www.sims.monash.edu.au 1 ims9043 it in organisations week 3 it architecture and infrastructure

www.sims.monash.edu.au

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IMS9043 IT in Organisations

Week 3IT Architecture and Infrastructure


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Lecture objectives

Understand the strategic arrangement of IS/IT in modern organisations


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Information Systems & People


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Information Infrastructure

• There are five major components of the infrastructure:• Computer hardware• Development software• Networks and communication facilities

(including the Internet and intranets)• Databases• Information management personnel


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Information Architecture

• Information architecture is a high-level map or plan of the information requirements in an organization.


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Information Architecture

• In preparing information architecture, the designer requires two kinds of information:• The business needs of the organization—that is, its

objectives and problems, and the contribution that IT can make.

• The information systems that already exist in an organization and how they can be combined among themselves or with future systems to support the organization’s information needs.


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Computer hardware environments (1)

• Mainframe environment. In the mainframe environment, processing is done by a mainframe computer. • The users work with passive (or “dumb”)

terminals, which are used to enter or change data and access information from the mainframe.


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Mainframe (server-based)

Earliest computerised information systems:

•Information problem brought to the computer

•Number crunching

•Technicians in control

•Specific tasks


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Computer hardware environments (2)

• PC environment. In the PC configuration, only PCs form the hardware information architecture.

• Networked (distributed) environment. Distributed processing divides the processing work between two or more computers.


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Personal computer (client-based)

•The purpose of client/server architecture is to maximize the use of computer resources.


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Client/Server Architecture

• A client/server architecture divides networked computing units into two major categories; clients and servers.

• A client is a computer such as a PC or a workstation attached to a network, which is used to access shared network resources.

• A server is a machine that is attached to this same network and provides clients with these services.

• Client/server architecture gives a company as many access points to data as there are PCs on the network.


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Client/Server Architecture

•PC LAN (local area network) – PCs, each with its own storage

•Flexible

•Device sharing

•Scalability – increased load catered absorbed by adding workstations


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Processing architectures: Distributed Systems

• Processing divided (not necessarily evenly) between client and server

• Mainframe or PC combinations• One location or several

– inter-organisational cooperation

– access vast amounts of data

– team geographically dispersed computers

– new software supports info. exchange/ collaboration


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Distributed systems: Electronic Data Interchange (EDI)

• Electronic data interchange (EDI) is the electronic movement of specially formatted standard business documents, such as orders, bills, and confirmations sent between business partners.

• The cost of VANS limited EDI to large business partners. However, the situation is changing rapidly with the emergence of Internet-based EDI.


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Distributed systems: Web-based Systems

• Web-based systems refer to those applications or services that are resident on a server that is accessible from anywhere via the WWW.

• The only client-side software needed to access and execute Web-based applications is a Web browser environment.

• Two important features of Web-based functionality; • The generated content/ data is updated in real time.• They are universally accessible via the Web to users

(dependent on defined user-access rights).


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www vs. internet

• WWW: application which handles digital standards for storing and retrieving data. GUI-based.

• Internet: transport mechanism, protocols.


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Distributed systems: Internet and intranet

• The Internet is a worldwide system of computer networks--a network of networks in which users at any one computer can, if they have permission, get information from any other computer. Transport mechanism. (cf. WWW - applicationwhich handles digital standards for storing, retrieving data. GUI based.)

• An intranet is the use of WWW technologies to create a private network, usually within one enterprise.

• A security gateway such as a firewall is used to segregate the intranet from the Internet.


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Internet, intranet as business technologies

• Corporate portals: Web-based personalised gateway to ‘work-appropriate’ information and knowledge from disparate IT systems.

• A response to information overload

• An Extranet (use of the internet between firms) can be viewed as an external extension of the enterprise intranet.


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IS Infrastructure Areas

The basic facilities, services, and installations needed for the functioning of an Information System.

Critical areas:1. network design and management

2. processing architecture

3. desktop environment

4. operations support strategy

• these are critical for a number of reasons; for instance , an organization would want good performance marks in these areas before an internet-commerce initiative could be sustained


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· IT Infrastructure

IT Infrastructure supports the flow and processing of information and includes:

• Hardware• Communication network• Middleware • Application software• Database management software• Data


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Hardware

• Location– Reach

• Workstations– Range


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Communication network

• Physical communications– Coax, twisted pair, fibre, wireless– Broadband, baseband

• Redundancy– Backup– Alternative paths to nodes

• Protocols: – ASCII, Ethernet (for LANs), ISDN (Integrated

Services Digital Network), TCP/IP (Transmission Control/Internet Protocols), Many others

– Mixed, proprietary vendor protocols


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Application architectures

• An Information System can be looked at as: – Functionality layer (application domain)

– HCI layer (user interface)

– Persistent elements layer (dbms)

– System architecture layer (middleware)

– Foundation layer (building blocks)


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Middleware software

Hardware, software and communication technologies for data presentation, analysis and management.

• Handles messages from the business logic to the database

• Transparent to the application• WWW middleware — browsers, search engines• Distributed data management• Distributed transaction processing


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Application Software

• Can reside on one computer or over several

• Receives requests from the interface layer as messages

• Communicates with middleware


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Database management software

Choices:• Relational database• Object-Relational database• Object database• Single database server• Distributed database


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Choosing which technology

• Commitment to installed DBMS• Legacy systems• Extent of OO development in the

organisation• Availability of relevant expertise• Future Plans (IT strategy)


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Relational database

• Currently the most common form of implementing databases

• Only practical option in heterogeneous environments

• RDBMS expertise is readily available• Object-oriented paradigm is compromised


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Object-Relational database

• Fundamentally a RDBMS• Extended with specially defined data types• Objects in different tables from attribute values• Still compromised by its tabular structure• Some OO features restricted by language

dependence


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Object databases

• Not well penetrated into the industry yet• Steep learning curve for existing

developers and relational DBAs• Supports inheritance (language

dependent)• Supports repeating groups and multi-

valued attributes (not in ORDBMS because of normalisation constraints)


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Other infrastructure considerations

• Security versus Ease of Access• Response time of the network (if the

delay between key press and response is greater then 3 seconds … frustration)

• Breadth of network access


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References

• Turban McLean & Wetherbe• Martin, Brown, DeHayes, Hoffer &

Perkins (2005). Managing Information Technology (5th Edition). Pearson, Prentice Hall. Chapter 14.

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