anchor.diff:  
   \ try-files and try-partitions
   
  -: (interpose-filesystem) ( str len -- )
  -   find-package IF args args-len rot interpose THEN
  -;
  -
   : try-dos-files ( -- found? )
      no-mbr? IF false EXIT THEN
   
  
positive.code:    s" fat-files" (interpose-filesystem)
     true
  ;
  
  : try-ext2-files ( -- found? )
     2 read-sector               \ read first superblock
     block d# 56 + w@-le         \ fetch s_magic
     ef53 <> IF false EXIT THEN  \ s_magic found?
     s" ext2-files" (interpose-filesystem)
     true
  ;
  
  
  : try-iso9660-files
     has-iso9660-filesystem 0= IF false exit THEN
  
negative.code:      seek-pos gpt-part-size + to seek-pos
     LOOP
     false
  ;
  
  : (interpose-filesystem) ( str len -- )
     find-package IF args args-len rot interpose THEN
  ;
  
  : try-ext2-files ( -- found? )
     2 read-sector               \ read first superblock
     block d# 56 + w@-le         \ fetch s_magic
     ef53 <> IF false EXIT THEN  \ s_magic found?
     s" ext2-files" (interpose-filesystem)
     true
  ;
  
  : try-gpt-dos-partition ( -- true|false )
  