Glossary · Automation software engineering and architecture
Process (computing)
Also known as: Operating system process
German: Prozess
In operating systems, a process is an instance of a program in execution, with its own address space, resources and one or more threads, isolated from other processes by the operating system.
- Software engineering
In one sentence
A process is a running instance of a program with its own address space and resources, isolated from other processes by the operating system.
Example
On the industrial PC, the soft PLC runtime, the HMI and the OPC UA server each run as a separate process, so a crash of the HMI does not stop the control program.
How it applies
- Engineering: Separating functions into processes isolates faults and allows separate privileges. Processes exchange data through inter-process communication such as sockets or Shared memory.
- Operation: Service tools list processes and their resource use; a process that restarts repeatedly is a common diagnostic finding.
- Documentation: Installation and security documentation should list the processes and services the product runs, the user accounts they run under and the ports they open.
Process (computing) vs. process (industrial)
In this entry, a process is an operating-system concept. In process automation, a process is the physical or chemical transformation of materials in a plant, which the control system controls. Documentation for automation software should make clear which meaning is intended.