“Filing System” is a term defined in Art. 4 para 6 of the EU General Data Protection Regulation (GDPR). It means any structured set of personal data which are accessible according to specific criteria, whether centralised, decentralised or dispersed on a functional or geographical basis.
On a more general level, in computing the file system or filesystem is a piece of software and logic which controls how data is stored and retrieved. Without a file system, information placed in a storage medium such as a hard disk would be one large, unstructured mass of data with no way to tell where a specific piece of information is stored, and where the next begins. A filing system is also a necessary to implement access control rights, i.e. measures that permit only certain users of a computer to access a particular piece of information.