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?
Hype Versus Action in the Developer's World

Often times technologies start as hype but with time become adopted. As a developer or technologist, it is worth reading the hype and knowing the... Read More »

Microsoft Hyper-V Network Virtualization Q&A

The top 5 Hyper-V questions with answers provided by Nirmal Sharma, a MCSEx3, MCITP and Microsoft MVP in Directory Services. Read More »

Storage Trends: Solid State and Software Defined

Solid state drives and software defined storage are two leading trends in the rapidly growing storage market.  Read More »

QUICK REFERENCE
How to Create a Desktop Shortcut to a Website

Creating desktop shortcuts to a websites is useful. When you double-click the icon from your desktop it automatically launches the browser and... Read More »

Flash Data Storage Vendor Trends

Although it is almost impossible to keep up with the pace of ongoing product releases, here are three recent highlights in the flash data storage... Read More »

15 Important Big Data Facts for IT Professionals

Keeping track of big data trends, research and statistics gives IT professionals  a solid foundation to plan big data projects. Here are 15... Read More »