Free communications software for linux

"You don`t have to be an America Online member to experience the immediate cross-Internet communication made possible by AOL Instant Messenger.
This program allows Internet users to communicate via private, personalized text messages.
The program indicates when friends, family members, and business colleagues are online, making Internet communications faster, easier, and more efficient.
AOL Instant Messenger combines AOL`s popular Buddy List and Instant Message features, enabling users to send and respond to messages immediately."
Enhancements:
- Improved Popups Preferences
- Support for @mac.com addresses
- The wireless icon is the visual indication on the buddy list that a buddy is using a mobile device.
- File Transfer (with Drag&Drop support)
- Displays idle time
- Ability to install anywhere. (Extract everything into a single directory and then run aim with option "--install_dir %path" where %path is the path to directory containing all the libraries)

stic bundles a few Linux tools which are intended to support the task of collecting an unreasonable amount of pictures (preferrably in JPEG format).
similar
a program for detecting duplicate or very similar images. It maintains a
database of characteristic color samples which it compares with submitted
pictures. similar depends on libjpeg and ImageMagick s convert (on a
modern Linux desktop system these components should already be present).
Storage medium may be a usual filesystem or a MySQL database. There
also is a MySQL UDF extension to compare image samples within SQL queries.
similar contains the communications module described at sagent.
simv
a core program to perform file management tasks on an image collection.
Its main purpose is to coordinate file movements with the content of
similars database. This applies to importing new files which get tested
against the existent collection, as well as to inform similar about moving
and deleting files within the collection.
simv depends on an external image viewer like ImageMagick s display
(should already be present on a modern Linux desktop system) or John
Bradleys xv (quite a fast one).
simv contains the communications module described at sagent.
sagent
a standalone version of the communications module used in simv and
similar. This software receives input from its start terminal and multiple
clients, distributes several types of output back to them, and is also
able to act itself as such a client.
Since communications mainly use TCP/IP there is an encryption layer
(Blowfish with 128 bit keys) which provides user authentication. Any
single activity of such a user may be particularly permitted or denied.
Secure connections should be possible that way as long as one can defend
the keyfiles and programs on client and server host against foreign
access.
Front-end connection software is available in C, Tcl/Tk and PHP3 to build
custom clients. In the most primitive case even telnet can act as a
client.
The standalone program sagent may be used as communications node in a tree
of clients. Another purpose is to be a shell frontend which sends commands
to a server and receives its replies.
snntpbatch
a command line based NNTP (newsgroups) client. It is mainly intended for
automatic download of images by use of a filter language. Nevertheless it
also downloads the message texts and converts them to HTML code which
includes the downloaded images. Also, it is capable of automatically
posting sets of images to the newsgroups.
The tools are designed to be very independent of the system flavor. On an
average Linux desktop there should be no need to update existing system
components. Actually one could use stic without having display equipment for
graphics.
Any program activity which is possible in dialog may also be performed in
batch runs. Therefore the tools are quite suitable for users who like to get
boring tasks automated and manual tasks simplified.
All tools code is open source and distributed under BSD license.
Example images Credit: U. S. Fish and Wildlife Service (see images/CREDITS)
Enhancements:
- The new encrypted protocol version 0.2 is standard now : SHA-1 seal, 256 bit keys, variable chaining initialization vector.
- The protocol of a connection is chosen by the client and may or may not be accepted by the server.
- See sagent command -security options clientprotocol , serverprotocol.

Zircon is an X Window System interface to Internet Relay Chat. The software is written in tcl/tk and uses the native network communications of tcl.
Suggestions for improvements to Zircon are welcome. I am particularly interested in making the system useful for those users in groups where JIPS and other national character sets are used.
Zircon has more features than you could possibly imagine and implements nearly everything that the irc II clients support as well as many other useful and interesting features.
Main features:
- There is no JIS support. This needs a kanjified tcl/tk and some changes to zircon. Someone in Japan used to provide support for this but seems no longer to do so. Tcl 8.1 has proper unicode support included so this problem will go away soon.
- Character escaping in the low level CTCP protocol is not done everywhere, but it *is* done for SED encrypted messages
- You cannot configure anything other than Channels using the configuration panel. If you wish to configure Message channels then you have to do them by hand in the rc file. One day I will completely redo the configuration system....
- The Sketch Pad facility is (still!!) not completely finished. (and will probably move out into the plugin system when I get that done)
- The Clear button does not clear the screen. This is a tcl/tk problem and I cannot do anything (useful) to solve it. If you Shift-click on the button then the screen and the history are cleared, this does work

GAMMA is a low latency, high throughput communication system for clusters of PCs.
Network Of Workstations (NOWs) and clusters of PCs interconnected by modern, industry-standard LAN fabrics (Gigabit Ethernet, Myrinet, SCI) and running the Linux operating system, have became an attractive and cost-effective architecture for parallel and distributed applications.
The usual drawback of a standard PC cluster is the poor performance of the support to inter-process communication over the interconnect.
Current implementations of industry-standard communication primitives, APIs, and protocols, usually show high communication latencies and low communication throughput.
We have developed a system for inter-process communication, called the Genoa Active Message MAchine (GAMMA). GAMMA runs on Linux clusters of PCs with Intel IA-32 processors (Intel Pentium, AMD K6, and superior models), networked by a Gigabit Ethernet.
The core of GAMMA is a custom Linux network device driver, which operates the Network Interface Card (NIC).
The GAMMA driver delivers low latency, high throughput communication services based on Active Ports, a mechanism derived from Active Messages.
Both point-to-point and broadcast communications are provided. Broadcast communication exploits the Ethernet broadcast directly.
The GAMMA driver is able to manage standard IP traffic as long as no parallel job is running. Therefore, all IP services are up and running whenever the cluster is not in use by any parallel job.
The communication mechanisms implemented in the GAMMA driver are made available to application writers through the GAMMA user library.
The GAMMA library provides support to application launch, process grouping, point-to-point/broadcast communications based on the Active Ports mechanisms, and some collective routines (barrier synchronization, and broadcast).
GAMMA provides two levels of QoS. The lower one, corresponding to the fastest communications, is a best-effort service. With this service, network congestion and ``hot spots may cause the receiver NIC or even the LAN switch to loose packets by overrun.
The other QoS level provides flow-controlled communication, ensuring reliability up to hardware faults, at a negligible performance penalty.
Installing the GAMMA driver requires only two small and marginal patches to the original Linux kernel. The Linux kernel extended by the GAMMA driver must be installed on each PC in the cluster.
Main features:
- Supports both single and dual CPU processing nodes (Intel IA-32)
- Runs on Gigabit Ethernet
- SPMD parallel processing with message passing
- Can run IP traffic when not in use
- Good programmability thanks to fairly high abstraction level
- Reliable thanks to mechanisms for retransmission of missing packets
- Implemented as a network device driver for Linux 2.6, and released under GNU GPL
Version restrictions:
GAMMA allows more process instances of the same parallel job to run on the same CPU. Thread safety is granted with point-to-point communications when running on distinct GAMMA ports.
However, collective routines (barrier synchronization, and broadcast) are not thread compatible, as they use predetermined GAMMA ports.
The packet retransmission mechanism is not perfect. It will not work if the missing packet originates from a non-blocking send.

The GNU Gatekeeper GUI visualizes all registrations and VoIP calls the gatekeeper is managing.
GNU Gatekeeper GUI also allows the user to send commands to the gatekeeper (e.g., to terminate calls or unregister H.323 endpoints).
According to Recommendation H.323, a gatekeeper shall provide the following services:
- Address Translation
- Admissions Control
- Bandwidth Control
- Zone Management
- Call Control Signaling
- Call Authorization
- Bandwidth Management
- Call Management
The GNU Gatekeeper implements most of these functions based on the OpenH323 protocol stack.
Recommendation H.323 is an international standard published by the ITU. It is a communications standard for audio, video, and data over the Internet. See also Paul Jones A Primer on the H.323 Series Standard.
Enhancements:
- A bug has been fixed that prevented usage with a non-password-protected status port.
- Small visual changes were also made.

Eligante is software for archival, management and browsing (with full-text search functions) of all your communications, be it via email, chat (IRC, ICQ, MSN, etc.), or even messaging Web sites (hi5, orkut, etc.).
Messages are fetched from their original source and stored in a MySQL database. A Web interface allows you to search all data.
In this way, you can see all the conversations you had with someone, independently of where the conversation took place.
Enhancements:
- MS Windows support was added.
- An internal lightweight HTTP server was added for those who dont want to install Apache.
- SQLite support was added.

jMOS is an open Java implementation for the Media Object Server (MOS) communications protocol.
MOS is a six year old, evolving protocol for communications between Newsroom Computer Systems (NCS) and Media Object Servers (MOS) such as Video Servers, Audio Servers, Still Stores, and Character Generators. The MOS Protocol development is supported through cooperative collaboration among equipment vendors, software vendors and end users.
Main features:
- 100% Java
- Specification v.2.8.2
- Support for MOS profiles 0 and 1
Enhancements:
- Profile 2, multiple listeners and repliers, and the ability to add filters in listeners and repliers were implemented.