Bartlang, U: Architecture and Methods for Flexible Content M

2010
ISBN: 978-3-8348-1023-6
Verlag: Vieweg+Teubner Verlag

Buch, Englisch, 240 Seiten, Format (B × H): 148 mm x 210 mm, Gewicht: 354 g

At times when the IT manager’s best friend is systems consolidation (which is a euphemism for centralisation), it may come somewhat as a surprise for you that this book investigates decentralisation in the context of content management systems. It may seem quite obvious that content will and should be managed by the party who creates and owns the content, and hence should be held in a—somewhat—centralised and managed location. However, over the past few years, we have been witnesses of some important trends and developments which call for novel ways of thinking about content management and maybe even broader, about computer systems in general. First, ongoing business globalization creates natural distribution of information at a corp- ate level, as well as decentralization of control over business resources and business processes. Changing alliances with partners require ?exible architectures for content management that canadapttochangingconstellations, roles, andaccessrights. Second, theneedforoutsourcing and resource e?ciency has brought about concepts of virtualization, recently culminating in the cloud computing buzzword. Virtualization of content management services requires - tremely scalable and ?exible underlying information and communication architectures. These kinds of solutions are theoretically and practically impossible to implement based on c- tralised client-server architectures. Third, we are currently experiencing a dramatic shift in the roles of consumers in the Internet. The times have gone when quality content was only delivered by publishers and news agencies. Wikis and other Web 2. 0 tools empower consumers to produce and publish their personal content.

Zielgruppe

Researchers, lecturers, and students in computer science, software architects and software engineers in the area of distributed systems and algorithms, especially of decentralised and/or peer-to-peer systems.

Autoren/Hrsg.

Bartlang, Udo

Fachgebiete

• Mathematik | Informatik EDV | Informatik Computerkommunikation & -vernetzung Verteilte Systeme (Netzwerke)
• Mathematik | Informatik EDV | Informatik Programmierung | Softwareentwicklung Algorithmen & Datenstrukturen
• Mathematik | Informatik EDV | Informatik Programmierung | Softwareentwicklung Software Engineering

Inhaltsverzeichnis

Background.- Analysis of Content Repository Requirements in a Peer–to–Peer Case.- Design of a Generic Peer–to–Peer Content Repository System Architecture.- Methods for Flexible Content Repository Functions in Structured Peer–to–Peer Overlays.- Methods for Flexible Content Repository Functions in Hybrid Peer–to–Peer Overlays.- Evaluation.- Conclusion and Outlook.

Leseproben

4 Design of a Generic Peer–to–Peer Content Repository System Architecture (S. 71-72)

The architecture of a software system may be regarded as its essential description to understand it. For instance, such understanding refers to the role of the major system components and, in particular, their coupling. A “software architecture shall de?ne a simple model of major components and their interactions, it may act as reusable, transferable abstraction of a software system” [55].

An architecture acts as a method to organize and structure a system. An important aim is to reduce the overall complexity to illustrate such system promoting the principles of decomposition and transparency, for example, as functionality is encapsulated within certain system parts, the details should be hidden, turning the focus rather on each part’s characteristics. Hence, architectural design has major impact on a system’s functionality, as it de?nes the degree of modularity a?ecting maintenance and reliability.

In this chapter, the architecture illustrates the responsibilities each system part has and how these parts interact to ful?l functional and non-functional requirements of peer–to–peer (P2P) based content repository functions, as presented in Chapter 3. One key to meet the imposed requirements is ?exibility. This motivates a generic architecture, which is suitable for di?erent communication and storage paradigms. Thereby, the term generality refers to “the degree to which a system or component performs a broad range of functions” [176]: accordingly, the generic architecture needs to support, for example, the introduced concepts of sessions and workspaces, and to integrate di?erent storage back-ends, the latter may comprise the integration of local systems, distributed client–server systems, or decentralised (structured or hybrid) P2P systems.

This chapter is structured as follows: Section 4.1 introduces the applied methodology to present the P2P-based content repository architecture. Then, Section 4.2 describes the generic architecture for the overall content repository system. It introduces a layer model to decompose the system into several parts of responsibility, and illustrates the management to cope with persistent storage. Next, Section 4.3 introduces a method for generic content mapping, which supports transparency at di?erent levels. It explains a concept to bundle items and introduces ?exible content data policies. Subsequently, Section 4.4 shows a generic peer architecture explaining a peer’s basic services and introducing a method to dynamically integrate additional peer services. Section 4.5 discusses related work.

Finally, Section 4.6 concludes and summarises this chapter. 4.1 Architectural Model Overall, a software architecture deals with the design and implementation of a software’s highlevel structure [108]: it is basically the result of composing an amount of architectural elements in some well-determined way to satisfy the major functional and non-functional requirements of the system. The methodology to present the P2P-based content repository architecture is oriented on the “4+1” view model of software architectures [108]: the organisation of the architecture’s description uses multiple, concurrent views—each one addressing a speci?c set of concerns. This allows to cope separately with the functional and non-functional imposed requirements— as introduced in Chapter 1.1 Figure 4.1 [108] illustrates the ?ve main views.

Über Autor(innen)

Dr. Udo Bartlang completed his doctoral thesis at the Faculty of Mathematics/Computer Science and Mechanical Engineering (Department of Informatics, Business Information Technology Unit), Clausthal University of Technology. The thesis was conducted at Siemens Corporate Technology, Munich.