A GASCA system has two aspects, the architecture and the software. The GASCA architecture is composed of several modules running in several cabinets connected by the system, backplane and maintenance buses. A fundamental concept of GASCA is the partition, adopted from ARINC 653. The operating system software is the only software layer defined in GASCA, interacting with the application layer through the GASCA API. The project is still in the demonstration phase, and the OS, Configuration Manager, Fault Manager, Sample Applications and Distribution tool are presented.