It's not that I can't google anything; I searched in a lot of places in KDE documentation, but can't find anything on what nepomuk is.
I'm used to using grsync for back ups to my external HDD.
Is it a comparable tool, or is it only an indexer with tag/comment options, like I found out so far?

Nepomuk is a general semantic system, which has searching capabilities. It's main use so far in KDE has been for ratings and tags - along with the indexing of files using Strigi. It also indexes email and other information stored in Akonadi.

It does not perform any backup tasks.

bcooksley wrote:Nepomuk is a general semantic system, which has searching capabilities. It's main use so far in KDE has been for ratings and tags - along with the indexing of files using Strigi. It also indexes email and other information stored in Akonadi.

It does not perform any backup tasks.

I was misled by the term "nepomuk back up" in the applications I guess. Thanks for clarifying.

In this case, Nepomuk Backup is for backing up the contents of Nepomuk's own database - which contains tags, ratings, etc which the user may want to protect.

bcooksley wrote:In this case, Nepomuk Backup is for backing up the contents of Nepomuk's own database - which contains tags, ratings, etc which the user may want to protect.

Not at all what I was looking for, for nevertheless a neat tool I'll start using. Thanks

A little info I thought I'd share, in case there's another KDE-newbee passing by reading this
My desktop crashed yesterday, probably being overheated.
I've been trying to sort out what caused this, and I concluded it was Nepomuk.

I had indexing "on" including on removable disks, since my data is on an external disk.
CPU was running around 40% most of the time. Looking in "top" I noticed "virtuoso-t" plus several Nepomuk thingies being the cause.

I googled some and found the advice to set Nepomuk's memory to 512MB instead of 50.
Since I have 8GB of RAM that shouldn't be a problem.
I also restricted indexing to the home folder.
Still CPU is higher than normal (usually between 0,1 and max 10%, even with heavy use of many programs).
I finally set Nepomuk to "suspend" in the tray and the problem is gone.

I might let Nepomuk index again when at some point the pc is on and I don't really use it, and see if a completed indexing will also lower CPU-usage, but for now I'll stick to Catfish for doing searches.