To me, it's interesting that after all this time and with the prevalence of languages that rely heavily on garbage collection, garbage collectors still don't seem to scale to large heaps.

Large heaps mean long pauses when doing the "mark" phase of the generation holding most of the objects. That seems like a big problem that will increase as memory sizes increase.

Maybe the way I'm looking at it is too simplistic and there are better methods now. But even in Java, which has had plenty of time to work these issues out, I have seen issues with long GC pauses.

My impression right now is that GCs just don't scale to large heaps. To use more memory, you need to either manage memory yourself (which not a lot of modern languages allow), or increase the number of independent heaps (by using more tasks/processes).

Please enlighten me if I'm wrong here.