Re: Boeing 787 integer overflow

[robin.vowels@gmail.com]

On Monday, May 4, 2015 at 9:34:59 AM UTC+10, Dennis Lee Bieber wrote:
> On Sun, 3 May 2015 12:03:51 -0400, Peter Chapin <P.nospam@vtc.vsc.edu>
> declaimed the following:
> 
> >I guess it depends on if there is a *requirement* to reboot the system 
> >periodically (less than 8 months) in the maintenance plan. The matter 
> >should be handled somewhere and it seems like it wasn't. In other words it 
> >was just "luck" that these systems have been getting restarted frequently 
> >enough.
> >
> 	Also depends upon just what "reboot" means in this environment... If
> this is some sort of elapsed time counter, then it is something saved in
> flash memory and will survive a normal power-cycle operation.

The article has pointed out that 248 days corresponds to 2**31 centiseconds,
which suggests that the integer is associated with a timer that
is running continuously.  Timers usually have a lithium battery
to keep them going, just as they do in the humble PC.

> 	"Reboot" in this case may mean erasing and reloading the operational
> flight program, databases, and other stuff in "permanent" memory.

Reboot of the humble PC doesn't usually change the timer's value.