Well, here's my 2 cents worth. Most of my Japanese was learned during my three years in Japan and my 500 hours at Berlitz. I've forgotten now more than I've learned. But I hit the books from time to time even now. I always thought Katagana was more like the printing style where the hiragana is more like the writing style. Kanji, of course, is taken from the Chinese characters. For example, you might see a store sign and most letters are in katagana. That's the best I can come up with.