# 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.

- Source : https://industryhub.site/en/learn/foundations/ot-vs-it
- Track : foundations
- Level : Discovery
- Reading time : 5 min
- Language : English

## In brief

OT (operational technology) commands the physical world — sensors, controllers, machines. IT (information technology) handles data and management systems. Their priorities are reversed: OT targets availability and safety, IT targets confidentiality.

## 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](/en/learn/cybersecurity/modele-purdue) and the [IEC 62443](/en/standards/iec-62443) standard.