Geekly Music...

Love the retro touches, like the EICO Model 460 'scope.  Passed along by reader Doug S.:





I have a couple personal connections to that video. First, the EICO 460 'scope – today the thing is a museum piece.  Around 1969 or 1970, that exact same 'scope was the centerpiece of my little electronics workshop.  I found one broken somewhere, bought it, fixed it, and then paid a metrology shop in Philadelphia $40 to recalibrate it (back then, $40 was a substantial sum for me!).

Then there's the stepper motor noise that forms the main “instrument” in this video (the stepper motor is what's positioning the scanner imager).  Back in the late '70s and early '80s, I made a little money selling a nifty piece of software to computer manufacturers who were making systems that included floppy disk drives.  Those early floppy disks used stepper motor head positioners that made an annoying grinding/whining noise.  My software changed the way the steppers were used: instead of sending step commands at a constant rate, it smoothly accelerated and decelerated it.  The constant rate steps made the motor move and stop on each step, “shaking” it, and making the objectionable noise.  With my software, the motor never shook like that, and there was then almost no noise.

While I was developing that software, I noted that I could make the stepper motor make nearly whatever noise I wanted it to make.  But it never occurred to me to make music with it!

Driverless Cars...

A great, thought-provoking short post on the unintended consequences of driverless cars.

Flight 447: the Rest of the Story...

Popular Mechanics has a great summary of what really happened in the crash of Air France's flight 447 two years ago off the coast of Brazil.  Bottom line: profound pilot error combined with an apparent lack of understanding of how the automated flight systems on board their Airbus 330.  Some of the pilot errors were apparently caused by the pilots expecting the plane's flight control systems to work like older, less automated systems worked.  Said another way, the pilots appeared to be unprepared to handle the complexities of their automated flight controls.

This is a problem familiar to any modern software developer: users, in general, have little idea how the software they use actually works.  It's common – in fact, normal – for the users' mental model of the software package to be badly flawed.  For most kinds of software, the outcome of this is frustrated users and angry tech support calls.  This is not the case for flight control software, as this article makes very clear...

Gypsum on Mars...

Gypsum is a mineral, the stuff that's in the core of drywall.  It's very common on Earth, and had been previously detected on Mars.  What's new here is that the Mars rover Opportunity spotted a vein of gypsum (at right, click to enlarge) – and the only way anybody knows of that such a vein could be formed requires the presence of liquid water.  In other words, this is the equivalent of an old sign saying “Liquid water was once present here!”  Lots of other things found on Mars were already hinting that liquid water was once present on Mars – but this finding makes it all but certain...