So, let me explain more. There are a number of competing best practices for software development. I can find that many teams have benefited from Agile practices in some cases. In some other cases, using the Unified Process has been championed by large companies like IBM. The common themes that I find seemed to work well for teams that mainly develop software. I am interested to know what has worked best for people who have worked in shops where there is a team on the other side that produce the hardware that your software is running on. For example, one team puts together a crate with several custom hardware on it; while you need to develop the software that would run on those crates. I can't find a development model (agile, spiral ...) that works best in this case. Any wisdom is this area will be well appreciated.