AT&T UNIX™PC Unix System V Users Manual - tenox

FS (4) FS (4)
NAME
file system - format of system volume
SYNOPSIS
#include
#include
#include
DESCRIPTION
Every file system storage volume has a common format for certain
vital information. Every such volume is divided into a certain
number of 512 byte long sectors. Sector 0 is unused and is available
to contain a bootstrap program or other information.
Sector 1 is the super-block. The format of a super-block is:
I*
* Structure of the super-block
*I
struct filsys
{
};
ushort s_isize;
daddr_t s_fsize;
short s_nfree;
daddr_t s_free[NICFREE] ;
short s_ninode;
ino_t s_inode[NICINOD];
char s_flock;
char s_ilock;
char s_fmod;
char s_ronly;
time_t s_time;
short s_dinfo[4] ;
daddr_t s_tfree;
ino_t s_tinode;
char s_fname[6];
char s_fpackf6];
long s_fi11[13 ;
long s_magic;
long s_type;
#define FsMAGIC Oxfd187e20
#define Fs1 b
#define Fs2b
1
2
- 1 -
I* size in blocks of i-list *I
/* size in blocks of entire *I
I* volume *I
I* number of addresses *I
I* in s_free *I
/* free block list *I
/* number of i-nodes in *I
I* s_inode *I
/* free i-node list *I
/* lock during free list *I
/* manipulation *I
/* lock during i-list *I
/* manipulation *I
I* super block modified *I
I* flag * I
/* mounted read-only flag * I
I* last super block update *I
I* device information *I
/* total free blocks *I
I* total free inodes *I
I* file system name *I
I* file system pack name *I
/* ADJUST to make size *I
/* of file system be 512 *I
/* magic number to *I
I* indicate new file system *I
I* type of new file system *I
/* s_magic number *I
/* 512 byte block *I
/* 1024 byte block *I