Asynchrony, in software programming, refers to events that occur outside of the primary program flow and methods for dealing with them. External events such as signals or activities prompted by a program that occur at the same time as program execution without causing the program to block and wait for results are examples of this category. Asynchronous input/output is an example of the latter case, and allows programs to issue commands to storage or network devices that can process these requests while the processor continues executing.