How does the operating system act as a resource manager and extended machine?

An operating system is the interface between the user and the machine which controls and coordinates the use of the hardware among the various application programs for the various users. The OS serves two fundamental roles: as an extended machine that provides abstraction, and as a resource manager that efficiently allocates system resources.

Operating System as Extended Machine

The operating system acts as an extended machine by providing a layer of abstraction that hides the complexity of hardware from programmers and users.

Key Features of Extended Machine

• At the machine level, a computer's structure is complicated to program, especially for input/output operations. The OS provides abstraction so programmers can focus on software implementation rather than hardware details.

• Operating systems provide abstractions for hardware resources such as files for disk storage, which allows programs to create, write, and read files without dealing with low-level hardware operations.

• This level of abstraction is key to managing complexity by turning impossible tasks into manageable ones.

• Good abstractions divide complex problems into two parts: defining and implementing the abstractions, and solving the actual problem at hand.

Example − It is easier to work with photos, emails, songs, and web pages than dealing with the raw bits and sectors on disk drives.

Operating System as Resource Manager

The operating system manages and allocates system resources among competing programs and users in an orderly and controlled manner.

Resource Management Techniques

Modern computers consist of processors, memory, timers, network interfaces, printers, and other devices. The OS provides controlled allocation through two main approaches:

• Time Multiplexing − Resources are shared by taking turns. Different programs use the CPU one after another in a scheduled manner. Example: printer sharing where jobs are processed sequentially.

• Space Multiplexing − Resources are divided into portions, with each program getting a part simultaneously. Example: main memory is partitioned among multiple running programs.

Comparison of Both Roles

Conclusion

The operating system serves dual roles as both an extended machine that abstracts hardware complexity and a resource manager that efficiently allocates system resources. These complementary functions enable multiple programs to run simultaneously while providing users with a simplified interface to interact with complex computer hardware.