I haven't got time to type loads of messages. These are in a roughly random order. First, thanks to Pete, Allison and others for explaining the PDP11-23 stuff. I stand corrected, I suppose. Tony Duell wrote: AFAIK, you both do. You own the copyright in the diagram you've drawn out, and the original designer/manufacturer owns the copyright in the circuit it represents. So if I want to copy it I need permission both book I need permission from both the author and the publisher.) Allison Parent wrote: A long running discussion. Allison, I don't understand how you can say that the PDP11, with its very simple instruction set, is _more_ CISC than (say) the 80286, with which you compare it here. To my mind the only really CISC feature of the PDP11 is the MARK instruction. I fear we may be talking at cross purposes, and may mean different things by RISC and CISC - could you give some specific examples, please? For those who think a souped up PDP11 could be a pentium killer, bear in mind that there was a 32 bit PDP11. I don't mean the VAX, and I don't mean the PDP11-68: I mean the Motorola 68000. AFAICT the two architectures are very, very similar. Is it a Pentium killer? The 68070 might have been but it's rather faded away now... Just my half groat's worth again! (Yes, Tony, half a groat == tuppence == two pence == two pennies = (in some sense) $0.02, which seems to be the value most people set on their opinions here. About right in most cases (no offence intended)) Philip.