Client/Server Model

Suitable Servers and Software

 File Server

File Server Example

• File Servers are important for information sharing across networks.

• Client’s requests for file records, in a manner that it is considered a primitive type of data service used for intercommunication via messages over the network to find relevant data.

• In a usual implementation remote server processers can be accessed through file server and also the software, corporate data, databases and backups are stored on primary (hard drive) or secondary(magnetic tape, optical storage) devices, are managed by the file server.

2. Database Server

• The communication with the database server is gained through the SQL requests of clients and the appropriate response by the server (Client/Server Architecture,2011). 

• The server is capable of using its own processing power to search the relevant data, instead of passing all records to the client as the SQL code responsible of querying the requested data resides on the server itself resulting an efficient use of distributed processing. Due to the fact that the application code resides on the client machine its possible either to write a code or to purchase a shrink-wrap query tool (Client/Server Architecture,2011). 

• Database servers contribute towards the implementation of Decision Support Systems and acts as a key role in data warehousing (Client/Server Architecture,2011). 

Client/ Server with Database Servers

3. Transaction Servers

Clients can appeal to distant procedures and services offered by servers with SQL database engine using the transaction server.

• The network exchange resides on a single request/ reply basis. A transaction is a set of SQL statements which work as a unit (Client/Server Architecture,2011). 

• For the client/server application in a transaction server, it’s necessary to implement codes in both components (Client/Server Architecture,2011). 

• User Interface (GUI) is used for client components and the server components comprises of a set of transactions related to a database. These applications are known as Online Transaction Processing or OLTP, considered as mission critical applications with fewer throughputs (1-3 sec) (Client/Server Architecture,2011). 

• OLTP applications necessitate adequate security measurements along with database integrity. The two components of OLTP are, 

• TP-Lite: comprises of stored procedures provide by database-vendors.

• TP-Heavy:  comprises of TP Monitors offered by OLTP-vendors.

Client/ Server with Transaction Servers

4. Groupware Servers

• Groupware servers are used to handle semi-structured information such text and images, mail, bulletin boards etc (Client/Server Architecture,2011)

• The usage of these servers in a client/server system enables direct communication between people, e.g. - software-Lotus Notes, Microsoft Exchange.(Client/Server Architecture,2011)

• Usually dedicated groupware software is built on top of a vendor’s canned set of client/server API’s since entitled applications are created with the help of scripting language and form-based interfaces deployed by the vendor.(Client/Server Architecture,2011) 

• Today Internet has become the frequent middleware platform for groupware where communication is attained through emails. 

5. Object Application Servers.

• Here the application interface of client/server is created as a bundle of inter-communicating objects.(Client/Server Architecture,2011)

• The client-side object seeks the help of Object Request Broker (ORB) to communicate with server objects which responses to the relevant method, locating an instance of the appropriate server class.( slideshare 2011)

• Server objects should conclude concurrency and sharing support which are fulfilled by new generation applications such as COBRA and ORB.(Client/Server Architecture,2011)

• The commercial ORB’s act in accordance with Object Management Group’s CORBA comprises of,
• Iona’s Orbix
• Inprise’s VisiBroker
• ICL’s DAIS
• JavaSoft’s Java IDL
• BEA’s ObjectBroker
• IBM’s SOM
• Expersoft’s PowerBroker (www.slideshare.net)

• CORBA is also the basic foundation technology for the Enterprise JavaBeans component model. The new generation CORBA application servers are also called as the Object Transaction Monitors (OMTs) provide      server-side component coordination services.

• COBRA acts as the key basis for the Enterprise JavaBeans constituent model and new generation COBRA application models are known as Object Transaction Monitors (OMTs) dedicated to offer synchronization services.

• Currently the main competitor identified for COBRA is Microsoft hat Distributed Component Object Model (DCOM)- key basis for Microsoft’s enterprise software and its ActiveX constituent, derives the service of Microsoft Transaction Server (MTS) as the application server, also known as COM+.

6. Web Application Server

Considered as new category of Internet software these are responsible in connecting standard HTTP servers with server-side constituent frameworks also being operationally similar to object servers.

• Client/server architectures that engage web servers comprise of thin, portable, universal clients entitled to communicate with fat servers- handles the bulk of data processing. The inter-communication is gained through a protocol similar to RPC, called as HTTP which interprets set of parameters to be passed as strings, without provisioning typed data.(Client/Server Architecture,2011)

• Overlook of products include parallel operation of Microsoft’s MTS object server as a Web Server and an Application Server and also CORBA/Java; Enterprise JavaBeans being the demand. Some servers capable of offering the COM/CORBA bridges.(Client/Server Architecture,2011)

• The CORBA/Java Web application servers,

• Netscape /Kiva’s Application Server
• BEA’s WebLogic
• Bluestone’s Sapphire Web
• IBM’s WebSphere
• SilverStream’s SilverStream Application Server 2.0
• Novera’s jBusiness Application Server

Bibliography

·         slideshare. (2011). Client Server Architecture. [Online]. Available from: http://www.slideshare.net/suks_87/client-server-architecture-presentation. [Accessed: 20th January 2011]

·         bhuvana. (2006). Two-Tier Architecture. [Online].Available from: http://bhuvans.wordpress.com/2006/08/22/two-tier-architecture/. [Accessed: 27th January 2011]

·         Chapple. (2011). Two-Tier or n-Teir. [Online].Available from: http://databases.about.com/od/specificproducts/a/architectures.htm. [Accessed: 27th January 2011]