Visualizing a nanosecond

We’re so glad to have run across this video where [Rear Admiral Grace Hopper] explains how to visualize a nanosecond. Now we had never heard of [Grace Hopper] before, but once you watch the clip (also embedded after the break) you’ll want to know who this person is. We work with divisions of seconds all the time when developing with microcontrollers. But those concepts are so abstract we never had a need to think about them as a physical distance. After all they’re a measure of time, right?

You can’t make it out, but she’s holding a length of wire between her hands. It is 11.8 inches long and represents how far electricity can travel in one nanosecond (one billionth of one second). She goes on to explain that this is a calculation of the distance which light can travel in one nanosecond, then really hits the concept home when she uses it to explain latency in satellite communications. For us, the waste of not putting a chip into sleep mode when it’s just stuck in the loop waiting for an interrupt is where we made the connection.

So back to the woman herself. We think you’ll really enjoy reading through her Wikipedia biography page. [Grace] was a computer science pioneer. She is credited with writing the very first computer compiler. She postulated and articulated the concepts that led to the development of COBOL, and popularized the term ‘debugging’. In short, she is one of the giants whose shoulders we all stand upon.

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How Canonical automates Linux package compilation

pandaboard

What do you do when it’s time to port the most popular Linux distribution to a completely different architecture? Canonical employee [David Mandalla] works on their ARM development team and recently shared the answer to that question with his fellow Dallas Makerspace members.

Canonical needed a way to compile about 20,000+ packages for the ARM platform, however they did not want to cross-compile, which is quite time consuming. Instead, they opted to build a native solution that could handle the load while ensuring that all packages were compiled securely. To tackle this immense task, [David] and his team constructed a 4U server that runs 20 fully-independent ARM development platforms simultaneously.

The server is composed of 21 PandaBoards, small OMAP development boards featuring a dual-core ARM cortex processor with just about all the connectivity options you could possibly ask for. One board operates as the server head, keeping track of the other 20 modules. When someone requests server time to build a package, the main board checks for unused server, triggering a relay to reboot it before the server is automatically reimaged. Once the pristine, secure environment is ready to go, it’s handed off to the customer who requested it.

If you’re interested in learning more about the build process, [David] has put together a blog with additional details.

[Thanks Leland]

AVR Programming 02: The Hardware

You may be able to write the most eloquent code in the history of embedded systems but without a way to run it on the hardware it will be worthless. In this installment of the tutorial series we will:

  • Look at some of the available AVR programmer options
  • Place the microcontroller on a breadboard and connect it to a power supply and a programmer.
  • Use programming software to send some example code to the microcontroller

If you missed Part 1 take a few minutes to review that portion of the tutorial and then join us after the break.

Series roadmap:

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CoffeeScript: like aspirin for JavaScript

CoffeeScript is a language that compiles down into JavaScript. “But why? JavaScript is so simple?” Bullcorn.

If you don’t use JavaScript everyday the language is wonky and frustrating. When you need quick snippet of Javascript to build into a page you may know how to do it with three or four different languages but struggle with the touchy syntax that has long given developers headaches.

Give CoffeeScript a try, you’ll like it. If you do, give them a hand with development too.

[via @hornbeck]