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Links:
[1] http://www.uspto.gov
[2] http://www.boondog.com/tutorials/8255/8255.htm
[3] http://www.ohiolink.edu/etd/view.cgi?bgsu1120167127
[4] http://www.jameco.com
[5] http://sourceforge.net
[6] http://www.tldp.org/HOWTO/IO-Port-Programming.html
[7] http://www.tdlp.org/LDP/lkmpg/2.6/html/index.html