Seagate ST3500830A Serial ATA Native Command Queuing (670K, PDF)
Seagate ST3500830A - 500GB UDMA/100 7200RPM 8MB IDE Hard Drive Manual
![]() |
UPC - 683728089030
View all Seagate ST3500830A manuals
Add to My Manuals
Save this manual to your list of manuals |
Seagate ST3500830A manual content summary:
- Seagate ST3500830A | Serial ATA Native Command Queuing (670K, PDF) - Page 1
July 2003 Serial ATA Native Command Queuing An Exciting New Performance Feature for Serial ATA A JOINT WHITEPAPER BY: Intel Corporation and Seagate Technology www.intel.com www.seagate.com - Seagate ST3500830A | Serial ATA Native Command Queuing (670K, PDF) - Page 2
Serial ATA NCQ thereby creating higher performance applications. Introduction Accessing media on mass storage devices, such as hard disc drives (HDD protocol in Serial ATA that allows multiple commands to be outstanding within a drive at the same time. Drives that support NCQ have an internal - Seagate ST3500830A | Serial ATA Native Command Queuing (670K, PDF) - Page 3
ATA Native Command Queuing sides of the discs, is collectively called a cylinder. Thus, data is laid out across the discs sequentially in cylinders starting from the outer diameter of the drive trivial as it may sound, most of today's hard drives in the desktop environment still operate exactly in - Seagate ST3500830A | Serial ATA Native Command Queuing (670K, PDF) - Page 4
but instead takes into account the rotational position of the drive head in determining the best command to service next. A second-order optimization is to use a providing the additional benefit of improved endurance. Serial ATA II provides an efficient protocol implementation of tagged command queuing called - Seagate ST3500830A | Serial ATA Native Command Queuing (670K, PDF) - Page 5
command into the DMA engine, and the transfer can proceed without any software intervention. This is the means by which the drive can effectively re-order defined. There are two NCQ commands that were added as part of the NCQ definition in Serial ATA II, Read FPDMA Queued and Write FPDMA Queued. The - Seagate ST3500830A | Serial ATA Native Command Queuing (670K, PDF) - Page 6
Low (exp) LBA 39:32 Cylinder High LBA 23:16 Cylinder High (exp) LBA 47:40 Device/Head FUA 1 Res 0 Reserved Command 60h Figure 1 host and the device to identify a particular outstanding command. Tag values can be between 0 and 31, although the drive can report support for a queue depth - Seagate ST3500830A | Serial ATA Native Command Queuing (670K, PDF) - Page 7
ATA Native Command Queuing To program the DMA engine for a data transfer, the drive issues a DMA Setup FIS to the host, shown in Figure 2. There are a few key fields in the DMA Setup FIS that are important for programming the DMA engine . Analogously, drives cannot send a Set Device Bits FIS before - Seagate ST3500830A | Serial ATA Native Command Queuing (670K, PDF) - Page 8
to generate only one interrupt. Since the drive can return a Set Device Bits FIS without a host handshake, it is possible to receive two Set Device Bits FISes very close together in time. If the second Set Device Bits FIS arrives before host software has serviced the interrupt for the first, then - Seagate ST3500830A | Serial ATA Native Command Queuing (670K, PDF) - Page 9
Serial ATA Native Command Queuing an event to be signaled or by receiving a callback. Since the call returns immediately, the application can continue to do useful work, - Seagate ST3500830A | Serial ATA Native Command Queuing (670K, PDF) - Page 10
Serial ATA Native Command Queuing &overlap); // Contains event and offset for asynchronous // operation // // Make sure there was NCQ are realized when a queue of commands is built up in the drive such that the drive can optimally re-order the commands to reduce both seek and rotational latency. - Seagate ST3500830A | Serial ATA Native Command Queuing (670K, PDF) - Page 11
the Advanced Host Controller Interface (AHCI) definition. Amber holds a BSE in Computer Engineering from the University of Michigan and has been with Intel for 6 years. Joni Clark, Product Marketing Manager, Seagate Technology Joni Clark is a product marketing manager for desktop interfaces at - Seagate ST3500830A | Serial ATA Native Command Queuing (670K, PDF) - Page 12
Serial ATA Native Command Queuing 12
![](/manual_guide/products/seagate-st3320620a-serial-ata-native-command-queuing-670k-pdf-0919eea/1.png)
July 2003
Serial ATA
Native Command Queuing
An Exciting New Performance Feature for Serial ATA
A JOINT WHITEPAPER BY:
Intel Corporation and Seagate Technology
www.intel.com
www.seagate.com