Native command queuing

from Wikipedia, the free encyclopedia
Native command queuing

Native Command Queuing ( NCQ translated integrated command ranking ) is a technique that was developed to improve the performance of hard drives to improve under certain conditions.

Functions

NCQ enables several requests to be sent to the hard disk at the same time and it then decides for itself in which order it processes them. By avoiding unnecessary head movements, throughput and, above all, latency can be improved. The drive itself, the controller and the driver must support command queuing in order to use it.

Due to the delays caused by NCQ, it is also possible that this procedure can lead to poorer access times for some applications. The phenomenon can occur in games and sequential reads.

Seagate introduced Native Command Queuing in 2003 for SATA drives. Apart from small differences, it is similar to Tagged Command Queuing (TCQ), which has been supported by SCSI drives since the early 1990s . Unusual for ATA drives, TCQ was only introduced by IBM in 2002 (IBM Deskstar 180GXP), but hardly used due to lack of support from the controller side.

Web links