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:    drop 0
  ;
  
  \ Check for GPT PReP partition GUID. Only first 3 blocks are
  \ byte-swapped treating last two blocks as contigous for simplifying
  \ comparison
  9E1A2D38            CONSTANT GPT-PREP-PARTITION-1
  C612                CONSTANT GPT-PREP-PARTITION-2
  4316                CONSTANT GPT-PREP-PARTITION-3
  AA268B49521E5A8B    CONSTANT GPT-PREP-PARTITION-4
  
  : gpt-prep-partition? ( -- true|false )
     block gpt-part-entry>part-type-guid
     dup l@-le     GPT-PREP-PARTITION-1 <> IF drop false EXIT THEN
     dup 4 + w@-le GPT-PREP-PARTITION-2 <> IF drop false EXIT THEN
     dup 6 + w@-le GPT-PREP-PARTITION-3 <> IF drop false EXIT THEN
         8 + x@    GPT-PREP-PARTITION-4 =
  ;
  
  \ Check for GPT MSFT BASIC DATA GUID - fat based
  EBD0A0A2            CONSTANT GPT-BASIC-DATA-PARTITION-1
  B9E5                CONSTANT GPT-BASIC-DATA-PARTITION-2
  4433                CONSTANT GPT-BASIC-DATA-PARTITION-3
  87C068B6B72699C7    CONSTANT GPT-BASIC-DATA-PARTITION-4
  
  : gpt-basic-data-partition? ( -- true|false )
     block gpt-part-entry>part-type-guid
     dup l@-le     GPT-BASIC-DATA-PARTITION-1 <> IF drop false EXIT THEN
     dup 4 + w@-le GPT-BASIC-DATA-PARTITION-2 <> IF drop false EXIT THEN
     dup 6 + w@-le GPT-BASIC-DATA-PARTITION-3 <> IF drop false EXIT THEN
         8 + x@    GPT-BASIC-DATA-PARTITION-4 =
  ;
  
  \
  
negative.code:    s" fat-files" (interpose-filesystem)
     true
  ;
  
  : try-iso9660-files
     has-iso9660-filesystem 0= IF false exit THEN
  