Chapter A-1
Introduction: –
Client / Server is one of the slogans of the computer industry’s newest and hottest. There is no general definition of client / server, how it is used to estimate the number of nature, development and anticipateologies length. However, the general idea that clients and servers, logical units, which together with care, a network to have a job to do.
Client-server is very fashionable. As such, it could just a fad, but it is generally accepted that there is something fundamental and far reaching, for example, the Gartner Group, the major industry analysts in this area, predicted that
“In 1995, client-server computing is synonymous with.”
Most of the original customer / server success stories have little to offer applications that provide direct or indirect access to the transactional data systems. The company needs to provide access to data for decision-makers, the relative immaturity of the client / server technology and tools, the use of the development of wide area networks and the lack of client / server expertise, these companies are still attractive make low-risk drivers. As companies move up the learning curve of these small projects to critical applications, there is a corresponding increase in performance expectations, the time for the availability and the need to remain flexible and scalable. In such a scenario requires the selection and implementation of appropriate architecture is critical. In fact, one of the most important questions that practitioners face the beginning of every client / server is proposed – “The architecture is best suited for this project – two or three animal animal?”. It is interesting that 17% of all mission-critical client / server are three levels, and the trend is rising, according to Standish Group International, Inc., a market research firm.
Architecture affects all aspects of software design and technology. The architect believes that the complexity of the application, the degree of integration and interface requirements, the number of users, their geographical distribution, the nature of networks and the needs of the entire transaction request before deciding on the nature of the architecture. An architectural design inappropriate or incorrect implementation could lead to terrible response time. The choice of architecture also affects the development time and flexibility, and maintainability of the application. Current literature does not adequately take into account all these aspects of client / server architecture. This document defines the basic concepts of client / server architecture, describes the level two and three-tier architectures and discusses their respective advantages and limitations. Differences in the development efforts, flexibility and ease of reuse is also compared with others in choosing the appropriate architecture for a specific project to help.

Chapter A-2
History & definition: –
History
The University of Waterloo implemented Oracle Government Financials (OGF), May 1996. UW accounting systems that moved to a vendor supported package on a Unix / Solaris and away from locally developed package (s) on IBM / VM. The plans were then moved over to (if not all) business systems) to a single supplier on a single platform and database (Oracle for standardizing both. A very important state art system of Solaris was bought with the intention of co-localization of these other services from Oracle on the same system with the FAQ provided. Network security architecture was expected to take part in administrative isolated networks, these networks with firewall log filtering and monitoring systems. The systems were purchased and used to implement the security architecture.
Much has changed in the meantime. While the FAQ is now more services through the end of 1996, the project comprises of all the systems have failed. Above all we must pay the People Soft / HRMS (Human Resources Management System) (in the fourth quarter of 1998, followed in use) with People Soft / SIS (Student Information Services) a few years Oracle failed to provide these key elements of our business. Also, we found, then it is reasonable to Oracle as the database when other applications need to be specified, it is unreasonable to expect that the same be certified versions of the Oracle database and / or the underlying operating system. Technology changes too quickly: the state of the art Solaris system is outdated. Networks have been restructured to the administrative systems in the isolation of the “Red Room” and administrative users across the campus. But to actively monitor the firewall administration and transport, was never realized – recently it has degraded.

Definition:
Despite the massive media coverage of client / server computing, there are a lot of confusion around the definition of client / server is. Client and server are not units of software and hardware. In its simplest form, requires client / server software company) (builder, a specific request that is filled by another software company (server). Figure 1 shows the Client / Server Exchange. The client process sends a request to the server. The server interprets the message and then tries to process the application. To satisfy the request, the server needs to be a source of knowledge (database) data) (calculations, controller, or make an additional request to another server, refer to. In many architecture, a client can make requests to multiple servers and a server can serve multiple clients.

Figure 1 – Client / server transactions
It is important to understand the relationship between the client and the server, is a command / control relationship. In each exchange, the client initiates the request and the server responds accordingly. A server can not start a dialogue with the customer. Since the client and server software company, they can be placed on any suitable material. A client process, for example, could reside on a network server hardware, and request data from a server process running on a different server hardware or even on a PC. In another scenario, the client and server processes on the same physical hardware can be displayed. In fact, in the prototype phase, a developer can choose to both client and server template database on the same PC have hardware. The server can then be distributed to migrate () to an even greater has been completed for pre-production test for the main board of the development of applications and data structure.
Although the client and server are on the same machine, this paper focuses on the architecture used for distributed applications to create I. e. where the client and server on separate physical devices. According to Beaver (et al.), A distributed application consists of different parts on different nodes of the network and have a common goal. The infrastructure should include the inherent complexity of distributed processing for the user invisible. The client in a client / server does not display a graphical user interface (GUI), but the mass-marketing of client / server has been created primarily to the proliferation of GUI clients. Some client / server support for very specific functions such as print queue (ie, queuing network printing) or the presentation of services (eg X window). Although these specialized implementations are important, this paper focuses with the client / server architectures, the flexibility in the functionality needed

Chapter 3
Sense of client-server architecture: –
Direction of client-server: –
Client-server is generally perceived as the next step in the operational efficiency of IT systems. This is illustrated in Figure 1, which shows the cumulative earnings from a number of innovations.
The computing power began in the 1960s with the batch. The main innovation in the 1970s has left the processing of online transaction processing (OLTP), which has enabled the information technology (IT) for office, and made an integral part of business. Batch and OLTP in combination will remain the focus of information systems for the company. Then in 1980 the “personal computing, so that the economic and scattered throughout the company. But in the 1990s, client-server in general as a way to integrate different parts of the IT systems to see together again. The is its role and its importance.
Figure 1

perceived impact on the business client-server –
Under these circumstances, client (server or client / server) has become a popular brand that is used for almost all product types and all types of business and technical knowledge and marketing messages. This is discussed in public special meaning, while in fact confirmed its almost universal applicability.
Technical meaning of client-server: –
A good starting point for understanding the client-server is used, the informal definition of the Gartner Group:
“Client-Server is the division of an application into tasks that are running on separate computers, one of which is a programmable workstation (for example, a PC).”
This definition states that are divided on client-server architecture, distributed computing and software (programs into tasks that are on separate computers). It coincides with the main point of client-server is the way to integrate computers into all kinds of information.
Three generations of the E-mail:

architecture is based on the host (not a client / server):
With the software architectures all intelligence is in mainframe mainframe. The interaction with the host via a terminal, the Records keystrokes and sends this information to the host. Mainframe software architectures are not tied to a hardware platform. The user can interact with the PCs and UNIX workstations. A limitation of mainframe software architectures is that they simply do not support graphical user interfaces or access to multiple databases from geographically dispersed locations. In recent years, mainframes, a new use as a server in client / server architectures have found
LAN file sharing architecture (not a client / server): –
The original PC networks were based on file-sharing architectures, where the downloaded file server from the shared location for the desktop environment. The requested user job is then run (including logic and data) in the desktop environment. File sharing architectures work if shared usage is low, the confirmation of updating is low and the volume of data transmitted is low. Changed in the 1990s, PC LAN (local area network) computing, because the capacity of file-sharing has been changed, has increased the number of online users (it can meet only about 12 users simultaneously) and graphic interfaces (GUI) have become popular (which will appear outdated mainframe and terminal). PCs are now in client / server architectures
Internet client-server architecture: –
The goal here is to build a foundation of basic skills that the rest of the course are destroyed.
In many areas of technology, one gets the impression that the technology existed as yet in its current form. But of course technology has a history as any other natural or artificial phenomenon. It is for the Internet and the World Wide Web. In this discussion, we first consider some important developments took place in the last thirty years, the Internet what it is today. After examining this timeline, we will focus on two underlying technologies that support the Internet. The first is Ethernet, the home network (LAN) technology and remains a use of communication systems most commonly used to connect computers located only a few hundred meters from each other. The second is the TCP / IP, the standard software that distributes computers around the world to send messages and communicate with each other reliably.
After discussion, the Internet, we focus our attention on the World Wide Web. The discussion begins with an examination of its basic client / server architecture, which communicates in a client program on a computer running a server program that is conducted on a further request for specific information or particular services. The Web is a client-server architecture where a web browser (client) communicates with different servers for Web pages for information or an application to the server through the Common Gateway Interface (CGI). As the Internet / WWW is always a general computing and communications infrastructure will be extended to this strict client / server. This expansion requires Java. Learn about the latest developments in the later stages, but now we will concentrate on the traditional Web client / server.
Clients and servers, Web language is to speak to each other HTTP (Hypertext Transfer Protocol). You do not need to learn to HTTP in detail, but you will build core messages using HTTP to do CGI programming, and we must understand the underlying philosophy and its basic shape and volume.

Chapter-4
Process: –
Client Process: –
The client is a process (program) that sends a message to a server process) (Program and requested that the server is a task (service) is running. Client programs usually manage the user interface portion of the application, validate data entered by the user, sending requests to server programs, and sometimes business logic result. The client, based on
The process is the front-end of the application that the user sees and interacts. The client process contains solution-specific logic and provides the interface between the user and the rest of the application system. The client process also manages the local resources that the user interacts with, such as a monitor, keyboard, workstation CPU and peripherals. An essential element of a client is the graphical user interface (GUI). Normally part of the operating I. e. the window manager detects user actions, managing windows on the screen and displays the data in the windows.

Process Server: –
A server process (program) to the demand of customers by fulfilling the desired task. Server programs generally receive requests from client programs that perform database retrieval and data manage updates, data integrity and to send responses to client requests. Sometimes server programs execute common or complex business logic. The process server on the basis of “May” on another computer on the network. This server is the host operating system or a network file server, the server that is both file system services and application services. Or in some cases provides another desktop application services. The process server acts as a software engine that resources such as databases, printers, communications links, or high-voltage processors are managed jointly. The server process performs the tasks backend are similar applications together.

Client-Server Computing –
• Customer unique single-server

• Several clients, single server
Client / server is a computer architecture that involves client processes requesting service from server processes client / server is the logical extension of modular programming. The modular programming is the basic assumption that separation creates a large piece of software into its component parts ( “modules”) the opportunity to develop and improve maintainability. / Computer server client is this comparison a step further by acknowledging that the modules do not necessarily all be executed in the same area of memory. With this architecture, the calling module “customers” (the service required) and the module is called “server” (who provides the service). The corollary of this is that clients and servers that have the appropriate hardware and software platforms for their functions. Is For example, the server system management databases specially configured platforms that perform queries, or file servers running on platforms with special elements for managing files.

Network Computing Architecture –
Oracle Network Computing Architecture (NCA) can be explained by three concepts are covered
1. The World Wide Web is a truly everywhere Service.
2. The JVM is (or soon to be) a service truly ubiquitous and integrated into the browser.
3. To grant a three-tier model for applications with an engine of Oracle database (on a large UNIX server), a small Java application on the client and middle-tier “Forms Server to provide the bridge between two .
Oracle began shipping Release 10. 7 (NCA delivery of web applications) in January 1998. . . . 2000 require
With Version 10 7 NCA, Oracle has responded to customer feedback on the difficulties of patches in smart client. Although the functionality is the same between 10 and SC 10 NEC, Oracle web application returned an exit strategy of patches more granular. This strategy is also better preserved adjustments. Because the technology is used on the server in the network communication, relining and regeneration after patching became easier. Because of differences in the strategy of patching Oracle recommends not using people about smart client and Release 10th 7 ANC in the same instance. Oracle does not support this configuration. Facilities should Customerncharactermode directly to the used Web
Release
Chapter A-5
Client-server technology: –
The client-server technology is better understood if we treat in four areas:
1. Staff platforms
2. Server platforms
3. Client-server middleware
4. Client-server tools and services
Each of these areas is unique, although it certainly overlaps between them.
The term platform is used here to refer is a computing platform, a complete combination of hardware and software operating system.
Staff platforms: –
Staff platforms are perhaps the most striking area of client-server technology. We define a personal platform:
A platform that is connected to a network, perform and provides a single intuitive user interface and support staff for tasks on behalf of the company.
These functions are shown in Figure 2. Staff platforms are relatively inexpensive and very efficient, and there is a wide choice of suppliers. Many different types of computers can be platforms for personal (eg MS-DOS, PC, PC Windows, OS / 2 PCs, UNIX workstations, Apple Macintosh, and various hand devices), but most often the case today is an IBM compatible PC operating system Microsoft Windows.
These platforms are now widely available, where they are needed. This makes the architecture of computer systems on the contrary, the old focus scarce resources of the central engine, away from their users, the new direction, the wealth of personal resources is now within reach of every user. This trend has become increasingly visible, because the PC price / performance ratio by a factor of two every eighteen months or improve further.
This change is intended to discuss changes in the organizational structure: organizational hierarchies are flat, the decision-making power is delegated, and IT-based processes can now offer processes that were formerly provided by the staff available. A combined effect of these trends is the commercial and technical management of the individual at the reception.
Enter PC personal productivity and independence, but this individuality, multiplied by the number of PCs also can create anarchy. Client Server solves these problems. With the funds provided by the shared client (on the server platforms), and not only the personal resources, client-server structure allows all hardware and software in the context of architectural control and management. He transforms the PC into the inter-personal computing and enterprise use. These functions help, order, cohesion of the group are working to establish the productivity and flexibility of business processes.
While the platforms of the major personal and economic driving force for the transfer to the client-server, they are only the first five ingredients, techniques, and the 2nd in the previous section
Server platforms: –
We define a platform for server as:
A platform, on which the software provides computer services for use in other parts of the system.
Finally, be used with services for personal platforms, but services are also provided for use with other server platforms. A platform server can provide services through support for devices that do not as a personal platform.
Almost all types of computer platform can be used as server platform. Therefore, there are many different providers, and many types of server platforms, from supercomputers to PCs. Each is good for certain types of workloads for different quality requirements, and in various areas of price and performance range. Business users can choose different platforms to respond to different needs.
This breadth of choice is shown in Figure 3, the user can access a personal platform to services in many server platforms have shows presented. It also shows the shift in focus to the individual user, a personal platform, which now can provide services from many different sources, with the rest of the computer select Network.
The polarization of the systems in client-server platforms, and identifies differences between personal and collective resources. Any personal platform is a personal independent resource that can be mobile and is exposed to the risk of accidental loss or damage. In contrast, with a server platform to protect, firm and carefully managed environment for shared resources.

Even if the same technology for both client and server platforms (eg PC with similar hardware and operating system) is used, these distinctions are made between personal and collective resources. Ultimately, the same machine can be both a personal platform and server platform (for example, is in a peer-to-peer, see 3. 2). As always, the server includes role obligations to ensure the availability and integrity of shared resources.
Client-Server Middleware: –
We define the client-server middleware as:
From software to the various parts of a software client-server support and enable them to work together.
This is by far the most complex client-server technology. Due to the concentration of the complexity here, we can in other areas still relatively simple. It contains many types of functions, each May are themselves distributed, of which most are linked. Some key areas are:
• Network services
• Distributed Application Services
• Distributed Systems Management
• Distributed security
• Distributed Management object>
• User Interface Management
• Print Management
• Data management
• Transaction management
• Workflow Management
Figure 4 is a symbolic display of support for middleware software client-server application. He stressed the importance of middleware that enable client / server technology, the whole range of activities engaged in for the tasks set by the user. This may be an interaction of time between the different departments and are functionally involved and perhaps the corporate boundaries.

Client-server tools and services to: –
The client-server systems can be very complex, integrated systems, but with very good and well-designed user interfaces from technical complexities should not be visible to the user, it is essentially a problem for application developers and service providers. You need software development tools and professional services to help manage the complexity and hide. Many tools and services are needed, as always, but there must be a client-server systems.
A general point which is important for packaging (shrink wrapped) software application, the user enterprise shall not schedule construction tools. Packaged products to client-server are now generally available (eg distributed desktop applications and groupware applications, accounting, personnel and payroll applications).
Another important trend is that different tools (and languages) for the different parts of the application necessary systems are modular. The main differences are:
• User Interface: Languages and tools for creating graphical user interfaces and business logic, all closely associated with them eg GUI tools and Visual Basic.
• Database: Languages and tools for the creation of databases, file systems and object stores, and building the application logic closely associated with them eg data manipulation languages and relational databases, 4GL.
g.
g.

1.
2.
3.
4.
5.
6.