Interesting; I just noticed that also versions of the GEM source code are available (see e.g. http://www.deltasoft.com/downloads.htm).

Wow, these devices apparently had an amazing quality. The interviewee runs a campsite and bought an Atari ST in 1985 because it had more RAM than a PC, and he also had to write the management software himself, which he still has in daily use (starts it in spring and shuts it down in october). He didn't say which language/database he used for implementation; any ideas?

For the ones interested, is also an earlier interview by the Computer History Museum, see https://www.youtube.com/watch?v=29RkHH-psrY and https://www.youtube.com/watch?v=SVgSLud50ss.

Wirth and Gutknecht originally designed the system for teaching. In the first years, the system ran only on special hardware (Ceres) and had a minimal user interface. System 3, which put much more emphasis on a graphical user interface than the original system, and also had an interesting component technology with the gadgets, had competition from technologies like Delphi, which were easier to use and more easily available and integratable with mainstream systems.