On a linux system, this will dump the contents of your computers memory to the soundcard, allowing you to hear what the computer is thinking. While it mainly sounds like a bunch of random noise, if you listen closely you will be able to hear patterns. This is because the data in you computers memory isn't random - it has form and structure, even if this isn't obvious when you first look at it.

The SparcStation2 technical docs recommend catting your /vmunix file to /dev/audio as a speaker test. If you go nearly deaf from the painful noise, then your speaker works.