Formats of HAR and other Fortran files

The Header Array files used by GEMPACK are stored on disk in a special format compatible with the Lahey Fortran compilers. Some years ago, Lahey decided to change this disk-file format. So now there are two special formats:

•the old format, which we call Lahey, is compatible with the obsolete F77L3-EM32 and LF90 compilers, which are not supported by modern GEMPACK.

•the new format, which we call Fujitsu, is compatible with the modern compilers supported by GEMPACK.

ViewHAR opens either style. A tiny panel at bottom right indicates the type of the currently open file. It shows blue for Lahey files, and green for Fujitsu files.

Fortran-based EXES supplied with or created with GEMPACK will produce one or the other type of file according to which compiler was used to create those EXEs.

Fortran-based EXES supplied with or created with GEMPACK 6.0 or below will not read the Fujitsu type of file and will only create the Lahey type of file.

Fortran-based EXES supplied with or created with GEMPACK 7.0 or later will read both types of files but will only write one type (according to which compiler was used to create those EXEs).

When a user installs the source code version of GEMPACK he or she decides which compiler is to be used and whether supplied EXE files are of the LF90 or LF95 type. So on a given PC, the GEMPACK system is also either of Lahey or Fujitsu flavour. The executable image version of GEMPACK (which needs no compiler) is of Fujitsu flavour.

When a GEMPACK EXE compiled with LF90 has to read a Fujitsu file, it first creates a temporary copy in Lahey format and then reads that. Similarly, when a GEMPACK EXE compiled with LF95 has to read a Lahey file, it first creates a temporary copy in Fujitsu format and then reads that. The process is automatic and transparent to the user -- although there will be a performance cost.

To avoid this performance hit, or to enable GEMPACK 6 users to read data stored in Fujitsu files, you may need to translate data files between Lahey and Fujitsu formats. GEMPACK offers several conversion programs for this purpose. The official program is DOS-based, and called CONLF.EXE. ConvHAR is a Windows based program, written by Mark Horridge, which converts groups of files simultaneously. Also, ViewHAR can read or save in either format (so could be used to convert).

Note: When a GEMPACK EXE internally converts a HAR file by making a temporary copy, the log file will refer to the temporary copy as the input file -- which might be confusing.

URL of this topic: www.copsmodels.com/webhelp/rungtap/hc_lhfilefmt.htm

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