Asynchrony, in
computer programming, refers to the occurrence of events independently of the main
program flow and ways to deal with such events. These may be "outside" events such as the arrival of
signals, or actions instigated by a program that take place
concurrently with program execution, without the program
blocking to wait for results.
Asynchronous input/output is an example of the latter cause of asynchrony, and lets programs issue commands to storage or network devices that service these requests while the
processor continues executing the program. Doing so provides a degree of
parallelism.