Architecture and Real-Time Systems (ARTS) Laboratory

 Architecture and Real-Time Systems (ARTS) Laboratoryclock

RAMP: Reliability Model

Traditional Measures

These included reliability, throughput, availability, and measures derived from these (e.g., point availiability, capacity). These were difficult to use for two reasons:

    They did not take key dynamic factors into account (e.g., scheduling, recovery)

    They were computer-centric

Application-Specific Measures

These included:

Performability (Meyer, 1980) - accomplishment levels of the application must be precisely defined and the computer performance linked to them.

Cost Functions and Probability of Dynamic Failure (Krishna & Shin, 1983) - linked the computer response time to the performance of the application

These were measured by tools including HARP, SHARPE, ULTRASAN, CARE-III, etc.

Such measures were often difficult to use for real-time applications because they required complete details about the application, which can be unavailable.