This document discusses operating systems and provides details on various topics including processes, threads, computer system structures, and types of operating systems. It defines what an operating system is and its role in managing computer hardware and resources. It also describes different types of operating systems including mainframe systems, desktop systems, real-time systems, and handheld systems. The document discusses concepts like processes, threads, multiprocessing, distributed systems, and client-server models.
Environment encompasses all living and non-living things occurring naturally on Earth or some region thereof. It encompasses the interaction of all living species. Physical, biological, social, economical and cultural atmosphere affect human survival and economic activity. Concisely, the factors that affect living things are called environment .Environment contributes to our future, and if we don’t control the environment now, we can regret this some time.