One of the really good features of the old Research Machines RM380Z was that its firmware included a software front panel, documented in the 380Z Firmware Reference Manual. This allowed the user to examine and load registers, I/O and memory as well as single-step and many other features. I believe that this facility was influenced by the front panels on the minicomputers of the time i.e. DEC PDP8 (LINC8). Does anyone else think that such a feature would be possible and indeed useful in this latest generation educational computer? I have no experience with the ARM having spent the last thirty odd years with Intel, Motorola and Microchip processors. If I remember correctly, the trick with the Z80 was to force an interrupt which in turn stored the register values on the stack. These could then be read and altered before a return from interrupt restored them. This could be an interesting project and could work with the monitor, keyboard and mouse or perhaps a touch screen.