So in NTFS, the Master File Table is itself a file. That means it can have extents. An easy way to process its records is thus to read it as a file using functions in core/fs/fs.c. However, the functions in core/fs/fs.c mostly assume the "global," Syslinux, booted-from filesystem ('this_fs'). The Syslinux filesystem drivers try to tie all data to a particular FS instance. So if an FS driver wants to open a file, it probably wants to do it _from_ a particular FS instance, such as opening the MFT. Anyway, please see commit bcb5af34d4fd02c5bd2970c89d30275cd9176168[1] and please advise how this could be done better. For example, what are the interfaces going to be like in the future, when code can specify a desired filesystem to open a file on? - Shao Miller [1] http://git.zytor.com/?p=users/sha0/syslinux.git;a=commitdiff;h=bcb5af34d4fd0 2c5bd2970c89d30275cd9176168