains trust that is forming up behind this work.

Sub Carrier Variable Bit Rate

HF and VHF channels vary wildly in quality due to multipath fading. If the channel is really poor it’s essential to push through with low quality, but intelligible speech. However if the channel is good, you may have 20dB more signal to noise ratio available. Current digital (and to a lessor extent analog) voice radio systems just toss that 20dB away. Systems are designed for the worst case, with power heaped on to survive the fading.

I’ve been brainstorming a sub-carrier idea. We send the must-have information using a full power, low bit rate to survive the worst case. On HF this might be 450 bit/s. At the same time, we transmit a higher bit rate sub-carrier at say 10dB less power. When the channel is good, we use the high bit rate carrier. When it’s poor, we fall back to just the low bit rate carrier.

This is better than a protocol based system that negotiates the bit rate, as it requires no back channel and can handle rapid changes in channel quality. It does however require a demodulator that can determine when the sub-carrier is viable. This needs some smarts to avoid rapid high/low quality switching, or for Ham radio could be manually switch-able so the operator has full control.

Sending a second, low power carrier has negligible impact on our total transmit power, e.g. 11 W total rather than 10W (0.4dB). It does use more bandwidth, and will require some implementation tricks (e.g. two class C amplifiers at VHF, but no changes at HF with a linear amplifier). The addition of a low power sub-carrier will have a small impact on peak/average power ratio (PAPR) compared to multiple carriers at the same power. Another bonus.

It’s an idea we can implement as we have complete control over the stack. From microphone to antenna and back again. Go Open Source.

I’d like to try this trick for both HF and VHF.

Daniel has illustrated it well for GMSK carriers:

Old school, analog colour TV worked like this. You get the black and white image information and sync signals on one carrier, then a sub-carrier carries the colour information. In weak signal situations you get black and white. Hmm, I wonder if this analog analogy is too dated. Showing my age.

Codec 2 and AMBE 2+

I recently compared a few AMBE 2+ samples with Codec 2, both at 2400 bit/s. I think they are close enough, except for the $100k up-front license fee, several $ per-unit license fee, policy of eternal lock-in through standardisation, patent encumbrances, and being forbidden by law to modify and learn anything about the algorithm. Not sure why Codec 2 is louder. I listen to them through my laptop speaker as that’s close to a radio.

Codec Female Male Original female male AMBE 2+ female male Codec 2 female male

I cheated a bit, and ran both of them through a a 200Hz high pass filter. AMBE does a better job between 0 and 200 Hz. However most radio systems use an audio bandwidth of 400 to 2600 Hz. Indeed analog FM in VHF applications is sharply filtered at 400Hz so various control tones are not heard.

This isn’t the best we can do with Codec 2, it can be improved further.

Get Involved

There is a fine group of people who are already working with me. They are having fun and working on a really useful and meaningful project. Here are some examples:

  • Rick, KA8BMA and I have had a great year building the SM1000 together.
  • Mel Whitten K0PFX and his band of merry Hams have done a fantastic job promoting HF DV and testing FreeDV.
  • Daniel, VA7DRM has been zooming around British Columbia testing VHF diversity and prototypes of a 2nd generation VHF DV system.
  • Richard Shaw has been doing fine work on cross platform build systems and packaging of FreeDV and Codec 2.
  • Many people have provided invaluable, high level technical advice on RF, Modems, HF and VHF channels and DSP. You know who you are.
  • Many other contributors, large and small, through donations, testing, donations of test equipment, promotion, porting, contract development or small patches, some of which have expressly asked to remain anonymous (e.g. for commercial reasons).

Don’t Just Talk. Act

What did you do during the Open Source Digital Radio revolution?

Contributions count much more than suggestions. Suggestions add to my TODO list, contributions make it shorter. I’m just one guy working part time for nearly zero income and have my limits. If you can help make my TODO list shorter rather than longer please contact me!

If you have a great, must-have suggestion, then I will politely ask you to step up and submit a patch for it. Now you have my attention!

Can you code in C, use Octave/Matlab, write a radio or protocol specification, provide me with RF test equipment, or use a soldering iron to design and make VHF radios? Please contact me.

If you don’t have time or skills then you can still support this work by buying a SM1000 or simply donating. I also need my sig-gen and spec-an either replaced or fixed! Let me know if you need my shipping address

Donation in US$:

Michael Still: Stromlo and Brown Trigs

Mon, 2015-03-09 16:28
So, the Facebook group set off for our biggest Trig walk yet today -- Stromlo and Brown Trigs. This ended up being a 15km walk with a little bit of accidental trespass (sorry!) and about 600 meters of vertical rise. I was expecting Stromlo to be prettier to be honest, but it wasn't very foresty. Brown was in nicer territory, but its still not the nicest bit of Canberra I've been to. I really enjoyed this walk though, thanks to Simon, Tony and Jasmine for coming along!


Interactive map for this route.

Tags for this post: blog pictures 20150309-stromlo_and_brown photo canberra bushwalk trig_point

Related posts: Goodwin trig; Big Monks; Narrabundah trig and 16 geocaches; Cooleman and Arawang Trigs; A walk around Mount Stranger; Forster trig


Pia Waugh: Technocracy: a short look at the impact of technology on modern political and power structures

Mon, 2015-03-09 07:27

Below is an essay I wrote for some study that I thought might be fun to share. If you like this, please see the other blog posts tagged as Gov 2.0. Please note, this is a personal essay and not representative of anyone else

In recent centuries we have seen a dramatic change in the world brought about by the rise of and proliferation of modern democracies. This shift in governance structures gives the common individual a specific role in the power structure, and differs sharply from more traditional top down power structures. This change has instilled in many of the world’s population some common assumptions about the roles, responsibilities and rights of citizens and their governing bodies. Though there will always exist a natural tension between those in power and those governed, modern governments are generally expected to be a benevolent and accountable mechanism that balances this tension for the good of the society as a whole.

In recent decades the Internet has rapidly further evolved the expectations and individual capacity of people around the globe through, for the first time in history, the mass distribution of the traditional bastions of power. With a third of the world online and countries starting to enshrine access to the Internet as a human right, individuals have more power than ever before to influence and shape their lives and the lives of people around them. It is easier that ever for people to congregate, albeit virtually, according to common interests and goals, regardless of their location, beliefs, language, culture or other age old barriers to collaboration. This is having a direct and dramatic impact on governments and traditional power structures everywhere, and is both extending and challenging the principles and foundations of democracy.

This short paper outlines how the Internet has empowered individuals in an unprecedented and prolific way, and how this has changed and continues to change the balance of power in societies around the world, including how governments and democracies work.

Democracy and equality

The concept of an individual having any implicit rights or equality isn’t new, let alone the idea that an individual in a society should have some say over the ruling of the society. Indeed the idea of democracy itself has been around since the ancient Greeks in 500 BCE. The basis for modern democracies lies with the Parliament of England in the 11th century at a time when the laws of the Crown largely relied upon the support of the clergy and nobility, and the Great Council was formed for consultation and to gain consent from power brokers. In subsequent centuries, great concerns about leadership and taxes effectively led to a strongly increased role in administrative power and oversight by the parliament rather than the Crown.

The practical basis for modern government structures with elected official had emerged by the 17th century. This idea was already established in England, but also took root in the United States. This was closely followed by multiple suffrage movements from the 19th and 20th centuries which expanded the right to participate in modern democracies from (typically) adult white property owners to almost all adults in those societies.

It is quite astounding to consider the dramatic change from very hierarchical, largely unaccountable and highly centralised power systems to democratic ones in which those in powers are expected to be held to account. This shift from top down power, to distributed, representative and accountable power is an important step to understand modern expectations.

Democracy itself is sustainable only when the key principle of equality is deeply ingrained in the population at large. This principle has been largely infused into Western culture and democracies, independent of religion, including in largely secular and multicultural democracies such as Australia. This is important because an assumption of equality underpins stability in a system that puts into the hands of its citizens the ability to make a decision. If one component of the society feels another doesn’t have an equal right to a vote, then outcomes other than their own are not accepted as legitimate. This has been an ongoing challenge in some parts of the world more than others.

In many ways there is a huge gap between the fearful sentiments of Thomas Hobbes, who preferred a complete and powerful authority to keep the supposed ‘brutish nature’ of mankind at bay, and the aspirations of John Locke who felt that even governments should be held to account and the role of the government was to secure the natural rights of the individual to life, liberty and property. Yet both of these men and indeed, many political theorists over many years, have started from a premise that all men are equal – either equally capable of taking from and harming others, or equal with regards to their individual rights.

Arguably, the Western notion of individual rights is rooted in religion. The Christian idea that all men are created equal under a deity presents an interesting contrast to traditional power structures that assume one person, family or group have more rights than the rest, although ironically various churches have not treated all people equally either. Christianity has deeply influenced many political thinkers and the forming of modern democracies, many of which which look very similar to the mixed regime system described by Saint Thomas Aquinas in his Summa Thelogiae essays:

Some, indeed, say that the best constitution is a combination of all existing forms, and they praise the Lacedemonian because it is made up of oligarchy, monarchy, and democracy, the king forming the monarchy, and the council of elders the oligarchy, while the democratic element is represented by the Ephors: for the Ephors are selected from the people.

The assumption of equality has been enshrined in key influential documents including the United States Declaration of Independence, 1776:

We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.

More recently in the 20th Century, the Universal Declaration of Human Rights goes even further to define and enshrine equality and rights, marking them as important for the entire society:

Whereas recognition of the inherent dignity and of the equal and inalienable rights of all members of the human family is the foundation of freedom, justice and peace in the world…1st sentence of the Preamble to the Universal Declaration of Human Rights

All human beings are born free and equal in dignity and rights.Article 1 of the United Nations Universal Declaration of Human Rights (UDHR)

The evolution of the concepts of equality and “rights” is important to understand as they provide the basis for how the Internet is having such a disruptive impact on traditional power structures, whilst also being a natural extension of an evolution in human thinking that has been hundreds of years in the making.

Great expectations

Although only a third of the world is online, in many countries this means the vast bulk of the population. In Australia over 88% of households are online as of 2012. Constant online access starts to drive a series of new expectations and behaviours in a community, especially one where equality has already been so deeply ingrained as a basic principle.

Over time a series of Internet-based instincts and perspectives have become mainstream, arguably driven by the very nature of the technology and the tools that we use online. For example, the Internet was developed to “route around damage” which means the technology can withstand technical interruption by another hardware or software means. Where damage is interpreted in a social sense, such as perhaps censorship or locking away access to knowledge, individuals instinctively seek and develop a work around and you see something quite profound. A society has emerged that doesn’t blindly accept limitations put upon them. This is quite a challenge for traditional power structures.

The Internet has become both an extension and an enabler of equality and power by massively distributing both to ordinary people around the world. How has power and equality been distributed? When you consider what constitutes power, four elements come to mind: publishing, communications, monitoring and enforcement.

Publishing – in times gone past the ideas that spread beyond a small geographical area either traveled word of mouth via trade routes, or made it into a book. Only the wealthy could afford to print and distribute the written word, so publishing and dissemination of information was a power limited to a small number of people. Today the spreading of ideas is extremely easy, cheap and can be done anonymously. Anyone can start a blog, use social media, and the proliferation of information creation and dissemination is unprecedented. How does this change society? Firstly there is an assumption that an individual can tell their story to a global audience, which means an official story is easily challenged not only by the intended audience, but by the people about whom the story is written. Individuals online expect both to have their say, and to find multiple perspectives that they can weigh up, and determine for themselves what is most credible. This presents significant challenges to traditional powers such as governments in establishing an authoritative voice unless they can establish trust with the citizens they serve.

Communications– individuals have always had some method to communicate with individuals in other communities and countries, but up until recent decades these methods have been quite expensive, slow and oftentimes controlled. This has meant that historically, people have tended to form social and professional relationships with those close by, largely out of convenience. The Internet has made it easy to communicate, collaborate with, and coordinate with individuals and groups all around the world, in real time. This has made massive and global civil responses and movements possible, which has challenged traditional and geographically defined powers substantially. It has also presented a significant challenge for governments to predict and control information flow and relationships within the society. It also created a challenge for how to support the best interests of citizens, given the tension between what is good for a geographically defined nation state doesn’t always align with what is good for an online and trans-nationally focused citizen.

Monitoring – traditional power structures have always had ways to monitor the masses. Monitoring helps maintain rule of law through assisting in the enforcement of laws, and is often upheld through self-reporting as those affected by broken laws will report issues to hold detractors to account. In just the last 50 years, modern technologies like CCTV have made monitoring of the people a trivial task, where video cameras can record what is happening 24 hours a day. Foucault spoke of the panopticon gaol design as a metaphor for a modern surveillance state, where everyone is constantly watched on camera. The panopticon was a gaol design wherein detainees could not tell if they were being observed by gaolers or not, enabling in principle, less gaolers to control a large number of prisoners. In the same way prisoners would theoretically behave better under observation, Foucault was concerned that omnipresent surveillance would lead to all individuals being more conservative and limited in themselves if they knew they could be watched at any time. The Internet has turned this model on its head. Although governments can more easily monitor citizens than ever before, individuals can also monitor each other and indeed, monitor governments for misbehaviour. This has led to individuals, governments, companies and other entities all being held to account publicly, sometimes violently or unfairly so.

Enforcement – enforcement of laws are a key role of a power structure, to ensure the rules of a society are maintained for the benefit of stability and prosperity. Enforcement can take many forms including physical (gaol, punishment) or psychological (pressure, public humiliation). Power structures have many ways of enforcing the rules of a society on individuals, but the Internet gives individuals substantial enforcement tools of their own. Power used to be who had the biggest sword, or gun, or police force. Now that major powers and indeed, economies, rely so heavily upon the Internet, there is a power in the ability to disrupt communications. In taking down a government or corporate website or online service, an individual or small group of individuals can have an impact far greater than in the past on power structures in their society, and can do so anonymously. This becomes quite profound as citizen groups can emerge with their own philosophical premise and the tools to monitor and enforce their perspective.

Property – property has always been a strong basis of law and order and still plays an important part in democracy, though perspectives towards property are arguably starting to shift. Copyright was invented to protect the “intellectual property” of a person against copying at a time when copying was quite a physical business, and when the mode of distributing information was very expensive. Now, digital information is so easy to copy that it has created a change in expectations and a struggle for traditional models of intellectual property. New models of copyright have emerged that explicitly support copying (copyleft) and some have been successful, such as with the Open Source software industry or with remix music culture. 3D printing will change the game again as we will see in the near future the massive distribution of the ability to copy physical goods, not just virtual ones. This is already creating havoc with those who seek to protect traditional approaches to property but it also presents an extraordinary opportunity for mankind to have greater distribution of physical wealth, not just virtual wealth. Particularly if you consider the current use of 3D printing to create transplant organs, or the potential of 3D printing combined with some form of nano technology that could reassemble matter into food or other essential living items. That is starting to step into science fiction, but we should consider the broader potential of these new technologies before we decide to arbitrarily limit them based on traditional views of copyright, as we are already starting to see.

By massively distributing publishing, communications, monitoring and enforcement, and with the coming potential massive distribution of property, technology and the Internet has created an ad hoc, self-determined and grassroots power base that challenges traditional power structures and governments.

With great power…

Individuals online find themselves more empowered and self-determined than ever before, regardless of the socio-political nature of their circumstances. They can share and seek information directly from other individuals, bypassing traditional gatekeepers of knowledge. They can coordinate with like-minded citizens both nationally and internationally and establish communities of interest that transcend geo-politics. They can monitor elected officials, bureaucrats, companies and other individuals, and even hold them all to account.

To leverage these opportunities fully requires a reasonable amount of technical literacy. As such, many technologists are on the front line, playing a special role in supporting, challenging and sometimes overthrowing modern power structures. As technical literacy is permeating mainstream culture more individuals are able to leverage these disrupters, but technologist activists are often the most effective at disrupting power through the use of technology and the Internet.

Of course, whilst the Internet is a threat to traditional centralised power structures, it also presents an unprecedented opportunity to leverage the skills, knowledge and efforts of an entire society in the running of government, for the benefit of all. Citizen engagement in democracy and government beyond the ballot box presents the ability to co-develop, or co-design the future of the society, including the services and rules that support stability and prosperity. Arguably, citizen buy-in and support is now an important part of the stability of a society and success of a policy.

Disrupting the status quo

The combination of improved capacity for self-determination by individuals along with the increasingly pervasive assumptions of equality and rights have led to many examples of traditional power structures being held to account, challenged, and in some cases, overthrown.

Governments are able to be held more strongly to account than ever before. The Open Australia Foundation is a small group of technologists in Australia who create tools to improve transparency and citizen engagement in the Australian democracy. They created Open Australia, a site that made the public parliamentary record more accessible to individuals through making it searchable, subscribable and easy to browse and comment on. They also have projects such as Planning Alerts which notifies citizens of planned development in their area, Election Leaflets where citizens upload political pamphlets for public record and accountability, and Right to Know, a site to assist the general public in pursuing information and public records from the government under Freedom of Information. These are all projects that monitor, engage and inform citizens about government.

Wikileaks is a website and organisation that provides an anonymous way for individuals to anonymously leak sensitive information, often classified government information. Key examples include video and documents from the Iraq and Afghanistan wars, about the Guantanamo Bay detention camp, United States diplomatic cables and million of emails from Syrian political and corporate figures. Some of the information revealed by Wikileaks has had quite dramatic consequences with the media and citizens around the world responding to the information. Arguably, many of the Arab Spring uprisings throughout the Middle East from December 2010 were provoked by the release of the US diplomatic cables by Wikileaks, as it demonstrated very clearly the level of corruption in many countries. The Internet also played a vital part in many of these uprisings, some of which saw governments deposed, as social media tools such as Twitter and Facebook provided the mechanism for massive coordination of protests, but importantly also provided a way to get citizen coverage of the protests and police/army brutality, creating global audience, commentary and pressure on the governments and support for the protesters.

Citizen journalism is an interesting challenge to governments because the route to communicate with the general public has traditionally been through the media. The media has presented for many years a reasonably predictable mechanism for governments to communicate an official statement and shape public narrative. But the Internet has facilitated any individual to publish online to a global audience, and this has resulted in a much more robust exchange of ideas and less clear cut public narrative about any particular issue, sometimes directly challenging official statements. A particularly interesting case of this was the Salam Pax blog during the 2003 Iraq invasion by the United States. Official news from the US would largely talk about the success of the campaign to overthrown Suddam Hussein. The Salam Pax blog provided the view of a 29 year old educated Iraqi architect living in Baghdad and experiencing the invasion as a citizen, which contrasted quite significantly at times with official US Government reports. This type of contrast will continue to be a challenge to governments.

On the flip side, the Internet has also provided new ways for governments themselves to support and engage citizens. There has been the growth of a global open government movement, where governments themselves try to improve transparency, public engagement and services delivery using the Internet. Open data is a good example of this, with governments going above and beyond traditional freedom of information obligations to proactively release raw data online for public scrutiny. Digital services allow citizens to interact with their government online rather than the inconvenience of having to physically attend a shopfront. Many governments around the world are making public commitments to improving the transparency, engagement and services for their citizens. We now also see more politicians and bureaucrats engaging directly with citizens online through the use of social media, blogs and sophisticated public consultations tools. Governments have become, in short, more engaged, more responsive and more accountable to more people than ever before.


Only in recent centuries have power structures emerged with a specific role for common individual citizens. The relationship between individuals and power structures has long been about the balance between what the power could enforce and what the population would accept. With the emergence of power structures that support and enshrine the principles of equality and human rights, individuals around the world have come to expect the capacity to determine their own future. The growth of and proliferation of democracy has been a key shift in how individuals relate to power and governance structures.

New technologies and the Internet has gone on to massively distribute the traditionally centralised powers of publishing, communications, monitoring and enforcement (with property on the way). This distribution of power through the means of technology has seen democracy evolve into something of a technocracy, a system which has effectively tipped the balance of power from institutions to individuals.


Hobbes, T. The Leviathan, ed. by R. Tuck, Cambridge University Press, 1991.

Aquinas, T. Sum. Theol. i-ii. 105. 1, trans. A. C. Pegis, Whether the old law enjoined fitting precepts concerning rulers?

Uzgalis, William, “John Locke”, The Stanford Encyclopedia of Philosophy (Fall 2012 Edition), Edward N. Zalta (ed.),

See additional useful references linked throughout essay.

Sridhar Dhanapalan: Twitter posts: 2015-03-02 to 2015-03-08

Mon, 2015-03-09 01:27

Simon Lyall: Static networking in Ansible the quick and dirty way

Sun, 2015-03-08 11:29

I’m in the process of setting up a server at home to replace an old one. I’m maintaining the new one via Ansible to try and get keep as tidy as possible. Part of the setup involves setting up a bridge interface so that I can run kvm virtual machines on the box.

In order to make the box a little more stable I decided to make the ethernet settings static rather than via DHCP. Unfortunately ansible doesn’t really have a nice standard way of setting up network ports (there are a few modules around but none in the main distribution).  After looking around I decided just to make a simple ansible role to handle the files.

The machine is running centos7. The networking initially looked like:

/etc/sysconfig/network-scripts/ifcfg-enp2s0 :::::::::::::: HWADDR=9C:B6:54:07:E8:49 TYPE=Ethernet BOOTPROTO=dhcp NAME=enp2s0 ONBOOT=yes #

I decided the easiest way was to just manually create and copy the files. So I created a static_networking role.

roles/static_networking/handlers/main.yml roles/static_networking/files/grey/ifcfg-enp2s0 roles/static_networking/files/grey/ifcfg-bridge0 roles/static_networking/tasks/main.yml roles/static_networking/tasks/setup-redhat.yml

Inside the tasks the main.yml just loads up the setup-redhat.yml which is:

--- - name: copy files if they are listed in var copy: src={{ ansible_hostname }}/ifcfg-{{ item }} dest=/etc/sysconfig/network-scripts/ owner=root mode=0644 with_items: static_interfaces notify: - restart network

Which is fairly simple. It just goes though a list of “static_interfaces” for a host and copies these files from the local machine to the machine I am setting up. If the copy makes any changes it sends a notify.

For the machine “grey” I just create some entries in hosts_vars/grey.yml

static_interfaces: - enp2s0 - bridge0

and then the files themselves:

roles/static_networking/files/grey/ifcfg-bridge0 :::::::::::::: DEVICE="bridge0" ONBOOT="yes" TYPE=Bridge BOOTPROTO=static IPADDR= NETMASK= GATEWAY= :::::::::::::: roles/static_networking/files/grey/ifcfg-enp2s0 :::::::::::::: DEVICE="enp2s0" ONBOOT="yes" NM_CONTROLLED="no" BOOTPROTO="none" BRIDGE=bridge0 HWADDR="9c:b6:54:07:e8:49"

which are the actual files to be copied. If any files are actually updated the handler will be triggered

roles/static_networking/handlers/main.yml --- # Called by "name" when network config files are changed - name: restart network service: name=network state=restarted

Overall it seems to work and I only broke networking once (the ip on enp2s0 keep getting re-added until I forced network manager to forget about it). I wouldn’t really recommend this sort of thing for non-trivial sites though. Keeping per-site configs in roles isn’t really the best way to do things.

Andrew Pollock: [tech] Honey, I wrote my first Chrome extension!

Sat, 2015-03-07 19:26

I love reading Linux Weekly News. It's a great source of high quality Linux and FOSS journalism, and I've been a subscriber for years.

One mild annoyance I have with the site is the way articles are cross-linked. All the article URIs are in the format /Article/531114/, which isn't particularly descriptive about that article's content.

When faced with an article that links to another article, with perhaps a word of anchor text, it's hard to tell if the new article is worth opening in a tab, is indeed already open in a tab, or has been previously read. (Yes, the "visited link" colour can help to a small degree, but even then, it doesn't tell you which previously read article it is).

This is what God the W3C invented the title attribute for.

Back in April 2011, I emailed Jonathan Corbet and asked if his content management system could just do this, but it was apparently a bit tricky, and it got filed in the "feature request" bucket.

I was sufficiently irritated by this deficiency last Monday, when doing some heavy reading on a topic, and so I decided to take matters into my own hands, and also learn how to write a Chrome Extension into the bargain.

I was delighted to have scratched the itch under 24 hours later and developed something that solved my particular problem - lwn4chrome I'm calling it.

I'm just finalising an icon for it, and then I'll have a stab at putting it in the Chrome Web Store as a freebie.

I might even have a crack at writing a Firefox extension as well for completeness, but I suspect the bulk of LWN's readership is using Chrome or Chromium.

Ian Wienand: Acurite 02032CAUDI Weather Station

Fri, 2015-03-06 10:26

I found an Acurite Weather Center 02032CAUDI at Costco for $99, which seemed like a pretty good deal.

It includes the "colour" display panel and a 5-in-1 remote sensor that includes temperature, wind-speed and direction, humidity and rain gauge.

The colour in the diplay is really just a fancy background sticker with the usual calculator-style liquid-crystal display in front. It does seem that for whatever reason the viewing angle is extremely limited; even off centre a little and it becomes very dim. It has an inbuilt backlight that is quite bright; it is either off or on (3-levels) or in "auto" mode, which dims it to the lowest level at certain hours. Hacking in a proximity sensor might be a fun project. The UI is OK; it shows indoor and outdoor temperature/humidity, wind-speed/rain and with is able to show you highs and lows with a bit of scrolling.

I was mostly interested in its USB output features. After a bit of fiddling I can confirm I've got it connected up to Meteobridge that is running on a Dlink DIR-505 and reporting to Weather Underground. One caveat is that you do need to plug the weather-station into a powered USB hub, rather than directly into the DIR-505; I believe because the DIR-505 can only talk directly to USB2.0 devices and not older 1.5 devices like the weather station. Another small issue is that the Meteobridge license is €65 which is not insignificant. Of course with some effort you can roll-your-own such as described in this series which is fun if you're looking for a project.

Luckily I had a mounting place that backed onto my small server cupboard, so I could easily run the cables through the wall to power and the DIR-505. Without this the cables might end up a bit of a mess. Combined with the fairly limited viewing angle afforded, finding somewhere practical to put the indoor unit might be one of the hardest problems.

Mounting the outdoor unit was fine, but mine is a little close to the roof-line so I'm not sure the wind-speed and direction are as accurate as if it were completely free-standing (I think official directions for wind-speed are something like free-standing 10m in the air). It needs to face north; both for the wind-direction and so the included solar-panel that draws air into the temp/humidity sensor is running as much as possible (it works without this, but it's more accurate with the fan). One thing is that it needs to mounted fairly level for the rain-gauge; it includes a small bubble-level on the top to confirm this. Firstly you'll probably find that most mount points you thought were straight actually aren't! Since the bubble is on the top, if you want to actually see it you need to be above it (obviously) which may not be possible if you're standing on a ladder and mounting it over your head. This may be a situation that inspires a very legitimate use of a selfie-stick.

It's a fun little device and fairly hackable for an overall reasonable price; I recommend.

Ian Wienand: On VMware and GPL

Fri, 2015-03-06 10:26

I do not believe any of the current reporting around the announced case has accurately described the issue; which I see as a much more subtle question of GPL use across API layers. Of course I don't know what the real issue is, because the case is sealed and I have no inside knowledge. I do have some knowledge of the vmkernel, however, and what I read does not match with what I know.

An overview of ESXi is shown below

There is no question that ESXi uses a lot of Linux kernel code and drivers. The question as I see it is more around the interface. The vmkernel provides a well-described API known as vmkapi. You can write drivers directly to this API; indeed some do. You can download a SDK.

A lot of Linux code has been extracted into vmkLinux; this is a shim between Linux drivers and the vmkapi interface. The intent here is to provide an environment where almost unmodified Linux drivers can interface to the proprietary vmkernel. This means vendors don't have to write two drivers, they can re-use their Linux ones. Of course, large parts of various Linux sub-systems' API are embedded in here. But the intent is that this code is modified to communicate to the vmkernel via the exposed vmkapi layer. It is conceivable that you could write a vmkWindows or vmkOpenBSD and essentially provide a shim-wrapper for drivers from other operating systems too.

vmkLinux and all the drivers are GPL, and released as such. I do not think there could be any argument there. But they interface to vmkapi which, as stated, is an available API but part of the proprietary kernel. So, as I see it, this is a much more subtle question than "did VMware copy-paste a bunch of Linux code into their kernel". It goes to where the GPL crosses API boundaries and what is considered a derived work.

If nothing else, this enforcement increasing clarity around that point would be good for everyone I think.

Binh Nguyen: Fried Fish with Butter Fried Potatoes Recipe

Thu, 2015-03-05 07:23
This is based on recipes online and an interpretation by a local restaurant that I used to frequent. While there are other alternative recipe that possibly taste better, I find that this is the quickest and easiest version.

- potatoes

- pre-made frozen, battered, fish

- sour cream

- tartare sauce

- salt

- butter

- bacon bits (optional)

- spring onion (optional)

Fry fish in pan. In meantime, chop potatoes into rough chunks and place into microwave until soft (to reduce cooking time. Boiling can take a long time). When fish cooked remove from heat. Place potatoes pieces into pan with a knob of butter to provide it with a crunchy 'crust'. Add bacon bits to same pan to add some 'crispness' as well. 

To serve, garnish fish with lemon juice and tartare sauce and serve potatoes and bacon bits with salt, chopped spring onion, and sour cream.

Would go really well with a salad to help you to cut through the fatty nature of the dish.