Xcas/Giac is an open-source project developed by Bernard Parisse's et al. at the Joseph Fourier University of Grenoble ( Isère) since 2000. It is based on experiences gained with Parisse's former project Erable.
Giac has a compatibility mode with Maple and MuPAD software and TI-89, TI-92 and Voyage 200 calculators. Users can use Giac/Xcas as well as a free software compatible with Maple to develop formal algorithms or use it in other software.
Pocket CAS and CAS Calc P11 utilize Giac. In 2013, it was also integrated into GeoGebra's CAS view.
CmathOOoCAS, an OpenOffice.org plugin which allows formal calculation in Calc spreadsheet and Writer word processing, uses Xcas to perform calculations.
The system was also chosen by Hewlett-Packard as the CAS for their HP Prime calculator, which utilizes the Giac/Xcas 1.1.2 engine under a dual-license scheme.