The following devices are known to work with RISC OS 5.24 on the Raspberry Pi.
This list is incomplete, but we have to start somewhere…
1 Some memory card readers present as multiple disc drives for different card types. Trying to use a “7-in-1” card reader could cause SCSIFS to run out of drive numbers.
2 Standard (e.g. 105-key) keyboards will work. Keys over and above the standard set (e.g. “multimedia” keys) may not work, and more arcane keyboards (e.g. with “intelligent touch bars”) are right out.
3 SDXC cards are exFAT-formatted by default. If the card is reformatted to FAT32 it can be used.
4 Work is underway to offer support for DOS-format floppies, but the technical limitations of the USB floppy specification means that ADFS-format floppies will not be supported in the foreseeable future.