Rainier
What is the position with your systems re reset/reboot in flight? Possible or impossible?
I must say I am very impressed with your products, especially the ability to scan charts/topo maps and put them into your display.
John
Melbourne
Australia
Our stance is to have a watchdog to detect a hung system. This is not 100% effective of course since watchdogs tend to be "stupid".
Typically, in most of our systems we have a watchdog that is part of the CPU and a seperate one that is outside of the system (usualy as part of the power supply monitoring circuitry).
Resets are usualy generated as a result of something unpleasant on the power supply bus which tends to result in an emergency shutdown of the system and a rapid restart after that. This is necessary to protect important system data that could otherwise get corrupted, i.e. we don't allow the processor to run if power conditions are marginal. Apart from that, practically everything that is of importance data wise is stored in static memory chips that have a seperate backup supply. Expensive but very effective.
Hung systems due to a software malfunction are very rare. While it is not possible to rule this out (after all we are only human), we follow the somewhat unusual dictum that every single byte of software that runs on these systems MUST be written in-house. This includes everything. No 3rd party software, drivers or anything else (including difficult things like USB host drivers, operating systems, file systems etc) are allowed (we even write our own compilers from scratch and make our own development systems).
While this does not prevent bugs, it does make finding them a lot easier and faster since you are in full knowledge of every tiny aspect of the system.
So, we never had a reset button on our systems. Of course, the BIG reset button is the power cycle. You can do this at anytime, no problem. It is recommended that it is done when you are in reasonable stabilized flight if you would also be reseting the AHRS (which is always external with our systems). This will allow the AHRS to find its orientation near instantly.
From experience gained so far, I think it is safe to state that the majority of issues (by far) are hardware related. Perhaps a bad solder joint somewhere or iffy connector or a chip that gives up the ghost for some unknown reason. That happens. Software malfunction is almost a non-event compared to this.
Right, let me get back to work, have to get the ARINC on the new Odyssey sorted out...
Rainier
CEO MGL Avionics