distributed systems lecture 13. today lecture an aerospace company case example: client-server...

Distributed Systems

Lecture 13

Today Lecture

AN AEROSPACE COMPANY

Case example: Client-Server Systems

CHUBB & SON INSURANCE COMPANY

Case example: Internet-Based Computing

THE SABRE GROUP


The IT Infrastructure

• 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 objects


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


Case example: Client-Server Systems cont.

• 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


Case example: Client-Server Systems cont.

Benefits of Client-Server Computing:

Better access to information:

Allow companies to compete better.

Types of Distributed Systems:5. Client-Server Systems cont.

Improved customer service

Ability to communicate customer needs, and

Anticipate customer needs.

Reduce cycle times and


Empowered employees:

Blend autonomy of PCs with system wide rules and connectivity of traditional IS.

Shifts focus of computing to users


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


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)

Types of Distributed Systems:6. Internet-Based Computing

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!

Types of Distributed Systems:6. Internet-Based Computing cont.

– 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


• The company took advantage of the Internet by converting their legacy cargo certificate issuance system to a Java-based 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


Case example: Internet-Based Computing Cont..

• 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 SABRE GROUP


• 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 web-enabled mobiles e.g. text messaging

THE SABRE GROUP

Case example: Internet-Based Computing Cont..

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


• 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

3i

Case example: Server-Based Computing (mobile)

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


Peer-to-Peer Computing

The main issue now is how to make money in this environment. One answer: subscriptions, where people pay for access rather than for ownership


Types of Distributed Systems: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 computer-to-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

Types of Distributed Systems:7. Web Services cont.

Hot topic (the future?):

1. Next generation of distributed systems (big!)

2. Makes the Internet the hub of computing

3. Permits flexible systems not possible before


4. Releases companies from ‘building’ and maintaining systems ‘in house’

5. 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!


Web Services Standards:

Three software standards:

XML (eXtensible Markup Language)

WSDL (Web Services Definition Standard)

UDDI (Universal Discovery, Description, and Integration


Web Services Standards:

Three communication standards

SOAP (Simple Object Access Protocol)

HTTP (HyperText Transfer Protocol)

TCP/IP (Transmission Control Protocol / Internet Protocol)

5-31


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

GENERAL MOTORSCase 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-to-order 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

GENERAL MOTORSCase Example: Web Services cont.

Another Web Service is order-to-delivery 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

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

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)

An Enterprise Architecture Framework Cont..

Designer (model of the information system)

Builder (technology model).

Subcontractor (description of the components).

User (functioning system).

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.

An Enterprise Architecture Framework cont..

• Also:

– People (who)

– Time (when)

– Motivation (why)

An Enterprise Architecture Framework cont..

• 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

FMC CORPORATIONCase 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

FMC CORPORATIONCase Example: IT Architecture

Development

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

THE SABRE SYSTEMCase 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 SABRE SYSTEMCase Example: IT Architecture Cont..

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

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

The Coming Architecture:Service–Oriented Architecture Cont..

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

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.

The IT Infrastructure- What is an IT Infrastructure?

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

The IT Infrastructure- What is an IT Infrastructure? cont.

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Infrastructure investments are a vital part of corporate information systems portfolios

Yet they are the most difficult to cost-justify initially and to quantify benefits afterwards

The Importance of 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 Importance of IT Infrastructure- The Structure of the IT Infrastructure

The Importance of IT Infrastructure- The Structure of the IT Infrastructure..

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)

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

The Importance of IT Infrastructure- Similar to Public 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

2. Support for business programs (dependent): Infrastructure treated as business expense Measured by short-term business benefits Infrastructure planning in current business plan Network = critical

Three views of Infrastructure

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

Three views of Infrastructure..

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

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

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

CITY OF SUNNYVALE, CALIFORNIA

Case example: Investing in Infrastructure

CITY OF SUNNYVALE, CALIFORNIACase example: Investing in Infrastructure

• Like a foundation for a home

– 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

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

Summary





THE SABRE GROUP


The IT Infrastructure

distributed systems lecture 13. today lecture an aerospace company case example: client-server...

Documents

clientserver trend

tenets of clientserver

internet heart

distributed systemslecture

internetbased computing13

internet model

networkcentric computing

clients company