Re: [TUHS] core

You've just managed to hit one of my hot buttons. I can't speak to the motivations of everyone who repeats these stories, but my professional career has been littered with examples of poor vision from technical colleagues (some of whom should have known better), against which I (in my role as an architect, which is necessarily somewhere where long-range thinking is - or should be - a requirement) have struggled again and again - sometimes successfully, more often, not. So I chose those two only because they are well-known examples - but, as you correctly point out, they are poor examples, for a variety of reasons. But they perfectly illustrate something I am _all_ too familiar with, and which happens _a lot_. And the original situation I was describing (the MIT core patent) really happened - see "Memories that Shaped an Industry", page 211. Examples of poor vision are legion - and more importantly, often/usually seen to be such _at the time_ by some people - who were not listened to. Let's start with the UNIBUS. Why does it have only 18 address lines? (I have this vague memory of a quote from Gordon Bell admitting that was a mistake, but I don't recall exactly where I saw it.) That very quickly became a major limitation. I'm not sure why they did it (the number of contact on a standard DEC connector probably had something do with it, connected to the fact that the first PDP-11 had only 16-bit addressing anyway), but it should have been obvious that it was not enough. And a major one from the very start of my career: the decision to remove the variable-length addresses from IPv3 and substitute the 32-bit addresses of IPv4. Alas, I was too junior to be in the room that day (I was just down the hall), but I've wished forever since that I was there to propose an alternate path (the details of which I will skip) - that would have saved us all countless billions (no, I am not exaggerating) spent on IPv6. Dave Reed was pretty disgusted with that at the time, and history shows he was right. Dave also tried to get a better checksum algorithm into TCP/UDP (I helped him write the PDP-11 code to prove that it was plausible) but again, it got turned down. (As did his wonderful idea for bottom-up address allocation, instead of top-down. Oh well.) People have since discussed issues with the TCP/IP checksum, but it's too late now to change it. One place where I _did_ manage to win was in adding subnetting support to hosts (in the Host Requirements WG); it was done the way I wanted, with the result that when CIDR came along, even though it hadn't been forseen at the time we did subnetting, it required _no_ hosts changes of any kind. But mostly I lost. :-( So, is poor vision common? All too common. Noel