Add original unix v6

sys/file.h

@@ -0,0 +1,19 @@
+/*
+ * One file structure is allocated
+ * for each open/creat/pipe call.
+ * Main use is to hold the read/write
+ * pointer associated with each open
+ * file.
+ */
+struct	file
+{
+	char	f_flag;
+	char	f_count;	/* reference count */
+	int	f_inode;	/* pointer to inode structure */
+	char	*f_offset[2];	/* read/write character pointer */
+} file[NFILE];
+
+/* flags */
+#define	FREAD	01
+#define	FWRITE	02
+#define	FPIPE	04