Software tools are an essential part of any IC design system but there are dangers associated with the introduction of CAD systems. This paper attempts to lift the software cloak which, along with the ubiquitous workstation, tends to cover the finer points of CMOS design. This paper should help to make the designer or user of gate arrays more aware of the important features such as power dissipation, the use of transmission gates, latch-up prevention, the pitfalls of using circuit simulators, and the importance of selecting the correct package.