Our had sophisticated mathematical models written for our industry. These were developed in the late 90's/early 2000's. When they tried to port these models t

Our had sophisticated mathematical models written for our industry. These were developed in the late 90's/early 2000's. When they tried to port these models to "a more modern format" to programming language code, they realised that it was far more complex than they had anticipated, and even small mistakes would be disastrous for the company. Their solution? Dozens of virtual servers around the world, each one hosting a copy of Excel with a 20-30MB workbook, communicating with the outside world via TCP/IP and COM interface code.