I believe many Atari ST models had their graphical OS (TOS/GEM) on ROM. The Archimedes with RISC OS felt revolutionary at the time, however. Several of the grap

I believe many Atari ST models had their graphical OS (TOS/GEM) on ROM. The Archimedes with RISC OS felt revolutionary at the time, however. Several of the graphical desktop programs were written in BBC Basic and you could look at the source.