I have also been waiting a long time to be able to use Saturn Calc and Graph. Over the years, I’ve collected various distributions but the licenses that I had for the RSX version no longer seemed to work. It was distributed as task images, instead of object libraries which would have been easier to hack. The Saturn Calc task would check for a couple files and it is had not been modified by the license key program it just exited. 

   A good friend, Lee Gleason developed some fantastic tools (see https://rsx11.blogspot.com/2026/02/ ) to be able to get a t-bit trace of the executing Saturn Calc task that recorded the PC and the first word of the instruction being executed. However RSX works very hard not to allow a task to run with the t-bit trap set. Lee had to modify both INS and FIX in multiple places to NOT clear the t-bit trap in the task header PSW if it is set. When the program exited since the license had not activated it, we would look at the last instruction, an EMT 377, to call RSX EXIT$ directive. Then we would work backward to the conditional branch that could have skipped over the exit and make it unconditional. 

    These tasks are heavily overlaid so one also has to find which overlay has a EMT 377 in the correct PC value, then find the location of that overlay in the task image. This involved a lot of octal decoding to PDP-11 instructions with ZAP. Each of the many Saturn tasks had to be hacked and they had a couple spots that had to be ZAPped. But now we have working versions of Saturn Calc, Graph and WP and are just finishing checking to see if anything is broke.

   So far it looks good, but there are a couple caveats. First, the RSX Saturn software doesn’t understand named directories so you should be in a UIC based directory when you use it. Second, there is an obscure bug that I have not been able to solve and don’t know if it was always there or was somehow introduced by our hacks and zaps. It involves SUM or AVG calculations across a range when the range of input values are calculated. If they input cells have standard numbers, it works fine. I came up with a work around that can be used if one really needs that functionality.

  Saturn Graph is working very well. I can create a line, bar or pie chart either in SIG or from a Calc spreadsheet, then display it on a VT240, VT330 or VT340 Regis terminal, then when I’m ready to make a hard copy send it to a (HPGL) HP7550 plotter or even a LA50 (sixel) printer. The VT340 mouse even works with the drawing program.

   I’ve created a command file that will install everything and I would be interested in a beta tester or two who are somewhat familiar with Saturn to see if there are any issues remaining. Saturn provided many example files and I’m including them as well. There are in total  about 7500 blocks in 190 files.

  If you have an RSX system on HECnet, I can put them where you could NFT them back to your system. If not let me know and I can package things in a disk image for ftp or wget. Ultimately, Johnny said he might be interested in creating an RPM package.

Best,

Mark Matlock