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Serial ATA
"Serial ATA (SATA)" is a storage interface specification designed for high-speed serial communication.
As part of our IP Core line-up, our ASIC products provide Serial ATA solutions best suited for your needs.
| What is Serial ATA? | Features of NEC Electronics' IP Core |
What is Serial ATA?
The widespread popularity of broadband and digital media has fuelled a dramatic expansion in hard-disk applications. Moreover, the rising density and speed of hard-disk drives is creating an increased demand for host-drive interfaces with faster transfer rates.
Until recently, the Parallel ATA interface was the most common type of storage device interface. However, as hard-disk data transfer rates started approaching the Parallel ATA interface's maximum transfer rate, the performance improvement reached a technical limit, and thus a breakthrough in storage device interface technology was needed. It was at this point, in 2001, that with an eye to the future, a scalable, performance-enhancing interface standard-Serial ATA-was established.
Serial ATA is downward-compatible with Parallel ATA at the software level, but with the adoption of high-speed data transfer technology for its I/O interface, it is capable of transferring data at 300MB/s (3.0Gbps), 2.25 times the rate of Parallel ATA (UltraATA/133). Serial ATA also offers improved reliability, and is more compact. By 2005, Serial ATA has become the de-facto standard PC storage interface, and is now expected to become the mainstream storage interface for digital home appliances. The upcoming SATA 3.0 specification promises further improvement in performance to 600MB/s, and is scheduled to be finalized by the end of 2008.
Serial ATA vs. Parallel ATA
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Notes
- PM: Port multiplier
Enables an increase in the number of connectable devices. Similar to Ethernet or USB hub. - PS: Port selector
A switch used to share a device between two hosts. Usually used to raise the reliability of the system by switching to the remaining host when one of two hosts is faulty, thus creating a "fault-tolerant" system. - Number of connected HDDs
Although not restricted in either specifications of Serial ATA or Parallel ATA, this number is estimated as the practical limit per host.
It is assumed that in the case of Serial ATA, a 1-to-15 port multiplier (PM) is connected to each channel of an 8-channel host. - Command queuing
A method whereby several commands are issued by the host without waiting for completion of disk reading/writing by the HDD device. The HDD device reads/writes the disk in the optimal order, thus improving the performance. TCQ (tagged command queuing) used by Parallel ATA did not gain popularity because hard-disk manufacturers disliked the effect-reducing large overhead. However, with NCQ (native command queuing) used by Serial ATA, manufacturers had an input from the initial specification creation stage, resulting in a large number of vendors expressing support.
Features of NEC Electronics' IP Core
NEC Electronics provides IP Core for the "Serial ATA" storage interface specification, as well as consultation and technical support for its implementation.
- Conform to SerialATA2.6
- Provides the physical layer (PHY), link layer, transport layer, and some application layers. Integrated cores with interfaces (DMA, on-chip bus I/F) with the application layer are also available for the host controller.
