The emergence of some simple APIs (Application Programming Interfaces) and GUIs (Graphical User Interfaces) has led to the rapid growth of new user-friendly applications in the Internet. Information services provided by archive and Web servers are accessible through WWW and Mosaic, Archie and Prospero, gopher, and WAIS and Z39.50.
In picture 1.5, we can see a "screendump" of a workstation running Mosaic, the most popular client program for accessing the Web Servers around the world. In this picture, we can see a window showing a map of the UK, and two other pictures, both GIF (Graphics Interchange Formats) or photographs. The Top right is a picture of UCL, where we work. The lower right is a satellite image stored on Edinburgh University Computing Service's Web Server every hour, from a live satellite weather feed, which comes from one of the many weather satellites that send out unencrypted images periodically over the ether. Many sites simply point a satellite dish in the right direction, and soak up the data, for later dissemination on the terrestrial Internet.
Figure 1.5: Spot on Surf
The value of the service is now becoming clearly the value of the information, rather than the communications channel. This means that some mechanism for charging and auditing access to information is a new requirement. This must be a secure mechanism to assure people that charges (or audit trails) are correct.
In picture 1.6, we can see a screendump with three application running. The top left is a Gopher Client, the top right is archie, and the bottom right is WAIS.
Figure 1.6: Information Servers Galore
Gopher allows us to access information through a menu/browsing system. In this example, you can see a list of subjects that we can browse. Archie allows us to search for software or documents in some of the large archive server repositories. In this example, we have retrieved a list of sites that have a document introducing TCP/IP! This and other services are explained further in chapter 2.
The Wide Area Information Service allows servers to build searchable indexes of many types of documents. In this example, we have retrieved from a set of servers that hold information about ecology, a list of documents about Acid Rain.
From all of these interfaces, having found a piece of information, we can retrieve it, print it, mail it to other people.
New end-systems such as lap-tops and palmtops are leading to the requirement for access to home systems by travelers. This leads to a new requirement for mobile communications support in the Internet, both while people are travelling and when they arrive at a new site.
Most new systems have the power to handle sound and vision, as well as text and graphics. This multimedia requirement leads to the need for integrated services in the network, to support the delay intolerant applications that are emerging from the Research and Development world into products. In the third picture, we see a multimedia conferencing system running on a workstation attached to the Internet, with windows onto remote sites in other countries, and shared drawing areas and so forth.
The vast number of systems attaching to the Internet leads to whole new problems in management. We foresee a time when every home will have many devices networkable (VCRs, heating/lighting, surveillance and so on). WWW is just the start of this revolution.