Example of Multitasking

Question

In the case of a computer with a single CPU, only one task is said to be running at any point in time.
How is it possible to play a song concurrently when we are working on other applications? I think
a running mp3 needs continuos execution(please mention if I am not correct) then why dont it
stop(even for seconds) when we open/work on other application?

Answer 1

The CPU is way faster than the sound card and can feed it as needed when its buffer is empty. The operating system can also use DMA which can take care of feeding data directly from memory to any output card without CPU intervention.