I just thought I'd puts an upper bound to the duration for which these weak patents can be even arguably relevant. Of the three patents concerning long filenames on FAT32, #5579517's earliest filing date was April 1, 1993 (being a continuation of abandoned application #41497), #5758352's earliest filing date was the same for the same reason, and #6256642's earliest filing date was Jan. 29, 1992. In the event that the "continuation from earlier applications" isn't the relevant earliest filing date specified in current US patent law (as I'm not a patent or any other type of attorney), then the actual filing dates for the cited patents are: April 24, 1995, Sept. 5, 1996, and Jan. 29, 1992, respectively.
So, these patents will be all gone by either April 1, 2013 or Sept 5, 2016, depending -- four or seven years from now.
(USPTO has special situations where applicants can get patents extended, but they don't seem to apply, here.)