--- xinu/h/file.h	2018/04/24 17:39:02	1.1.1.1
+++ xinu/h/file.h	2018/04/24 17:39:09	1.1.1.2
@@ -1,20 +1,38 @@
 /* file.h */
 
-#define	FLREAD		001		/* file mode bit for "read"	*/
-#define	FLWRITE		002		/* file mode bit for "write"	*/
-#define	FLRW		003		/* file mode bits for read+write*/
-#define	FLNEW		010		/* file mode bit for "new file"	*/
-#define	FLOLD		020		/* file mode bit for "old file"	*/
+/* Local disk layout: disk block 0 is directory, then index area, and	*/
+/* then data blocks.  Each disk block (512 bytes) in the index area	*/
+/* contains 8 iblocks, which are 64 bytes long.  Iblocks are referenced	*/
+/* relative to 0, so the disk block address of iblock k is given by	*/
+/* truncate(k/8)+1.  The offset of iblock k within its disk block is	*/
+/* given by 64*remainder(k,8).  The directory entry points to a linked	*/
+/* list of iblocks, and each iblock contains pointers to IBLEN (29) data*/
+/* blocks. Index pointers contain a valid data block address or DBNULL.	*/
 
-/* Definition of characters in the mode argument to open */
+#include <iblock.h>
 
-#define	FLOMODE		'o'		/* Old  => file exists		*/
-#define	FLNMODE		'n'		/* New  => file does not exist	*/
-#define	FLRMODE		'r'		/* Read => open read-only	*/
-#define	FLWMODE		'w'		/* Write=> open for writing	*/
+#define	EOF		-2		/* value returned on end-of-file*/
+#define	FLREAD		001		/* fl_mode bit for "read"	*/
+#define	FLWRITE		002		/* fl_mode bit for "write"	*/
+#define	FLRW		003		/* fl_mode bits for read+write	*/
+#define	FLNEW		010		/* fl_mode bit for "new file"	*/
+#define	FLOLD		020		/* fl_mode bit for "old file"	*/
 
-/* Universal file control functions (additional args in parentheses)	*/
+struct	flblk	{			/* file "device" control block	*/
+	int	fl_id;			/* file's "device id" in devtab	*/
+	int	fl_dev;			/* file is on this disk device	*/
+	int	fl_pid;			/* process id accessing the file*/
+	struct	fdes	*fl_dent;	/* file's in-core dir. entry	*/
+	int	fl_mode;		/* FLREAD, FLWRITE, or both	*/
+	IBADDR	fl_iba;			/* address of iblock in fl_iblk	*/
+	struct	iblk	fl_iblk;	/* current iblock for file	*/
+	int	fl_ipnum;		/* current iptr in fl_iblk	*/
+	long	fl_pos;			/* current file position (bytes)*/
+	Bool	fl_dch;			/* has fl_buff been changed?	*/
+	char	*fl_bptr;		/* ptr to next char in fl_buff	*/
+	char	fl_buff[DBUFSIZ];	/* current data block for file	*/
+};
 
-#define	FLREMOVE	3001		/* remove file (name)		*/
-#define	FLACCESS	3002		/* test access (name, mode)	*/
-#define	FLRENAME	3003		/* change file name (old, new)	*/
+#ifdef	Ndf
+extern	struct	flblk	fltab[];
+#endif