fs(4)                              (bfs)                              fs(4)


   NAME
         fs (bfs) - format of the bfs file system volume

   SYNOPSIS
         #include <sys/types.h>
         #include <sys/fs/bfs.h>

   DESCRIPTION
         The bfs superblock is stored on sector 0. Its format is:

               struct bdsuper
               {
                     long bdsupbfsmagic;          /* Magic number                 */
                     offt bdsupstart;            /* Filesystem data start offset */
                     offt bdsupend;        /* Filesystem data end offset   */

                     /*
                      * Sanity words
                      */
                     daddrt bdcpfromblock;       /* "From" block of current transfer */
                     daddrt bdcptoblock;         /* "To" block of current transfer   */
                     daddrt bdcpbfromblock;      /* Backup of "from" block           */
                     daddrt bdcpbtoblock;        /* Backup of "to" block             */
               };

               #define BFSMAGIC 0x1BADFACE  /* bfs magic number */

         The sanity words are  used to promote sanity during compaction.  They
         are used by fsck(1M) to recover from a system crash at any point
         during compaction.  See "Storage Blocks under bfs" in the "The bfs
         File System" section of chapter 5 in the System Administratror's
         Guide for a description of compaction.

   SEE ALSO
         bfs-specific inode(4)


















   8/91                                                                 Page 1