Is the elevator disk scheduling algorithm the same as NCQ?

Is there any differ开发者_如何转开发ence between these two? Both of them has an entry in Wikipedia, but I don't see any difference between them?

NCQ is a mechanism to enqueue multiple requests to a disk for it to handle them in some preferred order. The classic elevator scheduling algorithm is one possible way to reorder a queue full of I/O requests. The former is a hardware mechanism tied to a disk, the latter is a software algorithm that may be performed by the OS or the disk.