User and Reference Guide for the Intel® Fortran Compiler 14.0
When porting nonnative data, consider the following:
Vendors might use different units for specifying the record length (RECL specifier) of unformatted files. While formatted files are specified in units of characters (bytes), unformatted files are specified in longword units for Intel Fortran (default) and some other vendors.
To allow you to specify the RECL units (bytes or longwords) for unformatted files without source file modification, use the assume byterecl compiler option.
Certain vendors apply different OPEN statement defaults to determine the record type. The default record type (RECORDTYPE) with Intel Fortran depends on the values for the ACCESS and FORM specifiers for the OPEN statement.
Certain vendors use a different identifier for the logical data types, such as hex FF and hex 00 instead of 01 to denote .TRUE. and .FALSE. See the assume byterecl compiler option.
Source code being ported may be coded specifically for big endian use.