Middleware Technologies

Robert Orfali

MIDDLE WARE TECHNOLOGIES

B.TECH III YR II SEMESTER

UNIT 1 PPT SLIDES

TEXT BOOKS:

1.Client/Server programming with Java and CORBA Robert Orfali and Dan Harkey, John Wiley & Sons,SPD 2nd Edition

2. Java programming with CORBA 3rd Edition, G.Brose, A Vogel and K.Duddy, Wiley-dreamtech, India John wiley and sons

INDEX UNIT 1 PPT SLIDES

S.NO. TOPIC LECTURE NO. PPTSLIDES

1. Introduction to client server computing L1 L1. 1 TO L1.4

2. Evolution of corporate computing models L2 L2. 1 TO L2.5 from centralized to distributed computing 3. client server models L3 L3. 1 TO L3.4

L4 L4. 1 TO L4.4

4 Benefits / pitfalls client server computing L5 L5. 1 TO L5.5

5 5.. REVISION L6

lecture 1 slide 2

UNIT1 SYLLABUS

• Introduction to client server computing: Evolution of corporate computing models from centralized to distributed computing , client server models. Benefits for client server computing, pitfalls of client server programming.

lecture 1 slide 1

What is client/server

• Clients and servers are separate logical

Entitles that work together over a network

To accomplish a task

lecture 1 slide 2

Client/server characteristics

• Service• Shared resources• Asymmetrical protocols• Transparency of location• Mix and match• Message based exchanges• Encapsulation of services• Scalability• integrity

lecture 1 slide 3

Types of client/server architectures

• File servers

• Database servers

• Transaction servers

• Groupware servers

• Object application servers

• Web application servers

lecture 1 slide 4

Monolithic computing

• Early computing was performed on a single processor

Makes use of a single cpu to execute one or more programs for each application

Ex: A uni-processor

lecture 2 slide 1

Distributed system

• A distributed system is a collection of independent computers ,interconnected via a n/w.

Ex: WWW,email,ftp

lecture 2 slide 2

Historical trends

• Mainframe of 60’s

• Minicomputer

• Workstation

• Pc

• Community culture

• web

lecture 2 slide 3

Distributed computer advantages

• The affordability of computers and availability of network access

• Resource sharing

• Scalability

• Fault tolerance

lecture 2 slide 4

Distributed computer disadvantages

• Multiple prints of failure

• Security concerns

lecture 2 slide 5

Specific types of servers

• App-servers

• File servers

• Mail servers

• Terminal servers

lecture 2 slide 5

Servers can be

• Stateless servers: do not keep any information b/w requests

Ex: http

• Stateful servers : can remember information

Ex: apache tomcat

lecture 3 slide 1

Types of clients

• Fat client

• Thin clients

• Hybrid clients

lecture 3 slide 2

Skills required by client/server applications development

• Transaction processing

• Database design

• Communications experience

• Gui design

• Internet server

• Knowledge of distributed objects and component instructors

lecture 3 slide 3

ERP

• ERP vendors now offer client/server solutions for• Consumer packaged goods• Automotive• Sales force automotive• Online catalogs• Retail• Oil and gas• Supply chain management• Banking• E-commerce

lecture 3 slide 4

Comparison of 2-tier with 3-tier

• 2-tierSecurity :lowPerformance :poorScale :poorApplication reuse :poorEase of development :highServer to server infrastructure :noLegacy application :noInternet support :poorSystem administrations :complex

lecture 4 slide 1

Comparison of 2-tier with 3-tier

• 3-tierSecurity :highPerformance :highScale :goodApplication reuse :goodEase of development :lowServer to server infrastructure :yesLegacy application :yesInternet support :goodSystem administrations :less complex

lecture 4 slide 2

Benefits of client/server programming

• You can develop big applications in small steps• Applications can reuse components.• Clients can access data and functions easily and

safely• Custom applications can incorporate off-the-

shelf components• Component environments don’t get older – they

only get better

lecture 4 slide 3

Benefits of client/server programming

• Vendor independence as compared to the traditional mainframe computing. This includes application development methodologies, programming paradigms, products and architectures

• Organization have changed from steep hierarchies to flattened hierarchies. Decisions making are carried out by many lower ranked managers across the organization rather than performed only by CEOs in the past.

lecture 4 slide 4

Benefits of client/server programming

• Network management is replacing vertical management

• Faster response and flexibility to changing environment of business world outside

• The customer has a single point of contact for all business with the organization

• The time required to complete the work will be minimized

lecture 5 slide 1

Benefits of client/server programming

• Better sharing of critical database resources and other application software's among clients through the network.

• Companies can cut costs on maintenance in employing Client- Server Computing since servers are usually cheaper than mainframe (1/10 of mainframe) and the performance of servers and mainframe are nearly identical.

• Networked webs of small, powerful machines. If one machine goes down, the organization can still function properly.

lecture 5 slide 2

Benefits of client/server programming

• Systems grow easily. It is easy to updated and modernize system, both hardware and software as the companies evolved and has new requirements.

• Individual client operating environments. You can mix and match computer platforms to suit the needs of individual departments and users.

lecture 5 slide 3

Pitfalls of client/server computing

– Dependability - when the server goes down, operations cease

– Lack of mature tools - it is a relatively new technology and needed tools are lacking

• e.g.. Automated client software distribution– Lack of scalability - network operating systems (e.g..

Novell Netware, Windows NT Server) are not very scalable.

– Higher than anticipated costs– Can cause network congestion– What some call advantages, others call

disadvantages

lecture 5 slide 4

Database servers

lecture 5 slide 5

File servers