After this Gen 1 effort, the second generation (Gen 2) effort defined a whole series of optional features to enhance and improve the first SATA specification. First there was a Serial ATA organization working group that authored the SATA 1. One of these enhanced optional features was the Gen 2 PHY, which has double the speed of first generation and is 3Gbps. 5Gbps. 0a specification, which supports a first generation (Gen 1) PHY at 1.

Staggered Spin-Up?

It is possible to put a RAID controller behind a SATA host port and provide protected performance striping as well. In summary, if you want to fully utilize your SATA host port, then a port multiplier can provide expanded storage capacity and enhanced performance.

Can I use, a 3Gbps Gen 2 PHY?

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“NCQ can also improve your overall system performance from booting your system to file copying.

But, if your host controller supports port packet steering and supports bandwidth aggregation, then the port multiplier acts like a performance striped array and can effectively utilize the SATA host port bandwidth. Based on these numbers, it would take about three drives to effectively utilize a single SATA Gen 1 port. The average drive supports about 50-60MBbps, and a single SATA Gen 1 port is capable of 150MB/s peak bandwidth. So, if your host controller supports only port packet steering and does not support bandwidth aggregation, then the port multiplier acts like a JBOD interface without any performance aggregation.

[FIGURE 1 OMITTED]

There is a flash demo on the SATA IO site that reads:

Do I Need a Port Multiplier?

As for reliability, the drive moves less to deliver the same data request, and this will produce less heat and less mechanical wear and tear. org/featureofmonth. asp, there is an article discussing the NCQ feature. If you look at the SATA website www. So, the reliability improvement is a result of a more optimized system operation–very logical, but I have not seen any measurement data as of yet. NCQ stands for native command queuing and is designed to improve storage performance and reliability. If your host controller supports the NCQ protocol and the drive supports it as well, then your drive performance and reliability can be increased.

This article has some performance data that states a performance improvement of 9-12% over a non-NCQ drive. The drive can optimize (re-order) the completion of multiple commands to reduce mechanical workload and improve performance. sataio.

The hard drive on the right without NCQ, requires two, and three quarters complete rotations to execute the same four commands (A, B, C, and D) as a result of poor ordered operations. “

“The hard drive on the left, with NCQ, can execute four commands (A, B, C, and D) with one and a quarter complete rotations due to proper ordering of the operations.

The Gen 2 PHY can deliver 300MB/s peak bandwidth, and this means it would take a device that supports port packet steering, bandwidth aggregation and at least six drives to fully utilize a Gen 2 PHY host SATA port. Most system host motherboards do not support a Gen 2 PHY, and a separate card is needed to upgrade the system.

In summary, if you need to replace or add drives while your system is operating, use the Hot Plug feature.

0a be good enough for the needs of my system? The group has reformed and is now called the SATA IO (international organization). This Gen 2 PHY began to be called SATA II by the press in the market. “

Some of the new enhanced optional features also began to be called SATA II by the press, even if the product had a Gen 1 PHY. So I will go through the key enhanced optional SATA features, one at a time, and address the real question: “Do I need the new enhanced optional features of SATA or would SATA 1. Currently there is confusion in the market as to what is meant by SATA II. Some of the other key enhanced SATA features were published by the SATA II working group in several specifications and included Native Command Queuing (NCQ), Port Multiplier, Staggered Spin Up, Port Selector External, SATA, and Hot Plug.

In summary, if you need more performance and improved reliability, a NCQ system design is your ticket.

Does NCQ Provide a Real Advantage?

0a specification. This feature allows for drives to be added or removed without any downtime for your system design.

Hot plug requires a focus on upgraded cables and improved signaling from the original SATA 1.

[FIGURE 2 OMITTED]

In summary, if you want to fully utilize your SATA Gen 2 host port, then a port multiplier or another similar device can provide expanded storage capacity and enhanced performance.

Many host ports do not support the port packet steering control bits necessary to make the port multiplier work. Once you have verified that your host controller supports port packet steering, then you might want to test for the next feature called bandwidth aggregation. When a port multiplier is added to a single SATA port, a single host port can access up to 15 drives.

Hot Plug?

The load on the power supply is one issue with system design when using multiple drives. One of the peak loads happens at spin-up and can worsen if all the drives spin-up at the same time. This SATA feature staggers the spin-up to lower the load on the power supply.