Database is divided into pages. Page is the smallest unit of data transfer between AUX and memory. All the record occurrences are stored in pages. Every IDMS page has a unique page number and each record within the pages has unique line number. Pages in the database are grouped into areas. One page belongs to only one area. Same type of record occurrences is stored in one area. All areas of the database are stored in one or more files. One area can be stored on more than one file.