National Aeronautics and Space Administration

Portability

In the design of the FTOOLS, portability was given the highest consideration. The software specifications called for ANSI FORTRAN and C as the base languages. To bind the differences in these languages between supported architectures, the C macro package CFORTRAN develop by Burkhard Burows and distributed by CERN is used. The FTOOLS design also required a common user interface in the three most popular environments used by the astronomical community today, Unix, VMS and IRAF. Under Unix and VMS, the FTOOLS are referred to as stand-alone or ``Host'' to distinguish this environment from IRAF. However, the user interface to the FTOOLS is identical in all environments. To achieve this cross environment support, a user interface based on the IRAF parameter file was adopted. This particular interface provides for command line assignment of any or all parameters, range checking, defaults and user prompts. By isolating the interface to the data and parameter files files to standardized subroutines common to all environments, the differences in making FTOOLS for Unix, VMS and IRAF are resolved by linking to the appropriate libraries such as IRAF or the stand-alone XPI parameter interface. This is illustrated on top in Figure 1.

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Figure 1: FTOOLS Task and Package Design.