Hacker News Reader

Comment by bullen | Hacker News Reader

16 billion gigabytes not enough for you?

An internet search tells me there are somewhere between 10^76 and 10^82 atoms in the universe. We must not rest until all atoms are mmap-able. That should require at least a 273-bit length type to be safe. Since we need a power of two, 512-bit length. This size also gives us a little room for fat pointers.

> That should require at least a 273-bit length type to be safe. Since we need a power of two, 512-bit length.

The size of memory is a power of two because the bits in a pointer have two possible values.

But why do you need the length of a pointer to also be a power of two? Are you addressing the bits in the pointer?

>But why do you need the length of a pointer to also be a power of two? Are you addressing the bits in the pointer?

Indeed. The entanglement code will crawl without easy direct addressing of the bits. We wouldn't want the universe to run even slower, would we now? It would also make the development emulator impossible to run leading to even more bugs and missed deadlines.

Beats having to expand later with Gate A272.

So the computer that simulates the universe is likely a 512-bit machine.

How does it simulate subatomic particles then?

It doesn't seem there are many orders of magnitude more subatomic particles. 3 quarks in a proton. At most O(10^2) protons in a atom. So it should all fit comfortably in a 512-bit type.

* As for photons, this estimate finds 4*10^84 photons since start of universe:

https://cosmosmagazine.com/science/physics/how-many-photons-...

“3 quarks in a proton” is an oversimplification; the reality involves “zillions” of particles, as per https://profmattstrassler.com/articles-and-posts/largehadron...

Maybe we need to use 1024-bit types?

The universe is expanding, we need it to be scalable

It’s virtual memory and it has a TLB.

CHERI[1] anyone?

[1] https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/

This is probably posted in jest, but there was a time - not so long ago - where folks firmly believed nobody would need more than 16 memory bits, and even 1 Gigabyte of storage was considered outlandish.

Things have gotten exponentially larger in the meantime... with your average home computer going from < 1GB of RAM to 8GB and ever increasingly larger (my cell phone has 12GB of RAM and 512GB of storage for what it's worth).

Having storage ranging in the Terabyte category is simply the norm, and things like Petabytes of storage are rapidly becoming more accessible for average users.

Saying "X is enough" - ever - in computing is foolhardy.

Upvote from me. I have been at 32GB of RAM for more than 5 years. I am genuinely surprised. I'm basically a big corporate programmer that runs Microsoft Outlook (surprisingly low memory), a giant (8GB RAM) IDE, and a squillion Google Chrome tabs. I struggle to think how/when I will need more than 32GB RAM. I have 64GB at home from a COVID-era new build, only because it seemed short sighted to "only" buy 32GB RAM in 2021. I have never once come close to needing it. :)

That said, I completely agree with your sentiment about "X is enough". What has changed in the last 20 years: When we double RAM/storage/network now, the increase is enormous. It does feel like GPUs are still in the insane growth period. Very soon they will be more powerful and have more on-board RAM than whole rest of the computer.

but there was a time - not so long ago - where folks firmly believed nobody would need more than 16 memory bits

This is not true, no one seriously thought 65 KB was ever going to be any sort of a limit. If you're talking about the Bill Gates quote, it's basically a myth that never happened or was taken WAY out of context. Bill Gates himself has given interview where he talks about the entire state of released and upcoming computers of that time and exactly what everyone thought was going to happen and what actually did happen.

No, it was not just Gates that thought this. Look around you, all of your old tech was designed for smaller numbers. Even IP addresses were designed with "we'll never need more than X", and look at the mess we're in today.

Every time someone in tech has said "that number is large enough", the number gets surpassed in no time.

So while 64 bit memory addresses seems way more than ample today, it will not be forever. That was the point...

No, that's not how it went. People were not stupid and lacking any foresight in the past. Constrained storage space has been a concern since Charles Babbage's analytical engine, that is since forever in computing. No one ever thought let's stop at 16 bit pointers or whatever and it will be enough for the rest of time. It's an engineering tradeoff to make the best of the technology available at the time. Pointer sizes are not just a number, they correspond to realities down to the electronics and physical design of your system. Longer pointers mean larger address bus, larger registers, more transistors on your chip that won't be available for something else. They are more wasteful if you don't actually have that much memory to address. It's incredibly naive to think today's standards were even a possibility decades ago.

> No, that's not how it went. People were not stupid and lacking any foresight in the past

It truly is in so many cases. Not stupidity, but perhaps hubris. The same hubris that says nobody will need more than 64 bits today. Given time, 64 bits will fall waste to 128 bits and more.

The people who designed IPv4 truly thought the number of IP's would be more than enough forever. They literally had no concept that one day your average person would own multiple computing devices and require multiple IP's just to get through a normal day. They were very wrong, and found out in only a few year's time.

The only constant in tech is our assumptions today will be wrong tomorrow. Assuming "X" is big enough is foolhardy in just about every scenario.

Well, they had no idea IP was going to be used by consumers full stop.

You realize that limitations like 16 bit addressing was because of the extreme limitations of the time right? The 6502 can address 65KB of memory, had 13 address modes, 55 instructions and was made out of 3,510 transistors. Modern CPUs have over a million times the transistor count.

Every year was another iteration of these limits being updated, no one ever thought any of these numbers were going to stay static. It took 1MB of memory just to have a 24 bit color frame buffer at NTSC resolution.

IP addresses were set at 4 billion when you could print out a list of known computers and put it in a binder and we still use it today.

This idea that people had a general lack of foresight was completely untrue. What people did with limitations like 3,510 transistors is astounding.

2 EiB to be precise.

2.305843009213694 ;-)

2^64 bites should be exactly 2EiB.

Reply on news.ycombinator.com