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In the same vein, since I heard about the US Army's 500 PS4 super computer I've thought it should be simple to plug multiple computers together to multiple thei

In the same vein, since I heard about the US Army's 500 PS4 super computer I've thought it should be simple to plug multiple computers together to multiple their power. Why cant I connect an old laptop, a few old cellphones and a hard drive all together and have one computer use the resources of the other devices? Collectively we have SO MUCH available ram just sitting around unused.

multimoon 2y ago
Because it’s not as simple as you’re making it out to be. This is highly workload dependent - you can’t just connect multiple CPUs that are designed to (even with old hardware) have lightning fast connections to their neighboring hardware with a slow USB cable and expect it to just linearly multiply power. The CPUs end up actually running slower because they spend most of their time sitting around waiting for instructions to execute. This even used to be a problem with multi-GPU set ups, just much less of a factor. This is why cluster computing is far more dependent on software being able to distribute work and load balance than the actual hardware. There exists software where you can connect random devices together in your house over Ethernet and make a cluster. This is why every supercomputer is geared towards massive number crunching where you can break up the work into many smaller tasks and give each node a task to work on. Cluster computing sucks and is inefficient for anything resembling a normal workload.
DaiPlusPlus 2y ago
> I've thought it should be simple to plug multiple computers together to multiple their power. It is simple - it's so simple it became a meme: https://en.wikipedia.org/wiki/Beowulf_cluster https://en.wikipedia.org/wiki/Beowulf_cluster - almost every Slashdot comments-thread in the early-to-mid-2000s would reference it somehow. But distributed-computing isn't popular because it just isn't particularly useful for the things people want to do with their computers: combining all of my own computers together isn't going to make watching YouTube any better, not even make my games run faster.
yencabulator 2y ago
Current day operating systems assume a cache-coherent system. Without that assumption, you're basically just looking at a bunch of networked computers. This is done because you get much, much more performance out of systems like that (see e.g. https://blog.acolyer.org/2015/06/05/scalability-but-at-what-cost/ https://blog.acolyer.org/2015/06/05/scalability-but-at-what-... ) You might enjoy reading about research projects into distributed operating systems, e.g. https://en.wikipedia.org/wiki/Amoeba_(operating_system) https://en.wikipedia.org/wiki/Amoeba_(operating_system) , https://en.wikipedia.org/wiki/Sprite_(operating_system) https://en.wikipedia.org/wiki/Sprite_(operating_system) or https://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs https://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs

multimoon 2y ago

Because it’s not as simple as you’re making it out to be. This is highly workload dependent - you can’t just connect multiple CPUs that are designed to (even with old hardware) have lightning fast connections to their neighboring hardware with a slow USB cable and expect it to just linearly multiply power. The CPUs end up actually running slower because they spend most of their time sitting around waiting for instructions to execute. This even used to be a problem with multi-GPU set ups, just much less of a factor. This is why cluster computing is far more dependent on software being able to distribute work and load balance than the actual hardware. There exists software where you can connect random devices together in your house over Ethernet and make a cluster. This is why every supercomputer is geared towards massive number crunching where you can break up the work into many smaller tasks and give each node a task to work on. Cluster computing sucks and is inefficient for anything resembling a normal workload.

DaiPlusPlus 2y ago

> I've thought it should be simple to plug multiple computers together to multiple their power. It is simple - it's so simple it became a meme: https://en.wikipedia.org/wiki/Beowulf_cluster https://en.wikipedia.org/wiki/Beowulf_cluster - almost every Slashdot comments-thread in the early-to-mid-2000s would reference it somehow. But distributed-computing isn't popular because it just isn't particularly useful for the things people want to do with their computers: combining all of my own computers together isn't going to make watching YouTube any better, not even make my games run faster.

yencabulator 2y ago

Current day operating systems assume a cache-coherent system. Without that assumption, you're basically just looking at a bunch of networked computers. This is done because you get much, much more performance out of systems like that (see e.g. https://blog.acolyer.org/2015/06/05/scalability-but-at-what-cost/ https://blog.acolyer.org/2015/06/05/scalability-but-at-what-... ) You might enjoy reading about research projects into distributed operating systems, e.g. https://en.wikipedia.org/wiki/Amoeba_(operating_system) https://en.wikipedia.org/wiki/Amoeba_(operating_system) , https://en.wikipedia.org/wiki/Sprite_(operating_system) https://en.wikipedia.org/wiki/Sprite_(operating_system) or https://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs https://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs