Circuits are the technical fundament of PCs. In ICs, processors and circuit boards you find a lot of transistors. As you could imagine, they are very complex and confusing, because they are composed out of many electrical parts For that reason, IBM invented technologies to solve this problem. In 1964 the IBM/System 360 was published. In this mainframe they build in some new technologies. The main idea is very easy: get a lot of parts on a small board. Important for economy was also, that they could produce that boards in series. In this way they could stick this boards parallel in a mainframe. On the next pages you will see, which technologies had lead to today's ICs and computer architecture.