From isacommons.org:
At the heart of this open source framework is the general-purpose [**ISA-Tab file format**](http://www.isa-tools.org/), built on the ‘Investigation’ (the project context), ‘Study’ (a unit of research) and ‘Assay’ (analytical measurement) metadata categories. The extensible, hierarchical structure of this format enables the representation of studies employing one or a combination of technologies, focusing on the description of its experimental metadata (i.e. sample characteristics, technology and measurement types, sample-to-data relationships). The [**ISA software suite**](http://www.isa-tools.org/) - the second element of this framework – acts to create and edit ISA-Tab files, store, serve and covert them to a growing number of other related format.