holds the low 16 bits.
@item
-The file system number of the file system that the file is in. This
-element and the file's inode number together give enough information to
+The file system number of the file system that the file is in.
+Depending on the magnitude of the value, this can be either an integer
+or a cons cell, in the same manner as the inode number. This element
+and the file's inode number together give enough information to
distinguish any two files on the system---no two files can have the same
values for both of these numbers.
@end enumerate