[maemo-developers] What's wrong with folder browsing?

[From: Gustavo Sverzut Barbieri]

On 5/21/07, Frantisek Dufka <dufkaf at seznam.cz> wrote:
> Gustavo Sverzut Barbieri wrote:
> >
> > Just hack scripts (both init.d and dbus/service) and launch it with
> > lower priority, it should be the default in next release.
>
> This still puts big stress on memory subsystem and slows device by
> flushing caches.

:-(


> >  - data is deleted when SD is removed in order to avoid DB growing
> > indefinitely, maybe you'll not see the same card again (it was a
> > friend's SD, for example) or data there will not be present anytime
> > soon (you just deleted those files using PC or other device)
>
> You could have option to purge old data when card was not seen for some
> time (like few days). It is much better then scanning card again when
> rebooting or quick removal and reinsert (can be quite frequent with some
> use cases).

I don't like the "timer" thing, but yes, it can help and I've already
considered it.

As for reboot, remember that on reboot, it's not re-parsed (files are
not opened), just re-scanned (stat and compare mtimes). We must do
this stat in order to check for files that changed elsewhere.


> Also if you fear of huge DB size you may consider to optionally keep DB
> directly on card with media files if it is writable and there is free
> space and also user sets it in preferences (or even if user moves it by
> hand there if canola is smart enough to keep one DB per scanned card,
> why not?).

keep db in mmc is problematic, since users want a unified view of
every data and this requires us to merge selects from every db, either
by creating a virtual db with data or doing that with code (our own
virtual db). That creates more problems than it saves.

> You can also do MD5 sum of directory listing (even output of ls -R or
> -lR) and do not scan files at all if listing hash is same.

this is easy, but not much faster than the stats... and you still may
have inconsistencies, imagine you noticed incorrect id3 and then you
plugged in your device using USB cable (your media get unmounted), use
some app on your pc to fix those incorrect id3 and then remove the
cable, you want your data to be updated.

> Same applies to metalayer-crawler of course.

I hope in future we can just use device-wide db and do no scanning at
all. If metalayer-crawler export its data somehow, I'd be really glad
to remove the scanning from Canola, it no benefit having it on our
side.

-- 
Gustavo Sverzut Barbieri
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