JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD MCA 2022 OPERATING SYSTEMS Previous Question Paper (October/November - 2022 - R20)

A parallel system is a tightly coupled system where multiple processors share a common physical memory and a single clock, managed by a single operating system. Its primary goal is to increase computational speed by executing tasks simultaneously on shared data.

A distributed system is a loosely coupled system where processors do not share memory or a clock. Each node has its own local memory and operating system, communicating via a network. Its primary goal is resource sharing, scalability, and fault tolerance.

Operating systems provide a set of services to ensure the efficient operation of computer systems and to facilitate the development and execution of user programs:

• Program Execution: The system loads programs into memory and manages their execution, providing mechanisms for process creation, scheduling, and termination.
• I/O Operations: Since users cannot access hardware directly, the OS provides a uniform interface to manage various input and output devices.
• File System Manipulation: The OS provides services for creating, deleting, reading, writing, and managing access permissions for files and directories.
• Communications: It facilitates data exchange between processes, whether they are on the same computer (via shared memory or message passing) or across a network.
• Error Detection: The OS constantly monitors the system for potential errors in CPU, memory, I/O devices, or user programs to ensure consistent computing.
• Resource Allocation: It manages system resources like CPU cycles, main memory, and file storage among multiple users or jobs.
• Accounting: The OS tracks which users use how much and what kind of resources, which is useful for performance tuning and billing.
• Protection and Security: It ensures that access to system resources is controlled, preventing unauthorized users from interfering with system integrity or other users' data.