Welcome to the WUDSN ursel home page

WUDSN ursel - or short WUDSN - is a demo group founded in 1991. There is an explanation why the group and the site are named like that, but that's a different story you can find in the FAQ. For the time being it should be sufficient for you to know that me, aka JAC! am one of the members ever since. I have created this web site to offer my tools and productions and to share the fun I have had for more than 20 years now with my Atari-8 bit computer and other classic computers. To learn more about me and what I'm doing, check out this personal interview that I gave for ANTIC - the Atari 8-bit podcast.

Working hard on DIS6502

I finally managed to escape the real life daily job business and had a great week with sun, beach and DIS6502.You don't believe that? Check the commits. Again a lot of the monolithic plain C has been transformed into readable classes with clear interaces and dependencies. Now I feel I understand the code good enough to implement the new load/save for the new workspace structure.

Me at the beach bar in Italy

The!Cart Studio update released


  • The download now contains a "TheCartStudio.exe" for Windows users. This wrapper program comes with a proper icons, a version and location test for the Java Runtime and the required Java parameters to ensure enough heap memory is available.
  • The download now also contains a "TheCartStudio.sh" for Linux users. This script provides Java with the required parameters to ensure enough heap memory is available.
  • The download now also contains a "TheCartStudio.app" for Mac OS X users. This one is still very experimental and is not yet tested as I don't own a Mac OS X machine. But I wanted to get this version out now.
  • Online help has been revised. New sections and diagrams in now explain the overall workflow and creating and flashing workbooks. Also the different options to add files directly or via Maxflash Studio and MegaCart Studio are now explained.
  • The selected line in the extended menu now uses black text and a more constant and darker flashing. This reduces bending and artifacts on CRT TV.


  • Player missile graphics of the extended menu are now disabled correctly before an entry is started. That was an issue for example with Flop Magazine 56 Intro.
  • An exception that occurred with ATR files that do neither have a boot manager menu nor are DOS 2.5 disks is fixed.
  • New Atari software version 2014-04-07 included. It includes a fix for the CAR or MyPicoDOS when loading OSS modules.
  • The "-createSampleFiles" command now correctly creates separate folders "ROM-Correct", "ROM-Size-Too-Small", "ROM-Size-Too-Large".
  • Console output for error messages is now routed to "System.err", so the command line can properly distinguish between information and error messages.

Compilers Download Update

RevEng pointed my to some issues related to using DASM on 64-bit machines. So I took the chance and updated the archive containing all compilers and the zero installation distributions. They now include

  • DASM (2.20.11-20140304/2015-04-04) 
  • KICKASS (V3.39/2015-03-26)
  • XASM (3.1.0) for Mac OS X Intel provided by 0xF

For the exact versions, dates and platforms see section Installing Compilers. I've also automated my build for the compilers process on Windows, Linux and Mac OS X, so I can provide future updates hopefully with less effort. I also contacted Mark Schmelzenbach so hopefully I can update ATASM to version 1.08 soon, too.

Interview for ANTIC - The Atari 8-bit Podcast

Randy Kindig, Kevin Savetz and Brad Arnold are the hosts of the very entertaining ANTIC podcast that focuses on Atari 8-bit computers. In December of last year, I had the pleasure to give an interview to Randy via Skype that has now been released. The download as MP3 is available at http://ataripodcast.libsyn.com. Enjoy 50 minutes of stories and funny explanations why nerdy people do nerdy things.