In order to face fragmentation, a method for storing and organizing files on a storage medium via a file system reserves on the storage medium a non-fragmented segment for taking up a file by storing within the file system an identification of an address range of the segment. The file is written within the segment and information is stored in the file system. The information is suited to find the file. The size of the segment is derived by statistical methods from file sizes of a kind of the file.