After the release of the Iyonix PC in 2002, RISC OS started moving from 26-bit architecture towards 32-bit. Nowadays all modern RISC OS machines are 32-bit, but an awful lot of older applications are still not compatible with modern 32-bit RISC OS.
Aemulor, originally a commercial application but now free to download, is a software emulator that allows RISC OS applications which were written for a 26-bit ARM systems to be used on more recent CPUs that provide only 32-bit addressing modes. RISC OS itself is unaware that there is anything unusual about the 26-bit applications that are running under Aemulor, to RISC OS they appear as normal applications – they appear on the icon bar and can communicate fully with other 26 or 32-bit applications.
I’ve bought a Raspberry Pi 3 Model B+ just for RISC OS, so hopefully, I can start posting more about this old but venerable operating system in the future. Any tips or interesting things for me to investigate are welcome.