Software Engineering - Critical Systems

Flashcards about critical systems, dependability, and security.

Safety-critical systems

Failure results in loss of life, injury or damage to the environment

Mission-critical systems

Failure results in failure of some goal-directed activity

Business-critical systems

Failure results in high economic losses

System dependability

Reflects the user’s degree of trust in that system

Availability

The ability of the system to deliver services when requested

Reliability

The ability of the system to deliver services as specified

Safety

The ability of the system to operate without catastrophic failure

Security

The ability of the system to protect itself against accidental or deliberate intrusion

Repairability

Reflects the extent to which the system can be repaired in the event of a failure

Maintainability

Reflects the extent to which the system can be adapted to new requirements

Survivability

Reflects the extent to which the system can deliver services whilst under hostile attack

Error tolerance

Reflects the extent to which user input errors can be avoided and tolerated

System failure

An event that occurs when the system does not deliver a service as expected

System error

An erroneous system state that can lead to unexpected system behavior

System fault

A characteristic of a software system that can lead to a system error

Human error or mistake

Human behavior that results in the introduction of faults into a system

Fault avoidance

Techniques to minimize mistakes or trap them before they become system faults

Fault detection and removal

Verification and validation to detect and correct errors before the system goes into service

Fault tolerance

Run-time techniques to ensure system faults do not result in errors or failures

Safety

The system’s ability to operate without causing human injury, death, or damage to the environment

Primary safety-critical systems

Embedded software systems whose failure can cause hardware failure and directly threaten people

Secondary safety-critical systems

Systems whose failure results in faults in other systems which can threaten people

Accident (or mishap)

An unplanned event resulting in human death/injury, property/environmental damage

Hazard

A condition with the potential for causing or contributing to an accident

Damage

A measure of the loss resulting from a mishap

Hazard severity

Assessment of the worst possible damage from a hazard

Hazard probability

The probability of events occurring which create a hazard

Risk

Measure of the probability that the system will cause an accident

Hazard avoidance

Designing the system so that some classes of hazard cannot arise

Hazard detection and removal

Designing the system so that hazards are detected and removed before they result in an accident

Damage limitation

Including protection features to minimize the damage from an accident

Security

The system’s ability to protect itself from accidental or deliberate external attack

Exposure

Possible loss in a computing system, such as data damage or loss of time

Vulnerability

A weakness in a computer-based system that may be exploited

Attack

An exploitation of a system vulnerability, often from outside the system

Threats

Circumstances that have the potential to cause loss or harm

Control

A protective measure that reduces a system vulnerability

Denial of service

The system is forced into a state where normal services are unavailable or degraded

Corruption of programs or data

Programs or data are modified in an unauthorized way

Disclosure of confidential information

Confidential information is exposed to unauthorized individuals

Vulnerability avoidance

Designing the system so that vulnerabilities do not occur

Attack detection and elimination

Designing the system to detect and neutralize attacks on vulnerabilities

Exposure limitation

Designing the system to minimize the adverse consequences of a successful attack