On Mon, Jan 3, 2011 at 2:01 PM, Alan Kay <alan.n...@yahoo.com> wrote:
> Please say more ... > > The Alto didn't have any hardware for this ... nor did it have any regular > code ... it was microcoded and almost a Turing Machine in many ways. The > main feature of the hardware architecture was the 16-way zero-overhead > multitasking of the microcode pre-triggered by simple events. > > Are you actually commenting on the way the first Ethernet interface was > done? > > Cheers, > > Alan > > Thought about this... I think I confused three different projects. The Interim Dynabook OS for Smalltalk-72, the Alto, and Butler Lampson's much later work on secure distributed computing ( http://research.microsoft.com/en-us/um/people/blampson/Systems.html#DSsecurity). I don't think I've ever read a hardware description of the Alto. I'm 26 years old and there are only so many bits an eye can see ;-) >From what I read about the Alto, it was fairly cool in that, if I understood the description right, the network was basically a virtual paging system for the local computer, and you could essentially have your local computer be whatever was the most important local features for you to have (.e.g, in the event of network failures and unavailability of services). But I think it was reading Butler's later work that made me think the Alto was half-baked in this regard and mainly a hacked together good idea. For example, I didn't see anywhere where it said that the image could be persisted locally, and that the contents of that image could be named elsewhere on the network (e.g., some metadata describing the content of that image, imagine content-based routing for programs, since programs are really just content; you kind of see the modern Web Browser edging slowly in this direction vis a vis MS Research showing that the best way to partition programs is by their features; given that, it is a short jump to realize that through modular definition you can basically share lots and lots of code throughout a network, but the key is that the representation of the code has to be at a suitably high level of abstraction so that the content can be cached closer to the edges of the network). Basically, an operating system should be a recursively defined resource and anybody who wants a copy of that operating system should be able to just point to an address where an image of that resource is located, and automatically suck in that image and start running. And there should be no obligation that once the thing starts running that it has to be the same thing forever. Hope that helps.
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