modeling architectures

8/12/2019 Modeling Architectures

1/48

Modeling InformationSystems Architectures

Paul Grefen

(DB|MA-IS-CS)|[email protected]


2/48

Purpose of this lecture

The purpose of this lecture is notto present pre-cooked solutions to

architectural problems, but ratherto clarify architectural issues and

discuss a number of important

topics in this context.


3/48

Table of contents

What are IS architectures ?

Aspects of IS architectures

Types of IS Architectures

Reference Architectures Designing IS architectures

Architectural platforms Conclusions


4/48

What are ISarchitectures ?


5/48


6/48

Software architecture

The architecture of a software systemdefines that system in terms of

computational components andinteractions among those components.

Software Architecture; Shaw & Garlan;

Prentice Hall, 1996


7/48

Example architecture


8/48

Information system architecture

The architecture of an information

system defines that system in termsof components and interactions

among those components,from the viewpoint of specific aspectsof that system,

and based on specific structuringprinciples.


9/48

Interpreting IS architectures

Syntax:structure of the architecture

Semantics:meaning of components and interactions

Pragmatics:

reasons behind structure & meaning


10/48

Aspects of ISArchitectures


11/48

Aspects architecture

data

system

configu-

rationcommu-

nication

organi-

zation

Truyens

et al.;

1990


12/48

Data aspect architecture

data

system

configu-

rationcommu-

nication

organi-

sation

Architecture of data managed by systems,

e.g. using (E)ER diagrams.


13/48

System aspect architecture

data

system

configu-

rationcommu-

nication

organi-

sation

Architecture of application software,

e.g. using data flow diagrams ormodule diagrams.

trip data fin. data

booktrip

proc.

ackn.proc.

inv.

proc.

docs.

proc.

paym.

1

2

3

4

5

a b

Req.

Pay.


14/48

Configuration aspect architecture

data

system

configu-

rationcommu-

nication

organi-

sation

Architecture of hardware and low-level

software (e.g. OS, DBMS),e.g. using configuration diagrams.

SPARCSPARCUNIXUNIX

OracleOracle FlowMarkFlowMark


15/48

Communication aspect architecture (I)

data

system

configu-

rationcommu-

nication

organi-

sation

Architecture of communication infrastructure

(networks, communication software),using e.g. topology diagrams.

3174

3174

3745

ES/9000

(HBS)

ES/9000

(APL)

Token Ring

3174

3174

PDP

11/74

3174PC

PC

PC

OLD

LOS

SpecialistenSystemen

PMK

Commun.Controller

ClusterController

Haemo-dialyseSysteem

2 Mb/s

19,2 Kb/s


16/48

Communication aspect architecture (II)

data

system

configu-

rationcommu-

nication

organi-

sation

3174

3174

3745

ES/9000(HBS)

ES/9000(APL)

Token Ring

3174

3174

PDP

11/74

3174PC

PC

PC

OLD

LOS

SpecialistenSystemen

PMK

Commun.Controller

ClusterController

Haemo-dialyseSysteem

2 Mb/s

19,2 Kb/s


17/48

Organization aspect architecture

data

system

configu-

rationcommu-

nication

organi-

sation

Architecture of organization structure andprocesses related to administration andmaintenance of systems, using e.g.organigrams and procedure handbooks


18/48

A design path with aspects

start arch.:major apects

combined

global arch.:major apects

combined


19/48

Types of ISArchitectures


20/48

Type of IS architectures

Based on structuring principles:

Monolithic / Layered / Columned / OO Single-Level versus Multi-Level

Based on purpose:

Conceptual versus Technical

Application versus General System

Reference versus Concrete


21/48

Structuring principles (I)

Monolithic

Columned

Layered

Object-Oriented

and combinations


22/48

Structuring principles (II)

Multi-level architectures:allow for multiple aggregation

levels of functionality


23/48

Structuring principles (III)

Columned

Syntax: several system

modules in the same layer.Semantics: multiple subsystems at the same

abstraction level usingeach others functionality.

Pragmatics: separation of concerns (system arch.)or distribution (conf. arch.).Pipe


24/48

Purpose of architecture (I)

Conceptual architecture: describes structure of conceptual design of systemTechnical architecture: describes structure of implementation of system

conceptual technical


25/48

Purpose of architecture (II)

Application: describes architecture for specific

application and contextGeneral system: describes architecture for general application and context

Concrete: describes architecture of a specific system to be directly appliedReference: describes blue-print of abstract system to be concretized before application


26/48

Reference Architectures


27/48

Reference architecture

A reference architecture is a general,

abstract architecture that can beinstantiated for specific situations.

Instantiated =filled in, detailed

parameterized, adaptedextended, selected


28/48

ISO-OSI reference architecture

application

presentation

session

transport

network

data link

physical

Structure:layered

Aspects: system

configuration communicationPragmatics:

standard interface levels for horizontal communication


29/48

ANSI/SPARC reference architecture

external

model

conceptual

model

internalmodel

Structure:layered

Aspects: system

data organizationPragmatics:

separation between database levels for different purposes


30/48

ANSI/SPARC in DDBS

Glob.Ext.Schema

Glob.Ext.Schema

Glob.Ext.Schema

Glob.Conc.

SchemaFragm.Schema

Alloc.

Schema

Loc.Map.Schema

Loc.Map.Schema

Loc.Map.Schema

Loc.Conc.

Schema

Loc.Conc.

Schema

Loc.Conc.

Schema

Loc.Int.Schema

Loc.Int.Schema

Loc.Int.Schema

DB DB DB

Structure:idem

Aspects:idem +

communicat.Pragmatics:

idem

+ distribution

Connolly, Begg &

Strachnan, 1995


31/48

WfMC reference architecture (I)

Workflow API & Interchange Formats

WorkflowEngine(s)

Workflow Enactment Service

Workflow ClientApplications

ProcessDefinition Tools

Adminstration

&Mngmnt Tools

InvokedApplications

IF1

IF2 IF3

IF4IF5 Workflow

Engine(s)

Other WF Enactment Service(s)


32/48

WfMC reference architecture (II)

Workflow EngineWorkflow Engine

Process

Definition

Process

Definition

Workflow

Clients

Workflow

Clients

Administr.

& Mngmnt

Administr.

& Mngmnt

ApplicationsApplications

Structure: first layered, then columned


33/48

Designing ISArchitectures


34/48

Example architecture design

Mercurius initiative (1995)

Purpose:specification of reference WFMS

Focus:

detailed system architecture

Participants:

2 universities, polytechnicconsultancy firm,financial institution


35/48

Mercurius architecture design principles

Flexibility (detail, aspect) Top-down architecture design strategy

WF design versus WF enactment

Kernel versus additional functionality

Positioning in context

Explicit interfaces to environment


36/48

Mercurius overall WFMS architecture

data

stores

UIS UIS

WF

Design

WF

Clients

WFServer

DBMS AS/OS

CS WFServer

AS/OS/

DBMS

data

stores

configuration

system

communication

organi-zation

data


37/48

Mercurius design module architecture

AS

Interface

WF Design

Engine

DBMS

Interface

def.

data

proc.

data

appl.

data

UIS

Interface

Extension

Module

organ.

data

software bus


38/48

Mercurius design engine architecture

def.

data

proc.

data

Organisat.

Design

organ.

data

appl.

data

Product

Design

Global

Design

Detail

Design Tuning


39/48

Mercurius enactment module architecture

ASInterface

WFS

Engine

OS

Interface

DBMS

Interface

CS

Interface

Extension

Module

proc.

data

man.

data

appl.

data

WFCInterface

AS

software bus

def.

data

organ.

data


40/48

Mercurius enactment engine architecture

AS

Interface

Event

Analyzer

Action

Synthesizer

def.

data

proc.

data

Event

ReceptorClock

Module

Action

Executor

CS

Interface

W FC

Interface

appl.

data

software bus

O S

Interface


41/48

Architectural Platforms

i ib d bj hi


42/48

Distributed Object Architectures

object model architecture

vs. system model architecture application object access

vs. server system access

fine grain computationvs. coarse grain computation

transparent distributionvs. no/explicit distribution

E l hi di i l


43/48

Example architecture traditional

Workflow

Engine

Transaction

Manager

Workflow

Client

case

datatrans

data

E l hit t l DOA


44/48

Example architecture a la DOA

casecase

scheduler

client

transact.

transact.

client

OMG OMA


45/48

OMG-OMA

Application Objects Common Facilities

Object Services

Object Request Broker

E l hit t WIDE WFMS


46/48

Example architecture: WIDE WFMS

WorkflowEngine

BAL

DBMS

LTM

Local Trans.

Interface

Global

Trans. Man.

GT LT


47/48

Conclusions

Conclusions


48/48

Conclusions

Modeling of architectures ofparamount importance CIS design

Modeling of CIS architectures hasmany aspects

Modeling of CIS architectures is adiscipline that is in its infancy

modeling architectures

Documents