Microsoft's controversal FAT patent upheld by German Federal Court of Justice

As reported here and elsewhere, the German Federal Court of Justice (BGH) has overtuned in his decision X ZR 27/07 dated April 20, 2010 the first-instance nullity decision 2Ni 2/05 of the Federal Patent Court (BPatG) to revoke Microsoft's German patent DE 69 429 378 (national part of EP 0 618 540) relating to a "common name space for long and short filenames" in relation to the FAT file system (see the notification of the BGH). Granted independent method claim 1 of the patent reads: 1. A method of operating a data processing system (10) comprising memory (16) holding an operating system (17), and a processor (12) for running the operating system (17), the method comprising: storing (58, 59) in the memory (16) a first directory entry (18) holding a short filename for a file; storing (58, 59) in the memory (16) a second directory entry (20) being associated with the first directory entry (18) and holding a long filename for the file, said long filename having more characters than said short filename, said second directory entry (20) further holding information (42) indicating that said second directory entry (20) holds said long filename; and in case that the operating system (17) permits only short filenames and said information (42) is set to make said second directory entry (20) invisible to the operating system (17), locating the file by accessing said first directory entry (18) or, in case that the operating system (17) permits long filenames and said information (42) is set to make said second directory entry (20) visible to the operating system (17), locating the file by accessing said second directory entry (20). By the claimed subject-matter, the patent solves the problem that the length of file names in older MS-DOS versions is limited to only eight characters in that a second directory entry holding a long file name for the file is associated with a first directory entry representing the short file name, such that the first or second entry can be activated depending on the operation system. In the first-instance nullity proceedings, the Federal Patent Court has decided on October 26, 2006 that the claims granted by the German Patent and Trademark Office (DPMA) are not based on an inventive step over the Rock Ridge Interchange Protocol (RRIP) for reading files on CD-ROMs, since RRIP extends the ISO 9660 standard towards CD-ROM contents access via the POSIX file system by exactly utilising the claimed method. In the appeal instance, however, the BGH did not agree with that ruling of the BPatG and interpreted the claimed subject-matter differently. According to the BGH's interpretation, the claimed teaching enables concuerrently using short and long file names (as enabled e.g. by the VFAT format used in Windows 95) in a way compatible with the older FAT file system, which is achieved by a file attribute (the claimed "information (42)") stored in the second file entry with the help of which the second file entry (repre…