Client/Server Technology
To understand what client/server computing is, we will start by defining the requirements for a client/server computing environment. The requirements are a client, a server, and a network.
A client is a user machine that is generally a PC or a workstation that provides a highly userfriendly interface to the end user. The client has a mouse and keyboard attached to it and uses interfaces that end users are generally comfortable with. Examples of these interfaces are Microsoft Windows and Macintosh OS X.
A server is a computer that proviedes a set of shared user services to the clients. The most common type of server is the database server that controls a relational database. The server enables the clients to share access to the same database and enables the use of a high-performance comptuer system to manage the database.
Client/server computing is distributed computing; therefore, it requires a network to operate. Clients and servers are usually connected over a Local Area Network or a Wireless Area Network; however, they can also be connected through the Internet.
The main feature of a client/server architecture is the allocation of application tasks between the server and the client. The client and the server must both have an operating system installed with communications software (such as TCP/IP) to transport the application information and instructions.
The most common application used in client/server architecture is the database application. An example of this would be programming a web-based interface that connects to your server's database. Anyone with access to that web interface could add data or change data in your database depending on what access permissions you give them on the server.
Middleware is a standard programming interface and protocol that sits between the application above and communications software and operating system below. This software enables easy implementation of the same application on a variety of server types and workstation types. Middleware enables distributed client/server computing. The entire distributed system can be viewed as a set of applications and resources available to users. Users don't need to be concerned with the location of data or indeed the location of applications. all applications operate over a uniform application programming interface, or API. The middleware then will route client requests to the appropriate server.
An intranet is a term that refers to the use of Internet technologies within a corporate organization, rather than for external connection to the global Internet. This technology has resulted in the most rapid change of direction in the history of business data communications. The reason for this is the long list of features that this provides. A few of the advantages are scalability, cross-platform implementation, and flexibility. For example, a corporation could use an intranet to allow its employees access to anything from job-related data to safety regulations data.
An extranet is like an intranet except that it allows access to corporate resources from outside clients. This is typically done through suppliers of a company and the company itself. An extranet usually requires a username and password to connect to it, or a pre shared certificate that must be placed on the outside client by the company.
Client/server computing is the key to realizing the potential of information systems and networks to significaltly improve productivity in organizations.
Chad Lamb
E-mail: cllamb@usieagles.org
Ryan Greenlee
E-mail: rmgreenlee@usieagles.org