WWW5 tutorial: collecting and serving information


this tutorial covered exactly the problems we are currently facing at the ETH in general and the "informatikdienste" in particular: the pros and cons of having multiple independent WWW servers versus one centralized WWW server.
of course, there is no way to centralize ALL HTML documents currently available at the ETH in ONE PLACE and it would not make any sense at all to try to do so. nevertheless, there are now discussions about subjects addressed by this speech such as:

different models of WWW server structures:

there are various ways to structure one or more WWW servers within one organization. the two major approaches are "distributed structures" and "centralized structures". in this tutorial, they distinguished the following five structures ranging from "anarchy" to "dictatorship" with the first two structures considered "distributed":

  1. multiple independent servers
  2. multiple coordinated servers
  3. generally accessible central server
  4. subscription server
  5. controlled centralized server

three of the above models (1, 3 and 4) have been discussed in greater detail and the advantages and disadvantages were compared from the user's, the information provider's and a global point of view. at the ETH, we basically have dozens of more or less independent servers (there is some minimal coordination particularely in the addressing scheme of the servers), but at the same time, we run some generally accessible central servers ( APACHE, ezInfo, WAWONA) that are used by many different organizational units which do not run their own WWW server for various reasons.

multiple independent servers:

many organizational units inside the organization run their own WWW server. at the ETH, this organizational units are departments, institutes, working groups etc. these organizational units operate their server on their own, but can get support from the "informatikdienste" if they want to.



generally accessible central server:

the information providers use a central server to create and maintain their own documents. at the ETH, the "informatikdienste" operate three central servers that are used by various organizational units to provide their Web pages. once the so called Web moderator has received a username and a password to access the server, she or he create and maintain her/his documents on her/his own responsibility. most providers create the documents on their own workstation or PC and transfer the documents to the server when they are ready to be published. others may create and maintain the documents directly on the server. it is also possible to use NFS or AFS so that the provider can maintain the documents on her/his private workstation while the files still reside on the server. another convenient way would be the use of an authoring tool that supports remote save.



subscription server:

a subscription server is a centralized server which does not give information providers direct access to their Web pages. instead, it provides means to transfer data to the server, usually via HTML forms. documents may not only be transferred from the provider's system to the central server, but they may also be checked, converted and registered in a database. currently, we do not operate a subscription server at the ETH.




all of the above mentioned structures have their advantages and disadvantages. in an organization such as the ETH, a mixture of distributed and centralized servers is probably the only practical solution.
in my opinion, centralized servers are good for:

on the other hand, pages that changes very often shall be located on the organizational unit's server. this is particularly true if the information is dynamically created either from a database or by a cgi script.

information shall never be duplicated, it should always be available from its source !

the slides of this presentation are available on the Web.

back to WWW5 main document.

WWW5 tutorial 11 / 22-may-96 (ra) / reto ambühler