Saw this on sinclairzxworld.com.
http://floppydays.libsyn.com/floppy-day ... 0-os-basic
Floppy Days 85 - Interview with John Grant
Re: Floppy Days 85 - Interview with John Grant
Nice, that was interesting. The part about having a hardware addon in the ZX81 to override a memory access and fix a ROM bug sounds pretty crazy.