anchor.diff:  
   (in-package #:device)
   
  -(defstruct device 
  -  handle geometry)
  -
   ;; access 
   ;;#define GENERIC_READ                     (0x80000000L)
   ;;#define GENERIC_WRITE                    (0x40000000L)
  
positive.code: 	   (type integer block)
  	   (type (vector (unsigned-byte 8)) sequence))
    (let ((count (- (or end (length sequence)) start))
  	(offset (* block (geometry-bytes (device-geometry device)))))
      (pounds::read-file (device-handle device)
  		       sequence
  		       offset
  
negative.code: 		(foreign-slot-value overlapped '(:struct pounds::overlapped)
  				    'pounds::offset-high)
  		offset-high)
  	  (let ((res (pounds::%write-file (device-handle device)
  					  buffer 
  					  length 
  					  nbytes
  					  overlapped)))
  	    (unless res
  	      (pounds::get-last-error))))))))
  
  
  	  
  