Enterprise Application Integration (EAI) - Guide to Cloud Computing for Business and Technology Managers - page 91

and to consumer. HR Management solutions provide a coherent approach
to the recruitment and management of people working in organizations.
4.1.1 Management of Enterprise Applications
4.1.1.1 Manageability
Enterprise application systems are confronted by ever-changing require-
ments and environments and should be able to adapt to these changes
dynamically. Consequently, better solutions have the following features:
• A high degree of adaptability and extendibility of the whole system
built into the design
• Support for mass deployment
• Support for business-driven configuration scenarios
• A configurable security management system based on users, roles,
and access control lists with distinct and configurable privileges
• Tracing capability for user actions
Another aspect of application complexity is the ability to manage software
components that constitute the application. With the shrinking average life-
time of applications due to the increasingly competitive markets, incorporating
updates to provide newer or latest features over time becomes an obstacle for
managing software components. The problem is not new but became increas-
ingly important with the growing number of two-tier applications at the end
of the 1990s. The applications that are often built as rich clients and capable
of directly accessing back-end databases are prime candidates for version
conflicts and data integrity frauds, if the software update is not planned and
enforced perfectly. All clients have to be updated before they attempt to inter-
act with a new version of the back-end system. If this is not possible, a proper
mitigation solution has to be deployed. Such a solution may sound promis-
ing upfront but can become very difficult to manage over time. Releasing a
mitigation solution for every version deployed soon becomes a maintenance
nightmare and may actually hinder future development, because every itera-
tion of the software has to be aware of all previous combinations. The root
cause of this problem is that client software has to keep track of the changes to
remain up-to-date. This problem is avoided in three-tier applications as only
the application deployed on the server needs to be updated, which is also the
major reason for the success of typical three-tier Web applications.
Depending on the usage scenario, the necessary downtimes for updating
software have to be minimized and made as transparent as possible for the
user. This is one of the main reasons behind new concepts like the OSGi
(Open Service Gateway initiative) that supports hot deployment with 24 × 7
availability (24 h/day and 7 days/week).