High Dependability Computing Program Modeling Dependability(11)

Individuals and organizations increasingly use sophisticated software systems from which they demand great reliance. “Reliance ” is contextually subjective and depends on the particular stakeholder’s needs; therefore, in different circumstances, the sta

o LD: Availability is the capability to maximize the function of time that the system will provide stakeholder-desired levels of service with respect to a system’s operational profile (probability distribution of transaction frequencies, task complexities, workload volumes, others) [Boehm03]. due to external events (EVENT).

FA: The adjustments concern the Software component of the Framework:

Stopping failures are defined as failures preventing the system from

providing the stakeholder-desired levels of service.

The system’s operational profile (probability distribution of transaction

frequencies, task complexities, workload volumes, others) is added as

further Scope characterization.

o LD: Availability is the ability of the system to provide service at any given time. It is the probability of being operational, under given use condition, at a given instant in time [Melhart00]. events (EVENT).

FA: The adjustments and extensions concern the Software component of the Framework:

Use condition is added as further Scope characterization.

o LD: Accuracy is the capability to minimize the difference between delivered computational results and the real world quantities that they represent [Boehm03]. FA: The adjustments and extensions concern the Software component of the Framework:

Accuracy failures are defined as differences between delivered computational results and the real world quantities that they represent.

o LD: Survivability is the capability of the system to minimize the expected value of the information, property, human life and health losses due to natural causes

[Boehm03]. FA: The adjustments and extensions concern the Software component of the Framework:

Hazards are defined as system states that can lead to information,

property, human life and health losses.

Adverse conditions are defined as all natural causes.