Monday, December 27, 2010

Avionics Grade

Our sales process involves explaining what makes our parts different from Commercial Off The Shelf parts. Usually it starts with temperature operation, commercial (0-70C) versus industrial (-40 to 85C). The operating temperature range showcases two important features: control of a laser and receiver over a broad operating environment and higher quality components. The development of the temperature table took us nearly a year to develop and contains a lot of knowledge and practice. And the components we use are very high quality from manufacturers who support their design for years. The ruggedness goes beyond temperature.

We also test the individual components BEFORE we put them into the transceivers. This means that when we get a laser or board we screen it for performance and vigorously inspect and test it at each stage of assembly. Optical transceivers are ecosystems where the electrical capabilities can hide marginal optical performance (overdriving). Or mechanical slop can be made up for in optical (larger spot), and so on. For commercial temperature parts where there is no shock or vibration consideration, the final system can work without fail…but in a harsh environment, one leg of the table will fail without warning and could have been prevented from screening individual parts.

Our transceivers have no software but that doesn’t mean we shy away from it. The team that builds our test fixtures is DO-178B certified for work they do elsewhere in the industry. It enables us to have a great “plug and play” setup for optical test boards and links to our test equipment from Agilent. Software is terribly complex because in Avionics, it becomes this big “black box” that can’t be seen in its parts. Two extremely different views of this showed up recently.

The 787 continues to be plagued by delays. The fire aboard the test flight in November was due to a hardware component but the failure that scared everyone was software related. To fix it, the code needs changed and then the whole runtime and use in the aircraft needs to be retested. This could take months in testing but only a few days in software. There is a great book called “the mythical man month” and the fire could not illustrate the need to follow the advice of that book any better.

Avionics software is a specialized art. But not all software in airplanes is so complex. In IFE, there is a move to use iPads as the default devices for passengers. Apple’s MacOS is probably as good as it gets, but it’s not built for airplane use. Neither is Linux for that matter. On a recent trip to Europe I experienced an IFE SNAFU that was shocking. An hour into the flight, the IFE server had to be rebooted. No joke…the movies and music stopped and for 15 minutes the seat IFE’s rebooted. Blue Screen Of Death…was nothing compared to the 15 minutes of watching a Smiling Penguin. Right in front of all of us were all the boot code and versions and proprietary IP running up the screen. In an industry that is notoriously paranoid about technology, to see the entire software map was amazing.

But even more incredible…that the stewards and stewardesses knew how to reboot the IFE system mid flight. They actually restarted Linux servers and 300 client stations at 35,000 feet with no help line or web support. Watching the first hour of Harry Potter over again wasn’t all that impressive, but I’ll take the software recovery in stride. It was free afterall.
Linux Reboot