Packet Cluster Node Software

From LinuxHam
Jump to: navigation, search


Franta Bendl, DJ0ZY, and Bernhard ("Ben") Buettner, DL6RAI,


A PacketCluster like system running on Linux.


Released in October 1995.

System Requirements

Linux Kernel version 1.2.0 or greater with Alan Cox's AX.25 version 025 driver, TCP/IP networking, SysV IPC. Also needs Perl and KISS TNC hardware on serial device.


PacketCluster nodes have been available for about six years. The original software was written by Dick Newell, AK1A, and is running under DOS. clx is a system which clones a PacketCluster node. To the outside user commands and features are mostly identical, remote PacketCluster nodes, which can be networked, don't see the difference between a generic PacketCluster node and clx. So it fits well into an established network of PacketCluster nodes.

Clx is not a user application, it is network node software. As such it is not of much use for the individual amateur. SysOPs of PacketCluster nodes with some experience on both PacketCluster and Linux will find this application interesting.

Here are some of the features of CLX:

  • It is fully compatible with the internal PCxx protocol and from a users' point of view. It allows multitasking and different priorities for different things.
  • The software detects looping DX spots without generating endless messages. clx filters out such duplicate information. We have implemented a concept which allows us to connect the network at multiple points, which would formerly have been called a "Cluster Loop". clx knows of so-called "active" and "passive" links. The outcome is that more DX information is seen by clx.
  • An interface to call your external programs (even dialog programs).
  • clx uses modern programming concepts like shared memory for common data, lex & yacc to implement command language, shared libraries to keep binaries small (this is still on our wish list), remote procedure calls for inter process communication. It is strictly modularized with its own dedicated process for every major task.


  • con_ctl interfaces AX.25 kernel code and provides a socket for local users.
  • rcv_ctl manages receive spooling.
  • snd_ctl manages transmit spooling.
  • rm_disp receive message dispatcher, forwards messages to other processes.
  • usr_req user database requests, forks a process for every database task to make it run in the background. The background process later sends the results directly to send_ctl.
  • mb_ctl mailbox control. The mailbox keeps messages in a file system, header information is stored in the database.
  • usr_ctl user administration (logins, logouts, logbook).
  • usc_mng manages external user commands and command extensions.
  • iu_com inter user communication (talk, conference).
  • send_ctl transmit spooling, handling priorities.
  • icl_com inter node communication (processing and generating PCxx messages).
  • clx_ctl system administration, installing shared memory pages.
  • int_com manages internal program communications.
  • loc_usr allows console operator(s) to log in like a normal user. This is the only application which can be run on the console.

Future enhancements planned are

  • A console monitor to watch ongoing activities
  • Speed optimization
  • An internal clx protocol
  • An additional command shell for experienced users

Where and How to obtain it

There are five files that make up the package:

  • 00Index
  • clx_200.tgz
  • install.clx


clx (c) by Franta Bendl (DJ0ZY) and is available for non-commercial use, but the authors want to keep track of who is using their product, so before you can actually use the software you have to ask for an encrypted callsign string to be placed in the configuration file. You must send mail to <> to organise this.

Contributed by

Bernhard ("Ben") Buettner, DL6RAI