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 bdsup_bfsmagic; /∗ Magic number ∗/
off_t bdsup_start;/∗ Filesystem data start offset ∗/
off_t bdsup_end;/∗ Filesystem data end offset ∗/
 /∗
∗ Sanity words
∗/
daddr_t bdcp_fromblock; /∗ "From" block of current transfer ∗/
daddr_t bdcp_toblock; /∗ "To" block of current transfer ∗/
daddr_t bdcpb_fromblock; /∗ Backup of "from" block ∗/
daddr_t bdcpb_toblock; /∗ Backup of "to" block ∗/
long bdsup_filler[121]; /∗ Padding ∗/
};
 #define BFS_MAGIC   0xBADFACE /∗ 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 the sections on the bfs file system in the Machine and User Management book for a description of compaction. 

SEE ALSO

bfs-specific, inode(4). 

  —  bfs