Distributed Processing. The Internet and the New Information Technology Infrastructure. Reasons for Implementing Distributed Systems

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M7011 © Peter Lo 2005 1

The Internet and the New Information

Technology Infrastructure

M7011 © Peter Lo 2005 2

Distributed Processing

Distributed Processing can be

defined as a system in which both computer processing and data occur at more than one site; application programs are run at more than one site.

Distributed processing is associated with all type of

networks: including WAN, LAN, PBX, and even the Internet.

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Reasons for Implementing

Distributed Systems

Improved Response Time

Reduced Costs

Improve Accuracy

Reduced Mainframe Costs

Smoother Growth

Increased Reliability

Resource Sharing

Increased User Satisfaction

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Improved Response Time

When data and processing power are located

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Reduced Costs

When branch office can key in, edit and process

much of the data locally, those transmission costs are substantially reduced.

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Improve Accuracy

A branch department clerk entering branch data is

likely to know more about the data and therefore spot errors more frequently.

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Reduced Mainframe Costs

Collections of microprocessors offer a better price/

performance ratio than large mainframes

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Smoother Growth

If a new small system is added at a remote site,

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Increased Reliability

In a distributed system, failure of one processor

disrupts only the operations dependent on that particular processor.

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Resource Sharing

Computers have different functional capabilities

yet may need to share resources Client / server

Data gathering / data processing

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Increased User Satisfaction

Users may welcome more control over computing

power so that they can reduce the time they wait for their tasks to be addressed.

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Distributed Processing Concerns for

Managers

Lack of Professional MIS Staff

Standardization Documentation Data Loss Security Data Consistency System Maintenance

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Lack of Professional MIS Staff

Small branch sites on the distributed network may

be run by personnel with little or no training or experience with computing systems.

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Standardization

Without control, local units might acquire

incompatible equipment and software, and the system will be unable to provide integrated computing resources to everyone on the network.

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Documentation

Application-program development at remote site

increases the risk that these programs may not be fully documented.

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Data Loss

Without some form of central control or

enforcement of archiving procedures, inexperienced users of minicomputers and microcomputers at remote sites may treat

archiving of data too casually, and data loss is like to result.

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Security

Without some form of organization-wide control,

security procedures for confidential data or small, remote computing sites may easily become lax [slack, careless] or they may not exist at all.

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Data Consistency

Without careful planning, monitoring and controls,

the situation invites increased risks of data redundancy and therefore data inconsistency.

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System Maintenance

Large, centralized data centers have trained

professionals who are experienced in program and system maintenance.

It may be very difficult to provide system

maintenance promptly at every distributed site.

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An Effective Distributed Processing

System

Distributed processing systems must be managed very carefully to be effective.

Some form of organization-wide monitoring,

supervision, training, and control is necessary to ensure the system does not get out of hand.

It should be easy to use, User should not have to be

concerned with where the data are or where the processing is occurring: data must exhibit location transparency.

It should also guard against loss of data consistency.

The software and procedures should provide automatic system-wide updates. Automatic system wide updates through update transparency.

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Centralized Databases

In a centralized system, the computer system and

the database of an organization are both found at one location.

Databases in this setting are called Centralized

Databases.

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Distributed Databases

Organizations that need to decentralize their

computer processing may also need to decentralized their database.

When computing databases are scattered rather

than centralized, they are called Distributed

Database Systems.

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Distributed Databases

There are two ways to distribute a database

Replicated Databases

Partitioned Databases

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Replicated Databases

It provide duplicates of all data at all sites.

If every location must have frequent access to the

same data, replication of database may be recommended.

It is very expensive in terms of computer system

resources, and it can be difficult and costly to maintain consistency for each data element.

It does provide some measure of security by

providing duplicates of the database in case of failure at one location.

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Partitioned Databases

The database may be divided into segments that

are appropriate for certain locations and

distributed only to those locations. This approach is called Partitioned Database.

The database may be partitioned along functional

lines; e.g. financial, marketing, and administrative data are kept at corporate headquarters, and

relevant production and personnel data are kept at each manufacturing plant and office site.

Partitioning may also be achieved along geographical lines.

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Advantages of Distributed Databases

They usually reduce costs for an organization

because they reduce costs of transferring data between remote sites and organization’s headquarters

They may also provide organization with faster

response times for filling orders, answering customer requests, or providing managers with information.

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Disadvantages of Distributed

Databases

They compound problems with control and

security for the database; increase data redundancy and the resulting data inconsistency; require and increase the need for more computer resources.

Unless the distribution of a database is done very

carefully, many of the advantages of having a database in the first place can be lost.

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Client/Server Computing

The basic notion of a client/server computing system is the application processing is divided between a client, which is typically a PC; and a server, which may be on a LAN, a minicomputer or a mainframe.

The client process run on the PC and make requests to the server processes. Typically components of client/server computing are a relational database, a powerful server or servers, personal computer workstations, network and client software for the workstations.

Application processing is on the client computer.

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SQL Server

A common application of client/server computing

is the use of special relation database software called Structured Query Language or a SQL server.

The SQL server computer usually devotes all its

energies to managing the database software and does not handle other network tasks.

The SQL server processes the request at the server

and sends only those records that meet the selection parameters.

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Downsizing

Organizations with high maintenance costs on

existing mainframe computer hardware and

software are increasing downsizing to LAN-based, client/server computing systems from older, pre-existing, “legacy” mainframe-based information systems.

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Internet Communications

Many people describe the Internet as a network of networks or a relatively ungoverned aggregation of computers and computer networks located throughout the world. In fact, the Internet provides yet another example of client/server computing.

The Internet allows you to connect your PC (client) to computers (server) located at sites around the world to use their services.

The Internet began in the 1960s as ARPANET (Advanced Research Projects Agency Network) to connect research, military, and government network.

The organization (or company) providing access to the Internet is known as the Internet Service Provider (ISP).

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How did the Internet Originate?

Goal: To function if part of network were disabled Became functional September 1969 Goal: To allow scientists at different locations to share information

ARPANET

Networking project by Pentagon’s Advanced Research Projects Agency (ARPA)

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Who provides the Internet’s Structure

Today?

Government Cable companies Satellite companies Telephone companies Networks from corporations, commercial firms, and other

companies

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How has the Internet grown?

Today

More than 100 million host nodes

1984

More than 1,000 host nodes

1969 Four host nodes

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Who Controls the Internet?

Nobody; it is public, cooperative, and an independent network

Several organizations set standards

World Wide Web Consortium (W3C)

• Oversees research, sets standards and guidelines

• Tim Berners-Lee, director

Internet2 (I2)

• Internet-related research and development project

• Develops and tests advanced Internet

technologies M7011 © Peter Lo 2005 36

What are ways to Access the Internet?

1 Regional ISP 2 National ISP 3 OSP (Ex. AOL) 4 Wireless Internet Service Provider local call long-distance call

1

local call

2

local call toll-free call

3

local call

4

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How can you Connect to the Internet?

Very high-speed connection

Digital subscriber line (DSL) and cable modem

Dial-up access

Very high-speed connection

Digital subscriber line (DSL) and cable modem

Dial-up access

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What are three parts of an Internet

connection?

Backbone

Client

Server

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How might data travel the Internet using a

telephone line connection?

Step 1 Step 2 Step 1 Step 2 Step 3 Step 1 Step 2 Step 3 Step 4 Regional ISP Step 1 Step 2 Step 3 Step 4 Step 5 Regional ISP National ISP Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Regional ISP National ISP National ISP Internet backbone Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Regional ISP Local ISP National ISP National ISP Internet backbone Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Regional ISP Local ISP National ISP National ISP Internet backbone 2: Modem converts digital

signals to analog signals. 3: Data travels through

telephone lines to a local ISP.

4: Data passes through routers. 5: Regional ISP uses

leased lines to send data to a national ISP. 6: National ISP routes

data across the country.

7: National ISP passes data to local ISP. 8: Server sends

data back to you. 1: Request data from the

a server on Internet.

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How the Internet Works

Individual Internet service provider (ISP) Phone company Network service provider (NSP) Backbone network Phone company Company Web site Dial-up: 33.3 - 56 Kbps ISDN: 128 Kbps DSL: 256 Kbps - 6 Mbps Cable: 1.5 Mbps Cable company T1: 1.544 Mbps T3: 44.736 Mbps OC3: 155.52 Mbps OC12: 622 Mbps

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Internet Features

Internet Features include magazines, databases,

bulletin boards, shopping malls, electronic mail…anything and everything.

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Sample Internet Features

Instant Messaging

Chat Room / Discussion Groups

Internet Telephony and Desktop Conferencing

Collaboration Groupware Searching Information Electronic Mail Transferring Files Remote Control M7011 © Peter Lo 2005 43

Instant Messaging (IM)

4: Instant message travels through messaging server and then to online buddy

2: Server checks if any established friends, family, or co-workers, called buddies, are online 3: Send instant messages to online buddy Step 2 Step 4 Step 3 messaging server 1: Login to the IM server

Step 1

IM server

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Chat Room / Discussion Groups

Area on the Web where users conduct written discussions about a particular subject

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Internet Telephony and Desktop

Conferencing

Enables you to talk to other people over the Internet such as Voice Over Internet Phone (VoIP)

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Collaboration

Working with other users connected to a server

You can conduct online meetings

Allows you to share documents with others in real time

Microsoft’s NetMeeting allows collaboration

NetMeeting window chat room everyone in online meeting can see and edit document M7011 © Peter Lo 2005 47

Groupware

Software application that helps groups of people work together on projects and share information over a network

Lotus Notes

Microsoft Exchange

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Searching Information

Search engines enable you to do key word

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Electronic Mail

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Transferring Files

File Transfer Protocol (FTP) using the Internet

enables uploading new software and software patches.

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Remote Control

Running programs at remote computers

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Telnet

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Gopher

A tool that enables the user to locate information

stored on Internet servers through a series of easy-to-use, hierarchical menus.

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Internet Protocol (IP) address

Number that uniquely identifies each computer or

device connected to Internet

IP address

199.95.72.10

first part identifies network last part identifies specific computer M7011 © Peter Lo 2005 55

Domain Name

The unique name of a collection of computers

connected to the Internet.

Text version of IP address

Example: [email protected] (peter-lo.com is

the domain name)

IP address

199.95.72.10 Domain name

scsite.com

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What is a URL?

Unique address for Web page located on Web server

protocol domain name path

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Domain Name System Registration

Internet World Real World DNS Registration 207.46.250.222 www.microsoft.com Microsoft Corporation One Microsoft Way Redmond, WA 98052 US Internic.org ISP Net Range 207.46.0.0 – 207.46.255.255 Microsoft-Global-Net Arin.net Internet entities are anchored to the real world through the DNS registration and through their ISP. If they tell the truth!

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Portal Web Site

Web site providing an initial point of entry to the

Web.

Offers a variety of Internet services from a single,

convenient location

Often called a Portal

Yahoo! is a portal

“Push” Technology

Method of obtaining relevant information on networks by having a computer broadcast information directly to the user based on pre-specified interests.

Multicasting – Transmission of data to a selected group of

recipients.

Internet Commerce

Web site containing adverting about a company and its products – even a small organization can reach millions of potential customers in the world.

However, advertising is not the only commercial venture on the Internet. Electronic Commerce (e-commerce) over the Internet being explored on a wide front by many organizations. For example:

Electronic magazines Online banking

Using the Internet to make reservations for hotels,

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Intranet Communications

By connecting the company network to the global Internet, the company also opens up itself to increased increase security problems (such as hacking, etc). To resolve these problems, some companies have chosen to use Internet technology within their organization.

An Intranet can be briefly described as a private, intra-organization communication network using the Internet technology without connecting to the Internet.

Intranet provides many of the same features and benefits of the Internet (such as email, etc) while avoiding some of the costs and risks.

Intranet Communications Security

Firewall – Hardware & Software placed between

an organization’s internal network and an external network to prevent outsiders from invading private networks.

Intranet Applications for E-Business

Finance & Accounting

Human Resources

Sales & Marketing

Manufacturing & Production

Intranet Applications for E-Business:

Finance & Accounting

Internet can provide an integrated view of

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Intranet Applications for E-Business:

Human Resources

HR can use intranets for on-line publishing of

corporate policy manuals, job postings and internal job transfers, company telephone directories, and training classes.

Intranet Applications for E-Business:

Sales & Marketing

Oversee and coordinate the activities of the sales

force. Sales staff can dial in for updates on pricing, promotions, rebates etc.

Intranet Applications for E-Business:

Manufacturing & Production

Intranet can make manufacturing information

more accessible to different parts of the

organization, increasing precision and lowering costs.

Extranet Communications

While an intranet is confined to your own

organization and the Internet is open to the world, an extranet lies somewhere between the Internet and an Intranet.

An Extranet is an extended intranet accessible to

selected group not open up to general public.

A typical extranet allows connections between

wide groups such as an organization’s customers and suppliers.

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Internet Benefits to Organizations

Connectivity and Global Reach

Reduced Communication Costs

Lower Transaction Costs

Reduced Agency Costs

Interactivity, Flexibility, and Customization

Accelerated Distribution of Knowledge

Internet Business Models

Virtual Storefront Marketplace Concentrator Information Brokers Transaction Brokers Electronic Clearinghouses Marketplace Concentrator Information Brokers Transaction Brokers Electronic Clearinghouses M7011 © Peter Lo 2005 71

Internet Business Models:

Virtual Storefront

Sells physical goods or service on-line

Internet Business Models:

Marketplace Concentrator

Concentrates information about products and

services from multiple providers at one central point

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Internet Business Models:

Information Brokers

Provide product, pricing and availability

information

Internet Business Models:

Transaction Brokers

Complete transaction.

Internet Business Models:

Electronic Clearinghouses

Auction

Internet Business Models:

Reverse Auction

Consumer submit a bid to multiple sellers to buy

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Internet Business Models:

Digital Product Delivery

Sell digital products

Internet Business Models:

Content Provider

Customer pay to access content

Internet Business Models:

On-line Service Provider

Provide service and support for hardware and

software users

Disintermediation

The removal of organizations or business process

layers responsible for certain intermediary steps in a value chain.

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Web Hosting Service

Company maintaining large web servers to

maintain the Web sites of fee-paying subscribers.

Electronic Payment System

The use of digital technologies such as electronic

funds transfer, credit cards, smart cards and Internet-based payment systems to pay for products and services electronically.

M-Commerce

Internet access everywhere Cell phones PDAs Laptops Great potential Limited usability Better than voice?

Cell Phones and Wireless

Communication

_{Wireless cells work by}

handing off the wireless connection to the next tower as the caller moves. Connections to multiple towers at one time enables the system to triangulate to get a fairly precise location of the cellular device--even when it is not in a call. Location knowledge will make it possible (although perhaps not desirable) to offer new business opportunities as people move into range.

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Global Telecommunications

Technical problems Multiple standards Language Developing nations Time zones

Limits to space & waves

Political complications

Transborder data flows

Taxes

Privacy Accessibility

Cultural issues

What is an object?