Saturday, October 13, 2007

Glass cockpits, social interfaces

The October 2007 issue of Computer has a good two page article about software and modern avionics. This is one of the few places where you will find definitions for such things as "full-authority" digital engine control. Here's a quote:
GE aircraft engines can downlink operational data during flight to GE's Remote Monitoring Center near Cincinnati, Ohio. The center can analyze the data in real time, thereby enabling the scheduling of essential maintenance if necessary while an aircraft is still in flight.
The article is available to everyone without subscription. Thank you John Knight.

If that interests you, I suggest looking at Lala and Harper's paper " Architectural principles for safety-critical real-time applications". Since that paper was written in the mid-1990s, the Boeing 777 avionics were being developed:
The Boeing 777 flight control computer ... takes design diversity well beyond what has ever been tried in pratice or even in a research laboratory. The initial concept rested on three quad redundant computers with each of the quads implemented in dissimilar hardware and programmed in dissimilar software ... The software design diversity has since been simplified to use only Ada, although three different compilers are still under consideration to generate code for the three types of microprocessors ... The hardware design has also been simplified to a 3 by 3 matrix of 9 processors.

Changing the subject, I like reading Joel on Software, but cringe when Joel goes too far. The almost-always-interesting Michael Feldstein takes Joel to task about social interfaces. It's from a couple of years ago, but still interesting.

Joel may be off about social interfaces, but he has an interesting recent post about a disturbing bug in Excel.