600.436
High-Assurance Systems
Fall 01/Introduction
3
Phases Defined (1)
¨Requirements
–Statement of the problem you are trying to solve
–Defines criteria for success
¨Rigorous Model
–Idealized capture of intent
–Abstraction/simplification of real system semantics
–Mathematically expressable
–Allows you to reason formally about the
architecture
¨Architecture
–Model qualified by reality
–Usually not mathematically expressable
–Establishes definitive (normative) specification of behavior [implementation is correct if matches architecture]
–May allow implementation-specific details (e.g.
performance)