Gnome and the Semantic Desktop

A work in progress – will it mature fast enough and meet the expectations

The state of semantic desktop in the Gnome desktop environment is still very fluid. Two projects seem to be the current favourites – Tracker and Zeitgeist. Zeitgeist is included by default by Ubuntu and Tracker is included by default by Fedora. The two projects are not competitors. Each one addresses a different set of concerns.


'Files and Folders' option of Unity interface relies on Zeitgeist – (zeit in German is time and geist is ghost). The first experience of using this Unity option was very disturbing. It found nothing! Zeitgeist keeps track of various activities on files – provided the application you are using informs it. 'Files and Folders' option searches for files within your activities. Obviously, there are no activities after a fresh install and nothing is found even though the home directory may be full of files from the previous version of Ubuntu. It's utility increases with time.

In the Gnome environment, you will need to install gnome-activity-journal, which will also install zeitgeist. After the installation, you will find 'Activity Journal' in the accessories menu on Fedora 15. The application aborts at the start. Fedora's bugzilla had numerous entries for this problem – most likely via abrt but no solution. You need to comment a few lines of code causing the crash. The crash is caused by code wanting to ensure that you have a recent version of Zeitgeist!

Activity journal makes the significance of Zeitgeist pretty straight forward. It is very much like searching your browser history based on date but with more options about the nature of files you may wish to search. The usefulness depends on applications making information available to Zeitgeist. It offers an option to know the web sites visited. However, at present using Firefox or Chrome does not result in Zeitgeist knowing anything about the websites visited. If you open a file from a terminal, Zeitgeist will not know about it. However, opening it through Nautilus creates an activity entry in Zeitgeist.

There is a full text search(fts) extension in Zeitgeist which uses Xapian. However, it indexes only the title sent to Zeitgeist by the application. For indexing the content, you will need to uncomment a line in python code. I did not try it as that is not what we would expect a user to do.

There is one more reason for not enabling full text search of content via Zeitgeist. Zeitgeist needs to coexist with projects like Tracker rather than try to include their functionality within Zeitgeist. There are efforts to integrate Zeitgeist and Tracker on Gnome and Zeitgeist and Nepomuk on KDE. Solution may lie in applications like gnome-activity-journal taking data from both Zeitgeist and Tracker and displaying it in a suitable context.


Functionality of Tracker is similar to that of Nepomuk discussed last month. The home page of the project - describes it as follows:

“Tracker is a semantic data storage for desktop and mobile devices. Tracker uses W3C standards for RDF ontologies using Nepomuk with SPARQL to query and update the data.”

Tracker will monitor and index content within the directories selected by you. It also allows you to add tags to files using Nautilus if tracker-nautilus-plugin is installed. However, searching for files from with Nautilus does not integrate with Tracker. Gnome search tool has an option to search for files based on content but appears to do nothing.

You will want to use tracker-needle included in tracker-search-tools to search for files using Tracker data. This will be 'Desktop Search' in the Accessories menu. The interface is minimal. Search results are not displayed well and do not seem to be informative enough. Titles of some documents selected did not seem reasonable.

I prefer to use single click to launch an application. Needle requires double click. It does not start an application but opens the directory in Nautilus for further action.

However tracker-needle is an interim solution until the desktop search is integrated with Tracker. Ultimately, the search should be via the gnome-shell's or Nautilus' search options. If possible, it may even be a part of the file open dialog.

Should one use these tools? The answer probably lies in the fact that these tools need data to be useful. Hence, it is better to keep them running and collect the data. Hopefully, the desktop applications designed to exploit this data will be available soon. These applications will then display useful information as soon as you start using them instead of showing you a blank page.