Log file restart area

Each copy of the restart area is 4KB in size, and has the following structure:

    Offset(length)         Description
    0(4)                   Magic number 'RSTR'
    1E(12)                 Fixup
    30(4)                  LSNa
    58(4)                  LSNb
    60(4)                  LSNc (==LSNa?)
    6C(1)                  Volume clear flag
    78(8)                  Unicode string 'NTFS'

The purpose of the various LSNs is unclear. It appears that the data around offset 3C deal with the clear/dirty state of the volume, too.