Hi
We are slowly trying to get up to speed with the Symbian Signed
criteria. One of the criteria specifies that 'The application should
only create files only on the drive it was installed onto'. However,
in our experience the external disk on at least Nokia devices
has been too flaky to put continuously updated files (log files,
databases, cached files) on. In one field test about 25% of MMCs
had file system corruption after 2 months when writing log files
to the MMC. I seem to recall that Opera had similar problems with
cache files on the MMC (Opera detects the problem and recreates
its cache folder in that case - but cached files can of course just
be thrown away with only a performance penalty, no data loss).
Could this be commented on by Symbian or added as a FAQ?
Or maybe somebody knows that the file-system handling has become
more reliable on newer devices? Our worst experiences were with
6600s.
Mika
Hi Mika
As far as I know there is no specific problem with Symbian's file
server/systems that could cause this level of corruption. What I have seen
is some use cases where the drive is so thrashed by read/writes that it
starts to reach the finite number of erase-write cycles inherent in use of
flash memory.
If this is the case then it would probably be an (even worse) problem on
internal drive, because once the internal drive is gone you can throw the
phone away.
My advice to you would be to look at the way you're doing read/writes and
see if there is any way you can buffer these to reduce the number of
read/writes of the card.
From a Symbian Signed perspective this will never be an exception - it needs
to be reviewed on a case by case basis. Getting a waiver is dependent on the
manufacturer. If my recommendation was asked I'd suggest to them they grant
IF:
a) You've thought through read/write issues as above (in other words, you've
coded as best you can to cope with hardware limitations)
b) Testing on target phone following doing "a" shows high failure rate on
card AND same testing on internal drive shows no significant degradation.
(you'd have to run your app in a test harness to emulate the time periods)
c) The reasoning is explained to user in an install prompt.
So by all means raise a waiver. Hope that helps.
Regards
Hamsih
"Mika Raento" <[email protected]> wrote in message
news:[email protected]...
> Hi
>
> We are slowly trying to get up to speed with the Symbian Signed
> criteria. One of the criteria specifies that 'The application should
> only create files only on the drive it was installed onto'. However,
> in our experience the external disk on at least Nokia devices
> has been too flaky to put continuously updated files (log files,
> databases, cached files) on. In one field test about 25% of MMCs
> had file system corruption after 2 months when writing log files
> to the MMC. I seem to recall that Opera had similar problems with
> cache files on the MMC (Opera detects the problem and recreates
> its cache folder in that case - but cached files can of course just
> be thrown away with only a performance penalty, no data loss).
>
> Could this be commented on by Symbian or added as a FAQ?
>
> Or maybe somebody knows that the file-system handling has become
> more reliable on newer devices? Our worst experiences were with
> 6600s.
>
> Mika