OT and IT: the two worlds of industrial computing
The founding distinction of digital industry: OT drives machines and the physical process, IT manages information and data. Two worlds with opposite priorities.
In one sentence
OT moves matter; IT circulates information. Understanding this boundary is understanding the entire architecture of a digital plant.
OT — operational technology
OT, Operational Technology, covers all the hardware and software that monitor and command the physical world: sensors, programmable controllers, control systems, drives, valves, robots. It is OT that runs a pump, opens a valve, stops a line in case of danger. Characteristics: real time (a command leaves within a few milliseconds), long service life (15 to 20 years), determinism, and physical consequences — an error can injure, pollute, destroy.
IT — information technology
IT, Information Technology, covers the systems that process, store and transmit information: servers, databases, email, ERP, workstations. It is the world of office computing, management, the cloud. Characteristics: frequent updates (a server is patched every month), short service life (a PC is replaced in 3 to 5 years), data first, and digital consequences — an error loses data, not lives.
In one table
| Criterion | OT | IT |
|---|---|---|
| Role | drive the physical world | manage information |
| Response time | millisecond, deterministic | a second is acceptable |
| Service life | 15–20 years | 3–5 years |
| Updates | rare, planned (stop required) | monthly, live |
| Priority #1 | availability / safety | confidentiality |
| Failure consequence | physical (safety, production) | digital (data) |
The reversed priority
This is the most important point. IT and OT rank security in the opposite order:
| Priority | IT | OT |
|---|---|---|
| 1 | Confidentiality | Availability |
| 2 | Integrity | Integrity |
| 3 | Availability | Confidentiality |
In IT, you accept cutting a service to secure it. In OT, cutting means stopping production — or even creating a hazard. You do not restart a blast furnace the way you restart a server. This inversion explains why you cannot apply IT recipes as-is to the industrial world.
IT/OT convergence
Long separated, the two worlds are coming together: shop-floor data rises to the cloud, the IIoT connects sensors, AI analyses production. This convergence creates value, but also opens OT to cyber threats coming from IT. That is the whole stake of industrial cybersecurity, structured by the Purdue model and the IEC 62443 standard.