All editions support 32-bit IA-32 CPUs and all editions except Starter support 64-bit 圆4 CPUs. The other editions focus on other markets, such as the software development world or enterprise use. Only Home Premium, Professional, and Ultimate were widely available at retailers. Windows 7, a major release of the Microsoft Windows operating system, was available in six different editions: Starter, Home Basic, Home Premium, Professional, Enterprise and Ultimate.