In which state does a process spend time waiting for I/O operations to complete?

When a process is in the blocked state, it indicates that the process is unable to continue executing because it is currently waiting for I/O operations to complete. During this time, the process has requested some form of input or output—such as reading from a disk or waiting for user input—but it cannot proceed until those operations are fulfilled.

This state is crucial for efficient resource management in an operating system, as it allows the CPU to execute other processes rather than sitting idle while waiting for the I/O operation to finish. Once the required I/O operation is completed, the process transitions back to the ready state, where it waits for the CPU to become available for execution.

In contrast, the running state refers to processes currently being executed by the CPU, the ready state indicates processes that are prepared to run as soon as the CPU is free, and the terminated state describes processes that have completed their execution and have been removed from the system. Each of these other states serves different functions that underscore the role of blocked processes in managing I/O in an operating system.