1What are emergent properties?
New characteristics that appear when system components are integrated and were not present in the individual parts
2What is a sociotechnical system?
A computer system that includes hardware, software, people, operational processes, and organizational politics
3What are wicked problems?
Complex problems with no definitive problem statement and conflicting stakeholder views
4What is middleware in the sociotechnical systems stack?
The layer above the operating system that handles data management and communications
5What is non-determinism in sociotechnical systems?
The characteristic where systems involving humans may react differently to the same input at different times
6What is the Social/Society layer?
The layer governed by regulations, laws, and ethical rules that dictate how a system must be operated
7What is system procurement?
The process of acquiring a system by defining scope and selecting suppliers
8What is operator error in a sociotechnical context?
A system failure caused by confusing interfaces rather than software bugs
9What is availability?
The ability of a system to deliver services when requested, focusing on uptime
10What is software maintenance?
The modification of a deployed system to correct errors or adapt to environmental changes
11What is security as an emergent property?
The system’s ability to resist external attacks or accidental intrusion
12What is the Business Process layer?
The set of organizational tasks and workflows supported by the software
13What is a technical computer-based system?
A deterministic system consisting only of hardware and software without human involvement
14What is repairability?
The ease with which a system can be repaired or modified after a failure
15What is systems engineering?
The interdisciplinary field covering specification, design, implementation, validation, deployment, and operation of systems
16Why is system reliability not guaranteed by reliable components?
Because reliability is an emergent property dependent on component interactions
17Why must engineers consider the Organizational layer?
Because office politics and power structures can cause technically sound systems to be rejected
18Why can non-determinism be beneficial?
Because human judgment can help handle unexpected situations
19Why is success harder to define in sociotechnical systems?
Because it depends on technical, human, and organizational factors
20What are dependability properties?
Collective properties like availability, reliability, safety, and security that reflect system trustworthiness
21What is reliability?
The probability that a system operates without failure over a specified time period
22What is safety?
The property ensuring a system does not cause harm even if it fails
23What is a hazard?
A system state or condition with the potential to cause an accident
24What is an accident?
An unplanned event that results in injury, damage, or environmental harm
25What is risk-driven specification?
An approach that focuses requirements on mitigating the most critical risks
26What is redundancy?
Including extra components to ensure system operation if one fails
27What is diversity in dependability engineering?
Using different implementations to reduce common-mode failures
28What is fault tolerance?
The ability of a system to operate correctly despite faults
29What is survivability?
The ability to continue delivering minimum service after partial system damage
30What is a timing failure?
A failure where correct results are delivered too late to be useful
31What is Probability of Failure on Demand (POFOD)?
A reliability metric for systems with irregular, high-stakes demands
32What is Rate of Occurrence of Failures (ROCOF)?
A reliability metric measuring how often failures occur in continuously running systems
33What does ALARP mean?
Risks should be reduced as low as reasonably practicable
34What is hazard identification?
The process of identifying potential dangers before a system is built
35What is a safety case?
A structured argument supported by evidence that a system is safe in a given context
36What is Mean Time to Failure (MTTF)?
The average time a component operates before failing
37What is a safe state?
A system state where failure does not threaten life or the environment
38What is risk assessment?
Evaluating the likelihood and severity of hazards
39What is a quantitative reliability requirement?
A reliability requirement expressed using numerical values
40Why can a system be reliable but unsafe?
Because it may consistently follow a flawed specification
41Why can a system be safe but unreliable?
Because it may fail frequently but fail into a safe state
42Why is 100% availability unrealistic?
Because hardware, networks, software, and humans inevitably fail
43Why is security not a functional requirement?
Because it describes system protection levels, not user-visible services
44Why does improving repairability increase availability?
Because faster recovery reduces system downtime