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Simon Lyall: Audiobooks – June 2018

Sun, 2018-07-01 09:03

Flash Boys by Michael Lewis

Well written story of how Wall Street firms didn’t even realize high-speed trading existed while they were losing hundreds of millions to traders practicing it, until a couple of guys told them. 8/10

Woodsman: Living in a Wood in the 21st Century by Ben Law

Write-ups about building his house and the area around it along with various descriptions of traditional crafts, his businesses, appearance on TV etc. Seems to balance well. 7/10

Mars Rover Curiosity: An Inside Account from Curiosity’s Chief Engineer by Rob Manning

Interesting stories about the project with the evolution on the landing method, experiments and project problems. A bit on the short side & published soon after landing. 6/10

The Adventures of Sherlock Holmes V by Sir Arthur Conan Doyle. Read by David Timson

The Adventure of the Reigate Squire, The Adventure of Beryl Coronet, The Boscombe Valley Mystery and The Yellow Face. All good stories, although ‘The Yellow Face’ has not aged well. 7/10

The Dark Forest by Cixin Liu

The 2nd book in the Three-Body Trilogy. A bit closer to the hard-core Sci Fi that I like although the author isn’t going for high accuracy. Feels real and kept my interest. 8/10

A History of Britain, Volume 1: At the Edge of the World? 3000 B. C. – A. D. 1603 by Simon Schama

Fairly straight history of Britain. An overview of everything so covers the main points rather than going into details. 7/10

Audacity: How Barack Obama Defied His Critics and Created a Legacy That Will Prevail by Jonathan Chait

A little overtaken by events (written before Trump elected). Highlights Obama’s wins that the author feels was overlooked. Okay but should have waited 10 years. 6/10

The Adventures of Sherlock Holmes VI by Sir Arthur Conan Doyle

Stories: The Adventure of the Final Problem, The Adventure of “Gloria Scott”, The Adventure of the Noble Bachelor, The Adventure of the Resident Patient. More read by Timson. Good as usual. 7/10

Amazing Stories of the Space Age: True Tales of Nazis in Orbit, Soldiers on the Moon, Orphaned Martian Robots, and Other Fascinating Accounts from the Annals of Spaceflight by Rod Pyle

A mix of the missions that never were & dramatic/odd missions 7/10

 

 

James Morris: Linux Security Summit North America 2018: Schedule Published

Wed, 2018-06-27 09:01

The schedule for the Linux Security Summit North America (LSS-NA) 2018 is now published.

Highlights include:

and much more!

LSS-NA 2018 will be co-located with the Open Source Summit, and held over 27th-28th August, in Vancouver, Canada.  The attendance fee is $100 USD.  Register here.

See you there!

OpenSTEM: QWERTY 150 years old

Sat, 2018-06-23 19:05
Did you realise that QWERTY and typewriters were from that long ago?  I certainly didn’t.  I did grow up in the late era of the typewriter (70s/80s), and I first learnt how to type on a mechanical typewriter.  It was a model with a dual-coloured ribbon (black/red) which I used to good effect for a variety […]

Steven Hanley: [mtb/events] UTA 100 2018, a result of yes fitness

Fri, 2018-06-22 23:00

Mt Solitary view at 60km (fullsize)
TLDR for the rest of this, I had an awesome day out, went under 12 hours (11:59:04), strava of the day is here enjoying the whole course once again with a 30 minute PB. (oh and for many years I have arbitrarily tried to claim I was not a runner, with my arbitrary switch been a sub 12 at UTA, guess I have to own up to being a runner now)

If however you want to read more, there is a bit more. My words and photos are online in my UTA 2018 gallery. A good day out testing some theories.

Linux Users of Victoria (LUV) Announce: LUV July 2018 Main Meeting: Google Home Mini and Makerbot

Fri, 2018-06-22 17:03
Start: Jul 3 2018 18:30 End: Jul 3 2018 20:30 Start: Jul 3 2018 18:30 End: Jul 3 2018 20:30 Location:  Kathleen Syme Library, 251 Faraday Street Carlton VIC 3053 Link:  http://www.melbourne.vic.gov.au/community/hubs-bookable-spaces/kathleen-syme-lib...

PLEASE NOTE NEW LOCATION

6:30 PM to 8:30 PM Tuesday, July 3, 2018
Training Room, Kathleen Syme Library, 251 Faraday Street Carlton VIC 3053

Speakers:

Many of us like to go for dinner nearby after the meeting, typically at Trotters Bistro in Lygon St.  Please let us know if you'd like to join us!

Linux Users of Victoria is a subcommittee of Linux Australia.

July 3, 2018 - 18:30

read more

Linux Users of Victoria (LUV) Announce: LUV July 2018 Workshop: Beginners guide to Docker

Fri, 2018-06-22 17:03
Start: Jul 21 2018 12:30 End: Jul 21 2018 16:30 Start: Jul 21 2018 12:30 End: Jul 21 2018 16:30 Location:  Infoxchange, 33 Elizabeth St. Richmond Link:  http://luv.asn.au/meetings/map

Docker is the currently the "kewl" way to both manage development environments and deploy applications at extreme scale.
However it has new terminology, and a different architecture compared to using virtual machines (the technology Docker is most frequently compared with), so it can be confusing at first.

The meeting will be held at Infoxchange, 33 Elizabeth St. Richmond 3121.  Late arrivals please call (0421) 775 358 for access to the venue.

LUV would like to acknowledge Infoxchange for the venue.

Linux Users of Victoria is a subcommittee of Linux Australia.

July 21, 2018 - 12:30

read more

Russell Coker: Cooperative Learning

Mon, 2018-06-18 23:02

This post is about my latest idea for learning about computers. I posted it to my local LUG mailing list and received no responses. But I still think it’s a great idea and that I just need to find the right way to launch it.

I think it would be good to try cooperative learning about Computer Science online. The idea is that everyone would join an IRC channel at a suitable time with virtual machine software configured and try out new FOSS software at the same time and exchange ideas about it via IRC. It would be fairly informal and people could come and go as they wish, the session would probably go for about 4 hours but if people want to go on longer then no-one would stop them.

I’ve got some under-utilised KVM servers that I could use to provide test VMs for network software, my original idea was to use those for members of my local LUG. But that doesn’t scale well. If a larger group people are to be involved they would have to run their own virtual machines, use physical hardware, or use trial accounts from VM companies.

The general idea would be for two broad categories of sessions, ones where an expert provides a training session (assigning tasks to students and providing suggestions when they get stuck) and ones where the coordinator has no particular expertise and everyone just learns together (like “let’s all download a random BSD Unix and see how it compares to Linux”).

As this would be IRC based there would be no impediment for people from other regions being involved apart from the fact that it might start at 1AM their time (IE 6PM in the east coast of Australia is 1AM on the west coast of the US). For most people the best times for such education would be evenings on week nights which greatly limits the geographic spread.

While the aims of this would mostly be things that relate to Linux, I would be happy to coordinate a session on ReactOS as well. I’m thinking of running training sessions on etbemon, DNS, Postfix, BTRFS, ZFS, and SE Linux.

I’m thinking of coordinating learning sessions about DragonflyBSD (particularly HAMMER2), ReactOS, Haiku, and Ceph. If people are interested in DragonflyBSD then we should do that one first as in a week or so I’ll probably have learned what I want to learn and moved on (but not become enough of an expert to run a training session).

One of the benefits of this idea is to help in motivation. If you are on your own playing with something new like a different Unix OS in a VM you will be tempted to take a break and watch YouTube or something when you get stuck. If there are a dozen other people also working on it then you will have help in solving problems and an incentive to keep at it while help is available.

So the issues to be discussed are:

  1. What communication method to use? IRC? What server?
  2. What time/date for the first session?
  3. What topic for the first session? DragonflyBSD?
  4. How do we announce recurring meetings? A mailing list?
  5. What else should we setup to facilitate training? A wiki for notes?

Finally while I list things I’m interested in learning and teaching this isn’t just about me. If this becomes successful then I expect that there will be some topics that don’t interest me and some sessions at times when I am have other things to do (like work). I’m sure people can have fun without me. If anyone has already established something like this then I’d be happy to join that instead of starting my own, my aim is not to run another hobbyist/professional group but to learn things and teach things.

There is a Wikipedia page about Cooperative Learning. While that’s interesting I don’t think it has much relevance on what I’m trying to do. The Wikipedia article has some good information on the benefits of cooperative education and situations where it doesn’t work well. My idea is to have a self-selecting people who choose it because of their own personal goals in terms of fun and learning. So it doesn’t have to work for everyone, just for enough people to have a good group.

Related posts:

  1. How to Start Learning Linux I was asked for advice on how to start learning...
  2. Open Source Learning Richard Baraniuk gave an interesting TED talk about Open Source...
  3. SecureCon Lecture On Thursday at Secure Con [1] I gave a lecture...

James Morris: Linux Security BoF at Open Source Summit Japan

Mon, 2018-06-18 19:01

This is a reminder for folks attending OSS Japan this week that I’ll be leading a  Linux Security BoF session  on Wednesday at 6pm.

If you’ve been working on a Linux security project, feel welcome to discuss it with the group.  We will have a whiteboard and projector.   This is also a good opportunity to raise topics for discussion, and to ask questions about Linux security.

See you then!

Michael Still: Rejected talk proposal: Design at scale: OpenStack versus Kubernetes

Sun, 2018-06-17 19:00

This proposal was submitted for pyconau 2018. It wasn’t accepted, but given I’d put the effort into writing up the proposal I’ll post it here in case its useful some other time. The oblique references to OpensStack are because pycon had an “anonymous” review system in 2018, and I was avoiding saying things which directly identified me as the author.

OpenStack and Kubernetes solve very similar problems. Yet they approach those problems in very different ways. What can we learn from the different approaches taken? The differences aren’t just technical though, there are some interesting social differences too.

OpenStack and Kubernetes solve very similar problems – at their most basic level they both want to place workloads on large clusters of machines, and ensure that those placement decisions are as close to optimal as possible. The two projects even have similar approaches to the fundamentals – they are both orchestration systems at their core, seeking to help existing technologies run at scale instead of inventing their own hypervisors or container run times.

Yet they have very different approaches to how to perform these tasks. OpenStack takes a heavily centralised and monolithic approach to orchestration, whilst Kubernetes has a less stateful and more laissez faire approach. Some of that is about early technical choices and the heritage of the projects, but some of it is also about hubris and a desire to tightly control. To be honest I lived the OpenStack experience so I feel I should be solidly in that camp, but the Kubernetes approach is clever and elegant. There’s a lot to like on the Kubernetes side of the fence.

Its increasingly common that at some point you’ll encounter one of these systems, as neither seems likely to go away in the next few years. Understanding some of the basics of their operation is therefore useful, as well as being interesting at a purely hypothetical level.

Michael Still: Accepted talk proposal: Learning from the mistakes that even big projects make

Sun, 2018-06-17 19:00

This proposal was submitted for pyconau 2018. It was accepted, but hasn’t been presented yet. The oblique references to OpensStack are because pycon had an “anonymous” review system in 2018, and I was avoiding saying things which directly identified me as the author.

Since 2011, I’ve worked on a large Open Source project in python. It kind of got out of hand – 1000s of developers and millions of lines of code. Yet despite being well resourced, we made the same mistakes that those tiny scripts you whip up to solve a small problem make. Come learn from our fail.

This talk will use the privilege separation daemon that the project wrote to tell the story of decisions that were expedient at the time, and how we regretted them later. In a universe in which you can only run commands as root via sudo, dd’ing from one file on the filesystem to another seems almost reasonable. Especially if you ignore that the filenames are defined by the user. Heck, we shell out to “mv” to move files around, even when we don’t need escalated permissions to move the file in question.

While we’ll focus mainly on the security apparatus because it is the gift that keeps on giving, we’ll bump into other examples along the way as well. For example how we had pluggable drivers, but you have to turn them on by passing in python module paths. So what happens when we change the interface the driver is required to implement and you have a third party driver? The answer isn’t good. Or how we refused to use existing Open Source code from other projects through a mixture of hubris and licensing religion.

On a strictly technical front, this is a talk about how to do user space privilege separation sensibly. Although we should probably discuss why we also chose in the last six months to not do it as safely as we could.

For a softer technical take, the talk will cover how doing things right was less well documented than doing things the wrong way. Code reviewers didn’t know the anti-patterns, which were common in the code base, so made weird assumptions about what was ok or not.

On a human front, this is about herding cats. Developers with external pressures from their various employers, skipping steps because it was expedient, and how throwing automation in front of developers because having a conversation as adults is hard. Ultimately we ended up being close to stalled before we were “saved” from an unexpected direction.

In the end I think we’re in a reasonable place now, so I certainly don’t intend to give a lecture about doom and gloom. Think of us more as a light hearted object lesson.

Donna Benjamin: The Five Whys

Sat, 2018-06-16 11:02
Saturday, June 16, 2018 - 09:16

Imagine you work in a hardware store. You notice a customer puzzling over the vast array of electric drills.

She turns to you and says, I need a drill, but I don’t know which one to pick.

You ask “So, why do you want a drill?

“To make a hole.” she replies, somewhat exasperated. “Isn’t that obvious?”

“Sure,” you might say, “But why do you want to drill a hole? It might help us decide which drill you need!” “

Oh, okay," and she goes on to describe the need to thread cable from one room, to another.

From there, we might want to know more about the walls, about the type and thickness of the cable, and perhaps about what the cable is for. But what if we keep asking why? What if the next question was something like this?

“Why do you want to pull the cable from one room to the other?”

Our customer then explains she wants to connect directly to the internet router in the other room. "Our wifi reception is terrible! This seemed the fastest, easiest way to fix that."

At this point, there may be other solutions to the bad wifi problem that don’t require a hole at all, let alone a drill.

Someone who needs a drill, rarely wants a drill, nor do they really want a hole.

It’s the utility of that hole that we’re trying to uncover with the 5 Whys.

Acknowledgement

I can't remember who first told me about this technique. I wish I could, it's been profoundly useful, and I evangelise it's simple power at every opportunity. Thank you who ever you are, I honour your generous wisdom by paying it forward today.

More about the Five whysImage credits

Creative Commons Icons all from the Noun Project

  • Drill by Andrejs Kirma
  • Mouse Hole by Sergey Demushkin
  • Cable by Amy Schwartz
  • Internet by Vectors Market
  • Wifi by Baboon designs
  • Not allowed by Adnen Kadri

Lev Lafayette: Being An Acrobat: Linux and PDFs

Sat, 2018-06-16 09:04

The PDF file format can be efficiently manipulated in Linux and other free software that may not be easy in proprietary operating systems or applications. This includes a review of various PDF readers for Linux, creation of PDFs from office documents using LibreOffice, editing PDF documents, converting PDF documents to images, extracting text from non-OCR PDF documents, converting to PostScript, converting restructuredText, Markdown, and other formats, searching PDFs according to regular expressions, converting to text, extracting images, separating and combining PDF documents, creating PDF presentations from text, creating fillable PDF forms, encrypting and decrypting PDF documents, and parsing PDF documents.

A presentation to Linux Users of Victoria, Saturday June 16, 2018

OpenSTEM: Assessment Time

Fri, 2018-06-15 15:05
For many of us, the colder weather has started to arrive and mid-year assessment is in full swing. Teachers are under the pump to produce mid-year reports and grades. The OpenSTEM® Understanding Our World® program aims to take the pressure off teachers by providing for continuous assessment throughout the term. Not only are teachers continually […]

Donna Benjamin: DrupalCon Nashville

Fri, 2018-06-15 11:02
Saturday, March 17, 2018 - 22:01

I'm going to Nashville!!

That is all. Carry on. Or... better yet - you should come too!

https://events.drupal.org/nashville2018

Donna Benjamin: Leadership, and teamwork.

Fri, 2018-06-15 11:02
Friday, April 13, 2018 - 04:09

I'm angry and defensive. I don't know why. So I'm trying hard to figure that out right now.

Here's some words.

I'm writing these words for myself to try and figure this out.
I'm hoping these words might help make it clear.
I'm fearful these words will make it worse.

But I don't want to be silent about this.

Content Warning: This post refers to genocide.

This is about a discussion at the teamwork and leadership workshop at DrupalCon. For perhaps 5 mins within a 90 minute session we talked about Hitler. It was an intensely thought provoking, and uncomfortable 5 minute conversation. It was nuanced. It wasn't really tweetable.

On Holocaust memorial day, it seems timely to explore whether or not we should talk about Hitler when exploring the nature of leadership. Not all leaders are good. Call them dictators, call them tyrants, call them fascists, call them evil. Leadership is defined differently by different cultures, at different times, and in different contexts.

Some people in the room were upset and disgusted that we had that conversation. I'm really very deeply sorry about that.

Some of them then talked about it with others afterwards, which is great. It was a confronting conversation, and one, frankly, we should all be having as genocide and fascism exist in very real ways in the very real world.

But some of those they spoke with, who weren't there, seem to have extrapolated from that conversation that it was something different to what I experienced in the room. I feel they formed opinions that I can only call, well, what words can I call those opinions? Uninformed? Misinformed? Out of context? Wrong? That's probably unfair, it's just my perspective. But from those opinions, they also made assumptions, and turned those assumptions into accusations.

One person said they were glad they weren't there, but clearly happy to criticise us from afar on twitter. I responded that I thought it was a shame they didn't come to the workshop, but did choose to publicly criticise our work. Others responded to that saying this was disgusting, offensive, unacceptable and inappropriate that we would even consider having this conversation. One accused me of trying to shut down the conversation.

So, I think perhaps the reason I'm feeling angry and defensive, is I'm being accused of something I don't think I did.

And I want to defend myself.

I've studied World War Two and the Genocide that took place under Hitler's direction.

My grandmother was arrested in the early 1930's and held in a concentration camp. She was, thankfully, released and fled Germany to Australia as a refugee before the war was declared. Her mother was murdered by Hitler. My grandfather's parents and sister were also murdered by Hitler.

So, I guess I feel like I've got a pretty strong understanding of who Hitler was, and what he did.

So when I have people telling me, that it's completely disgusting to even consider discussing Hitler in the context of examining what leadership is, and what it means? Fuck that. I will not desist. Hitler was a monster, and we must never forget what he was, or what he did.

During silent reflection on a number of images, I wrote this note.

"Hitler was a powerful leader. No question. So powerful, he destroyed the world."

When asked if they thought Hitler was a leader or not, most people in the room, including me, put up their hand. We were wrong.

The four people who put their hand up to say he was NOT a leader were right.

We had not collectively defined leadership at that point. We were in the middle of a process doing exactly that.

The definition we were eventually offered is that leaders must care for their followers, and must care for people generally.

At no point, did anyone in that room, consider the possibility that Hitler was a "Good Leader" which is the misinformed accusation I most categorically reject.

Our facilitator, Adam Goodman, told us we were all wrong, except the four who rejected Hitler as an example of a Leader, by saying, that no, he was not a leader, but yes, he was a dictator, yes he was a tyrant. But he was not a leader.

Whilst I agree, and was relieved by that reframing, I would also counter argue that it is English semantics.

Someone else also reminded us, that Hitler was elected. I too, was elected to the board of the Drupal Association, I was then appointed to one of the class Director seats. My final term ends later this year, and frankly, right now, I'm kind of wondering if I should leave right now.

Other people shown in the slide deck were Oprah Winfrey, Angela Merkel, Rosa Parks, Serena Williams, Marin Alsop, Sonia Sotomayor, a woman in military uniform, and a large group of women protesting in Tahrir Square in Egypt.

It also included Gandhi, and Mandela.

I observed that I felt sad I could think of no woman that I would list in the same breath as those two men.

So... for those of you who judged us, and this workshop, from what you saw on twitter, before having all the facts?
Let me tell you what I think this was about.

This wasn't about Hitler.

This was about leadership, and learning how we can be better leaders. I felt we were also exploring how we might better support the leaders we have, and nurture the ones to come. And I now also wonder how we might respectfully acknowledge the work and effort of those who've come and gone, and learn to better pass on what's important to those doing the work now.

We need teamwork. We need leadership. It takes collective effort, and most of all, it takes collective empathy and compassion.

Dries Buytaert was the final image in the deck.

Dries shared these 5 values and their underlying principles with us to further explore, discuss and develop together.

Prioritize impact
Impact gives us purpose. We build software that is easy, accessible and safe for everyone to use.

Better together
We foster a learning environment, prefer collaborative decision-making, encourage others to get involved and to help lead our community.

Strive for excellence
We constantly re-evaluate and assume that change is constant.

Treat each other with dignity and respect
We do not tolerate intolerance toward others. We seek first to understand, then to be understood. We give each other constructive criticism, and are relentlessly optimistic.

Enjoy what you do
Be sure to have fun.

I'm sorry to say this, but I'm really not having fun right now. But I am much clearer about why I'm feeling angry.

Photo Credit "Protesters against Egyptian President Mohamed Morsi celebrate in Tahrir Square in Cairo on July 3, 2013. Egypt's armed forces overthrew elected Islamist President Morsi on Wednesday and announced a political transition with the support of a wide range of political and religious leaders." Mohamed Abd El Ghany Reuters.

Donna Benjamin: Makarrata

Fri, 2018-06-15 11:02
Thursday, June 14, 2018 - 20:19

The time has come
To say fairs fair...

Dear members of the committee,

Please listen to the Uluru statement from the heart. Please hear those words. Please accept them, please act to adopt them.

Enshrine a voice for Australia’s first nation peoples in the Australian constitution.

Create a commission for Makarrata.

Invest in uncovering and telling the truth of our history.

We will be a stronger, wiser nation when we truly acknowledge the frontier wars and not only a stolen generation but stolen land, and stolen hope.

We have nothing to lose, and everything to gain through real heartfelt recognition and reconciliation.

Makarrata. Treaty. Sovereignty.

Please. I am Australian. I want this.

I felt sick shame when the prime minister rejected the Uluru statement. He did not, does not, speak for me.

Donna Benjamin
Melbourne, VIC.

Donna Benjamin: Makarrata

Thu, 2018-06-14 21:02
Thursday, June 14, 2018 - 20:19

The time has come
To say fairs fair...

Dear members of the committee,

Please listen to the Uluru statement from the heart. Please hear those words. Please accept them, please act to adopt them.

Enshrine a voice for Australia’s first nation peoples in the Australian constitution.

Create a commission for Makarrata.

Invest in uncovering and telling the truth of our history.

We will be a stronger, wiser nation when we truly acknowledge the frontier wars and not only a stolen generation but stolen land, and stolen hope.

We have nothing to lose, and everything to gain through real heartfelt recognition and reconciliation.

Makarrata. Treaty. Sovereignty.

Please. I am Australian. I want this.

I felt sick shame when the prime minister rejected the Uluru statement. He did not, does not, speak for me.

Donna Benjamin
Melbourne, VIC.

Julien Goodwin: Custom uBlox GPSDO board

Tue, 2018-06-12 23:03
For the next part of my ongoing project I needed to test the GPS reciever I'm using, a uBlox LEA-M8F (M8 series chip, LEA form factor, and with frequency outputs). Since the native 30.72MHz oscillator is useless for me I'm using an external TCVCXO (temperature compensated, voltage controlled oscillator) for now, with the DAC & reference needed to discipline the oscillator based on GPS. If uBlox would sell me the frequency version of the chip on its own that would be ideal, but they don't sell to small customers.

Here's a (rather modified) board sitting on top of an Efratom FRK rubidium standard that I'm going to mount to make a (temporary) home standard (that deserves a post of its own). To give a sense of scale the silver connector at the top of the board is a micro-USB socket.



Although a very simple board I had a mess of problems once again, both in construction and in component selection.

Unlike the PoE board from the previous post I didn't have this board manufactured. This was for two main reasons, first, the uBlox module isn't available from Digikey, so I'd still need to mount it by hand. The second, to fit all the components this board has a much greater area, and since the assembly house I use charges by board area (regardless of the number or density of components) this would have cost several hundred dollars. In the end, this might actually have been the sensible way to go.

By chance I'd picked up a new soldering iron at the same time these boards arrived, a Hakko FX-951 knock-off and gave it a try. Whilst probably an improvement over my old Hakko FX-888 it's not a great iron, especially with the knife tip it came with, and certainly nowhere near as nice to use as the JBC CD-B (I think that's the model) we have in the office lab. It is good enough that I'm probably going to buy a genuine Hakko FM-203 with an FM-2032 precision tool for the second port.

The big problem I had hand-soldering the boards was bridges on several of the components. Not just the tiny (0.65mm pitch, actually the *second largest* of eight packages for that chip) SC70 footprint of the PPS buffer, but also the much more generous 1.1mm pitch of the uBlox module. Luckily solder wick fixed most cases, plus one where I pulled the buffer and soldered a new one more carefully.

With components, once again I made several errors:
  • I ended up buying the wrong USB connectors for the footprint I chose (the same thing happened with the first run of USB-C modules I did in 2016), and while I could bodge them into use easily enough there wasn't enough mechanical retention so I ended up ripping one connector off the board. I ordered some correct ones, but because I wasn't able to wick all solder off the pads they don't attach as strongly as they should, and whilst less fragile, are hardly what I'd call solid.
  • The surface mount GPS antenna (Taoglas AP.10H.01 visible in this tweet) I used was 11dB higher gain than the antenna I'd tested with the devkit, I never managed to get it to lock while connected to the board, although once on a cable it did work ok. To allow easier testing, in the end I removed the antenna and bodged on an SMA connector for easy testing.
  • When selecting the buffer I accidentally chose one with an open-drain output, I'd meant to use one with a push-pull output. This took quite a silly long time for me to realise what mistake I'd made. Compounding this, the buffer is on the 1PPS line, which only strobes while locked to GPS, however my apartment is a concrete box, with what GPS signal I can get inside only available in my bedroom, and my oscilloscope is in my lab, so I couldn't demonstrate the issue live, and had to inject test signals. Luckily a push-pull is available in the same footprint, and a quick hot-air aided swap later (once parts arrived from Digikey) it was fixed.

Lessons learnt:
  • Yes I can solder down to ~0.5mm pitch, but not reliably.
  • More test points on dev boards, particularly all voltage rails, and notable signals not otherwise exposed.
  • Flux is magic, you probably aren't using enough.

Although I've confirmed all basic functions of the board work, including GPS locking, PPS (quick video of the PPS signal LED), and frequency output, I've still not yet tested the native serial ports and frequency stability from the oscillator. Living in an urban canyon makes such testing a pain.

Eventually I might also test moving the oscillator, DAC & reference into a mini oven to see if a custom OCXO would be any better, if small & well insulated enough the power cost of an oven shouldn't be a problem.

Also as you'll see if you look at the tweets, I really should have posted this almost a month ago, however I finished fixing the board just before heading off to California for a work trip, and whilst I meant to write this post during the trip, it's not until I've been back for more than a week that I've gotten to it. I find it extremely easy to let myself be distracted from side projects, particularly since I'm in a busy period at $ORK at the moment.

Francois Marier: Mysterious 'everybody is busy/congested at this time' error in Asterisk

Mon, 2018-06-11 12:01

I was trying to figure out why I was getting a BUSY signal from Asterisk while trying to ring a SIP phone even though that phone was not in use.

My asterisk setup looks like this:

phone 1 <--SIP--> asterisk 1 <==IAX2==> asterisk 2 <--SIP--> phone 2

While I couldn't call SIP phone #2 from SIP phone #1, the reverse was working fine (ringing #1 from #2). So it's not a network/firewall problem. The two SIP phones can talk to one another through their respective Asterisk servers.

This is the error message I could see on the second asterisk server:

$ asterisk -r ... == Using SIP RTP TOS bits 184 == Using SIP RTP CoS mark 5 -- Called SIP/12345 -- SIP/12345-00000002 redirecting info has changed, passing it to IAX2/iaxuser-6347 -- SIP/12345-00000002 is busy == Everyone is busy/congested at this time (1:1/0/0) -- Executing [12345@local:2] Goto("IAX2/iaxuser-6347", "in12345-BUSY,1") in new stack -- Goto (local,in12345-BUSY,1) -- Executing [in12345-BUSY@local:1] Hangup("IAX2/iaxuser-6347", "17") in new stack == Spawn extension (local, in12345-BUSY, 1) exited non-zero on 'IAX2/iaxuser-6347' -- Hungup 'IAX2/iaxuser-6347'

where:

  • 12345 is the extension of SIP phone #2 on Asterisk server #2
  • iaxuser is the user account on server #2 that server #1 uses
  • local is the context that for incoming IAX calls on server #1

This Everyone is busy/congested at this time (1:1/0/0) was surprising since looking at each SIP channel on that server showed nobody as busy:

asterisk2*CLI> sip show inuse * Peer name In use Limit 12345 0/0/0 2

So I enabled the raw SIP debug output and got the following (edited for clarity):

asterisk2*CLI> sip set debug on SIP Debugging enabled == Using SIP RTP TOS bits 184 == Using SIP RTP CoS mark 5 INVITE sip:12345@192.168.0.4:2048;line=m2vlbuoc SIP/2.0 Via: SIP/2.0/UDP 192.168.0.2:5060 From: "Francois Marier" <sip:67890@192.168.0.2> To: <sip:12345@192.168.0.4:2048;line=m2vlbuoc> CSeq: 102 INVITE User-Agent: Asterisk PBX Contact: <sip:67890@192.168.0.2:5060> Content-Length: 274 -- Called SIP/12345 <--- SIP read from UDP:192.168.0.4:2048 ---> SIP/2.0 100 Trying Via: SIP/2.0/UDP 192.168.0.2:5060 From: "Francois Marier" <sip:67890@192.168.0.2> To: <sip:12345@192.168.0.4:2048;line=m2vlbuoc> CSeq: 102 INVITE User-Agent: snom300 Contact: <sip:12345@192.168.0.4:2048;line=m2vlbuoc> Content-Length: 0 <-------------> --- (9 headers 0 lines) --- <--- SIP read from UDP:192.168.0.4:2048 ---> SIP/2.0 480 Do Not Disturb Via: SIP/2.0/UDP 192.168.0.2:5060 From: "Francois Marier" <sip:67890@192.168.0.2> To: <sip:12345@192.168.0.4:2048;line=m2vlbuoc> CSeq: 102 INVITE User-Agent: snom300 Contact: <sip:12345@192.168.0.4:2048;line=m2vlbuoc> Content-Length: 0

where:

  • 12345 is the extension of SIP phone #2 on Asterisk server #2
  • 67890 is the extension of SIP phone #1 on Asterisk server #2
  • 192.168.0.4 is the IP address of SIP phone #2
  • 192.168.0.1 is the IP address of Asterisk server #2

From there, I can see that SIP phone #2 is returning a status of 408 Do Not Disturb. That's what the problem was: the phone itself was in DnD mode and set to reject all incoming calls.

Chris Samuel: Submission to Joint Select Committee on Constitutional Recognition Relating to Aboriginal and Torres Strait Islander Peoples

Sun, 2018-06-10 23:01

Tonight I took some time to send a submission in to the Joint Select Committee on Constitutional Recognition Relating to Aboriginal and Torres Strait Islander Peoples in support of the Uluru Statement from the Heart from the 2017 First Nations National Constitutional Convention held at Uluru. Submissions close June 11th so I wanted to get this in as I feel very strongly about this issue.

Here’s what I wrote:

To the Joint Select Committee on Constitutional Recognition Relating to Aboriginal and Torres Strait Islander Peoples,

The first peoples of Australia have lived as part of this continent for many times longer than the ancestors of James Cook lived in the UK(*), let alone this brief period of European colonisation called Australia.

They have farmed, shaped and cared for this land over the millennia, they have seen the climate change, the shorelines move and species evolve.

Yet after all this deep time as custodians of this land they were dispossessed via the convenient lie of Terra Nullius and through killing, forced relocation and introduced sickness had their links to this land severely beaten, though not fatally broken.

Yet we still have the chance to try and make a bridge and a new relationship with these first peoples; they have offered us the opportunity for a Makarrata and I ask you to grasp this opportunity with both hands, for the sake of all Australians.

Several of the component states and territories of this recent nation of Australia are starting to investigate treaties with their first peoples, but this must also happen at the federal level as well.

Please take the Uluru Statement from the Heart to your own hearts, accept the offering of Makarrata & a commission and let us all move forward together.

Thank you for your attention.

Your sincerely,
Christopher Samuel

(*) Australia has been continuously occupied for at least 50,000 years, almost certainly for at least 60,000 years and likely longer. The UK has only been continuously occupied for around the last 10,000 years after the last Ice Age drove its previous population out into warmer parts of what is now Europe.

Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC

This item originally posted here:

Submission to Joint Select Committee on Constitutional Recognition Relating to Aboriginal and Torres Strait Islander Peoples