A Julia package for reading and writing Fortran unformatted (i.e. binary) files.


Currently the following features are implemented and working:

  • Sequential Access mode
    • 4-byte record markers, with subrecord support (allowing records larger than 2 GiB)
    • 8-byte record markers (used by early versions of gfortran)
  • Direct Access mode
    • fixed-size records without any record markers
  • Most standard Fortran datatypes, including arrays and strings
  • "Inhomogeneous" records, i.e. records made from multiple different datatypes
  • Byte-order conversion (little endian ⟷ big endian)

The following features are not (yet) supported:

  • Derived Type I/O
  • Equivalents of BACKSPACE and ENDFILE



The FortranFiles.jl logo has been produced with help of the Virtual Keypunch service from The punchcard artwork is Copyright 2012 Norbert Landsteiner, mass:werk – media environments. It is here used by kind permission.