An infinite loop is a sequence of instructions in a computer program which loops enlessly, either due to the loop having no terminating condition or having one that can never be met. In older operating systems with cooperative multitasking, infinite loops normally caused the entire system to become unresponsive. With the now-prevalent preemptive multitasking model, infinite loops usually cause the program to consume all available processor time, but can usually be terminated by the user. Busy-wait loops are also sometimes misleadingly called "infinite loops". One possible cause of a computer "freezing" is an infinite loop; others include deadlock and access violations.