The availability of the source code and the right to modify it is very important. It enables the unlimited tuning and improvement of a software product. It also makes it possible to port the code to new hardware, to adapt it to changing conditions, and to reach a detailed understanding of how the system works. This is why many experts are reaching the conclusion that to really extend the lifetime of an application, it must be available in source form. In fact, no binary-only application more than 10 years old now survives in unmodified form, while several open source software systems from the 1980s are still in widespread use (although in many cases conveniently adapted to new environments). Source code availability also makes it much easier to isolate bugs, and (for a programmer) to fix them.