An Open Source Web Conferencing System Copyright 1996-2003, Jan
Wolter and Steve Weiss
backtalk@hvcn.org
(sound effect)
Latest stable release: Backtalk 1.1.23 (Jan 13,
2003).
Latest development release: Backtalk 1.2.7 (Feb 17, 2003).
Overview:
Backtalk is an open-source, web-based computer conferencing system that
supports text-based, on-line discussions in structured forums. It is similar in
style to Picospan, Yapp, Caucus, or Motet.
The words "conferencing system" have been used to describe many
different things, so let's clarify what Backtalk is not. First, Backtalk is not
a multimedia system. It is primarily text-based. There is limited support for
importing images and such, but at it's heart it's primarily a tool to allow
people to type text at each other in a structured environment. Second, it is not
a real-time chat system. You wouldn't normally expect a response to your
postings within minutes. It's more the sort of thing where you post a message,
and come back later in the day to see if anyone has responded.
Backtalk is a mature program which has been heavily used at several public
sites for more than seven years. In addition to providing a full set of user
features, it also includes comprehensive administration tools, documentation and
automated installation scripts. It is very efficient and extremely configurable.
It is actively supported, with regular new releases still being made.
Backtalk was originally developed for use on two non-profit, public access
conferencing systems. HVCN needed a
stand-alone web based conferencing system usable both by people with modern
browsers and by people with access only to lynx. Grex
needed a web interface to its existing Picospan conferences that would run
reasonably fast even on their enormously over-burdened machines. Thus, Backtalk
was designed to fill some difficult and demanding niches, and to serve wide
ranges of users. Since then it has been extended to support even wider ranges of
communities, including school-aged children.
A demonstration
site is available.
Variations:
In addition to to the standard Backtalk conferencing system, there are some
derivative packages also available:
Booktalk is a
variation of the Backtalk system developed for the Canton Public Library PULSE
system. It designed to be used in schools, with conferences for each classroom
under the control of a teacher and all-school conferences shared by all. You can
see the original site at http://pulse.cantonpl.org/.
Just download the backtalk, bubblegum, and booktalk packages and follow the
installation instructions in the booktalk package to install them.
Fronttalk is a
command-line front-end to Backtalk. The look and feel is extremely similar to
the original Picospan program used on The Well and Grex (which is similar to the
command-line version of Yapp used in many places), but the program is actually a
specialized web-browser that makes HTTP requests to a Backtalk system to read
and post to the conferences. This means that it can be run on any Unix system to
access any Backtalk system on the web that supports it. Fronttalk is still
somewhat experimental, but it is the only open-source Picospan clone that I know
of.
Features
For a long-winded description of the system, see the Backtalk
feature page. Here is a summary:
- Backtalk uses a conference structure sometimes called "linear"
or "Well-style"
(because it was popularized by the Picospan software that ran on the Well).
Thus, it is similar to such products as Caucus, Yapp, and Motet. It supports
an unlimited number of "conferences", each of which can contain an
unlimited number of "items" or "topics" which begin with
a short article entered by the original poster, to which are attached a
linear series of "responses".
- Backtalk maintains a login and password for each user, and remembers which
articles a user has seen, so that only new material is presented on
subsequent visits. A web-based account creation tool is included which can
be configured for either open or validated accounts. It is possible to
construct conferences that are accessible only to restricted sets of users.
It is possible to allow people without logins to read conferences.
- Backtalk's user interfaces are scripted. Four different reasonably mature
web interfaces are currently available. These standard interfaces all have
lots of configuration switches, and, of course, the scripts themselves can
be customized. Scripts are precompiled for maximum performance.
- The user interfaces allow users to create their own conference "hot
lists", forget items they aren't interested in, and search the
conferences. Postings can be plain text or HTML. Tools to delete or edit old
messages or retitle topics are available and can be enabled either for all
users or for administrators only. Administrators can link items between
conferences, and delete, freeze, retire or retitle items. Extensive
"help pages" are available in the Pistachio interface.
- There are complete suites of web-based adminstrative tools for account and
conference administration. There are also command-line tools for most
operations. A detail "How-to" manual is included.
- Backtalk's conference database structure is compatible with Picospan and
Yapp 2.3, so it can run either stand-alone or sharing conference data with
one of these command-line interfaces. It even generates non-HTML versions of
messages for use by the command-line interfaces. Some backwards compatible
optimizations of the database have been done to improve performance.
- Backtalk is written in C and works on virtually any Unix-type system. No
Windows or Macintosh versions are available.
- The authentication system is very configurable, for simplified integration
with other software.
Documentation:
Backtalk is thoroughly documented. The user interfaces are documented through
help pages, not a separate manual. For administrators, there are several
documents available. Two versions are on line here:
Availability:
Backtalk may be downloaded
and used for free under a standard Gnu Public License. The terms of this license
allow its use by both commercial and non-profit organizations, but does not
allow software developed using Backtalk source to be resold. Anyone interested
in obtaining Backtalk under other licensing terms should contact the authors.
Backtalk is implemented in C. The distributions includes full source, and
portable scripts for compiling and installing the system, together with
extensive and detailed documentation.
Sites interested in hiring an expert to install and customize a Backtalk
system may contact Jan Wolter.
Future:
Though Backtalk is very sound and reliable, and contains a pretty complete range
of features, there are still a lot of things we want to do with it.
Which features appear in future development releases depends partly on what
seems cool to us at the moment that we have a bit of free time to work, and
partly on what new features paying customers want to see.
Options to migrate more data into SQL will be added, as will support for
additional SQL servers. However the conference content will probably not move to
SQL, simply because there is no advantage to doing so. The existing files are
well optimized for the specific queries made on that data. An SQL server is
designed to process much more general types of queries, and cannot be as heavily
optimized for this application as the existing files are. Add the communication
overhead and typical difficulties in handling arbitrarily large hunks of text,
and it becomes clear that putting conference content in an SQL database is not
going to be a win.
New features likely to show up include a facility to allow users to request
E-mail notification of new postings to a conference and a threaded interface.
Work on the Spanish-language interface has been halted due to a lack of
anyone who wants it.
More Information:
If you have questions about availability, installation or anything else
Backtalk-related send mail to us. We are
happy to help.
There is also the HVCN
design conference, a public discussion forum where Jan and Steve used to
hash out Backtalk design issues. Feel free to join in there, but we have to
admit we haven't been using it for a while, because only Jan is doing active
development.
backtalk@hvcn.org
Mon Feb 17 14:45:57 EST 2003
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