Which term is used for the sleep state that cannot be interrupted by a signal?

The term for the sleep state that cannot be interrupted by a signal is uninterruptible sleep. In this context, uninterruptible sleep refers to a state where a process is waiting for a resource and cannot be woken up by signals—typically because it is waiting on I/O operations. This is critical for system stability, as it prevents processes from being disrupted while they are in the midst of essential operations.

When a process is in this state, it is usually represented in the process status with a 'D' in the output of commands like top or ps, which indicates that the process is in an uninterruptible sleep due to waiting on input/output. This is a key aspect for system administrators and developers to understand, as it affects resource management and debugging efforts within a Linux environment.