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Cray-1 vs Raspberry Pi

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131–140 of 193 posts

Re: Cray-1 vs Raspberry Pi

#131
post #83
post #8

The RPi, unlike the Cray-1, does not offer ample sitting space.

yeah, the pi cases have been disappointing. Few have adequate cooling. (flirc is good, the ones with fans are just annoying) I'd love to have a pi case that had a built-in breadboard. ...or a case with comfortable seating.

I like the Flirc aluminum case. My Pi 5 case arrived last week. Now waiting for my new Pi.

Re: Cray-1 vs Raspberry Pi

#133

I'm waiting for the follow-up from Jeff Geerling where he fits a Raspberry Pi into a Cray-1 enclosure.

I would totally love a Cray1 shaped PC enclosure. A even smaller one for Raspberry Pis would also be cool.

https://www.thingiverse.com/thing:2610764

Re: Cray-1 vs Raspberry Pi

#134
post #92

When I see comparisons like this, the first thought I have is not the benchmarks, but rather what the most “heroic” real-world calculation of the day would have been on something like the Cray-1, and how to replicate those calculations today on something like a RPi. Weather/climate models? Rad-hydro? The fidelity would almost certainly be super low compared to modern FEA software, but it would be a fun exercise to tr…

nuclear weapons simulations the first machine went to Los Alamos https://www.theatlantic.com/technology/archive/2014/01/these...

> rad-hydro

These are incredibly expensive even on today’s hardware. If you look through some of the unclassified ASCI reports from the early 2000s, 3D calculations of this equation set were implied to be leadership-class computations. At the time of the Cray, it must’ve been coarse-grid 1D as the standard, with 2D as the dream.

Re: Cray-1 vs Raspberry Pi

#135

When I see comparisons like this, the first thought I have is not the benchmarks, but rather what the most “heroic” real-world calculation of the day would have been on something like the Cray-1, and how to replicate those calculations today on something like a RPi. Weather/climate models? Rad-hydro? The fidelity would almost certainly be super low compared to modern FEA software, but it would be a fun exercise to tr…

One of the early customers was the European Centre for Medium-Range Weather Forecasts, so, wild guess, they probably used it for medium-range weather forecasts.

Numerically, I’m currently what this would have looked like. I’m talking about the governing equation set, discretization methods, data, etc. It would be a fun project to try and implement a toy model like that.

Re: Cray-1 vs Raspberry Pi

#136
post #116

TL; DR: ten years ago, Raspberry Pis and Android phones were a handful times faster. Nowadays, they are around 100 times faster. Pretty impressive, considering they fit in our pockets.

Thank god they have a modern OS to slow them down. /s

No /s required, Wirth's law holds far more solidly than Moore's law. You may live to see man made software bloat beyond your comprehension.

Re: Cray-1 vs Raspberry Pi

#137
post #52

It's wild to imagine that 40 or so years from now, someone will have a drawer full of cheap plastic boxes, each with more power than the fastest computing cluster of 2023... promising to themselves that one day they're finally going to build that hobby project with one of them.

You really think so? Aren’t we at the end of Moore’s law, so I’m really doubtful that we’ll see massive leaps like that.

Moore's law will die when we have 3D stacks of silicon thick enough that even integrated liquid cooling can't keep it cool. With feature sizes measured in a few atoms.

Or when economics of fabricating such structures just aren't worth it.

Re: Cray-1 vs Raspberry Pi

#139
post #52

It's wild to imagine that 40 or so years from now, someone will have a drawer full of cheap plastic boxes, each with more power than the fastest computing cluster of 2023... promising to themselves that one day they're finally going to build that hobby project with one of them.

Didn’t the Apollo guidance computer, which took people to the moon, have 4K of RAM? Today, 1 million times that barely runs the OS and a few Chrome tabs.

Russians ran computers with ferrite-plate RAM of similar size on submarines well into 90s or maybe even 00s. Still using software written for them on Kilo submarines in some sort of VMs.

Re: Cray-1 vs Raspberry Pi

#140
post #22

Earlier quoted context omitted.

Those are largely simd but not vector.

How is vector different from simd?

The RISC-V Vector extension allows the vector length to vary at runtime whereas with SIMD the vector length is fixed at compile time (128 bit, 256 bit etc.). It means the code is more portable basically.

With x86 SIMD the standard solution is to compile the same code multiple times for different SIMD widths (using different instructions) and then detect the CPU at runtime. Though that is such a pain that it's only really done in explicitly numerical libraries (Numpy, Eigen, etc.). In theory with Vector you can compile once, run anywhere.

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