Research V6 development

[unix-history] / usr / sys / inode.h

diff --git a/usr/sys/inode.h b/usr/sys/inode.h
index c8c69de..88c7fe6 100644 (file)
--- a/usr/sys/inode.h
+++ b/usr/sys/inode.h
@@ -1,36 +1,47 @@
-struct inode {
+/*
+ * The I node is the focus of all
+ * file activity in unix. There is a unique
+ * inode allocated for each active file,
+ * each current directory, each mounted-on
+ * file, text file, and the root. An inode is 'named'
+ * by its dev/inumber pair. (iget/iget.c)
+ * Data, from mode on, is read in
+ * from permanent inode on volume.
+ */
+struct inode
+{

        char    i_flag;
        char    i_flag;

-       char    i_count;
-       int     i_dev;
-       int     i_number;
+       char    i_count;        /* reference count */
+       int     i_dev;          /* device where inode resides */
+       int     i_number;       /* i number, 1-to-1 with device address */

        int     i_mode;
        int     i_mode;

-       char    i_nlink;
-       char    i_uid;
-       char    i_gid;
-       char    i_size0;
-       char    *i_size1;
-       int     i_addr[8];
-       int     i_lastr;
+       char    i_nlink;        /* directory entries */
+       char    i_uid;          /* owner */
+       char    i_gid;          /* group of owner */
+       char    i_size0;        /* most significant of size */
+       char    *i_size1;       /* least sig */
+       int     i_addr[8];      /* device addresses constituting file */
+       int     i_lastr;        /* last logical block read (for read-ahead) */

 } inode[NINODE];
 
 /* flags */
 } inode[NINODE];
 
 /* flags */

-#define        ILOCK   01
-#define        IUPD    02
-#define        IACC    04
-#define        IMOUNT  010
-#define        IWANT   020
-#define        ITEXT   040
+#define        ILOCK   01              /* inode is locked */
+#define        IUPD    02              /* inode has been modified */
+#define        IACC    04              /* inode access time to be updated */
+#define        IMOUNT  010             /* inode is mounted on */
+#define        IWANT   020             /* some process waiting on lock */
+#define        ITEXT   040             /* inode is pure text prototype */

 
 /* modes */
 
 /* modes */

-#define        IALLOC  0100000
-#define        IFMT    060000
-#define                IFDIR   040000
-#define                IFCHR   020000
-#define                IFBLK   060000
-#define        ILARG   010000
-#define        ISUID   04000
-#define        ISGID   02000
-#define ISVTX  01000
-#define        IREAD   0400
+#define        IALLOC  0100000         /* file is used */
+#define        IFMT    060000          /* type of file */
+#define                IFDIR   040000  /* directory */
+#define                IFCHR   020000  /* character special */
+#define                IFBLK   060000  /* block special, 0 is regular */
+#define        ILARG   010000          /* large addressing algorithm */
+#define        ISUID   04000           /* set user id on execution */
+#define        ISGID   02000           /* set group id on execution */
+#define ISVTX  01000           /* save swapped text even after use */
+#define        IREAD   0400            /* read, write, execute permissions */

 #define        IWRITE  0200
 #define        IEXEC   0100
 #define        IWRITE  0200
 #define        IEXEC   0100