Buffer underrun

In computing, buffer underrun or buffer underflow is a state occurring when a buffer used to communicate between two devices or processes is fed with data at a lower speed than the data is being read from it. (The term is distinct from buffer overflow, a condition where a portion of memory being used as a buffer has a fixed size but is filled with more than that amount of data.) This requires the program or device reading from the buffer to pause its processing while the buffer refills. This can cause undesired and sometimes serious side effects because the data being buffered is generally not suited to stop-start access of this kind.