← Back to context

Comment by aogl

7 years ago

Moving beyond a 64-bit architecture will allow manipulation of memory address spaces that are larger than 16 Exabytes. Even high-end servers today do not contain more than 1TB of physical memory. It would take several decades if not more for memory densities to become high enough to begin to reach the boundary that 64-bit addressing limits computers.

So yes, highly likely for a little while..

11 comments

aogl

Reply
stochastic_monk  7 years ago

Current x86 architectures only use 48 bits for addressing. That’s still enough to address ~280TB of RAM. I expect that to change before upgrading to 128-bit pointers.

  • red75prime  7 years ago

    128 bits are nearly enough to address every atom in the Universe. Such pointers are mostly a waste of memory space.

    > I expect that to change before upgrading to 128-bit pointers.

    Or the joke was wasted on me. Did you mean it will never be feasible?

geocar  7 years ago

People where I work have workstations with more than 1TB of ram.

I think the value of a larger pointer (immediately) would be tags, not memory density, just as it was with 64-bit systems -- my old Alpha only had 256mb of ram, and maxed out at 512mb IIRC.

  • mehrdadn  7 years ago

    > People where I work have workstations with more than 1TB of ram.

    Wow. What kinds of workstation tasks need this kind of memory, if I may ask?

    • geocar  7 years ago

      Analysis; some model building.

      It is popular to buy a bunch of servers (or worse, host them on AWS), a bunch of sysadmins, and so on, so you can support a couple smart analysts with some complex hadoop java streaming somethingrather, but it is much cheaper to just buy them beefy workstations and use awk: A HP Z8 G4 with 1.5TB ram is under £30k, and it's hard to get a sysadmin that has any brains for that, let alone two and servers...

mitchty  7 years ago

> Even high-end servers today do not contain more than 1TB of physical memory.

??? I know of multiple high end servers with 1TiB+ memory footprints. What is your definition of high end?

Here, have a look at HP's page if you don't believe me: https://www.hpe.com/us/en/product-catalog/servers/proliant-s...

And I'd hardly consider those "high end", there are much larger memory servers out there if you want them.