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Robert Collins: Test processes as servers

Planet Linux Australia - Fri 29th Aug 2014 14:08

Since its very early days subunit has had a single model – you run a process, it outputs test results. This works great, except when it doesn’t.

On the up side, you have a one way pipeline – there’s no interactivity needed, which makes it very very easy to write a subunit backend that e.g. testr can use.

On the downside, there’s no interactivity, which means that anytime you want to do something with those tests, a new process is needed – and thats sometimes quite expensive – particularly in test suites with 10’s of thousands of tests.Now, for use in the development edit-execute loop, this is arguably ok, because one needs to load the new tests into memory anyway; but wouldn’t it be nice if tools like testr that run tests for you didn’t have to decide upfront exactly how they were going to run. If instead they could get things running straight away and then give progressively larger and larger units of work to be run, without forcing a new process (and thus new discovery directory walking and importing) ? Secondly, testr has an inconsistent interface – if testr is letting a user debug things to testr through to child workers in a chain, it needs to use something structured (e.g. subunit) and route stdin to the actual worker, but the final testr needs to unwrap everything – this is needlessly complex. Lastly, for some languages at least, its possibly to dynamically pick up new code at runtime – so a simple inotify loop and we could avoid new-process (and more importantly complete-enumeration) *entirely*, leading to very fast edit-test cycles.

So, in this blog post I’m really running this idea up the flagpole, and trying to sketch out the interface – and hopefully get feedback on it.

Taking as an example process to do this to:

  1. There should be an option to change from one-shot to server mode
  2. In server mode, it will listen for commands somewhere (lets say stdin)
  3. On startup it might eager load the available tests
  4. One command would be list-tests – which would enumerate all the tests to its output channel (which is stdout today – so lets stay with that for now)
  5. Another would be run-tests, which would take a set of test ids, and then filter-and-run just those ids from the available tests, output, as it does today, going to stdout. Passing somewhat large sets of test ids in may be desirable, because some test runners perform fixture optimisations (e.g. bringing up DB servers or web servers) and test-at-a-time is pretty much worst case for that sort of environment.
  6. Another would be be std-in a command providing a packet of stdin – used for interacting with debuggers

So that seems pretty approachable to me – we don’t even need an async loop in there, as long as we’re willing to patch select etc (for the stdin handling in some environments like Twisted). If we don’t want to monkey patch like that, we’ll need to make stdin a socketpair, and have an event loop running to shepard bytes from the real stdin to the one we let the rest of Python have.

What about that nirvana above? If we assume inotify support, then list_tests (and run_tests) can just consult a changed-file list and reload those modules before continuing. Reloading them just-in-time would be likely to create havoc – I think reloading only when synchronised with test completion makes a great deal of sense.

Would such a test server make sense in other languages?  What about e.g. vs – such a server wouldn’t want to use subunit, but perhaps a regular CLI UI would be nice…

Categories: thinktime

This week's sponsor: LessAccounting

a list apart - Fri 29th Aug 2014 05:08

Thanks to our sponsor, LessAccounting. You deserve simple bookkeeping to help you avoid the stresses of accounting.

Categories: thinktime

Announcing a fall internship

Seth Godin - Fri 29th Aug 2014 02:08
I'm hiring one or two paid interns. It's a great opportunity to learn, to experiment and to get some hands on experience. Find all the details right here. If you know someone who might be interested, I'd appreciate it if...         Seth Godin
Categories: thinktime

Glen Turner: Raspberry Pi versus Cray X-MP supercomputer

Planet Linux Australia - Thu 28th Aug 2014 23:08

It's often said that today we have in the phone in our pocket computers more powerful than the supercomputers of the past. Let's see if that is true.

The Raspberry Pi contains a Broadcom BCM2835 system on chip. The CPU within that system is a single ARM6 clocked at 700MHz. Located under the system on chip is 512MB of RAM -- this arrangement is called "package-on-package". As well as the RPi the BCM2835 SoC was also used in some phones, these days they are the cheapest of smartphones.

The Whetstone benchmark was widely used in the 1980s to measure the performance of supercomputers. It gives a result in millions of floating point operations per second. Running Whetstone on the Raspberry Pi gives 380 MFLOPS. See Appendix 1 for the details.

Let's see what supercomputer comes closest to 380 MFLOPS. That would be the Cray X-MP/EA/164 supercomputer from 1988. That is a classic supercomputer: the X-MP was a 1982 revision of the 1975 Cray 1. So good was the revision work by Steve Chen that it's performance rivalled the company's own later Cray 2. The Cray X-MP was the workhorse supercomputer for most of the 1980s, the EA series was the last version of the X-MP and its major feature was to allow a selectable word size -- either 24-bit or 32-bit -- which allowed the X-MP to run programs designed for the Cray 1 (24-bit), Cray X-MP (24-bit) or Cray Y-MP (32-bit).

Let's do some comparisons of the shipped hardware.


Basic specifications. Raspberry Pi versus Cray X-MP/EA/164 Item Cray X-MP/EA/164 Raspberry Pi Model B+ Price US$8m (1988) A$38 Price, adjusted for inflation US$16m A$38 Number of CPUs 1 1 Word size 24 or 32 32 RAM 64MB 512MB Cooling Air cooled, heatsinks, fans Air cooled, no heatsink, no fan


Neither unit comes with a power supply. The Cray does come with housing, famously including a free bench seat. The RPi requires third-party housing, typically for A$10; bench seats are not available as an option.

The Cray had the option of solid-state storage. A Secure Digital card is needed to contain the RPi's boot image and, usually, its operating system and data.


I/O systems. Raspberry Pi versus Cray X-MP/EA/164 Item Cray Raspberry Pi SSD size 512MB Third party, minimum of 4096MB Price US$6m (1988) A$20 Price, adjusted for inflation US$12m A$20


Of course the Cray X-MP also had rotating disk. Each disk unit could contain 1.2GB and had a peak transfer rate of 10MBps. This was achieved by using a large number of platters to compensate for the low density of the recorded data, giving the typical "top loading washing machine" look of disks of that era. The disk was attached to a I/O channel. The channel could connect many disks, collectively called a "string" of disks. The Cray X-MP had two to four I/O channels, each capable of 13MBps.

In comparison the Raspberry Pi's SDHC connector attaches one SDHC card at a speed of 25MBps. The performance of the SD cards themselves varies hugely, ranging from 2MBps to 30MBps.


What is clear from the number is that the floating point performance of the Cray X-MP/EA has fared better with the passage of time than the other aspects of the system. That's because floating point performance was the major design goal of that era of supercomputers. Ignoring the floating point performance, the Raspberry Pi handily beats out every computer in the Cray X-MP range.

Would Cray have been surprised by these results? I doubt it. Seymour Cray left CDC when they decided to build a larger supercomputer. He viewed this as showing CDC as not "getting it": larger computers have longer wires, more electronics to drive the wires, more heat from the electronics, more design issues such as crosstalk and more latency. Cray's main design insight was that computers needed to be as small as possible. There's not much smaller you can make a computer than a system-on-chip.

So why aren't today's supercomputers systems-on-chip? The answer has two parts. Firstly, the chip would be too small to remove the heat from. This is why "chip packaging" has moved to near the centre of chip design. Secondly, chip design, verification, and tooling (called "tape out") is astonishingly expensive for advanced chips. It's simply not affordable. You can afford a small variation on a proven design, but that is about the extent of the financial risk which designers care to take. A failed tape out was one of the causes of the downfall of the network processor design of Procket Networks.

Appendix 1. Whetstone benchmark

The whets.c benchmark was downloaded from Roy Longbottom's PC Benchmark Collection.

Compiling this for the RPi is simple enough. Since benchmark geeks care about the details, here they are.

$ diff -d -U 0 whets.c.orig whets.c @@ -886 +886 @@ -#ifdef UNIX +#ifdef linux $ gcc --version | head -1 gcc (Debian 4.6.3-14+rpi1) 4.6.3 $ gcc -O3 -lm -s -o whets whets.c

Here's the run. This is using a Raspbian updated to 2014-08-23 on a Raspberry Pi Model B+ with the "turbo" overclocking to 1000MHz (this runs the RPi between 700MHz and 1000MHz depending upon demand and the SoC temperature). The Model B+ has 512MB of RAM. The machine was in multiuser text mode. There was no swap used before and after the run.

$ uname -a Linux raspberry 3.12.22+ #691 PREEMPT Wed Jun 18 18:29:58 BST 2014 armv6l GNU/Linux $ cat /etc/debian_version 7.6 $ ./whets ########################################## Single Precision C/C++ Whetstone Benchmark Calibrate 0.04 Seconds 1 Passes (x 100) 0.19 Seconds 5 Passes (x 100) 0.74 Seconds 25 Passes (x 100) 3.25 Seconds 125 Passes (x 100) Use 3849 passes (x 100) Single Precision C/C++ Whetstone Benchmark Loop content Result MFLOPS MOPS Seconds N1 floating point -1.12475013732910156 138.651 0.533 N2 floating point -1.12274742126464844 143.298 3.610 N3 if then else 1.00000000000000000 971.638 0.410 N4 fixed point 12.00000000000000000 0.000 0.000 N5 sin,cos etc. 0.49911010265350342 7.876 40.660 N6 floating point 0.99999982118606567 122.487 16.950 N7 assignments 3.00000000000000000 592.747 1.200 N8 exp,sqrt etc. 0.75110864639282227 3.869 37.010 MWIPS 383.470 100.373

It is worthwhile making the point that this took maybe ten minutes. Cray Research had multiple staff working on making benchmark numbers such as Whetstone as high as possible.

Categories: thinktime

Rachel Andrew on the Business of Web Dev: Getting to the Action

a list apart - Thu 28th Aug 2014 22:08

Freelancers and self-employed business owners can choose from a huge number of conferences to attend in any given year. There are hundreds of industry podcasts, a constant stream of published books, and a never-ending supply of sites all giving advice. It is very easy to spend a lot of valuable time and money just attending, watching, reading, listening and hoping that somehow all of this good advice will take root and make our business a success.

However, all the good advice in the world won’t help you if you don’t act on it. While you might leave that expensive conference feeling great, did your attendance create a lasting change to your business? I was thinking about this subject while listening to episode 14 of the Working Out podcast, hosted by Ashley Baxter and Paddy Donnelly. They were talking about following through, and how it is possible to “nod along” to good advice but never do anything with it.

If you have ever been sent to a conference by an employer, you may have been expected to report back. You might even have been asked to present to your team on the takeaway points from the event. As freelancers and business owners, we don’t have anyone making us consolidate our thoughts in that way. It turns out that the way I work gives me a fairly good method of knowing which things are bringing me value.

Tracking actionable advice

I’m a fan of the Getting Things Done technique, and live by my to-do lists. I maintain a Someday/Maybe list in OmniFocus into which I add items that I want to do or at least investigate, but that aren’t a project yet.

If a podcast is worth keeping on my playlist, there will be items entered linking back to certain episodes. Conference takeaways might be a link to a site with information that I want to read. It might be an idea for an article to write, or instructions on something very practical such as setting up an analytics dashboard to better understand some data. The first indicator of a valuable conference is how many items I add during or just after the event.

Having a big list of things to do is all well and good, but it’s only one half of the story. The real value comes when I do the things on that list, and can see whether they were useful to my business. Once again, my GTD lists can be mined for that information.

When tickets go on sale for that conference again, do I have most of those to-do items still sat in Someday/Maybe? Is that because, while they sounded like good ideas, they weren’t all that relevant? Or, have I written a number of blog posts or had several articles published on themes that I started considering off the back of that conference? Did I create that dashboard, and find it useful every day? Did that speaker I was introduced to go on to become a friend or mentor, or someone I’ve exchanged emails with to clarify a topic I’ve been thinking about?

By looking back over my lists and completed items, I can start to make decisions about the real value to my business and life of the things I attend, read, and listen to. I’m able to justify the ticket price, time, and travel costs by making that assessment. I can feel confident that I’m not spending time and money just to feel as if I’m moving forward, yet gaining nothing tangible to show for it.

A final thought on value

As entrepreneurs, we have to make sure we are spending our time and money on things that will give us the best return. All that said, it is important to make time in our schedules for those things that we just enjoy, and in particular those things that do motivate and inspire us. I don’t think that every book you read or event you attend needs to result in a to-do list of actionable items.

What we need as business owners, and as people, is balance. We need to be able to see that the things we are doing are moving our businesses forward, while also making time to be inspired and refreshed to get that actionable work done.

Categories: thinktime

Ben Martin: Terry is getting In-Terry-gence.

Planet Linux Australia - Thu 28th Aug 2014 22:08
I had hoped to use a quad core ARM machine running ROS to spruce up Terry the robot. Performing tasks like robotic pick and place, controlling Tiny Tim and autonomous "docking". Unfortunately I found that trying to use a Kinect from an ARM based Linux machine can make for some interesting times. So I thought I'd dig at the ultra low end Intel chipset "SBC". The below is a J1900 Atom machine which can have up to 8Gb of RAM and sports the features that one expects from a contemporary desktop machine, Gb net, USB3, SATA3, and even a PCI-e expansion.

A big draw to this is the "DC" version, which takes a normal laptop style power connector instead of the much larger ATX connectors. This makes it much simpler to hookup to a battery pack for mobile use. The board runs nicely from a laptop extension battery, even if the on button is a but funky looking. On the left is a nice battery pack which is running the whole PC.

An interesting feature of this motherboard is no LED at all. I had sort of gotten used to Intel boards having blinks and power LEDs and the like.

There should be enough CPU grunt to handle the Kinect and start looking at doing DSLAM and thus autonomous navigation.

Categories: thinktime

Andrew Pollock: [life] Day 211: A trip to the museum with Megan and a swim assessment

Planet Linux Australia - Thu 28th Aug 2014 21:08

Today was a nice full day. It was go go go from the moment my feet hit the floor, though

I had a magnificent 9 hours of uninterrupted sleep courtesy of a sleeping pill, some pseudoephedrine and a decongestant spray.

I started off with a great yoga class, and then headed over to Sarah's to pick up Zoe. The traffic was phenomenally bad on the way there, and I got there quite late, so I offered to drop Sarah at work on the way back to my place, since I had no particular schedule.

After I'd dropped Sarah off, I was pondering what to do today, as the weather looked a bit dubious. I asked Zoe if she wanted to go to the museum. She was keen for that, and asked if Megan could come too, so I called up Jason on the way home to see she wanted to come with us, and directly picked her up on the way home.

We briefly stopped at home to grab my Dad Bag and some snacks, and headed to the bus stop. We managed to walk (well, make a run for) straight onto the bus and headed into the museum.

The Museum and the Sciencecentre are synonymous to Zoe, despite the latter requiring admission (we've got an annual membership). In trying to use my membership to get a discounted Sciencecentre ticket for Megan, I managed to score a free family pass instead, which I was pretty happy about.

We got into the Sciencecentre, which was pretty busy with a school excursion, and girls started checking it out. The problem was they both wanted to call the shots on what they did and didn't like not getting their way. Once I instituted some turn-taking, everything went much more smoothly, and they had a great time.

We had some lunch in the cafe and then spent some more time in the museum itself before heading for the bus. We narrowly missed the bus 30 minutes earlier than I was aiming for, so I asked the girls if they wanted to take the CityCat instead. Megan was very keen for that, so we walked over to Southbank and caught the CityCat instead.

I was half expecting Zoe to want to be carried back from the CityCat stop, but she was good with walking back. Again, some turn taking as to who was the "leader" walking back helped keep the peace.

I had to get over to Chandler for Zoe's new potential swim school to assess her for level placement, so I dropped Megan off on the way, and we got to the pool just in time.

Zoe did me very proud and did a fantastic job of swimming, and was placed in the second-highest level of their learn to swim program. We also ran into her friend from Kindergarten, Vaeda, who was killing time while her brother had a swim class. So Zoe and Vaeda ended up splashing around in the splash pool for a while after her assessment.

Once I'd managed to extract Zoe from the splash pool, and got her changed, we headed straight back to Sarah's place to drop her off. So we pretty much spent the entire day out of the house. Zoe and Megan had a good day together, and I managed to figure out pretty quickly how to keep the peace.

Categories: thinktime

The end of everyone

Seth Godin - Thu 28th Aug 2014 19:08
I'm not sure if it was ever possible to say, "everyone loves ___," "everyone respects ___" or even, "everyone really doesn't like ___", but there's no doubt at all that this isn't true any more. There is no more everyone....         Seth Godin
Categories: thinktime

Richard Jones: When testing goes bad

Planet Linux Australia - Thu 28th Aug 2014 18:08

I've recently started working on a large, mature code base (some 65,000 lines of Python code). It has 1048 unit tests implemented in the standard unittest.TestCase fashion using the mox framework for mocking support (I'm not surprised you've not heard of it).

Recently I fixed a bug which was causing a user interface panel to display when it shouldn't have been. The fix basically amounts to a couple of lines of code added to the panel in question:

+ def can_access(self, context): + # extend basic permission-based check with a check to see whether + # the Aggregates extension is even enabled in nova + if not nova.extension_supported('Aggregates', context['request']): + return False + return super(Aggregates, self).can_access(context)

When I ran the unit test suite I discovered to my horror that 498 of the 1048 tests now failed. The reason for this is that the can_access() method here is called as a side-effect of those 498 tests and the nova.extension_supported (which is a REST call under the hood) needed to be mocked correctly to support it being called.

I quickly discovered that given the size of the test suite, and the testing tools used, each of those 498 tests must be fixed by hand, one at a time (if I'm lucky, some of them can be knocked off two at a time).

The main cause is mox's mocking of callables like the one above which enforces the order that those callables are invoked. It also enforces that the calls are made at all (uncalled mocks are treated as test failures).

This means there is no possibility to provide a blanket mock for the "nova.extension_supported". Tests with existing calls to that API need careful attention to ensure the ordering is correct. Tests which don't result in the side- effect call to the above method will raise an error, so even adding a mock setup in a TestCase.setUp() doesn't work in most cases.

It doesn't help that the codebase is so large, and has been developed by so many people over years. Mocking isn't consistently implemented; even the basic structure of tests in TestCases is inconsistent.

It's worth noting that the ordering check that mox provides is never used as far as I can tell in this codebase. I haven't sighted an example of multiple calls to the same mocked API without the additional use of the mox InAnyOrder() modifier. mox does not provide a mechanism to turn the ordering check off completely.

The pretend library (my go-to for stubbing) splits out the mocking step and the verification of calls so the ordering will only be enforced if you deem it absolutely necessary.

The choice to use unittest-style TestCase classes makes managing fixtures much more difficult (it becomes a nightmare of classes and mixins and setUp() super() calls or alternatively a nightmare of mixing classes and multiple explicit setup calls in test bodies). This is exacerbated by the test suite in question introducing its own mock-generating decorator which will generate a mock, but again leaves the implementation of the mocking to the test cases. py.test's fixtures are a far superior mechanism for managing mocking fixtures, allowing far simpler centralisation of the mocks and overriding of them through fixture dependencies.

The result is that I spent some time working through some of the test suite and discovered that in an afternoon I could fix about 10% of the failing tests. I have decided that spending a week fixing the tests for my 5 line bug fix is just not worth it, and I've withdrawn the patch.

Categories: thinktime

"I made it my mission..."

Seth Godin - Wed 27th Aug 2014 19:08
These are the people you want to hire, the people who will become linchpins, the people who will change your organization for the better. Not people who merely accept a mission, or grudgingly grind through a mission, but people who...         Seth Godin
Categories: thinktime

Andrew Pollock: [life] Day 210: Running and a picnic, with a play date and some rain

Planet Linux Australia - Wed 27th Aug 2014 18:08

I had a rotten night's sleep last night. Zoe woke up briefly around midnight wanting a cuddle, and then I woke up again at around 3am and couldn't get back to sleep. I surprised I'm not more trashed, really.

It was a nice day today, so I made a picnic lunch, and we headed out to Minnippi Parklands to do a run with Zoe in the jogging stroller. It was around 10am by the time we arrived, and I had grand plans of running 10 km. I ran out of steam after about 3.5 km, conveniently at the "Rocket Park" at Carindale, which Zoe's been to a few times before.

So we stopped there for a bit of a breather, and then I ran back again for another 3 km or so, in a slightly different route, before I again ran out of puff, and walked the rest of the way back.

We then proceeded to have our picnic lunch and a bit of a play, before I dropped her off at Megan's house for a play while I chaired the PAG meeting at Kindergarten.

After that, and extracting Zoe, which is never a quick task, we headed home to get ready for swim class. It started to rain and look a bit thundery, and as we arrived at swim class we were informed that lessons were canceled, so we turned around and headed back home.

Zoe watched a bit of TV and then Sarah arrived to pick her up. I'm going to knock myself out with a variety of drugs tonight and hope I get a good night's sleep with minimum of cold symptoms.

Categories: thinktime

Maxim Zakharov: Central Sydney WordPress Meetup: E-mail marketing

Planet Linux Australia - Wed 27th Aug 2014 01:08

Andrew Beeston from Clicky! speaks about email marketing at Central Sydney WordPress meetup:

Categories: thinktime

Andrew Pollock: [life] Day 209: Startup stuff, Kindergarten, tennis and a play date

Planet Linux Australia - Tue 26th Aug 2014 21:08

Last night was not a good night for sleep. I woke up around 12:30am for some reason, and then Zoe woke up around 2:30am (why is it always 2:30am?), but I managed to get her to go back to bed in her own bed. I was not feeling very chipper this morning.

Today was photo day at Kindergarten, so I spent some extra time braiding Zoe's hair (at her request) before we headed to Kindergarten.

When I got home, I got stuck into my real estate license assessment and made a lot of progress on the current unit today. I also mixed in some research on another idea I'm running with at the moment, which I'm very excited about.

I biked to Kindergarten to pick Zoe up, and managed to get her all sorted out in time for her tennis class, and she did the full class without any interruptions.

After tennis, we went to Megan's house for a bit. As we were leaving, her neighbour asked if we could help video one of her daughters doing the ALS ice bucket challenge thing, so we got a bit waylaid doing that, before we got home.

I managed to get Zoe down to bed a bit early tonight. My cold is really kicking my butt today. I hope we both sleep well tonight.

Categories: thinktime

The best lesson from Fantasy Football's success

Seth Godin - Tue 26th Aug 2014 19:08
When people say, "my team," they mean it. In the top-down world of industrial marketing, the San Francisco 49ers say, "we built this team, buy a ticket if you want to come." Then, a few years later, it broadened to,...         Seth Godin
Categories: thinktime

BlueHackers: About your breakfast

Planet Linux Australia - Tue 26th Aug 2014 12:08

We know that eating well (good nutritional balance) and at the right times is good for your mental as well as your physical health.

There’s some new research out on breakfast. The article I spotted (Breakfast no longer ‘most important meal of the day’ | SBS) goes a bit popular and funny on it, so I’ll phrase it independently in an attempt to get the real information out.

One of the researchers makes the point that skipping breakfast is not the same as deferring. So consider the reason, are you going to eat properly a bit later, or are you not eating at all?

When you do have breakfast, note that really most cereals contain an atrocious amount of sugar (and other carbs) that you can’t realistically burn off even with a hard day’s work. And from my own personal observation, there’s often way too much salt in there also. Check out Kellogg’s Cornflakes for a neat example of way-too-much-salt.

Basically, the research comes back to the fact that just eating is not the point, it’s what you eat that actually really does matter.

What do you have for breakfast, and at what point/time in your day?

Categories: thinktime

Tridge on UAVs: APM:Rover 2.46 released

Planet Linux Australia - Tue 26th Aug 2014 08:08

The ardupilot development team is proud to announce the release of version 2.46 of APM:Rover. This is a major release with a lot of new features and bug fixes.

This release is based on a lot of development and testing that happened prior to the AVC competition where APM based vehicles performed very well.

Full changes list for this release:

  • added support for higher baudrates on telemetry ports, to make it easier to use high rate telemetry to companion boards. Rates of up to 1.5MBit are now supported to companion boards.
  • new Rangefinder code with support for a wider range of rangefinder types including a range of Lidars (thanks to Allyson Kreft)
  • added logging of power status on Pixhawk
  • added PIVOT_TURN_ANGLE parameter for pivot based turns on skid steering rovers
  • lots of improvements to the EKF support for Rover, thanks to Paul Riseborough and testing from Tom Coyle. Using the EKF can greatly improve navigation accuracy for fast rovers. Enable with AHRS_EKF_USE=1.
  • improved support for dual GPS on Pixhawk. Using a 2nd GPS can greatly improve performance when in an area with an obstructed view of the sky
  • support for up to 14 RC channels on Pihxawk
  • added BRAKING_PERCENT and BRAKING_SPEEDERR parameters for better breaking support when cornering
  • added support for FrSky telemetry via SERIAL2_PROTOCOL parameter (thanks to Matthias Badaire)
  • added support for Linux based autopilots, initially with the PXF BeagleBoneBlack cape and the Erle robotics board. Support for more boards is expected in future releases. Thanks to Victor, Sid and Anuj for their great work on the Linux port.
  • added StorageManager library, which expands available FRAM storage on Pixhawk to 16 kByte. This allows for 724 waypoints on Pixhawk.
  • improved reporting of magnetometer and barometer errors to the GCS
  • fixed a bug in automatic flow control detection for serial ports in Pixhawk
  • fixed use of FMU servo pins as digital inputs on Pixhawk
  • imported latest updates for VRBrain boards (thanks to Emile Castelnuovo and Luca Micheletti)
  • updates to the Piksi GPS support (thanks to Niels Joubert)
  • improved gyro estimate in DCM (thanks to Jon Challinger)
  • improved position projection in DCM in wind (thanks to Przemek Lekston)
  • several updates to AP_NavEKF for more robust handling of errors (thanks to Paul Riseborough)
  • lots of small code cleanups thanks to Daniel Frenzel
  • initial support for NavIO board from Mikhail Avkhimenia
  • fixed logging of RCOU for up to 12 channels (thanks to Emile Castelnuovo)
  • code cleanups from Silvia Nunezrivero
  • improved parameter download speed on radio links with no flow control

Many thanks to everyone who contributed to this release, especially Tom Coyle and Linus Penzlien for their excellent testing and feedback.

Happy driving!

Categories: thinktime

Tridge on UAVs: APM:Plane 3.1.0 released

Planet Linux Australia - Tue 26th Aug 2014 07:08

The ardupilot development team is proud to announce the release of version 3.1.0 of APM:Plane. This is a major release with a lot of new features and bug fixes.

The biggest change in this release is the addition of automatic terrain following. Terrain following allows the autopilot to guide the aircraft over varying terrain at a constant height above the ground using an on-board terrain database. Uses include safer RTL, more accurate and easier photo mapping and much easier mission planning in hilly areas.

There have also been a lot of updates to auto takeoff, especially for tail dragger aircraft. It is now much easier to get the steering right for a tail dragger on takeoff.

Another big change is the support of Linux based autopilots, starting with the PXF cape for the BeagleBoneBlack and the Erle robotics autopilot.

Full list of changes in this release

  • added terrain following support. See ... following/
  • added support for higher baudrates on telemetry ports, to make it easier to use high rate telemetry to companion boards. Rates of up to 1.5MBit are now supported to companion boards.
  • added new takeoff code, including new parameters TKOFF_TDRAG_ELEV, TKOFF_TDRAG_SPD1, TKOFF_ROTATE_SPD, TKOFF_THR_SLEW and TKOFF_THR_MAX. This gives fine grained control of auto takeoff for tail dragger aircraft.
  • overhauled glide slope code to fix glide slope handling in many situations. This makes transitions between different altitudes much smoother.
  • prevent early waypoint completion for straight ahead waypoints. This makes for more accurate servo release at specific locations, for applications such as dropping water bottles.
  • added MAV_CMD_DO_INVERTED_FLIGHT command in missions, to change from normal to inverted flight in AUTO (thanks to Philip Rowse for testing of this feature).
  • new Rangefinder code with support for a wider range of rangefinder types including a range of Lidars (thanks to Allyson Kreft)
  • added support for FrSky telemetry via SERIAL2_PROTOCOL parameter (thanks to Matthias Badaire)

    added new STAB_PITCH_DOWN parameter to improve low throttle behaviour in FBWA mode, making a stall less likely in FBWA mode (thanks to Jack Pittar for the idea).
  • added GLIDE_SLOPE_MIN parameter for better handling of small altitude deviations in AUTO. This makes for more accurate altitude tracking in AUTO.
  • added support for Linux based autopilots, initially with the PXF BeagleBoneBlack cape and the Erle robotics board. Support for more boards is expected in future releases. Thanks to Victor, Sid and Anuj for their great work on the Linux port. See ... t-on-linux for details.
  • prevent cross-tracking on some waypoint types, such as when initially entering AUTO or when the user commands a change of target waypoint.
  • fixed servo demo on startup (thanks to Klrill-ka)
  • added AFS (Advanced Failsafe) support on 32 bit boards by default. See ... iguration/
  • added support for monitoring voltage of a 2nd battery via BATTERY2 MAVLink message
  • added airspeed sensor support in HIL
  • fixed HIL on APM2. HIL should now work again on all boards.
  • added StorageManager library, which expands available FRAM storage on Pixhawk to 16 kByte. This allows for 724 waypoints, 50 rally points and 84 fence points on Pixhawk.
  • improved steering on landing, so the plane is actively steered right through the landing.
  • improved reporting of magnetometer and barometer errors to the GCS
  • added FBWA_TDRAG_CHAN parameter, for easier FBWA takeoffs of tail draggers, and better testing of steering tuning for auto takeoff.
  • fixed failsafe pass through with no RC input (thanks to Klrill-ka)
  • fixed a bug in automatic flow control detection for serial ports in Pixhawk
  • fixed use of FMU servo pins as digital inputs on Pixhawk
  • imported latest updates for VRBrain boards (thanks to Emile Castelnuovo and Luca Micheletti)
  • updates to the Piksi GPS support (thanks to Niels Joubert)
  • improved gyro estimate in DCM (thanks to Jon Challinger)
  • improved position projection in DCM in wind (thanks to Przemek Lekston)
  • several updates to AP_NavEKF for more robust handling of errors (thanks to Paul Riseborough)
  • improved simulation of rangefinders in SITL
  • lots of small code cleanups thanks to Daniel Frenzel
  • initial support for NavIO board from Mikhail Avkhimenia
  • fixed logging of RCOU for up to 12 channels (thanks to Emile Castelnuovo)
  • code cleanups from Silvia Nunezrivero
  • improved parameter download speed on radio links with no flow control

Many thanks to everyone who contributed to this release, especially our beta testers Marco, Paul, Philip and Iam.

Happy flying!

Categories: thinktime

The idea is not the (only) hard part

Seth Godin - Tue 26th Aug 2014 05:08
In 1989, I created and launched a new idea: videotapes of people playing video games. It was ridiculed by the hipsters of the day, and my publisher later admitted that they hadn't even bothered to bring it to market beyond...         Seth Godin
Categories: thinktime

10 Years Ago in ALA: Pocket Sized Design

a list apart - Mon 25th Aug 2014 22:08

The web doesn’t do “age” especially well. Any blog post or design article more than a few years old gets a raised eyebrow—heck, most people I meet haven’t read John Allsopp’s “A Dao of Web Design” or Jeffrey Zeldman’s “To Hell With Bad Browsers,” both as relevant to the web today as when they were first written. Meanwhile, I’ve got books on my shelves older than I am; most of my favorite films came out before I was born; and my iTunes library is riddled with music that’s decades, if not centuries, old.

(No, I don’t get invited to many parties. Why do you ask oh I get it)

So! It’s probably easy to look at “Pocket-Sized Design,” a lovely article by Jorunn Newth and Elika Etemad that just turned 10 years old, and immediately notice where it’s beginning to show its age. Written at a time when few sites were standards-compliant, and even fewer still were mobile-friendly, Newth and Etemad were urging us to think about life beyond the desktop. And when I first re-read it, it’s easy to chuckle at the points that feel like they’re from another age: there’s plenty of talk of screens that are “only 120-pixels wide”; of inputs driven by stylus, rather than touch; and of using the now-basically-defunct handheld media type for your CSS. Seems a bit quaint, right?

And yet.

Looking past a few of the details, it’s remarkable how well the article’s aged. Modern users may (or may not) manually “turn off in-line image loading,” but they may choose to use a mobile browser that dramatically compresses your images. We may scoff at the idea of someone browsing with a stylus, but handheld video game consoles are impossibly popular when it comes to browsing the web. And while there’s plenty of excitement in our industry for the latest versions of iOS and Android, running on the latest hardware, most of the web’s growth is happening on cheaper hardware, over slower networks (PDF), and via slim data plans—so yes, 10 years on, it’s still true that “downloading to the device is likely to be [expensive], the processors are slow, and the memory is limited.”

In the face of all of that, what I love about Newth and Etemad’s article is just how sensible their solutions are. Rather than suggesting slimmed-down mobile sites, or investing in some device detection library, they take a decidedly standards-focused approach:

Linearizing the page into one column works best when the underlying document structure has been designed for it. Structuring the document according to this logic ensures that the page organization makes sense not only in Opera for handhelds, but also in non-CSS browsers on both small devices and the desktop, in voice browsers, and in terminal-window browsers like Lynx.

In other words, by thinking about the needs of the small screen first, you can layer on more complexity from there. And if you’re hearing shades of mobile first and progressive enhancement here, you’d be right: they’re treating their markup—their content—as a foundation, and gently layering styles atop it to make it accessible to more devices, more places than ever before.

So, no: we aren’t using @media handheld or display: none for our small screen-friendly styles—but I don’t think that’s really the point of Newth and Etemad’s essay. Instead, they’re putting forward a process, a framework for designing beyond the desktop. What they’re arguing is for a truly device-agnostic approach to designing for the web, one that’s as relevant today as it was a decade ago.

Plus ça change, plus c’est la même chose.

Categories: thinktime

Andrew Pollock: [life] Day 208: Kindergarten, running, insurance assessments, home improvements, BJJ and a babyccino

Planet Linux Australia - Mon 25th Aug 2014 21:08

Today was a pretty busy day. I started off with a run, and managed to do 6 km this morning. I feel like I'm coming down with yet another cold, so I'm happy that I managed to get out and run at all, let alone last 6 km.

Next up, I had to get the car assessed after a minor rear-end collision it suffered on Saturday night (nobody was hurt, I wasn't at fault). I was really impressed with NRMA Insurance's claim processing, it was all very smooth. I've since learned that they even have a smartphone app for ensuring that one gets all the pertinent information after an accident.

I dropped into Bunnings on the way home to pick up a sliding rubbish bin. I've been wanting one of these ever since I moved into my place, and finally got around to doing it. I also grabbed some LED bulbs from Beacon.

After I got home, I spent the morning installing and reinstalling the rubbish bin (I suck at getting these things right first go) and swapping light bulbs around. Overall, it was a very satisfying morning scratching a few itches around the house that had been bugging me for a while.

I biked over to Kindergarten for pick up again, and we biked back home and didn't have a lot of time before we had to head out for Zoe's second freebie Brazilian Jiu-Jitsu class. This class was excellent, there were 8 kids in total, and 2 other girls. Zoe got to do some "rolling" with a partner. It was so cute to watch. They just had to try and block each other from touching their knees, and if they failed, they had to drop to the floor and hop back up again. For each of Zoe's partners they were very civilized and took turns at failing to block.

Zoe was pretty tired after the class. It was definitely the most strenuous class she's had to date, and she briefly fell asleep in the car on the way home. We had to make a stop at the Garage to grab some mushrooms for the mushroom soup we were making for dinner.

Zoe helped me make the mushroom soup, and after dinner to popped out for a babyccino. It's been a while since we've had a post-dinner one, and it was nice to do it again. We also managed to get through the entire afternoon without and TV, which I thought was excellent.

Categories: thinktime


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