Operating-System

Operation System is the Software that controls the Hardware. We See an operating System as the programs that make the hardware functionable. An operating system is the set of programs that control a computer.

Controlling the computer involves software at several level. we will differentiate kernel services, application-level services and library Services, all of which are part of the operating system. Processes run applications linked together with libraries that performs standard services. The kernel supports the processes by providing a path to the peripheral devices. The kernel respond to services call from the process and interrupts from the devices.

Operating system are resource managers. The main resource is computer hardware in the form of processors, storages, input/output devices, Communication devices, and data.

Examples of operating Systems

UNIX, Mach, MS-DOS MS-Windows, Windows/NT Chicago, OS/2, MacOS. 


Objectives of Operating System

  • To hide details of hardware by creating abstraction:- An abstraction is software that hide lower level details and provides a set of higher-level functions. An operation system transforms the physical world of instructions, devices, memory, and time into virtual world that is the result of abstractions built by the operating system.

  • To allocate resources to processes (Manage resource):- An Operating System controls how processes (the active agents) may access resources(passive entities). 

  • Provide a pleasant and effective user interface:- The user interacts with the operating system through the user interfaces and usually interested in the "look and feel" of the operating System. The important component of the user interface are the command interpreter ,applications integration, the file system, and on-line help.

  • Resource manager and Extended Machine:-  From Resources manager point of views  Operating Systems manage the different parts of the systems efficiently and from extended machines point of view Operating system provides a virtual machine to user that is more convenient to use.