Operating System Essay

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Q.1 a) What is meant by operating system? Define it in detail with the help of suitable examples. Answer: The 1960's meaning of an Operating system is "the programming that controls the Hardware". Not with standing, today, because of microcode we require an improved definition. We see an operating system as the program that make the equipment usable. In short, an operating system is the set of programs that controls a computer. A few illustrations of operating systems are UNIX, Mach, MS-DOS, MS-Windows, Windows/NT, Chicago, Os/2, Macos, VMS, MVS, and VM. Controlling the computer includes programming at several levels. We will separate kernel services, library services, and requisition level services, all of which are a part of the operating system. Methods run Applications, which are interfaced together with libraries that perform standard services. The kernel backs the methodologies by furnishing a way to the peripheral devices. . The kernel reacts to services calls from the processes and interrupts from the gadgets. The center of the operating system is the kernel, a control program that capacities in special state (an execution connection that permits all equipment guidelines to be executed), responding to hinders from peripheral devices.and to service request and traps from processes. For the most part, the kernal is a lasting inhabitant of the PC. It makes and ends processes and reacts to their solicitation for services. Operating Systems are resource managers. The main resource is computer hardware in the form of processors, storage, input/output devices, communication devices, and data. Some of the operating system functions are: implementing the user interface, sharing hardware among users, allowing users to share data am... ... middle of paper ... ...d the scheduler,& Algorithm it uses is called the scheduling algorithm. The following are the main objectives of Scheduling: Make best use of available system resources, Give preference to those processes which are holding the key resources. Give preference to processes which are having good behavior. CPU Scheduler basically selects the process from the different processes which are residing in the memory and are ready to execute, & then allocates the CPU to one of them. The Scheduling may be Preemptive or Non-Preemptive: Non-preemptive Scheduling Once CPU has been allocated to a process, the process keeps the CPU until Process exits OR Process switches to waiting state Preemptive Scheduling Process can be interrupted and must release the CPU. Need to coordinate access to shared data E.g. when we use “Ctrl + Alt + Delete” to terminate the process forcefully.

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