Mc nurlin 05

Distributed Systems:
The Overall Architecture
Chapter 5
Information Systems Management In
Practice 7E
McNurlin & Sprague
PowerPoints prepared by Michael Matthew
Visiting Lecturer, GACC, Macquarie University – Sydney Australia

Part II – Managing the Essential Technologies
- Next Few Chapters
• Part II – Chapters 5 through 8
– Focuses on infrastructure management (Figure P2-1)

• Purpose
– Present the technological underpinnings of a corporate IS
function and
– Point out the issues that must be addressed for it to be well
managed
• Chapters 5 & 6 deal with the structure of distributed systems
– Chapter 5 = various kinds of distributed systems architectures
• IT Architecture and Infrastructure
– Chapter 6 = Telecommunications

• Chapter 7 = ‘Content’ or Information Resources
– Data

• Chapter 8 = Operations
– Day-to-Day concerns of keeping systems, networks etc. up and
running
©2006 Barbara C. McNurlin. Published by Pearson Education.

5-2


5-3

Chapter 5
• This lecture / chapter
– Describes seven types of distributed systems
– Defines the overall IT architecture and
– Discusses the importance of IT infrastructure

• Case examples include Northwest
Airlines, an aerospace company, Chubb
& Son Insurance Company, The SABRE
Group, 3i, General Motors, FMC
Corporation, Credit Suisse and the City of
Sunnyvale
5-4

Today’s Lecture
• Introduction
– Four Attributes of Distributed Systems
– When to Distribute Computing Responsibilities
– Two Guiding Frameworks

• Seven Types of Distributed Systems
–
–
–
–
–
–
–

Host-Based Hierarchy
Decentralized Stand-Alone Systems
Peer-to-Peer LAN-Based Systems
Hybrid Enterprise wide Systems
Client-Server Systems
Internet-Based Computing
Web Services


5-5

Today’s Lecture cont.
• Defining The Overall IT Architecture
– An Enterprise Architecture Framework
– The ‘Coming Architecture’: Service-Oriented
Architecture

• The Importance of the IT Infrastructure
– The Structure of the IT Infrastructure
– Three Views of Infrastructure

5-6

Introduction - Definitions
• An IT architecture is a blueprint. A blueprint shows how a
system, house, vehicle, or product will look and how the parts
interrelate
• An IT infrastructure is the implementation of an architecture.
The IT infrastructure includes the processors, software,
databases, electronic links, and data centers as well as the
standards that ensure the components work together, the skills
for managing the operation etc.
• Lately = rather than talk about hardware, software, data,
communications etc. as the components of computing, some
people now refer only to applications and infrastructure

5-7

Introduction – The Evolution of
Distributed Systems
•

First IT architecture = mainframes (batch processing) with dumb
terminals (no processing capabilities)

•

With minicomputers = moved into departments but the ‘master-slave’
computing model persisted. Processing was mainly centralized

•

Microcomputer = model changed significantly because processing
power moved first onto desktops, then into briefcases and now into
pockets

•

Now = ‘interesting twist’: Power returning to a type of centralized
processing with networks of servers and the Internet
– Information appliances and diskless computers (‘thin clients’) make
requests
– More important in the future as Web Services continues to develop

5-8

Four Attributes of Distributed Systems
Degree to which a system is distributed
can be determined by answering four
questions:
1. Where is the processing done?
2. How are the processors and other devices
interconnected?
3. Where is the information stored?
4. What rules or standards are used?

5-9

Attributes of Distributed Systems:
1. Where is the processing done?

• Distributed processing is the ability for more than

one interconnected processor to be operating at the
same time, typically for processing an application on
more than one computer at a time

• Goal: move the appropriate processing as close to

the user as possible and to let other machines handle
the work they do best
• Permits interoperability-capability of different
computers using different O.S. on different networks
to work together on tasks
• Two forms of interoperability (capability for different
machines to work together on tasks):
– communication between systems
– two-way flow between user applications

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2. How are the processors and other
devices interconnected?
• Connectivity among processors means that
each processor in a distributed system can
send data and messages to any other
processor through electronic communication
links
• Desirable to have at least two independent
paths between two nodes to provide
automatic alternate routing (Planned
Redundancy)

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3. Where is the information stored?

• Distributed databases either:

– Divide a database and distribute its
portions throughout a system without
duplicating the data
• Users do not need to know where a piece of
data is located to access it, because the
system knows where all the data is stored

– Store the same data at several different
locations, with one site containing the
master file
• Issue: synchronization of data is a significant
problem

5-12

4. What rules or standards are used?
•

System wide rules mean that an operating discipline for the distributed
system has been developed and is enforced at all times

•

These rules govern communication between nodes, security, data
accessibility, program and file transfers, and common operating
procedures

•

Since the 1990s = “Open systems” concept-mix products from vendors
using open standards. Based on “open-systems” - standardized
interfaces that allow products to inter-operate across multi-vendor
networks, operating systems and databases

•

Now = also API’s - Application Program Interfaces: define the way to
present data to another system component. Makes writing distributed
systems much easier

5-13

When to Distribute Computing
Responsibilities

•

IS management needs a corporate policy
for deciding when the development,
operation and maintenance of an
application should be distributed

•

Individual end users and departments
should not be left on their own to make
such decisions, especially where
enterprise connectivity is important

5-14

When to Distribute Computing
Responsibilities cont.

Systems responsibilities can be distributed
unless the following are true:
1. Are the operations interdependent?
–

When it is important that one operation knows what other is doing;
their planning, development, resources, and operations must be
centralized

1. Are the businesses really homogenous?
–

If they have a lot in common; e.g., IT needs for a fast-food
franchise: processing may be distributed, but planning and
hardware selection should be centralized

1. Does the corporate culture support decentralization?
–

Even if the business units do quite different things and don’t need
to know what each other is doing, corporate culture (management
control?) might still centralize finance, HR, and systems planning


5-15

Two Guiding Frameworks
1. An Organizational Framework

•

A driving force behind distributed processing is
to give people more control over their work. This
autonomy can happen at any of seven levels:
1.
2.
3.
4.
5.
6.
7.

Business ecosystem or value chain (inter-enterprise)
Enterprise
Country or region
Site (plants, warehouses, branch offices)
Department or process
Work group or team
Individuals


5-16

Two Guiding Frameworks for DS:
1. An Organizational Framework

•
•
•
•
•

Locate processing power and DB at each level in
the organization
Top level deals with organizations that work
closely together as buyer-seller, partner etc.
Next three levels (Enterprise, Region and Site)
are traditional domain of IS, where computers
resided in the past.
Bottom three levels (Department, Team and
Individual) are where the bulk of employees are
Intent: give autonomy and decision-making
power to better serve customers

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5-18

2. A Technical Framework
•

Migration of computer power to end users will be driving
force for network-based IS. SUMURU - single user,
multiple user, remote utility.

1.

Processors:
• SU: single user, stand-alone and connected to LNs;
clients
• MU: multiple user, serve local groups of users;
server. Also heavy duty computation for SUs,
backups for MUs, program libraries for SUs, and
database management.
• RU: remote utility, heavy-duty computing, corporate
DB management, corporation mainframes and
value-added network services


5-19

2. Technical cont.
2. Networks:
• LN: local networks, high-speed
information transfer, LAN
• RN: remote networks, lower transfer
speeds, WAN, MAN, Internet


5-20

Technical cont.
3. Services that this network architecture
provides:

•
•
•

access
file transfer
e-mail

4. Standards needed in three areas:

•
•
•

OS
communication protocols: TCP/IP
DBMS: SQL


5-21


5-22


5-23

Seven Types of Distributed Systems:
1. Host-Based Hierarchy

• See Figure 5-4
• A central, controlling mainframe at the top, PCs
at the bottom, minicomputers in between
• Master/slave
• First data processing distributed system. Host
computer central, controlling component;
terminals are access systems
• Where is the data stored?:
– Could be at any level


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5-25

Types of Distributed Systems:
2. Decentralized Stand-Alone Systems
See Figure 5-5

• Decentralized but does not really form a distributed

system
• ‘Holdover’ from the past where departments put in their
own minicomputers with no intention of connecting them
to the corporate host or to other departmental systems
–

Still a valid method for some companies

• Many such “islands of computing”:
–

Little data flow amongst, except upward to corporate
systems

• A major goal in introducing ERP systems was to replace
such disparate systems – in finance, manufacturing,
administration – with a single platform of inter-connectable
modules to serve these various functions

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5-27

3. Peer-to-Peer LAN-Based Systems

• See Figure 5-6

• No hierarchy
• “Peer-to-peer” communications
• Interconnecting LANs rather than

hierarchical communications through a
central hub
• No “superior” computer

5-28


5-29

4. Hybrid Enterprisewide Systems

• See Figure 5-7
• Combination hierarchy (mainframe-based, favored for corporate
computing) and LAN-based (favored by departments)
• Connected via WANs etc.
• The structure of choice for many years
• Allows company to link “automation islands” and retain IT
investments, begin to automate business processes (cooperative
processing)

• Such cooperating processes allow companies to take advantage
of specialized computer programs, while at the same time
extending the usefulness of some legacy systems

–

The process of pulling together such individual applications or
components is called systems integration
5-30


5-31

NORTHWEST AIRLINES
Case example: Hybrid Enterprisewide Systems and
Systems Integration

•

Northwest Airlines built a distributed
passenger revenue accounting system with
products from eleven vendors and just about
as many different technologies:
–
–
–
–
–
–

Expert systems
Imaging
Relational databases
High-resolution workstations
Servers, and
LANs


5-32

NORTHWEST AIRLINES
Systems Integration cont.

•
•
•

Purpose: improve revenue estimate accuracy by
‘auditing’ all the redeemed tickets (few airlines did
this)
Developed with Accenture (Andersen Consulting) BIG
$$$
The system integrates products from 11 vendors
–
–

Uses a cooperative processing architecture and
Integrates expert systems, image processing, relational
databases, high resolution UNIX workstations, servers, and
LANs


5-33

NORTHWEST AIRLINES

Read the case for:
• Managements goals
– Reasons for investing BIG $ in ‘new’ systems and
infrastructure
•
•

•

Enforcing of rules
$$$

The Distributed Architecture
– Mainframe, WANs, LANs etc.
– Data communication = integral
– Image processing

•

Revenue Accounting Process


5-34

NORTHWEST AIRLINES
Lessons learned:
• Benchmark and prototype new technologies to verify
vendors’ claims
• An open architecture works on mission-critical
applications
• Large distributed system projects need a vendor
coordinator
• Use of CASE was mandatory
Huge system (65,000 workdays) which became a
‘model’ for airlines

5-35

5. Client-Server Systems

• The ’90s version of distributed systems
• Arose to take advantage of the processing

capabilities of both host machines and PCs in
the same system
• Splits the computing workload between the
client, which is a computer used by the user
and can sit on the desktop or be carried around
(e.g. WAP mobile phone), and the server, which
answers the request

5-36

5. Client-Server Systems cont.
• Figure 5-8 shows the possibilities for splitting work
between clients and servers. Three components being
split are:
– Presentation software: what user sees (P)
– Application software (A)
– Data (D)

•
•
•
•
•

Distributed presentation
Remote presentation
Distributed application function
Remote data management
Distributed database(s)


5-37


5-38

Another way to look at it = to view their
architecture
– Preferred: three-tier architecture (see Fig.5-9):

•
•
•

Tier 3: the superserver/mainframe. Allows inclusion of
legacy applications, short-lived and fast-changing data,
and integrity rules
Tier 2: specialized servers, dedicated to housing
databases or middleware-software to ease connection
between client and server. Also, department-specific
data that does not change often
Tier 1: clients (some of which could be portable)
connected through network


5-39


5-40

AN AEROSPACE COMPANY
Case example: Client-Server Systems

•

Systems group’s goal = never build
monolithic applications again

•

Builds client-server systems with:
–
–
–
–

•

Application code on the clients
Data on the servers
Communication middleware software shared
Object oriented technology, most from a library

Data = at the heart of the architecture is a
repository which allows the reuse of
5-41
objects


5-42

AN AEROSPACE COMPANY
Case example: Client-Server Systems cont.

•

Network = integral part of the architecture. Each
company site has three components:
–
–
–

Desktop machines
Servers
One or more site hubs

•

Architecture = ‘remote data management’. Data
resides on servers and applications reside on
clients

•

Company uses the distribution function and
remote data management because they minimize
total costs


5-43

• Benefits of Client-Server Computing:
– Better access to information:
• Improved customer service
– Ability to communicate customer needs, and
– Anticipate customer needs.

• Reduce cycle times and
• Allow companies to compete better.

– Empowered employees:
• Blend autonomy of PCs with system wide rules
and connectivity of traditional IS
• Shifts focus of computing to users

5-44

• Benefits of Client-Server Computing

(cont.):

– Increases organizational flexibility:
• allows new technology to be added more easily without affecting rest of
system
• streamlines work flow between functional areas
• encourages people to work together via networks
• Supports new organizational structures via its connectivity

• Drawbacks:
– Not lower in cost than mainframes because they entail so much
coordination
– Easier for users, far more complex for IS (drawback?)
– What looked like simple connections have turned into large, often
fragile, complex systems

5-45

6. Internet-Based Computing

•
•
•
•

In the late 1990s, the client-server trend was
‘interrupted’ (augmented?) by the ‘Internet’
Model of a distributed system includes the
Internet (heart?)
The tenets of client-server remain
Network-centric computing = a computer and
a cloud (Figure 5-11)


5-46


5-47

6. Internet-Based Computing cont.

•

Network computers have (had?) not taken off
(desktops) but the concept of utilizing
programs off the Internet has
–
–

‘Network’ computers (thin clients, toasters etc.)
now = coming into their own!
Thin clients = logical for hand held but now =
increasingly popular for the ‘desktop’




Updating new versions of software
Authorized software (firm and purchased)
‘One copy’ of software


5-48

CHUBB & SON INSURANCE COMPANY
Case example: Internet-Based Computing

•
•
•

The company took advantage of the
Internet by converting their legacy cargo
certificate issuance system to a Javabased extranet application
It has also done the same with other
applications
All the apps feed into Chubb’s mainframe
but have a Java-based Web front end so
that client machines only need access to
the Web to perform the application


5-49

THE SABRE GROUP
Case example: Internet-Based Computing

•
•
•

This airline reservation company is working with
Nokia (the handheld phone manufacturer) to create a
real-time, interactive travel service delivered via
mobile phone
The service draws on SABRE’s online corporate
travel purchasing system and Nokia’s server (which
transmits the travel information to a wireless network
and to its Internet-enabled phones)
Qantas etc. also have and doesn’t need to be webenabled mobiles e.g. text messaging


5-50

Server-Based Computing
•

With more use of laptops which do not have strong
security features
–
–

•

Updating en masse is not easy
Even individual downloads can require helpdesk support

Solution = server based computing
–
–

Applications reside on corporate servers rather than on
laptops
Applications can be securely accessed by any device, they
can be updated directly on the server, and they do not have
to be tailored to run on specific machines


5-51

3i
Case example: Server-Based Computing (mobile)

•
•

UK based venture capital firm
Needed to give its investment professionals
anytime-anywhere access to its systems

•
•

Remote employees dial in (secure modem)
Using Windows terminal server software and
Citrix software = the create a ‘virtual office’ for
themselves


5-52

Peer-to-Peer Computing

•
•
•

This form of Internet computing distributes a task over
a wide number of computers (peers) connected to the
Internet
This grassroots movement, like the open source
movement, is now taken seriously by some
corporations. It became famous with Napster, the
music swapping P2P network
The main issue now is how to make money in this
environment. One answer: subscriptions, where
people pay for access rather than for ownership


5-53

7. Web Services
• This second-generation Internet-based distributed
system gives software modules URLs (Internet
addresses) so they can be called upon to perform
their function as a service via the Internet
• This development will permit widespread computerto-computer use of the Internet. One computer
program or Web Service makes a request of another
Web Service to perform its task (or set of tasks) and
pass back the answer


5-54

7. Web Services cont.
•

Hot topic (the future?):
1.
2.
3.
4.
5.

•

Next generation of distributed systems (big!)
Makes the Internet the hub of computing
Permits flexible systems not possible before
Releases companies from ‘building’ and maintaining
systems ‘in house’
Will draw on existing systems

•

Wrapping – encapsulate functionality from an
existing application in an XML envelope
Exposing – for use by others

•

The promises go on! And the vying for position!


5-55

•

Web Services Standards:
– Three software standards:




XML (eXtensible Markup Language)
WSDL (Web Services Definition Standard)
UDDI (Universal Discovery, Description, and
Integration

– Three communication standards




SOAP (Simple Object Access Protocol)
HTTP (HyperText Transfer Protocol)
TCP/IP (Transmission Control Protocol /
Internet Protocol)


5-56

•

Significance of Web Services
–
–

Viewing IS as proprietary has led to rigid
business processes, which are slow to change
and respond to market changes
Web Services offers an IT architecture based on
the openness of the Internet. Rather than build
proprietary systems, companies can obtain the
functionality they need from the Internet
•
•

This modularity permits handling a huge variety of
possibilities by mixing and matching, and allows easier
cross-company system linking
Companies thus only pay for the functionality they use
when they use it, which reduces the number of IT
assets companies need to house and maintain


5-57

GENERAL MOTORS
Case Example: Web Services
• One GM executive believes that the Web
Services architecture could be used to move
GM from its supply-driven, build-to-stock
business model to a demand-driven, build-toorder business model – an otherwise
impossible feat
• To begin, GM first enhanced its supply-driven
model by offering new functions via a Web
Services architecture
• One Web Service is a locate-to-order service
that dealers can use to easily find a specific
car a customer might want in the inventory of
other GM dealers

5-58

GENERAL MOTORS
Case Example: Web Services

cont.

• Another Web Service is order-todelivery which shortens the time to
deliver a custom-ordered vehicle
– Paving the way to eventually convert to a
make to order business model

• The ‘Rewards’?:
– Cut its $25B inventory in half
– Potentially shave $1,000 off the cost of
each vehicle

5-59

Defining the Overall IT Architecture
• The intent of an IT architecture is to bring order to the
otherwise chaotic world of information systems by
defining a set of guidelines and standards, and then
adhering to them
• Because the architecture needs to support how the
company operates, it reflects the business strategy
• Furthermore = as business changes, the architecture
needs to keep pace
• Chief Technology Officer


5-60

An Enterprise Architecture Framework
• To describe the IS architecture, look at the roles
people and components play (5th edition Fig.5-12):
– Rows: Views must be taken into account when
building complex products:
•
•
•
•
•
•

planner (scope statement)
owner (model of the enterprise)
designer (model of the information system)
builder (technology model)
subcontractor (description of the components)
user (functioning system)


5-61


5-62

An Enterprise Architecture Framework
cont.

• Columns:
• IS components:
–
–
–
–

Data models (what it is made of)
Functional models (how it works)
Network models (where the components are located)
Represent physical manifestations of the system.

• Also:
– People (who)
– Time (when)
– Motivation (why)

• Use of the framework: When IS users bring in a package that follows
a data model inconsistent with the rules of the company, a lot will be
spent fixing the package.
• Figure 5-13 - the ‘whole’ picture

5-63


5-64

FMC CORPORATION
Case Example: IT Architecture Development
• When FMC split in two, it designed two new IT
architectures
• The architecture and technology director led five
teams – for data, applications, integration, desktop,
and platform
• Each created a today architecture, a tomorrow
architecture, and the “next minute” steps
• The companies have now split and the tomorrow
architecture has given FMC a standard that everyone
agrees with, making standard-setting far easier
• Now it is working on a new tomorrow architecture, for
2004-2005, when voice-over IP and Web Services
kick in

5-65

THE SABRE SYSTEM
Case Example: IT Architecture
• When they looked at the underlying databases
– Customer profiles, AAdvantage, NetSAAver
– = found heaps of data redundancy (common!) leading to a
huge redesign
– American consolidated and linked these databases to have
just one profile for each flyer

• The architecture underlying American Airline’s
Website is now modular
– The -existing SABRE computer reservation system serves
as “the reservation service” module
– Other modules perform the functions related to the Web

• Due to this component-based architecture, it was
fairly easy to add new functions

5-66

The Coming Architecture:
Service–Oriented Architecture
•
•

Importance of an architecture is that it spells out the
relationships between the components of an airplane, building,
system etc.
In the past with IS these interactions have been ‘hard-coded’
point-to-point
– Efficient but costly to maintain
– Changing one component might require changing the others that
interact with it

•

Relatively new system architecture moves away from this =
Service Oriented Architecture (SOA)
– Emergence parallels Web Services – uses the same architectural
concept
– Thinks about how to expose the data and functions in a way that
other systems can easily use

•

Holy Grail? Which has long eluded IS organizations and
addresses the need to be more agile


5-67

CREDIT SUISSE
Case example: Service Oriented Architecture
• Large Swiss global financial services company
– Pioneering the implementation of SOA
– Old = depended on proprietary middleware
• Maintenance = increasingly expensive

– Revamped its IT infrastructure to be a SOA by implementing
two “information buses”
• Service bus
– Takes a request-reply approach
– Integrates front-end and back-end applications (Figure 5-14)

• Event bus
– Integrates the back-end systems
– Also uses SOA but it uses a supply-push mode of operation using
publish and subscribe
• When an event occurs in one system it is “published”
• All of the systems that need to know about the event are
“subscribed” and are notified (update is pushed to them)

5-68


5-69

The IT Infrastructure
- What is an IT Infrastructure?
IT infrastructure is the foundation of an
enterprise’s IT portfolio:
• Provides the capability for reliable services
and sharing
• Includes both the technical and managerial
expertise required to provide these services
• Is linked to external industry infrastructure
– Banking payments, airline reservations etc.

5-70

The IT Infrastructure
- What is an IT Infrastructure?

cont.

• Shared characteristics differentiate an
infrastructure from IT investments used by just
one function
• Elements can include:
–
–
–
–

Company-wide networks
Data warehouses
Large scale computing facilities
EDI capabilities

• Applications ‘sit on top’ and directly support
the business Vs. infrastructure ‘indirect’
support


5-71

The Importance of IT Infrastructure
• Infrastructure investments are a vital
part of corporate information systems
portfolios
• Yet they are the most difficult to costjustify initially and to quantify benefits
afterwards


5-72

- The Structure of the IT Infrastructure
•

The IT infrastructure is the shared and reliable services that provide
the foundation for the enterprise IT portfolio. IT infrastructure is very
similar to public infrastructure; on top of an IT infrastructure sit
applications that perform a business’s processes.
– The bottom of four layers consists of technology components, such as
computers and database management system packages.
– The third layer is the human IT infrastructure layer, which translates the
components (which technologists can understand) into services (which
business users can understand).
– The second layer is shared IT services, which present the infrastructure
as a set of services that users can draw upon and share to conduct
business.
– The top layer is the shared and standard applications layer, which
includes stable applications (such as accounting and HR)

5-73


5-74


5-75

- Similar to Public Infrastructure
• Similar to public infrastructure:
–
–
–
–
–

Roads
Hospitals
Sewers
Schools
etc.

• Everyone wants but no-one wants to ‘pay’
• Provided by a ‘central authority’
– Government or IT Department
– Delicate and ‘difficult’ investment balance

5-76

Three views of Infrastructure
IT investments can provide:
1. Economies of scale (utility):
– Infrastructure cost as an administrative expense
– Minimize expense
– Outsourcing may be viewed favorably because the IT
infrastructure is not seen as strategic

1. Support for business programs (dependent):
–
–
–
–

Infrastructure treated as business expense
Measured by short-term business benefits
Infrastructure planning in current business plan
Network = critical


5-77

Three views of Infrastructure cont.
3. Flexibility to meet changes in the
marketplace (enabling):
– Primary benefit long-term flexibility
– Intended to provide the foundation for
changing direction in the future
– IT cost seen as business investment


5-78

CITY OF SUNNYVALE, CALIFORNIA
Case example: Investing in Infrastructure

•
•

Director of IT hired to “move the city into the future”

•

Provides connectivity between the city’s myriad of IT facilities:
mainframes, LANs, WANs, PCs etc.

•

Like a foundation for a home

First = get its house into order – “capturing accurate
information and delivering that information in a timely manner”

–

•
•

Able to withstand all the weight, noise and “things you
want to plug into it”

Infrastructure investments are paid through chargeback
“Super” rules guide technology investments


5-79

Conclusion
• Distributing processing, databases, and
communications allow companies to
move more quickly because they can
more easily “snap in” new products and
services into their existing systems
• The advent of Web Services is fueling
the use of the Internet to extend the
tenets of distributed systems even
further

5-80

Conclusion cont.
• Distributed systems dominate the computing
environment
– They create an enterprise architecture to cope
with complexity of change

• IT infrastructures should provide the platform
for allowing interconnection and
organizational flexibility
– Very challenging for CIOs, CEOs etc.

• Infrastructure is difficult to change BUT is
important to organizational success
– Need to make the ‘right’ decisions


5-81

Mc nurlin 05

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