Tagged Command Queuing

Tagged Command Queuing ( TCQ ) is a property that was originally introduced with the SCSI -2 and later also with the ATA -4 specification. Similar to the Native Command Queuing ( NCQ) feature of the S- ATAII specification, it provides a hard drive, for an acceleration of the read / write operations.

If there are, for example, multiple read requests in the command queue (English: Command Queue ), it is first each request with a marker ( engl. "tag" ), which corresponds to the place in the queue. Then, the hard disk controller to sort the requirements so that the total time of all requirements is minimized.