by Anton Shilov
05/06/2004 | 05:35 AM
Seagate Technology is promising to deliver its hard disk drives with support for Native Command Queuing – a technology that boosts performance of Serial ATA-150 drivers.
NCQ technology enables the hard drive to intelligently reorder and optimize both read and write command execution, improving the performance of queued workloads by minimizing mechanical positioning latencies on the drive.
NCQ is a command protocol in Serial ATA that can only be implemented on native Serial ATA hard drives. It allows multiple commands to be outstanding within a drive at the same time. Drives that support NCQ have an internal queue where outstanding commands can be dynamically rescheduled or re-ordered, along with the necessary tracking mechanisms for outstanding and completed portions of the workload. NCQ also has a mechanism that allows the host to issue additional commands to the drive while the drive is seeking for data for another command.
NCQ also allows the drive to set up the direct memory access (DMA) operation for a data transfer without host software intervention. This is also called first party DMA - it means that the device is capable of complex sequences of operations without CPU intervention. The drive itself knows the current angular and rotational position of the drive head. The drive then selects the next data transfer to minimize both seek and rotational latencies.
While some HDDs from Seagate Technology were reported to sport NCQ tech back in 2003, the volume shipments of hard disk drives with the technology are only expected to begin next month, Seagate said at WinHEC this week.