3.3 Some Emerging Web Concepts and Technologies

In the near term, many new innovative technologies will be critical in building WebWindows as well as services and applications on top of it. These include:

• Java [18]---This is a very powerful interpreted C++ like language (script), which, as in Figure 1, can be used to build fully interactive clients that allow one to build balanced client-server (server-server) systems. The CGI mechanism, as used in WebTools, is powerful but has limitations as extra functionality can only be added at the server.

• VRML [19], [20] can be thought of as a three-dimensional HTML that allows universal description of physical objects and graphics actions on them. There is some confusion as to relative importance and role of VRML and Java, but roughly one can consider VRML as the future data structure and Java the future language of the Web. VRML will be useful in such areas as telecollaboration, multiplayer gaming and distributed manufacturing, because it allows the interchange of virtual worlds and commercial product designs.

• PERL5 is a useful extension of PERL4 with full object oriented characteristics and extended pointer (array) constructs. Again, there is some unclear competition with Java, but the languages are optimized in different ways. Java is partially compiled and will produce code that executes faster than that from PERL(5). PERL5 is better suited for rapid prototyping and further has excellent special capabilities built in for dealing with operating system functions and text processing.

• Performance of future combined Web-Compute Servers will be enhanced by good light weight multi-threaded systems combined with new protocols, such as HTTP-NG.

These technologies are linked together into loosely coupled integrating concepts summarized in Table 3. We have already described WebTools as an early prototype of WebWindows illustrating primitive Web operating system services. Again, WebTop publishing and productivity underlied our discussion of software engineering in WebWork.

As already mentioned in Section 2.2, we see Web database systems WebDMBS combining distributed (as in Harvest, Lycos, etc.), object (as in VRML) and relational (as an Oracle) capabilities. In Figure 10, we show three extensions of base PC multimedia services [21].

• HPCC with high-speed networks and MPP servers
• Immersion with virtual reality metaphor for spatial navigation
• Multi-user shared distributed virtual worlds of information and simulation.

  
Figure 10: The three axes of multimedia extensions to give interactive services with different characteristics

WebSpace denotes this combination leading to a full televirtual Web collaboration environment.

An important deeper and perhaps more controversial concept is WebScript. This denotes the complex NII middleware of scripted languages where we expect no universal solution but a loose federation where each component has different optimizations---VRML for three-dimensional objects, PERL5 for text, Telescript for agent based communication, Java, and MOVIE [22] for computation, etc.