Developing Server-Side Infrastructure for Large-Scale E-Learning of Web Technology

Introduction

Many E-learning and E-business technology courses use some specialist software which, along with other course materials, such as Portable Document Format (PDF) documents and video, are distributed on Digital Versatile Disc (DVD) or by download.

Client-side software can be installed on student machines with the aid of a ‘wizard’ which guides the student through the installation steps and which can also try to ensure that the platform is suitable for the software to function properly. This type of software typically includes web browsers, programme development toolkits, libraries and Integrated Development Environments (IDEs), such as eclipse (http://www.eclipse.org/). The range of student platforms and pre-existing software which can interact with the course software presents one source of potential problems. In practice, the occurrence of problems can be greatly reduced by careful engineering of the installation, rigorous testing and, for example, providing a fully independent installation. An independent installation may duplicate supporting software which is already installed on the machine to ensure, for example, that appropriate software versions are used. A good example of this is the installation of Eclipse for which java may be installed, even if java has been installed on the machine previously, so that Eclipse runs on a known version of Java.

The rise of network computing and Internet based applications running on web and application servers has resulted in a greatly increased importance of providing students with reliable access to server-side applications and middleware.

Understanding, skills and experience of server-side aspects are of relatively greater value than comparable client-side aspects (Ehie, 2002) and in increasing demand. In response to this a wide range of higher education establishments have developed E-business courses which include server-side components and there have been evaluations of a range of the mainstream alternative platforms that can be deployed to support server applications (Sandvig, 2007).

Providing server-side facilities for students on their own machines is far more problematic than installing simpler client-side applications. Server software is more sensitive to platform variations and requires substantial expertise for configuration, management and the diagnosis and resolution of any problems.

Students cannot in general be expected to come with the necessary skills to successfully install and manage server-side software unaided. In addition, in the context of a course aimed at information technology management, students cannot be expected to be equipped with accomplished programming or software configuration skills. The consequence of these factors is that any provision of experience in server-side areas in a purely ‘at a distance’ E-learning context is extremely unusual.

There is also a need to provide a ‘level playing field’ for students and to be able to assess their work on a server-side platform. In terms of a level field it should be the case that a student should not be disadvantaged because they have some unforeseen problem installing the software against another student for whom the software installs without problem. For assessment purposes it is useful to be able to actually run, rather than rely on inspection alone, the server-side solutions which students have created and deployed. The only means by which student work can be assessed in this way, in a distance learning setting, is by providing a standard server platform onto which students can remotely deploy and test their own work.

In the following sections the development of an architecture is outlined which provides support for running a very large number of instances of a web application called ‘Axis2’. This web application has been chosen as an illustration as it provides the appropriate facilities for students to deploy and manage their own web services on a server, which is a non-trivial task in itself, and this is an interesting component used in a new course developed at the Open University (OU).

However, the architecture has far wider relevance in education and commerce for supporting very large-scale deployment of web applications and services. The same architecture and principles involved can be employed to support very large numbers of users accessing a single (multi-user) web application or service, or to support large numbers of instances of any other web application.