Organize Your Life with Nepomuk

Tagging is, of course, in itself, nothing new. Media players and photo management applications have been using tags for years to enable convenient views of files that are freed from a single, rigid directory structure. However, these systems have been largely incompatible. You can read basic tags embedded in Vorbis music files in KDE's Amarok and in other music players, but you cannot easily transfer other metadata, such as ratings or playcounts, between music players. Neither do tags applied to images in KDE's photo management application, digiKam, appear in Dolphin or Gwenview. For some file types, it is not possible to embed metadata at all.

As more applications make use of tagging to simplify organization and retrieval of content, there is a danger of redundancy with the same data being collected and stored multiple times, so sharing storage and resources makes sense. To work together, applications not only need to have a way of sharing metadata but also a way of understanding it. One of the main jobs of the Nepomuk Project is to define these common ways of representing metadata of differing types. E-mail messages that came from your friend Alice are different from e-mail messages that mention her, and you want your computer to understand that difference.

Figure 8. Bangarang lets you browse using information from Nepomuk.

Within the world of KDE software, the most visible users of Nepomuk are the Dolphin file manager, Gwenview image viewer and the Bangarang media player. The last integrates browsing of media by type (movies, TV shows, short clips), rating, playcount and date of last play. Although use of Nepomuk in KDE applications is limited at present, Peter is optimistic about the future take up of Nepomuk due to improvements in the ease of accessing the technology: “searching and filtering—it gets easier and easier from applications in each release”.

If going through all of your files and manually adding tags and ratings is not your idea of fun, good news is coming for you.

Nepomuk developers are working on automatically identifying the files you use most often and prioritizing those in search results. File use also can be linked to Plasma Activities, so that you could be presented with different files depending whether you were using your computer for work or play. Nepomuk also is able to keep track of the source of files you find on-line, recording the original file location. This not only helps you find images you have downloaded from your friend's on-line photo album, but also could work the other way around, enabling you to find the Web site where you downloaded a favorite desktop background.

KDE's personal information and communication suite, Kontact, is being ported to a new storage system, Akonadi (see Resources). This will make it easier to maintain semantic information on items that arrive in messages—for example, by linking file attachments with the person who sent them—so that you can find an image your friend sent you two weeks ago.

KDE and Mandriva developers also are working on integrating technologies from Scribo (Semi-automatic and Collaborative Retrieval of Information Based on Ontologies). This aims to automate the extraction of meaningful metadata from files. For example, it should be possible to determine keywords and topics from text-based documents to suggest tags or even apply them automatically. Scribo also has the ability to extract text from images, so that a photograph including a road sign bearing the word “Paris” might be found in a search for “Paris” without the need for manual tagging. Capabilities like this are not yet integrated into the KDE platform, but experimental code has been included in the KDE source repositories.

If you are curious about possible future directions of Nepomuk, Mandriva Linux 2010 includes some experimental features. It has special versions of KDE's Konqueror Web browser and KMail messaging program that enable tagging of Web pages and e-mail so they can be retrieved in searches. It also has the ability to offer tag autocompletion—for example, suggesting the tag “John Smith” from your address book when you begin to type the word “John” as a new tag.

It would be wrong to describe Nepomuk as feature-complete or without any flaws. Its developers see much greater potential than that currently realized in KDE software. However, enabling Nepomuk and Strigi indexing in your KDE workspace today gives you unobtrusive, fast and flexible desktop search to find your files easily. You also can begin to organize your files using tags rather than being limited to rigid directory structures, and you can save search queries as Places for easy access from any KDE application. You even can have sets of your most important files waiting for you when you log in. The Nepomuk house is not complete, but the foundations are strong, and it is now safe to go in and take a good look around. If you do so, you may discover you like what you find.