filetypes use metadata to distinguish file formats. Some common file formats from other systems are mapped to filetypes by the MimeMap module. Such mapping was previously handled by DosMap.
The MimeMap module maps filetypes to and from MIME content types, dotted filename extensions and Apple's Uniform Type Identifiers.
Requests for new filetype allocations for all versions are handled centrally by RISC OS Open.
Filetypes were originally classified by Acorn into distinct ranges:
This range of filetypes was intended for personal use in closed systems, not for general distribution. Nevertheless, many programs using these types were distributed, especially as Public-domain software. Consequently there are many clashes.