anchor.diff:  (defconstant +attribute-directory+ 4)
   (defconstant +attribute-archive+ 5)
   
  -(defun file-p (cluster offset)
  -  (/= (ldb (byte 1 +attribute-directory+)
  -           (aref cluster (+ 11 offset)))
  -      1))
  -
  -(defun read-file (fat32 disk cluster-n fat)
  +(defun file-p (directory offset)
  +  (= (ldb (byte 1 +attribute-archive+)
  +          (aref directory (+ 11 offset)))
  +     1))
  +
  +(defun directory-p (directory offset)
  +  (= (ldb (byte 1 +attribute-directory+)
  +          (aref directory (+ 11 offset)))
  +     1))
  +
  +;; WIP
  +(defun read-file (fat32 disk file-cluster fat)
     (let ((file-buffer #()))
  -    (do ((i cluster-n
  +    (do ((i file-cluster
               (sys.int::ub32ref/le fat (* i 4))))
           ((>= i #x0FFFFFF8) file-buffer)
         (setf file-buffer
  
positive.code:       (error "Bad trail-signature : ~a .
  Valid trail-signature is ~a" trail-signature +trail-signature+)))
  
  (defun read-fat32-info-structure (sector)
    (let ((lead-signature (sys.int::ub32ref/le sector 0))
          (structure-signature (sys.int::ub32ref/le sector 484))
          (trail-signature (sys.int::ub32ref/le sector 508)))
      (check-lead-signature lead-signature)
      (check-structure-signature structure-signature)
      (check-trail-signature trail-signature)
  
negative.code: ;; Mount partition
  ;; (let* ((disk-name "FAT32")
  ;;        (disk (nth 3 (mezzano.supervisor:all-disks)))
  ;;        (fat32 (read-fat32-structure disk))
  ;;        (fat32-info (read-fat32-info-structure disk fat32))
  ;;        (fat (read-fat disk fat32))
  ;;        (instance (make-instance 'fat32-host
  ;;                                 :name disk-name
  