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+Pathname Evaluation
+###################
+
+This chapter describes the pathname evaluation process for the
+RTEMS Filesystem Infrastructure.
+.. code:: c
+
+    XXX Include graphic of the path evaluation process
+
+Pathname Evaluation Handlers
+============================
+
+There are two pathname evaluation routines.  The handler patheval()
+is called to find, verify privlages on and return information on a node
+that exists.  The handler evalformake() is called to find, verify
+permissions, and return information on a node that is to become a parent.
+Additionally, evalformake() returns a pointer to the start of the name of
+the new node to be created.
+
+Pathname evaluation is specific to a filesystem.
+Each filesystem is required to provide both a patheval() and an evalformake()
+routine.  Both of these routines gets a name to evaluate and a node indicating
+where to start the evaluation.
+
+Crossing a Mount Point During Path Evaluation
+=============================================
+
+If the filesystem supports the mount command, the evaluate routines
+must handle crossing the mountpoint.  The evaluate routine should evaluate
+the name upto the first directory node where the new filesystem is mounted.
+The filesystem may process terminator characters prior to calling the
+evaluate routine for the new filesystem.   A pointer to the portion of the
+name which has not been evaluated along with the root node of the new
+file system ( gotten from the mount table entry ) is passed to the correct
+mounted filesystem evaluate routine.
+
+The rtems_filesystem_location_info_t Structure
+==============================================
+
+The ``rtems_filesystem_location_info_t`` structure contains all information
+necessary for identification of a node.
+
+The generic rtems filesystem code defines two global
+rtems_filesystem_location_info_t structures, the``rtems_filesystem_root`` and the ``rtems_filesystem_current``.
+Both are initially defined to be the root node of the base filesystem.
+Once the chdir command is correctly used the ``rtems_filesystem_current``
+is set to the location specified by the command.
+
+The filesystem generic code peeks at the first character in the name to be
+evaluated.  If this character is a valid seperator, the``rtems_filesystem_root`` is used as the node to start the evaluation
+with.  Otherwise, the ``rtems_filesystem_current`` node is used as the
+node to start evaluating with.  Therefore, a valid
+rtems_filesystem_location_info_t is given to the evaluate routine to start
+evaluation with.  The evaluate routines are then responsible for making
+any changes necessary to this structure to correspond to the name being
+parsed.
+.. code:: c
+
+    struct rtems_filesystem_location_info_tt {
+    void                                     \*node_access;
+    rtems_filesystem_file_handlers_r         \*handlers;
+    rtems_filesystem_operations_table        \*ops;
+    rtems_filesystem_mount_table_entry_t     \*mt_entry;
+    };
+
+*node_access*
+    This element is filesystem specific.  A filesystem can define and store
+    any information necessary to identify a node at this location.  This element
+    is normally filled in by the filesystem’s evaluate routine. For the
+    filesystem’s root node, the filesystem’s initilization routine should
+    fill this in, and it should remain valid until the instance of the
+    filesystem is unmounted.
+
+*handlers*
+    This element is defined as a set of routines that may change within a
+    given filesystem based upon node type.  For example a directory and a
+    memory file may have to completely different read routines.  This element
+    is set to an initialization state defined by the mount table, and may
+    be set to the desired state by the evaluation routines.
+
+*ops*
+    This element is defined as a set of routines that remain static for the
+    filesystem.  This element identifies entry points into the filesystem
+    to the generic code.
+
+*mt_entry*
+    This element identifies the mount table entry for this instance of the
+    filesystem.
+
+.. COMMENT: COPYRIGHT (c) 1988-2002.
+
+.. COMMENT: On-Line Applications Research Corporation (OAR).
+
+.. COMMENT: All rights reserved.
+