How do operating systems help computers run user programs?

An operating system (OS) acts as a manager of a computer's resources, ensuring that user programs can execute efficiently without interfering with one another. By functioning as a series of concentric shells, the OS insulates the hardware from direct access, allowing programs to run without needing to manage low-level details like memory addresses or specific input/output (I/O) devices.12

Key ways the OS facilitates program execution include:

• Resource Allocation: The OS manages the central processing unit (CPU), computer memory, and storage, scheduling their use to prevent conflicts.12
• Multiprocessing and Time-Sharing: Modern systems allow multiple programs to be active simultaneously. Through time-sharing, the OS rapidly switches CPU control between processes, ensuring no single program monopolizes the processor.1
• Protection and Isolation: Using virtual memory, the OS provides each program with its own address space, which prevents one program from corrupting the data or code of another.12
• Service Provision: The OS offers "system calls" that programs use to perform tasks like displaying graphics or accessing files, abstracting complex hardware operations into manageable services.1