A/UX® Programmer's Reference Sections

ufs(4)
NAME
u f s - format of a UPS file-system volume
SYNOPSIS
#include
#include
#include
#include
#include
ufs(4)
DESCRIYTION
Every Berkeley 4.2 file-system (UPS) storage volume (for example,
a hard disk or a floppy disk) has a common fonnat for certain
vital information. Each volume is divided into a certain number
of blocks. The block size is a parameter of the file system. Sectors
0 to 7 on a file system may be used to contain bootstrap programs.
The first superblock for the file system is located at sector
8.
The actual file system begins at sector 16 with the first alternate
superblock. The layout of the superblock as defined by the include
file is:
tdefine FS MAGIC Ox01l954
struct fs {
February, 1990
Revision C
struct fs *fs_Iink;
/* linked list of file systems */
struct fs *fs_rlink;
/* used for incore superblocks */
daddr t fs_sblkno;
/* addr of superblock in filesys */
daddr t fs cblkno;
-
/* offset of cyl-block in filesys */
daddr t fs iblkno;
-
/* offset of inode-blocks in filesys
daddr t fS_dblkno;
/* offset of first data after cg */
long fs_cgoffset;
/* cylinder group offset in cylinder */
long fs_cgmask;
time t fs_time;
long fs_size;
/* used to calc mod fs_ntrak */
/* last time written */
/* number of blocks in fs */
*/
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