Electronics Engineering (ELEX) Board Practice Exam

A process is moved to the wait queue when I/O request is made with ____________.

1. non-blocking I/O

2. blocking I/O

3. delay I/O

4. asynchronous I/O

The correct answer is: blocking I/O

When a process makes an I/O request that is classified as blocking I/O, it is moved to the wait queue. This situation occurs because blocking I/O operations require the process to wait until the operation is completed before it can proceed with its execution. The system temporarily suspends the process while the I/O operation, such as reading from a disk or waiting for user input, is performed. This is critical in ensuring efficient resource management within the operating system, as it allows other processes to utilize the CPU while the requesting process is in a waiting state. In contrast, non-blocking I/O allows a process to continue executing without waiting for the I/O operation to complete, enabling more efficient concurrent processing. Delay I/O is not a commonly recognized term in this context, and asynchronous I/O, while also non-blocking, involves mechanisms to notify the process of completion, which allows it to handle other tasks in the meantime. However, with blocking I/O, the inherent design necessitates moving the process to the wait queue due to its dependence on the completion of the I/O operation before it can resume its operation.