Freespacenotifier KDED module in kdereview

[Jacopo De Simoi]

> On Monday 17 of May 2010, Jacopo De Simoi wrote:
> > I've a question about this module, as far as I can understand it polls  the
> > disk on which $HOME is mounted every minute to check the available disk
> > space. This is something we carefully avoided to do in the plasma device
> > notifier because by doing so we keep the disks awake instead of letting
> > them sleep if unused if the user desires so. This module would probably
> > upset laptop users, am I right? (ervin?)
> 
>  Do you have some more details on this? I tried to keep my HDD spun down after 
> I had bought SSD and there was always something that kept spinning it up, so 
> eventually I've given up and I keep it unmounted until needed. 

I don't want to sound too simple-minded here, but usually what breaks this kind of things is 
file system journaling. 
I personally never managed to have this kind of things work in a satisfactory way for one reason of another.

> As far as I 
> know laptops have a special mode for allowing them to spin down the drive 
> that does more aggressive caching and I don't understand why free space, 
> which is something very easy to cache, should keep the actual drive active.

> > I would personally  like to have the service disabled _at the very least_
> > if running on batteries (you can get an idea of how to do it by looking at
> > how it's done for the strigi indexer),
> 
>  If we really need to do this by hand, could this be done somewhere in the 
> framework? I can't imagine this would be the only place in KDE that'd need 
> adjusting.

Indeed it's just a matter of listening to a dbus signal

> 
> > and  to check available space less 
> > often than every minute in the general case.
> 
>  No, and actually even a minute is not that short. The point of the service is 
> to avoid running out of space in $HOME, which can lead to loss of data as a 
> consequence of that. And running out of space is quite easy, a download 
> running in background, compilation, whatever. Which means the service should 
> ideally check all the time, everything 

> (and that means doing it in KIO is not enough)

Yep definitely KIO is not enough...

> . And having it disabled by default makes including it pointless, how 
> many users will turn it on? About the same number as those that turn on 
> quotas.

Absolutely, I wonder if solid (HAL?) is able to give us a signal when a disk 
goes in stand-by or comes back... this would at least give us some hints, and
we could do the caching ourselves.