348 D ETECTING P ATENT I NFRINGEMENT 23.2 E XAMINING THE S OFTWARE As I said earlier, patents can cover very broad technologies and categories of software, or they can cover a small individual function within a program. Because of this, investigating software for patent infringement is a difficult task and there is no set procedure for doing it. There are some general techniques that I have found to work, in particular Searching for comments Searching for identifier names Reviewing from a high level Instrumenting running software Each of these techniques is described in a subsequent section. All of these techniques alone or in combination are useful for finding infringing code. 23.2.1 S EARCHING FOR C OMMENTS