EPOXI towards Specification Carrying Software

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EPOXI - towards Specification Carrying Software -
Kestrel Institute Palo Alto, California www.kestre
l.edu June 2001
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Contents

• ADLs vs EPOXI
• Architecture of architecture
• Our contribution
• Specification Carrying Software
• Gauges from specifications
• Specs and Specware
• Kestrelwares
• Evolving specs and EPOXI
• Automating architectural composition
• Benefits and tech transfer

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ADLs vs EPOXI

• ADLs ? interoperability of components, and of
  systems
• EPOXI ? interoperability of ADLs, and of systems

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Architecture of architecture
But in the current ADLs
What do architects do?

• There are GAPS between
• high-level architectural views and
• low-level domain-specific extensions.

• they apply generic patterns and components
  (design and modify systems)

• behavior, dynamics uninterpreted
• all claim extensibility, but
• extensions and DSL interpretaters tend to be
  low-level

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Benefit of EPOXI

• all mathematically expressible properties can be
  represented without external imports
• easy scripting for domain-specific macro
  extensions (MONTAGES)

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Assembly problems...
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... and solutions
specs
interfaces
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Specification Carrying Software
Specification Carrying Software
EPOXI
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Specification Carrying Software
literate software

• software extended with
• comments in a generic specification language, or
• Floyd-Hoare annotations as first-class citizens
  (available to the runtime machine)

• specifications extended with
• executable (partial) implementations, or
• abstract, but verifiable behaviors

dynamic!
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Specification Carrying Software
? P,?????, S?
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Specification Carrying Software
simulates behavior
interprets structure
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Gauges from specifications
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Specs

• encapsulating presentations

spec Poset is sort X op lt XX -gt Bool
ax trans is xlty /\ yltz gt xltz ax
sym... end-spec
spec Semilattice is sort X op V in XX -gt
X cons b X ax assoc is (xVy)Vz
xV(yVz) end-spec
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Specware

• composing software using categories

VM
OS
pushout
PP
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Specware

• preserving design records

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Specware

• genericity, parametricity

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Specware

• systems of systems

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Kestrelwares domain-specific software synthesis
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Kestrelwaresour tech base
Planware
Designware
Specware
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Kestrelwaresour tech base
Specware
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EPOXI
Evolver??
Adaptaware?
EPOXI
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Specs

• encapsulating presentations

spec Poset is sort X op lt XX -gt Bool
ax trans is xlty /\ yltz gt xltz ax
sym... end-spec
spec Semilattice is sort X op V in XX -gt
X cons b X ax assoc is (xVy)Vz
xV(yVz) end-spec
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Especs

• adding behavior

espec Basic_Acct is spec end-spec
prog stad Create initX is stad
Amountself is step Deposself,d
Amountself -gt Amountself,d
cond dgt0 balance(self)-gt
balance(self)d end-step end-prog end-espec
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EPOXI

• states are models
• models are refinements

• building blocks

state descriptions
specs
steps (transitions)
interpretations
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Especs

• Def. Evolving spec (espec) A consists of
• specA
• progA
• stA shapeA? (specA /Spec )op
• condA edgeA ? L(specA )

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Especs

• Def. An espec morphism f A?B consists of

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Especs
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Especs

• ... satisfying the guard condition

?uf0(k)?n
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Composing especs
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Composing especs
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Composing especs
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Composing especs
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Architectural composition

• pushout of especs

comp
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Benefits

• Adaptable systems of specification carrying
  components
• Semantically based architectural composition
• genericity polymorphic components, connectors,
  patterns, classified in taxonomies
• glue automated generation of joint instances of
  parameters
• formal computation of composite systems
• Math foundation for automated dynamic assembly
• composition by pushouts
• not only of specs, but also of program modules
• computation of all possible interactions between
  processes
• including un(der)specified processes attacker in
  protocols
• dynamics reduced to logic theorem prover as
  universal gauge

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Tech transfer

• Collaborations
• WG CMU, SRI, Teknowledge
• Georgia Tech, UMass
• Oxford, T.U. Berlin, Nijmegen
• Potential customers
• Northorp-Grumann
• NSA