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I wondered if a city-wide synchronised Pulse-Width-Modulation of LED lights could allow astrophotography (or even naked-eye astronomy) to be possible again, with a filter synchronised to the off-cycle.
Reading the Steelman document is like reading a shopping list of everything that's gone into modern Fortran.
I wonder how this combines with Richardson's Theorem.
Except the 486 had hardware floating point, essential for technical work.
The 486 and https://www.delorie.com/djgpp/history.html changed everything.
Suddenly, it was possible to imagine running advanced software on a PC, and not have to spend 25,000 USD on a workstation.
One consequence of that is that the Earth, as seen from the nearside of the Moon's surface, just hangs there, never moving, apart from a small wobble.
Apollo Command Module interior colour is similar, and gorgeous.
I remember a 120MHz Pentium Linux box arriving at a cottage in Crete, where, with the aid of a 56k USRobotics modem, we (my wife and I) worked remotely in 1995-6. She had a Mac SE/30 for her tourist guidebook work. She later upgraded to a 6100 PowerMac "pizza-box", various iMacs, G3/G4/G5, whereas I saved a quad-200MHz PentiumPro monster (Compaq Professional Workstation 8000, tricked up to 3GB RAM) from the skip. I regret taking that to the recycling centre many years later.
There are two ways of constructing software: one way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult.
— C. A. R. Hoare
The sheer amount of dedication is awe-inspiring. In the 80s, at Imperial College, London, Theoretical Physics Group, we came across some correspondence intended for one of the professors, I think. This person had evidently "translated" his native Spanish into English, laboriously, via some dictionary we thought. We spent many tea breaks puzzling over phrases such as
"Is well-knew the refran: of the said to made it has a good road."
"The language assumes contiguous memory, column-major order, and no hidden aliasing between arrays."
One out of three ain't bad.
"Column-major order", that's the one. That just says that there is an implied order of elements of an array. This enables efficient mapping of an array of the language definition to storage with a linear address space. It does not require storage to be organised in any particular way.
"Contiguous memory". Not really, the language definition does not even use the word "memory". The language is carefully defined so that you can implement it efficiently on a linear address space in the presence of caches (no accident that IBM machines in the 80s were pushing caches while CRAY was pushing vector processors). The term "contiguous" in the language definition just means a collection whose parts are not separated by other data objects.
"no hidden aliasing between arrays". This is a crude mis-statement of the actual rule of argument association across subroutine/function caller-callee boundary. The rule takes pages to describe fully. A language that still has EQUIVALENCE statement (although marked obsolete) cannot be said to disallow aliasing. It is still quite hard to find a compiler that will reliably diagnose inadvertent aliasing at runtime. The actual rule in Fortran says something like "thou shall not cause any effect on (dummy name) A through a reference to some other name, unless (some-clause-x or y or z)".
Do as much as you can in a spreadsheet, then start a new spreadsheet.
Part I managed to miss the Antikythera Mechanism.
It is not suited to cases where the machine state is experienced by the user at all times (games, hardware-control, real-time transactions). It is very suited to cases where the machine is expected to act like a SSBN, disappearing from view until a large floating-point calculation is ready.
Can someone explain to me why although we've known that classical physics is not a correct description of the hardware of the universe for at least 100 years now, we are still hooked on 90-year-old Turing Machines which cannot physically exist (they violate quantum mechanics) and whose theoretical limitations are, consequently, irrelevant.
Before smartphones we had https://www.cambridge.org/turnleft
FORTRAN (IBM, 1956) introduced the "Computed GOTO".
SSA (IBM, 1988) introduced the "Computed COMEFROM".
At my age, I assume that everything that "everybody knows" has a large dollop of fiction pasted around it.
"Byzantine generals", anyone?
Ken, I love your work on the Apollo hardware.
But here, you don't present any argument that your recommended course of action will have a desirable outcome, or any outcome at all.
Which, ironically, fits like a glove.
Fine, I get it, the term has been over-used and has consequently become meaningless. Orwell noted the over-use of "fascist", in 1944! Feel free not to use it. But surely you are not expecting some kind of outcome?!
why some of the very best theoretical physicists, who were entirely free to work on whatever they wanted, continued working on string theory
Historically, it is not unusual for intellectual wrong turns to persist for decades or centuries. On the flip side, brilliant insights can also be abandoned too early.
The problem here is that data has dried up and cannot guide us. Some future tech will open up new data and then progress will resume. Without data, physics becomes theology.
__________________________________________ Feynman's talk "Seeking New Laws" excerpt: "But the age that we live in is the age in which we are discovering the fundamental laws of nature. And that day will never come again. I don’t mean we’re finished. I mean, we’re right in the process of making such discoveries. It’s very exciting and marvelous, but this excitement will have to go.
Of course, in the future there will be other interests. There will be interests on the connection of one level of phenomena to another, phenomena in biology and so on, all kinds of things. Or if you’re talking about explorations, exploring planets and other things. But there will not still be the same thing as we’re doing now. It will be just different interests.
Another thing that will happen is that if all is known– ultimately, if it turns out all is known, it gets very dull– the biggest philosophy and the careful attention to all these things that I’ve been talking about will have gradually disappeared. The philosophers, who are always on the outside, making stupid remarks, will be able to close in. Because we can’t push them away by saying, well, if you were right, you’d be able to guess all the rest of the laws. Because when they’re all there, they’ll have an explanation for it.
For instance, there are always explanations as to why the world is three dimensional. Well, there’s only one world. And it’s hard to tell if that explanation is right or not. So if everything were known, there will be some explanation about why those are the right laws.
But that explanation will be in a frame that we can’t criticize by arguing that that type of reasoning will not permit us to go further. So there will be a degeneration of ideas, just like the degeneration that great explorers feel occurs when tourists begin moving in on their territory."
https://wg5-fortran.org/N2201-N2250/N2212.pdf is John Reid's complete document.
Mid 1980s, trying to connect from one London University computer (at Imperial, a CDC Cyber?) to another (at Queen Mary?), to try some symbolic algebra package that was only available on a Unix minicomputer: spent a good 2 hours just finding the right terminal settings and configuration settings for all the intervening software. Left me feeling I would rather code what I could on an 8-bit 2Mhz 64K machine.
I suspect not. Children are exposed to far less text than LLMs. LLMs are parlour tricks that teach us nothing about how humans do it.
The point is, it shouldn't.
https://news.ycombinator.com/item?id=30022022 How ISO C became unusable for operating systems development
I don't see how C can match Fortran's abstraction level and still reliably control hardware that uses memory-mapped I/O.
C, as an operating system implementation language, is trying to do something fundamentally different than Fortran.
You live by memory address, you die by memory address.
People mention the no-aliasing, the compilers, the intrinsics, the libraries, and the expressivity but one aspect of the difference is ignored and it is this: C is a language for specifying behaviour of hardware (time sequence of detailed states), Fortran is a language for specifying computation of values. Fortran abstracts far more of the hardware than C and consequently, a Fortran compiler can benefit from quantum processors, mind-readers or time-machines, should they ever be invented.
A Fortran program that reads its input, calculates and finally writes out its output does not have to execute any particular instruction at all. As long as the answer is "AS IF" it had done the user-specified computation, the Fortran compiler has done its job. In between I/O, it submerges into the ineffable like a Cold War SSBN.
C is about the instruments, the players and the conductor, Fortran is about the music.
The only reason you would want bit-reproducibility is because you haven't done the numerical analysis and have no clue how many digits of your "answer" to trust.
As far as I know, two sectors claim they need it: finance and climate.
"Do you want a better answer?"
"No, I want the same wrong answer that I got last Tuesday."
Science/Mathematics can't fix this.
It is unsafe if the code was written by a numerical expert who understood the ISO/IEC 60559:2020 standard. Not many of those, so in all probability your garbage code continues to be garbage (but faster) with FMA.
print *, norm2(x)
"The result of NORM2 (X) has a value equal to a processor-dependent approximation to the generalized L2 norm of X, which is the square root of the sum of the squares of the elements of X. If X has size zero, the result has the value zero."
Readers, please don't accept anything anyone writes about "FORTRAN", unless in a historical context. They probably last encountered the leading edge of the language 40 years ago.