The document discusses different types of critical systems including safety-critical systems, mission-critical systems, business-critical systems, and socio-technical critical systems. It notes that critical systems must not experience hardware, software, or operational failures as their proper functioning is vital, important, and can be decisive. An example given of a safety-critical system is a software-controlled insulin pump that must correctly deliver the proper doses of insulin without excessive amounts.

2.  Important
 Vital
 Decisive

3.  Safety-Critical Systems
 Mission-Critical Systems
 Business-Critical Systems
Socio-technical Critical Systems

4. Safety-critical
systems

5. Mission-critical
systems

6. Business-
critical
systems

7. Socio-technical
means:
Systems having
both social and
technical aspects.

11.  Hardware failure
 Software failure
 Operational failure

12. A software-controlled insulin pump

13.  Deliver insulin when required.
Shall do
 Deliver the correct amount of insulin.
 Never deliver excessive doses. Shall not
Do