Old school Apple story, posted on Folklore.org by Andy Hertzfeld:
In 1980, a company called Franklin Computer produced a clone of the Apple II called the Franklin Ace, designed to run the same software. They copied almost every detail of the Apple II, including all of its ROM based software and all the documentation, and sold it at a lower price than Apple. We even found a place in the manual where they forgot to change “Apple” to “Ace”. Apple was infuriated, and sued Franklin. They eventually won, and forced Franklin to withdraw the Ace from the market.
Even though Apple won the case, it was pretty scary for a while, and it wasn’t clear until the end that the judge would rule in Apple’s favor.
This is where our story starts. Follow the link to see what Apple did to prevent someone from copying the Macintosh ROM. Damn clever.