97 Things Every SRE Should Know

Chapter 89. Following the Path of Safety-Critical Systems

Heidy Khlaaf

Adelard

SCSs (safety-critical systems) are systems whose failure or malfunction may result in death or serious injury to people, loss or severe damage to equipment or property, and environmental harm. Despite such high risks, SCSs are often riddled with complex software, raising the potential for detrimental behavior. As a result, these systems are subject to stringent regulatory frameworks that require the use of rigorous development techniques that may mitigate adverse behavior.

A prevalent myth within the tech community is that these techniques are unnecessarily rigorous and complex and reserved for only the most critical safety systems. Unfortunately, this means a considerable and rich set of guidance and methodologies developed by the SCS community is seldom used or even considered within the tech industry.

SCSs vary greatly in their requirements regarding the rigor and applicability of development techniques, often overlapping with systems that parallel those within the scope of SRE. For example, IEC 61508, the most prevalent safety standard, consists of methods on how to apply, design, deploy, and maintain safety-related systems. Although this standard may appear specific to only SCSs, a closer examination reveals that the principles mirror those of system dependability used in systems engineering, such ...