anchor.diff:  (defmethod sys.gray:stream-file-length ((stream fat32-file-stream))
     (read-buffer-size stream))
   
  -;;;; testing
  +;;; testing
   #|
   ;; Mount partition
   (let* ((partition-name "FAT32") ; Put your name here
  
positive.code:   (+ (fat32-reserved-sector-count fat32)
       (* (fat32-table-count fat32)
          (fat32-table-size-32 fat32))
       (root-dir-sectors fat32)))
  
  (defun first-root-dir-sector (fat32)
    (- (first-data-sector fat32)
       (root-dir-sectors fat32)))
  
  (defun first-sector-of-cluster (fat32 cluster)
    (+ (* (- cluster 2)
  
negative.code:                                   array)
      array))
  
  (defstruct virtual-dir
    (name nil)
    (attributes nil :type (unsigned-byte 8))
    (time-tenth nil :type (unsigned-byte 8))
    (time nil :type vector)
    (date nil :type vector)
    (access-date nil :type vector)
    (write-time nil :type vector)
    (write-date nil :type vector)
    (first-cluster nil :type (unsigned-byte 32))
    (file-size nil :type (unsigned-byte 32)))
  
  (defstruct dir
    (name nil)
    (attributes nil :type (unsigned-byte 8))
    (reserved nil) ; 12 1
    (time-tenth nil :type (unsigned-byte 8))
    (time nil :type vector)
    (date nil :type vector)
    (access-date nil :type vector)
    (first-cluster-high nil :type (unsigned-byte 16))
    (write-time nil :type vector)
    (write-date nil :type vector)
    (first-cluster-low nil :type (unsigned-byte 16))
    (file-size nil :type (unsigned-byte 32)))
  
  (defstruct long-dir
    (order nil :type (unsigned-byte 8))
    (name-0 nil :type vector)
    (attributes nil :type (unsigned-byte 8))
    (type nil :type (unsigned-byte 8))
    (checksum nil :type (unsigned-byte 8))
    (name-1 nil :type vector)
    (first-cluster-low nil :type (unsigned-byte 16))
    (name-2 nil :type vector))
  
  ;;; bit offset
  (defconstant +attribute-read-only+ 0)
  (defconstant +attribute-hidden+ 1)
  