contiki

Contiki OS for the ATARI XL comes in two formats:

Three 130kB disk images with DOS 2.5 (contiki-atari-1.atr - contiki-atari-3.atr).
One 800kB disk image with MyDOS 4.53/4 (contiki-atari.atr).

All four disk images are contained in the contiki-atari.zip file.

Contiki OS for the ATARI XL supports the Dragon Cart Ethernet device.

By default an ATARI ST mouse is supported. By renaming an alternative mouse driver to CONTIKI.MOU a different mouse can be supported (ATRXJOY.MOU for a standard joystick, ATRXAMI.MOU for an Amiga mouse, ATRXTRK.MOU ATARI trakball and ATRXTT.MOU for an ATARI touch tablet).

Programs:

IPCONFIG.COM
Needs to be run once on every disk (image) in order to configure the Contiki TCP/IP stack. Both manual configuration and automatic configuration via DHCP is possible. Use Request IP Address for the latter.
WEBBROWS.COM
Text-based web browser with mouse support. Offers to exec WGET.COM for non-HTML content. Quits on Ctrl+C. The video Visit Dragon Cart Web Site With ATARI 130XE And Dragon Cart shows the web browser in action.
WGET.COM
Downloads content from a web server and saves it as file on the disk (image).
IRC.COM
Bare bones Internet Relay Chat client. Quits on Ctrl+C.
WEBSERV.COM
Web server for static web pages. Just place *.HTM, *.CSS, *.PNG, *.GIF and *.JPG files on the disk (image) to have them served.
TELNETD.COM
Telnet daemon providing access to a simple shell for a Telnet client like PuTTY. In the shell you can type help to get a list of commands and use the pipe operator | to provide the output of one command as input to another command (e.g. wget www.google.com | write google.htm).