RPCEmu: problems with disk images

Hi everybody,
I am running RPCemu 0.8.8-devel on Mac OS 10.8.3.
Everytime I mount an disk image and try to open (doubleklick) it, the emulation terminates with the error message “Bad FDC command 56”

Any ideas? Suggestions?

Hi Carsten
As well as this forum, there is a dedicated RPCEmu Archive site which could be worth a look; see for instance
http://www.riscos.info/pipermail/rpcemu/2013-January/001805.html

Thanks George.
However, I can’t seem to find information on the error in question. Did I overlook something?

Bad FDC command 56

This is because the floppy controller emulation in RPCEmu doesn’t know about the verify-sector command. The 765 (and it’s close cousin the 665 used in the Risc PC) allows you to verify without transferring any data which is much faster in general, and in the case of the Iyonix, more reliable.

ADFS in RISC OS 5 started using this around 2001, but I guess RPCEmu was written by reverse engineering what RISC OS 3/4 uses, rather than a full emulation based on the datasheet.

So – as George suggests, probably worth requesting this be added to RPCEmu so it’s emulation more accurately reflects the 765/665 controller.