Data file formats used to store and distribute PSI are also extremely important, as is the software used to process them. Here we only want to mention a couple of points about these subjects because we will elaborate more on them in the final report of this research.
Only if the formats are the simplest possible ones and are truly open, that is usable without asking permission or paying any royalty in any software program it is possible to speak of Open PSI. In the case of office documents, the best solution for new office texts, spreadsheets and presentations is the OpenDocument format (ODF, standard ISO 26300). ODF is an example of XML (eXtensible Markup Language), a generic technique to create data formats that are both open and linkable.
As explained in an interview by Simone Cortesi: “XML is a format that allows data to be related to other data because it lets you refer to external content, that is to name an object and search about it via the Web, to retrieve further information on the same data… If we know that Rome is defined as city, we can go look in other databases on the web, always written in XML or accessible through XML, all information about objects of the city type that are called Rome and therefore interconnect the data. A further specification on XML, called RDF (Resource Description Framework), can connect to databases on the Internet. This enhances the value of a single database, because if we have a database it can be linked to other remote, independent databases in turn linked to other ones”. RDF is already used in this way: Richard Cyganiak’s Linking Open Data Cloud diagram now represents over 13 billion RDF statements connecting data from across a growing network of participating sites.
When it comes to software, practically all public services are based on it these days, so Free/Open Source Software (FOSS) that every developer can modify or reuse without license fees or similar restrictions is a necessary component of an open digital society. However, it is worthwhile to point out that, technically speaking, Open Data may happen even when proprietary, closed source software is used in their generation, analysis and distribution, as long as only really open standards are allowed for file formats and computer protocols.