Asynchronous

This literally means "Not at the same time".

In computer network, asynchronous data transfer between two computers means that the data clock rate coming out of the sending computer does not have to be running at same speed as the receiving computer.

For example, imagine a computer that sends data out at a rate of a 100 bits per second. The receiving computer might deal with data at 50 bits per second. So the fast asynchronous data is held in a buffer within the receiving computer, which then reads it in at 50 bits per second. If the buffer fills up, a signal is sent back to tell the other computer to stop sending data for a bit.

Another use of 'asynchronous' is within computer programs. An 'asynchronous' process (subroutine) runs independently of any other process (subroutine).

See also 'synchronous data' in the glossary.

2020-10