A platform is the basic hardware and software that allows other applications and technologies to be developed on top of it. There are many types of platforms including operating systems, computing platforms, database platforms, storage platforms, application platforms, mobile platforms, and web platforms. An operating system is system software that manages computer hardware, software resources, and provides common services. It performs functions like process management, memory management, file management, device management, I/O management, and security. Popular operating systems currently include Windows, Android, iOS, Mac OS, and Linux.