[stonemetal]

Nothing in the definition of Garbage Collection says it must be a separate post processing step. Therefore reference counting is in fact a garbage collection mechanism. Just because it is an eager algorithm rather than the usual lazy one doesn't change what it does, collect garbage in the system.

[marshray]

Nothing in the definition of Garbage Collection says it must be a separate post processing step.

My impression (based on reading up on the state-of-the-art some years ago) was that an actual concurrent-with-normal-execution GC needed to resort to putting a write barrier in front of the useful thread of execution much of the time. This would cause a noticeable perf hit.

There were architectures designed with hardware support for this kind of thing, but chips without it left them in the dust. Whether or not that is an accident of history or for a reason is an interesting discussion.

[yid]

Right, and garbage collection is just lazy memory manamgement--you go see it either way, so this whole point is rather pedantic.