Native Command Queuing

Why Trust Techopedia

What Does Native Command Queuing Mean?

Native command queuing (NCQ) is a technology enabling SATA hard drives to accept more than one command at a time by optimizing the order in which read and write commands are executed. This increases the performance of the drive by limiting the number of drive head movements when multiple read/write requests are queued.

Advertisements

Techopedia Explains Native Command Queuing

NCQ replaces tagged command queuing (TCQ), which is used with parallel ATA (PATA). The manner in which TCQ interacts with the operating system (OS) taxes the CPU in return for little performance gain.

Both in the hard drive and in the SATA host bus adapter, NCQ must be supported and enabled and the proper driver must be loaded into the OS. Some OSs include the required generic drivers (such as Windows Vista and Windows 7) whereas others require vendor-specific drivers to be loaded to enable NCQ, like Windows XP.

NCQ may also be used in solid-state drives (SSDs), drives containing data in non-volatile memory chips and contain no moving parts. Here, latency (the delay in processing commands) is found on the host not on the drive. The drive uses NCQ to ensure it has commands to process while the host adapter is processing CPU tasks.

Advertisements

Related Terms

Margaret Rouse
Technology expert
Margaret Rouse
Technology expert

Margaret is an award-winning writer and educator known for her ability to explain complex technical topics to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles in the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret’s idea of ​​a fun day is to help IT and business professionals to learn to speak each other’s highly specialized languages.