"The system is not an application, but rather an architecture for different modules that work together to track the records of a given patient. It was implemented in the Veterans Administration (VA) hospital system, and as time went on and more medical practice and experience was integrated into the system, the architecture that would be known as VistA would become so efficient, it has received more than a little credit for helping the VA healthcare system, Veterans Health Affairs, turn itself around in recent years.
"The interesting thing about VistA is that the entire architecture is public domain, which is even more free than the GPL. That means anyone can take the code and use it however they want. So anyone who wants to build an electronic patient record system has an $8.6 billion headstart investment in the code, courtesy of the US taxpayers. This has led to the deployment of VistA systems in several non-VA (and even non-US) hospitals, and quite a strong industry of firms that have grown up to implement VistA tools."
