Fold (J. Turin)
From Just Solve the File Format Problem
Fold is a compression utility for DOS, developed by J. Turin. It has a single-file format (.FOL), and a multi-file format (extension .ARK, as used in the documentation).
The included FOLTOEXE.EXE utility can convert a FOL or ARK file to a self-extracting EXE file. The self-extracting formats for FOL and ARK are seemingly distinct.
Only v1.16e has been found, but there were presumably other versions, probably including non-English (Dutch?) versions.
Identification
FOL files start with bytes 46 fa f6 fa 31.
ARK files start with ASCII signature "FARC1".
Self-extracting FOL→EXE files apparently have text "Program J. Turin 2000" at offset 11117.
Self-extracting ARK→EXE files apparently have text "Program J. Turin 2001" at offset 11517.
