Webopedia on Google+Webopedia on TwitterWebopedia on FacebookTech Bytes Blog
Main » TERM » T »

TCQ

Short for tagged command queuing, a method of processing requests from a host device to a hard drive that is storing the data requested. TCQ was first introduced with the SCSI-2 standard as a way to allow hard drives to accept multiple concurrent commands from a host PC. When commands arrive at the drive's buffer, they are tagged with an identifier and then reordered by the drive��s microprocessor to minimize the distance the drive's read head needs to move laterally along the platter looking for data. For example, if a command is looking for data in one section of the drive and a following queued command is looking for data in a neighboring area, the SCSI host adapter can reorder the commands to make the two occur sequentially. This is a different system than SCSI-1 or IDE/ATA, which will allow only a single command to be outstanding at a time to any device and processes requests serially.

Tagged command queuing also is called command queuing and reordering.

Also see What's Inside a Hard Drive? in the Did You Know . . . ? section of Webopedia.







TECH RESOURCES FROM OUR PARTNERS
DID YOU KNOW?
11 Tips to Boost Your Wi-Fi Signal

It's not just your lawnmower and household tools that your neighbor won't return. Our top picks include everything from updating device firmware... Read More »

Interesting Times: Transformation in the IT Channel

Business transformation will remain the buzzword of the moment as channel firms continue to assess the direction of their companies in the age of... Read More »

What is a Virtual Private network (VPN)?

Companies and organizations will use a VPN to communicate confidentially over a public network and to send voice, video or data. Read More »

QUICK REFERENCE
29 Free Android Apps for Cash-Strapped Students

From wacky alarm clocks to lecture hall tools and after class entertainment, these Android apps are a good fit for a student's life and budget. Read More »

Network Fundamentals Study Guide

A network is a group of two or more computer systems or devices, linked together to share resources, exchange files and electronic communications.... Read More »

Computer Architecture Study Guide

This Webopedia  study guide describes the different parts of a computer system and their relations. Read More »