If you had followed the legal tussle between TomTom and Microsoft, you would know it was about the implementation of FAT filesystem in TomTom’s GPSes. According to Ars Technica, Andrew Tridgell, one of the lead developers behind the Samba project, published a patch last week that will alter the behavior of the Linux FAT implementation. The specific patents in question describe techniques for implementing a “common name space for long and short filenames.” It is a hack for preserving backwards compatibility with the filename munging scheme that was used in MS-DOS when filenames could not exceed 11 characters and were displayed in the so-called “8.3″ format.
The patch will alter the behavior of the Linux FAT implementation so that it will not generate both short and long filenames. In situations where the total filename fits within the 11-character limit, the filesystem will generate only a short name. When the filename exceeds that length, it will only generate a long name and will populate the short name value with 11 invalid characters so that it is ignored by the operating system.
This is Tridgell’s second patch to address the patent issue. His first, which was published in May, completely disabled the creation of files with long filenames. The new patch is a more practical approach and one that will have less detrimental impact on end users. The Linux kernel community was not particularly happy with the first approach, but the new patch is said to have a better chance of being accepted in the mainline kernel.
The Linux Foundation arranged for the patch to undergo extensive review by patent lawyers. They are confident that the patch will effectively evade the common namespace method described by Microsoft’s patents. It will also function properly in virtually all cases. The only situation in which it will be problematic is when the data on the filesystem is accessed from old versions of DOS or Windows that still require the 8.3 filenames. Tridgell believes that such a scenario is rare enough that it will not impact a significant number of users. Those who require compatibility with those older versions of DOS or Windows can use the Linux “msdos” filesystem, which enforces 8.3 names and doesn’t use Microsoft’s patented dual-naming convention.
Source: Ars Technica.
Technorati Tags: Ars Technica, TomTom, Microsoft, GPS, FAT, Filesystem, Linux, MS-DOS
