Due to a perceived need that hardware manufacturers should provide the widest compatibility possible, legacy hardware generally remain entrenched for longer than it should. This can be observed for the AGP graphics interface and the same scenario is now happening with PATA (or IDE as it is more commonly known), which is gradually being supplanted by SATA. Despite the fact that most new motherboards now usually come with more SATA ports than IDE ones (Intel's new chipsets only have SATA interface), there is still a rather healthy market for IDE drives and more so when it comes to optical drives.



Link: HardwareZone