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  Function 17H (decimal 23) renames files or subdirectories in a modified
  FCB pointed to by DS:DX. For the rename operation, the FCB has a special
  format. The drive and original name are located in their usual positions,
  but the new name and extension are placed at offsets 11H through 1BH in
  the FCB.

  AL = 00H signals complete success, and AL = FFH signals that the original
  name wasn't found or the new name is already in use.

  If the new name contains wildcard characters (?), they are interpreted as
  ditto-from-old-name, and the characters in the original name that
  correspond to the positions of the wildcard characters are not changed.