command queuing


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command queuing

Storing multiple commands and executing them in the most efficient order. See NCQ.
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Definition of system-level device activity SATA command queuing, extended differential voltage ranges and LED behavior are included in the extensions.
SCSI disks also use sophisticated command queuing and reordering algorithms with multiprocessor architectures to improve the number of IOPS a drive can deliver.
DRIVE COMPARISON TABLE SATA PERFORMANCE (Access to Data) Latency + Seek Time 13msec @ 7200rpm Command Queuing and Reordering LBA based Rotational Vibration 5 rads/sec/sec Typical I/Os per sec/drive (no RV) 77 Typ I/Os per sec/drive 35 (10 rad/sec (2)) Typ I/Os per sec/drive < 7 (20 rad/sec (2)) Duplex Operation Half CUSTOMIZATION Unique Code and Hardware Limited Variable Sector Sizes No Mode Page Parameter Control No Inquiry Data No Diagnostic Pages No Capacity Controls No INDICATORS Activity LED No Fault LED No RELIABILITY MTBF 600K Hrs Duty Cycle 8 X 5 Interactive Error Management No Internal Data Integrity Checks No Dual Port No Serial Attached SCSI or Fibre Channel PERFORMANCE (Access to Data) Latency + Seek Time 5.
Though Ultra ATA supports a command queuing algorithm, it is rarely incorporated into devices, and thus the data bus is locked if a command to either drive is outstanding.
Including support for features such as Native Command Queuing and Asynchronous Notification, Mentor is ensuring their customers will continue reducing time to market with storage-based products, including hard and optical disk drives, network storage applications and consumer electronics.
Higher performance: Nearline drives include several performance enhancing features, including optimized command queuing and full duplex access.
Command queuing allows multiple requests to be issued concurrently to one or more devices on a bus and permits those devices to reorder those requests prior to their execution to reduce latency and enhance throughput.
The SATA platform used for interoperability testing included Mentor's updated SATA Host and Device Controllers with optional support for Native Command Queuing (NCQ) and Asynchronous Notification along with all the mandatory features of the SATA Revision 2.
0Gb SATA II features including native command queuing (NCQ), staggered spin up, hot-plug and asynchronous signal recovery.
These tables show an access density improvement over a queue depth of 1 when command queuing to the device is implemented.
It features a SATA 3Gb/s interface with native command queuing (NCQ) and many additional SATA features.
Powering Seagate's market leadership are its Barracuda 7200-RPM SATA disc drive family with Native Command Queuing (NCQ), a technology that increases performance and disc drive reliability by optimizing the way the drive processes data.

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