Paul Tarvydas <tarvydas@allstream.net> wrote:
+---------------
| http://space.com/missionlaunches/spirit_relay_040124.html
| "There is a growing feeling here that the robot may have been taxed too
| much that is, too many "do this, do that" instructions were sent. That
| multi-tasking could have sparked the problem, according to sources here.
+---------------
More recent news:
<URL:http://spaceflightnow.com/mars/mera/040126spirit.html>
suggests that it was a matter of the flash (EEROM) filesystem metadata
(or maybe filesystem cache?) overflowing RAM, due to the length of time
that the system had been running and the amount of data captured:
It is now believed that the rover's flash memory had become
so full of files that the craft couldn't manage all of the
information stored aboard. Spirit bogged down because it didn't
have enough random access memory, or RAM, to handle the current
amount of files in the flash -- including data recorded during
its cruise from Earth to Mars and the 18 days of operations on
the red planet's surface.
...
And in that we realized that we had this reset problem. Based
on just kind of the hunch of our lead software architect, he
believed that the problem was probably associated with the mounting
of flash and initialization. There is a hardware command that
we can send that bypasses the software where we can actually
tell the hardware to not allow us to mount flash on initialization.
When we the next day actually sent the command to do that, software
initialized normally and was behaving like the software that we
had always known. It was a fantastic moment.
...
Right now, our most likely candidate for the issue has been
narrowed down a little bit. It is really an issue with the
file system in flash. Essentially, the amount of space required
in RAM to manage all of the files we have in flash is apparently
more than we initially anticipated.
...
Tomorrow, we are might try to access flash and do a little bit
of a health check on it. The next day we might try to delete
some files to see if our hunch is correct that it's really due
to the number of files that we are trying to manage on the flash
file system.
...
-Rob
-----
Rob Warnock <rpw3@rpw3.org>
627 26th Avenue <URL:http://rpw3.org/>
San Mateo, CA 94403 (650)572-2607