Information distribution/sharing and information exchange/remote-collaboration
are two major Internet infomation services that have been the base Internet
applications for many years. Popular systems for text-based 
information distribution and sharing are FTP, Gopher, WAIS and ARCHIE etc.
These systems and the established protocol standards were developed to
satisfy particular yet basic needs of data access, distribution and searching
among distributed hosts over wide area networks. For example, FTP is used to
transfer data files from one machine to another and Gopher for publishing plain
text files. The WWW system has integrated almost all the major Internet
information distribution protocols into a single unified
networking navigation environment. 
The integration approach by WWW is to retain existing data transfer protocols
and server management while replacing the particular client programs
that were previously developed for accessing those non-HTTPD servers so that
The Web browser becomes a universal
client program that can access to information space on different
kinds of information servers.

Major Internet services for remote collaboration and information exchange
are mailing list, USENET news and chat systems.

A mailing list is a group of email addresses that can all be reached by 
sending messages to a single address/server. Mail sent to the mail server
is redistributed to all subscribers using the basic Internet email services.
The list of addressees are maintained on a central mail server running
an automated mailing list program such as Majordomo, ListServ and
ListProc.

The USENET news system is invented to reduce/improve the amount of resources
consumed in the mailing list approach. 
Articles are now stored in one central repository
on a receiving host instead of in ech subscriber's mailbox. 
A Network News Transfer Protocol
NNTP \cite{nntp} is developed for the distribution, inquiry, retrieval, and posting
of news articles using a reliable stream (such as TCP) client-server model. 
For news distribution, USENET news system also use a data propagation and
replication mechanism \cite{rfc1324} to reduce network traffic congestion
and the overhead of network bandwidth over wide area networks, by caching
recently arrived and retrieved news articles on a hiarachical intermediate
news servers that mediate regional and local requests. An article is usually
first posted on a local news server. That machine then forwards it to all its
neighbor news servers. The sites receiving the incoming article
stores it locally and in turn forward the article to all their interest
neighbors. This process continues until the entire USENET network has
seen the article. To read articles in a newsgroup, a user connects
to a local news server using a client news reader program.

While mailing list and USENET news system use slightly different 
distribution mechanism, they adopt the same text format in mail
and use asynchronized message passing model for text-oriented
collaboration. Mails usually are stored on a server one piece per file and
each sonsists of a series of heading text which contain the sender's
identification, timesteps, email reply path, subject, category, and other attributes
as specified in \cite{rfc822}. On the other hand, another 
collaborative system Internet Relay Chat \cite{irc} has been widely
used for text-based teleconferencing over wide area networks. IRC protocol
uses synchronized message passing model for real-time message delivery and
multiplexing. The execution model of IRC is also built on the generic
client-server architecture in which a single chat server forms
a central point for chat clients to
connect to and to exchange messages in real-time over wide area networks. IRC messages
are a stream of characters terminated with CR-LF pair.

While the three systems are developed for particular needs 
of Internet collaboration, they share several common features:

\begin{enumerate}
\item
Text-based messages as data content. Email format is the basic
data entity that is used to conceptually and physically carry
the information. The major body of an message is free-text with
key assoicated attributes including sender identity, timestamp,
subject text and receiver indentity.

\item
Client-server model as the execution arichtecture. Server management
and data transfer protocol are the key components and software
development effort. Client programs can be quite different and on different
platforms and there are usually various user interfaces for different
operating system environment. There is no unified client GUI that can
facilitate all the three collaborative modes. 

\item
Major functionality of these systems are focused on simple server management,
reliable message distribution and standard protocol design. They lack of
sophisticated search and archiving capability as found in advanced RDBMS-based
information systems, and they rely on file systems to store and index data thus
the logical representation of the collaboration information is almost the same as
physical representation. Browsing through the message list is the meta-index 
approach to locate interest messages. 

\item
Data propagation and caching, as well as server replication,
are the common approaches to leverage server performance 
and network traffic requirement imposed
on wide area networks. 

\end{enumerate}

We expect the three conventional collaboration systems will continue their
widespread use in various applications and believe that WWW  provides opportunities to 
integrate them together into a single unified framework.
In this case study, we build a powerful WWW collaborative
information system that integrate and enhance the functionality of
the three conventional Internet collaboration systems.
We use parallel Web and RDBMS server technology as the centralized 
high performance general collaborative server to store, synchronize
and distribute email-based messages over Internet. Built on this 
collaborative server is a RDBMS-based information management system
which serves as a search and archive engine for USENET news, mailing list and
a chat system to facilitate either asynchronized USENET news and mailing 
articles or synchronized chat messages. On the client side, we develop HTML-based
interface that can be embedded in any Web browser for basic collaborative
functions, including read/navigate,search,
compose,post, reply and receive. Sophisticted real-time search 
capabilities that are not possible in the conventional systems
are implemented, such as search by keyword, by date, by sender etc.
The integration appraoch used in this case study is on both client and server
sides. On the client, a unified GUI is developed so that any one of
the three collaborative modes can be switched to at any time
of collaboration by participates. On the server side, same data format of
email used by all the three systems are stored in the same Oracle database
and the server provides support for both SQL-based search in the
collaborative information space and concurrent control in the collaborative
threads. Overall, this prototype system provides support of
bulletin board type of USENET news and mailing list, and real-time IRC type
of email-based chat.
