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Ok, I don\u2019t normally like celebrity stories, but that is neat.<br>
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<blockquote type="cite">On Oct 21, 2022, at 4:03 PM, Frank Wimberly <wimberly3@gmail.com> wrote:<br>
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<div dir="auto">As for "NeXT machine's software RIP", Rick Rashid, who was central in the development of that software, was my office neighbor. He left to take a position at Microsoft as VP of Research. I wonder if the software is RIPing.<br>
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<div data-smartmail="gmail_signature">---<br>
Frank C. Wimberly<br>
140 Calle Ojo Feliz, <br>
Santa Fe, NM 87505<br>
<br>
505 670-9918<br>
Santa Fe, NM</div>
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<div dir="ltr" class="gmail_attr">On Fri, Oct 21, 2022, 3:08 PM Steve Smith <<a href="mailto:sasmyth@swcp.com">sasmyth@swcp.com</a>> wrote:<br>
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<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
FWIW, I dipped into the higher levels of real-time-systems development <br>
several times in my career. The earliest being a control system (circa <br>
1981) for the LANL Proton Storage Ring where one naturally can't afford <br>
anything *but* failsafe implementations, etc. The stakes are just too <br>
'ffing high and the coupling to electrooptomechanical systems quite <br>
intimate.<br>
<br>
The "digital" components of such systems might have had the opportunity <br>
to ignore timing issues and simply "execute the same steps" regardless <br>
of timing. But in fact many software-driven (sub)systems represented <br>
time-critical processes and sometimes were up agains the timing limits <br>
of the analog components which had no leeway in their "execution".<br>
<br>
There are all kinds of analogies in federated (distributed) simulation <br>
environments which Glen (and others here) probably know much better than <br>
I, where different "clocks" matter, and different levels of <br>
synchronization and reproducibility are in play. The Postscript <br>
interpreters, printers, and film recorders were also pseudo real-time <br>
systems since some of the timing components were in fact software <br>
controlled (for example, the film recorders were "stroke" devices with <br>
software driving D-A converters to "sweep" out vectors and "clip" the <br>
on/off of the beam with appropriate analog component delays/biases/gains <br>
needing to be calibrated for. Fortunately failures in this step did <br>
not (usually) damage anyone or risk anyone's health and safety (like the <br>
beam in the PSR did).<br>
<br>
Regarding identity and equivalence, I prefer the phrase: "close enough <br>
for who it's for"...<br>
<br>
<br>
On 10/21/22 11:18 AM, glen wrote:<br>
> Ha! If we're going to argue about words, then let's stick with the <br>
> word "identity" and skip the "metaphor" nonsense. You and Frank seem <br>
> to be using the word in a weird way. Identity means "the exact same <br>
> particular thing over any differencing available" or somesuch. I mean, <br>
> it's used that way in phrases like "identity theft" as well as <br>
> mathematical identity. It's equivalence sets all the way down. I just <br>
> can't imagine any working computationalist would ever say anything <br>
> like "executed identically" unless ... well ... the exact same <br>
> process, with the exact same steps, happened.<br>
><br>
> I suppose there are deep philosophical intuitions pried at by the <br>
> words "emulation" versus "simulation". And one can argue (again with <br>
> help from Christian List) about whether there exist fully closed <br>
> ontological walls like we try to create with things like Jails, <br>
> HyperV, Docker, VM's like Java's, etc. But "execute identically" is a <br>
> phrase that would only be used by someone who worked *way* above such <br>
> levels (assuming levels even exist at all). It's a bit like talking to <br>
> the kids programming websites these days, with access to infinite disk <br>
> space, infinite memory, steeped in continuous delivery, etc. [\u26e7]<br>
><br>
> Layers of abstraction are fine. Use 'em when you need 'em. But we <br>
> shouldn't posture by invoking things like "instruction sets" and <br>
> "execute identically" in the same breath. (Not that you did that ... <br>
> just sayin'.)<br>
><br>
><br>
> [\u26e7] Rant: This is a good talk <br>
> <<a href="https://www.youtube.com/watch?v=8Ab3ArE8W3s" rel="noreferrer noreferrer" target="_blank">https://www.youtube.com/watch?v=8Ab3ArE8W3s</a>>. But I get super
<br>
> irritated when people use *toy* code in their rhetoric and leave large <br>
> scale deployment as an exercise for the reader. Yeah, fine. The REPL <br>
> is cool and all. But when my simulation takes a fvcking WEEK to <br>
> execute, it's difficult to sympathize. I've recently been playing <br>
> around with VSCodium, which is pretty cool. But whatever, man. I still <br>
> have to upload the code somewhere and execute it. Get off my lawn!<br>
><br>
> On 10/21/22 09:24, Steve Smith wrote:<br>
>><br>
>> As a counter-example, we ran film recorders whose "guts" were built <br>
>> by Ed Fredkin's Information International company and were built to <br>
>> the spec of Dec PDP-11 (I think 11?) and it was anecdotally agreed <br>
>> among the user community (of a few thousand delivered units in the <br>
>> world?) that these PDP-clones *never* failed to execute the code <br>
>> identically to the machines they were patterned after. I don't <br>
>> remember the details of implementation of these 70's era hardware <br>
>> designs, but I understood that they III designed their own PCBs but <br>
>> (obviously?) used the same CPU chips... I don't know about all the <br>
>> other support components... A likely answer to this pondering is that <br>
>> these machines did not run a general purpose OS and the III <br>
>> software/system people probably made up for any differences in <br>
>> Software/Timing/Error Handling?<br>
>><br>
>> If Owen is listening in here, I think he was there for more than a <br>
>> little of this from inside Apple/Sun?<br>
>><br>
>> - Steve<br>
>><br>
>> PS. To concede/confront glen's sentiment that: " 'Metaphor' is an <br>
>> evil word, used only by manipulators and gaslighters", I would <br>
>> offer that the use of *conceptual metaphor* is to thinking as noise <br>
>> is to simulated annealing, and his point about "tighter or looser <br>
>> equivalence" might well be the best argument *for* the use of <br>
>> metaphorical thinking? I can't believe I'm stirring/kicking this can <br>
>> of worm-hornets down the street again...<br>
>><br>
><br>
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