> it's difficult to imagine what kind of new physics would let someone fit that many bytes into a machine that's practical to control with a single Linux kernel instance.
I nominally agree with most of your post. But I should note that modern systems seem to be moving towards a "one pointer space" for the entire cluster. For example, 8 GPUs + 2 CPUs would share the same virtual memory space (GPU#1 may take one slice, GPU#2 takes another, etc. etc.).
This allows for RDMA (ie: mmap across Ethernet and other networking technologies). If everyone has the same address space, then you can share pointers / graphs between nodes and the underlying routing/ethernet software will be passing the data automatically between all systems. Its actually quite convenient.
I don't know how the supercomputer software works, but I can imagine that 4000 CPUs + 16000 GPUs all sharing the same 64-bit address space.
I nominally agree with most of your post. But I should note that modern systems seem to be moving towards a "one pointer space" for the entire cluster. For example, 8 GPUs + 2 CPUs would share the same virtual memory space (GPU#1 may take one slice, GPU#2 takes another, etc. etc.).
This allows for RDMA (ie: mmap across Ethernet and other networking technologies). If everyone has the same address space, then you can share pointers / graphs between nodes and the underlying routing/ethernet software will be passing the data automatically between all systems. Its actually quite convenient.
I don't know how the supercomputer software works, but I can imagine that 4000 CPUs + 16000 GPUs all sharing the same 64-bit address space.