If you invest in semiconductor companies, you're probably well aware of the volatility of their businesses. Business conditions can change quickly, resulting in wild swings in revenue and stock prices. So even though Applied Materials (NASDAQ:AMAT) reported solid results for its first fiscal quarter in 2007 on Tuesday, not to mention a favorable outlook, I have to wonder when the pendulum will swing in the other direction. But before worrying about the future, let's look at the recent past.