The term information technology is mostly used today to denote anything even remotely related to data. IT is generally defined as the ability of computers to store, access, manipulate and transmit data or information. OT on the other hand helps manage and control activities of specific devices and processes within industrial workflows.
A very significant aspect in the evolution of operational technology was the ability to remotely access, monitor and control physical devices. The fusion of OT with IT based technologies like big data, and ML along with evolving machine-to-machine (M2M) communications and rapid proliferation of sensor technology further broadened the scope of innovations within terms of management of physical devices.
IT is highly standardized. For instance, the TCP/IP protocol that is in place in one infrastructure will work the same way the TCP/IP protocol would in another facility. This offers resilience to the system. In case of OT, the operations are relatively unique. There can be more than just a few ways to make a system do the same thing. Also, it is mostly created to perform specifically tailored tasks. In other words, most systems are custom built for specific purposes, and interoperability can be an issue.