An operating system (OS) consists of programs that regulate the implementation of application programs, and serving as a go between of the client and PC hardware. The operating system manages the computer hardware systems well as giving a structure for applications to run. A few examples referenced in the volume are: Windows, Windows/NT, OS/2 and MacOS. The volume presents OS as advantageous and simple to use for the client, and makes handling client issues simpler. For a PC to begin running-for example, when it is organized or rebooted-it must have a primary program to run. This core system, or bootstrap program, will in general be straightforward. Normally, it is put in read-only memory (ROM) or digitally erasable read-only memory (EEPROM), referred by overall term firmware, inside the PC equipment. It launches all parts of the framework, from CPU catalogs to device regulators to memory elements. In multiprogramming systems, the OS determines which cycle gets the processor when and the duration. This capacity is known as process planning. The volume discusses an Operating System as doing these activities: - Keeps check of processor and process status of interaction. ; - Allocates the processor (CPU) to a function, and - De-assigns processors whenever a cycle is not generally needed.