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Comment by davidst | Hacker News Reader

Rule of thumb: RAM size lags disk size by about ten years.

Ten years ago a typical workstation had around 32GB of disk storage. Today, 32GB of RAM in a workstation is perfectly ordinary.

Take the size of your local disk space today. Ten years from now that will be the amount of RAM in your computer.

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> 32GB of RAM in a workstation is perfectly ordinary.

I look around me and most of new systems have 4 GB of RAM. It's possible to have 32 GB of RAM, sure, but it is absolutely uncommon, and blatantly unnecessary (none of my own desktop machines have more than 2 GB).

I built Chromium from source the other day on my machine with 4GB of RAM. It hit swap while linking. Also, I'm running a 64-bit Linux distro. A 32-bit system I tried could not link Chromium at all.

All of this is documented in the Chromium wiki, of course. But the point is, 4GB memory is their minimum requirement, and insufficient for doing a lot of work on a project like Chromium.

Damn, I thought needing something like 3GB to compile PyPy on 64-bit put us in some class on unreasonable usage, interesting to see that it's apparently not so crazy for large projects.

I have 8 servers running distcc for my compilation chores, however none of them has more than 8 GB of RAM. IIRC I had no problem compiling firefox with my puny workstation. Chrome is as nasty as OOo :)

Linking Chromium on Windows hit swap for me with 8GB.

The machine I use as my workstation has 64GB of RAM.

Of course, it also has 32 cores... It's not exactly your standard i7 workstation.

I think I had a 4GB hard disk ten years ago.

20GB about 2 years later.

Nope. Both RAM and disk are asymptotic. We're getting to the point now where the laws of physics are preventing us from getting much smaller. Now, all of this is only applicable to the current paradigm; an entirely new kind of RAM could mean vastly higher ceilings, but if we keep making it the way we've more or less been making it for decades, we'll hit a wall.

That rule of thumb is from Jim Gray:

http://en.wikipedia.org/wiki/Jim_Gray_(computer_scientist)

It's held true for a long time. Like any rule of thumb, at some point it may no longer be correct, but we're not at that point yet.

Interesting. A citation would be informative. I tried the usual keyword searches of "memory disk space barriers asymptotic ceiling" but couldn't quickly fine anything. I'd be interested if you could provide us a pointer.

Right now DDR3 is made on a ~30nm process. We can't really shrink that too much more without the various pathways bleeding into each other. We're just running into insulation limits. They'll still be able to shrink it a bit, but this holds true for CPUs as well, and is one of many reasons why we're increasing cores in pursuit of higher performance.

We're scheduled to hit 11nm; after that I'm not sure. See the Wikipedia article on quantum tunnelling for an explanation that's mostly above my comprehension.

http://en.wikipedia.org/wiki/Quantum_tunnelling

edit: To get an idea of the scales we're talking about, 11nm is only about 50 silicon atoms wide.

http://www.wolframalpha.com/input/?i=11nm+/+width+of+silicon...

That just means we need to move to a three-dimensional process. Speaking of which, aren't memristors supposed to be layerable?

A back of the envelope calculation says that a linear shrink with a factor of three means nine times as many structures on a given die area. This is consistent with the factor of ten in a decade. There will be hard technical problems lurking in the details, but the end is not yet nigh.

I think the refute of this rule of thumb will not come from the asymptotic nature of them in about 1000 years or whatever, but from the new memristors technology.

So all memory will be the same.

Nowhere near 1000 years. We're scheduled to be at 11nm in 5 years. That's 1/3 the width. So, in 1000 years, it'd be 1/600th the width, or 50/600 = 1/12th the width of an atom.

We really don't have very long left with the current paradigm. Past about a decade or so, we'll need something new if we want to continue growth.

People have been saying that for decades. AMD, Intel et al. are still very confident that Moore's law is good till at least 2020.

Well, if you keep saying that Moore's law will fail, you will eventually be right. Like if you say a certain celebrity will die this year, eventually you will be right. Like how economists have predicted 8 out of the last 5 recessions.

We're reaching the scale of process where quantum effects are starting to rule. I didn't say we wouldn't be able to keep expanding, simply that this current model will run out of steam. You can't continue to get smaller ad infinitum.

Ten years ago it was because the features were smaller than the light wavelength used to print the mask (not sure of terminology here). There's always something that looks like an insurmountable barrier, but billions of research dollars can work miracles. Intel spent $5B on R&D in 2009.

And don't forget, that R&D is funded by RAM profits.

So, do your part, and upgrade soon. ;-)

32 GB ram is absurd in ordinary usage - what do you use your computer for?

Statistical machine learning and data mining. 32GB isn't enough but, then, it's hard to name any amount that would be enough this kind of work.

Almost all of our machines are either 32GB or 16GB.

As btmorex pointed out earlier, "Once your data set doesn't fit in memory, it is indeed a scarce resource. And 24 GB is really not very much data."

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