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How To Use a Terabyte of RAM

Posted by kdawson on from the every-factor-of-25-helps dept.

Spuddly writes with links to Daniel Philips and his work on the Ramback patch, and an analysis of it by Jonathan Corbet up on LWN. The experimental new design for Linux's virtual memory system would turn a large amount of system RAM into a fast RAM disk with automatic sync to magnetic media. We haven't yet reached a point where systems, even high-end boxes, come with a terabyte of installed memory, but perhaps it's not too soon to start thinking about how to handle that much memory.

6 of 424 comments (clear)

  1. You only need 16GB of RAM for this to be useful by 2nd+Post! · · Score: 5, Insightful

    Given that the core components of an OS are only a few GB, even 8GB systems might be able to do this, today.

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    GPL Deconstructed
    1. Re:You only need 16GB of RAM for this to be useful by Kjella · · Score: 5, Insightful

      Personally I just wish there was better cache hinting on current software. For example, playing a huge movie will swap out all my software to disk even though the 30GB Blu-Ray movie will likely be played start-to-finish once and give no benefit whatsoever. To the best of my knowledge (at least I've never seen it exposed to any API I've used), there's nothing like "Open, for reading, with READ cache but don't bother keeping it around in SYSTEM cache" flags.

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      Live today, because you never know what tomorrow brings
    2. Re:You only need 16GB of RAM for this to be useful by QuoteMstr · · Score: 5, Insightful

      See posix_fadvise. Using that API, a process can have as much control over a file as it needs; too bad the kernel does basically nothing with that information.

  2. Re:1 TB of memory... by frovingslosh · · Score: 5, Insightful
    I'm not sure why people are rating your post as funny. I have not had moderator points in a long time, but if I did I would mark it insightful.

    As to the problem of how to use 1 TB of RAM, spending any time at all thinking of this is foolish and wasteful. Of course, I remember the days when we rated our computers in how many kilo bytes of memory we had, and plenty of readers here will remember having 20 to 40 meg hard disks in PC's with far less than 1 meg of physical RAM memory. In those days (and I'll avoid the famous Bill Gates quote on the subject), how would you have spent your time deciding what to do with the memory if you had a computer with 1 gig, 2 gig or even 4 gig of memory? You may have come up with all sorts of amazing ideas. But none of them would have done you any good, because the developers (Mostly Microsoft, but Linux is far from lean and mean any more either) already decided what to do with it, waste it and leave you wanting more. And one of your ideas for a 4 gig system might not have even been to just pretend that most of the last gig of memory wasn't there and ignore it!

    So why even have a post about what to do with a terabyte of memory? The solution is simple, install Windows 9 and try to quickly order more memory on-line before the memory hungry service pack comes out, forces it's install on you, and your TB isn't enough.

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  3. Mobile much? by tepples · · Score: 5, Insightful

    Now that it's 2008 and every new computer has a few gigs of RAM Handheld computers don't.

    There is no reason to write tiny apps in assembly anymore. Other than the fact that embedded systems outnumber PCs?
  4. Re:1 TB of memory... by Usquebaugh · · Score: 5, Insightful

    In the early 80s there was this funny machine called a System/38 from IBM that morphed in the AS/400 that is now called an iSeries. Now this machine was a RDBMS engine with simple green screens attached.

    Under the covers the System/38 was a cisc box, the AS/400 could be CISC or RISC and the iSeries is all risc. From an app dev point the same compiled object code could run on all three. Stop and think about for a second.

    Now the System/38 had a very advanced constraint based security system. For example you could use an object that you could not see. But in general is allowed for very fine grain control of security. Of course this has been improved throught to the iSeries.

    Also, this machine had a single address space for all storage. An app didn't need to worry about memory size, the machine automatically used ram as disk and disk as ram.

    Of course this machine has had a life of 30+ years and most OS designers have zero idea about just how revolutionary it is same sort of thing as the MCP for a Burroughs B5000. People who do not know history are doomed to repeat it over and over again.