On 4/8/20 7:54 AM, Martin Gregorie wrote:
On Wed, 08 Apr 2020 06:43:22 -0700, towsked wrote:


Has anyone reported this problem to LXV, and if so what was their
response please? There seems to be an opportunity for a firmware fix to
this problem, not requiring any additional hardware.

In the specification for Flight Recorders, a new IGC file is not
started if power has been interrupted for less than one minute. This is
to allow a change of battery, breaker reset or change a fuse. Exactly
the problem we are discussing.

If the LX firmware were enhanced to inhibit re-calculating QNH where
power has been lost for less than n seconds, this problem goes away.

Discuss.


The LXNav manual says that the internal logger will continue to operate
'for a short time' if power is lost. The manual also says that the
proper shutdown procedure should always be used, eg when changing
batteries, since if power is suddenly cut the operating system may be
scrambled.

What OS does LXNav use these days?

I'm asking because this sounds remarkably like similar problems with
WinCE, where it was well-known that powering off without shutting down
properly was almost as certain to corrupt the SD card as yanking the
card out of a running PDA.



The Stratux ads-b receiver has the same issue, high probability of
corrupting the memory if you don't shut it down manually before removing
power. Developers are aware of the problem, but haven't come up with a
proper fix.

Runs an embedded linux, they're not storing any data during normal
operation, so baffling why that's so hard to fix.

-Dave