Sommerville-Software-Engineering-10ed

More and more systems are safety-critical systems, where system failure
can endanger people. Chapter 12 is concerned with safety engineering
and techniques that may be used to develop these safety-critical systems.
I explain why safety is a broader notion than reliability and discuss methods
for deriving system safety requirements. I also explain why defined
and documented processes for safety-critical systems engineering are
important and describe software safety cases—structured documents
that are used to justify why a system is safe.
Threats to the security of our systems are one of the major problems
faced by today’s societies and I devote two chapters to this topic.
Chapter 13 is concerned with application security engineering— methods
used to achieve security in individual software systems. I explain the
relationships between security and other dependability attributes and
cover security requirements engineering, secure systems design and
security testing.
Chapter 14 is a new chapter that addresses the broader issue of resilience.
A resilient system can continue to deliver its essential services
even when individual parts of the system fail or are subject to a cyberattack.
I explain the basics of cybersecurity and discuss how resilience is
achieved by using redundancy and diversity and by empowering people
as well as through technical mechanisms. Finally, I discuss systems and
software design issues that can contribute to improving the resilience of
a system.