IEEE Internet Computing

Clay Shirky describes PCs as the "dark matter of the Internet" because a lot of them are connected, but they're barely detectable. We can apply a similar analogy to middleware because the "mass" of the middleware universe is much greater than the systems - such as message-oriented middleware (MOM), enterprise application integration (EAI), and application servers based on Corba or J2EE - that we usually think of when we speak of middleware. We tend to forget or ignore the vast numbers of systems based on other approaches. We can't see them, and we don't talk about them, but they're out there solving real-world integration problems - and profoundly influencing the middleware space. These systems are the dark matter of the middleware universe.

802.11a represents the third generation of wireless networking standards and technology (behind 802.11 and .11b). It was actually approved as a standard earlier than 802.11b, but it presented a greater engineering challenge, and was delayed. Advances in technology (Moore's Law continues to prove true) helped Internet engineers overcome those challenges in a cost-effective manner and prepare the specification for market introduction. The result is the further extension of 802.11 networking capabilities. My previous article, "802.11: Leaving the Wire Behind," (Kapp, 2002) focused on 802.11b wireless networking and the various 802.11 task groups that will directly affect the future of 802.11 networking. In this article, I examine 802.11a networking in depth and compare it to 802.11b and the upcoming 802.11g networking.

Device manufacturers, users, and authors have differing needs and expectations when it comes to Web content. Web software and hardware manufacturers naturally try to differentiate their products by supporting a special combination of capabilities, but few can expect Web authors to create content for their product alone. Users, however, do expect to access the same content from any device with similar capabilities. Even when device capabilities differ, users might still want access to an adapted version of the content. Due to device differences, the adaptation might not produce an identical presentation, but device-independence principles suggest it should be sufficiently functional to let users interact with it successfully. Web application authors cannot afford to create multiple content versions for each of the growing range of device types. Authors would rather create their content once, and adapt it to different devices-but they also want to retain control of presentation quality. Device independence is about trying to satisfy these differing needs, spanning the delivery path between author and user by way of diverse manufacturers' devices. The field's continued evolution within the broader Web standards framework aims to find solutions that are beneficial for all.

By associating meaning with content, the Semantic Web will facilitate search, interoperability, and the composition of complex applications. The paper discusses the Semantic Content Organization and Retrieval Engine (SCORE, see vvww.voquette.com), which is based on research transferred from the University of Georgia's Large Scale Distributed Information Systems. SCORE belongs to a new generation of technologies for the emerging Semantic Web. It provides facilities to define ontological components that software agents can maintain. These agents use regular expression based rules in conjunction with various semantic techniques to extract ontology-driven metadata from structured and semistructured content. Automatic classification and information-extraction techniques augment these results and also let the system deal with unstructured text.

The popularity of large-scale Internet infrastructure services such as AOL, Google, and Hotmail has grown enormously. The scalability and availability requirements of these services have led to system architectures that diverge significantly from those of traditional systems like desktops, enterprise servers, or databases. Given the need for thousands of nodes, cost necessitates the use of inexpensive personal computers wherever possible, and efficiency often requires customized service software. Likewise, addressing the goal of zero downtime requires human operator involvement and pervasive redundancy within clusters and between globally distributed data centers. Despite these services' success, their architectures-hardware, software, and operational-have developed in an ad hoc manner that few have surveyed or analyzed. Moreover, the public knows little about why these services fail or about the operational practices used in an attempt to keep them running 24/7. As a first step toward formalizing the principles for building highly available and maintainable large-scale Internet services, we are surveying existing services' architectures and dependability. This article describes our observations to date.

Many of the Web applications around us are data-intensive; their main purpose is to present a large amount of data to their users. Most online trading and e-commerce sites fall into this category, as do digital libraries and institutional sites describing private and public organizations. Several commercial Web development systems aid rapid creation of data-intensive applications by supporting semiautomatic data resource publishing. Automatic publishing is typically subject to the constraints of database schemas, which limit an application designer's choices. Thus, Web application development often requires adaptation through programming, and programs end up intricately mixing data, navigation, and presentation semantics. Presentation is often a facade for elements of structure, composition, and navigation. Despite this frequently unstructured development process, data-intensive applications, based on large data sets organized within a repository or database, generally follow some typical patterns and rules. We describe these patterns and rules using WebML as a conceptual tool to make such notions explicit. WebML is a conceptual Web modeling language that uses the entity-relationship (ER) model for describing data structures and an original, high-level notation for representing Web content composition and navigation in hypertext form.

The paper considers the Araneus data model which employs database techniques and wrappers to extract data from and generate Web sites. The project features a logical model that abstracts physical aspects of Web sites. Araneus provides high-level descriptions of pages that let us both extract data from the Web and generate Web sites from databases.

Spring was a notable season in the virus world as Klez edged out SirCam as the all-time most virulent virus, and another virus landmark emerged with Simile.D - a polymorphic, entry-point-obfuscating virus that can infect both Windows and Linux platforms. Unlike the costly and destructive Nimba and Code Red viruses, Klez and Simile.D are more nuisance than financial nightmare. Nonetheless, they represent emerging challenges for antivirus developers. Both of these complex viruses take previous tricks to a new level, either by expanding their infection potential, at least in theory (Simile.D), or by combining multiple best-tricks into one insidious package (Klez).