Unifying Static and Dynamic Approaches to Evolution through the Compliant Systems Architecture

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Unifying Static and Dynamic Approaches to
Evolution through the Compliant Systems
Architecture

• Katrina Falkner
• The University of Adelaide

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Unified Evolution

• Static
• Structuring applications as separated
  abstractions.
• Dynamic
• Online change.
• Unified
• Online change of the application and the
  structuring.
• A new approach to unification

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So why is unification hard?

• A comprehensive model of evolution
• Changes to the implementation of an abstraction.
• The reallocation of responsibilities for an
  abstraction.
• The merging of abstractions through the
  construction of a higher-level abstraction.
• Continuous application operation throughout the
  evolution process.

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Function Static Dynamic
Change Implementation Yes Yes
Merge Abstractions Yes Yes
Reallocate Responsibilities Yes No
Continuous Operation No Yes
Anticipated changes?
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Compliant Systems Architecture

• Methodology
• Architectural compliance
• Language-level compliance
• Separation of mechanism and policy
• Instantiation
• Identification of operational abstractions
• Fixed point defines barrier of evolvable system
  components

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Example Instantiation
Policy Library
Policy Library
Application
Core Instructions
Decode Loop
Compliant Instructions
Abstract Machine
Communications Mechanism
Communications
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Example Instantiation
Concurrency Library
Distribution Library
Application
(a)
P
II
P
II
P
(b)
(d)
(c)
Function Invocation
II
Remote Method Invocation
Decode Loop
Abstract Machine
Serialisation
Communications
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Current Progress

• Proof of concept
• Compliance at the application level
• Reassociation of requirements
• Requires compliance at abstract machine (or
  equivalent) level
• Jikes RVM
• Compliance at application and AM level.