If you want to promote usage of real CPC computers, you can detect CPC emulators by:
*Checking if the memory is initialized with zeroes, as real machines have random memory values at boot
*Playing with the "floating" bus, using Z80 read I/O commands to write to chip registers, using undocumented I/O ports, writing to multiple chips simultaneously
*Focusing on the minute details in [[Z80]], [[CRTC]], [[8255|PPI]] and [[PAL16L8|PAL]] chips. They are most often wrong in emulators
*Examining the [[FDC]] chip. It is only replicated more or less superficially in all emulators because the internals of the chip are still unknown. Many emulators don't even support the FDC SCAN or FORMAT commands