A computer system includes one or more devices that are capable of multitasking (performing at least two tasks in parallel or substantially in parallel). In response to detecting that one of the devices is performing a first one of the tasks, the system prevents the devices from performing at least one of the tasks other than the first task (such as all of the tasks other than the first task). In response to detecting that one of the devices is performing a second one of the tasks, the system prevents the devices from performing at least one of the tasks other than the second task (such as all of the tasks other than the second task).