Usage share of operating systems Usage share of operating systems The usage share of operating systems is the percentage of computing devices that run each operating system at any particular time. All such figures are necessarily estimates because data about operating system share is difficult to obtain; there are few reliable primary sources—and no agreed methodologies for its collection. In the personal computing platform area of smartphones and watches two systems dominate: Google's Android with over 2.7 billion users and Apple's iOS and macOS combined with over 1.3 billion users. In the area of desktop and laptop computers, Microsoft Windows is generally above 75% in
Advanced Comprehensive Operating System Advanced Comprehensive Operating System Advanced Comprehensive Operating System is a family of mainframe computer operating systems developed by NEC for the Japanese market. It consists of three systems, based on the General Comprehensive Operating System family developed by General Electric, Honeywell, and Bull. Two of these systems, ACOS-2 (based on GCOS 4) and ACOS-4 (based on GCOS 7) are still sold, although only ACOS-4 is under active development. ACOS-6 (based on GCOS 8) is an obsolete high-end mainframe platform, which ceased active development in the early 2000s. In late September 2012, NEC announced a return from IA-64 to the previous