Geeta Khetan wrote: > > Is there a global bitmap that keeps track of busy/free blocks over the > entire file system ? Is there a API or command i can use for that map? > Thanks No, the bitmaps are stored on a per-cylinder group basis. You can use cgread() in libufs to read each group and then examine the bitmaps with the cg* macros in /sys/ufs/ffs/fs.h. Scott