As drivers are most often implemented by a 3rd party, most operating systems also have a polling mode that queries for pending interrupts at fixed intervals or in a round-robin fashion. This mode can be set globally, on a per-driver, per-interrupt basis, or dynamically if the OS detects a fault condition or excessive interrupt generation. A polling mode may be enabled dynamically when the number of interrupts or the resource use caused by an interrupt, passes certain thresholds. When these thresholds are no longer exceeded, an OS may then change the interrupting driver, interrupt, or interrupt handling globally, from an interrupt mode to a polling mode. Interrupt rate limiting in hardware usually negates the use of a polling mode, but can still happen during normal operation during intense I/O if the processor is unable switch contexts quickly enough to keep pace.