GCI General Calling Interface
The General Calling Interface was originally developed on Prime INFORMATION systems to allow the execution of FORTRAN routines, from inside Prime INFORMATION. GCI was extended to allow the execution of C, C# and C++ routines as well.
Prime INFORMATION Devcom, a Microdata reseller, wrote a Pick-style database system called INFORMATION in FORTRAN and assembler in 1979 to run on Prime Computer 50-series systems. It was then sold to Prime Computer and renamed Prime INFORMATION. It was subsequently sold to Vmark Software. INFO/BASIC, a variant of Dartmouth BASIC, was used for database applications, and GCI was used as a gateway to allow the execution of the older Fortran routines. PI/open Prime Computer rewrote Prime INFORMATION in C for the Unix-based systems it was selling, calling it PI+. It was then ported to other Unix systems offered by other hardware vendors and renamed PI/open.
Prime computer sold these operating systems to Vmark which later became Ardent, and then Informix. The core of Information and PI/open, by this time, were all rolled up into what was then (and still is) called the Universe database.
Informix sold Universe and the later acquired Unidata, both to IBM. IBM sold all of this to Rocket Software, the current owners.