Since this is not my area of expertise, I searched Google under the key words "computer input output" to get these possible sources:
http://en.wikipedia.org/wiki/Input/output
http://www.abcya.com/input_output.htm
http://www.ziplink.net/users/teachcte/comp-rel/misc/in-out1.htm
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.
I hope this helps. Thanks for asking.