New 'SATA Express' spec supports speeds up to 16Gb/s
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The Serial ATA International Organization (SATA-IO) has announced the development (PDF) of a new standard that combines SATA software infrastructure with the PCI Express interface. Colloquially dubbed "SATA Express," the new technology will allow manufacturers to create devices that can tap into the bandwidth of PCIe slots while remaining compatible with existing SATA applications.
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Read more here -
New 'SATA Express' spec supports speeds up to 16Gb/s
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After reading a certain line in the article, I was left confused. I ask a question in the comment area 3 days ago and have not received an answered.
This is the line that confuses me.
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The amalgamation will offer an affordable way to provide devices with interface speeds of 8Gb/s and 16Gb/s (one lane via PCIe 2.0 or two via PCIe 3.0)
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It is known that PCIe 3.0 effectively doubles PCIe 2.0 per lane of traffic.
Wikipedia link -
PCI Express
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PCIe 2.0 delivers 5 GT/s, but employs an 8b/10b encoding scheme which results in a 20 percent ((10-8)/10) overhead on the raw bit rate. PCIe 3.0 removes the requirement for 8b/10b encoding and instead uses a technique called "scrambling" in which "a known binary polynomial is applied to a data stream in a feedback topology. Because the scrambling polynomial is known, the data can be recovered by running it through a feedback topology using the inverse polynomial"[18] and also uses a 128b/130b encoding scheme, reducing the overhead to approximately 1.5% ((130-128)/130), as opposed to the 20% overhead of 8b/10b encoding used by PCIe 2.0. PCIe 3.0's 8 GT/s bit rate effectively delivers double PCIe 2.0 bandwidth.
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My confusion is that there is only a X2 factor between 8GB and 16GB. If SATA 3.0 is double the rate of SATA 2.0 then using two lanes should have a X4 factor. If this is so then wouldn't both 8GB and 16GB be using the same PCIe standard or the same number of lanes.
This quote from
SATA-IO would suggest that SATA Express only uses PCIe 3.0.
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The SATA Express specification provides SSD and hybrid drive manufacturers the advantages of performance and scalability enabled by PCIe 3.0
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I'm thinking the article mentioning "one lane via PCIe 2.0" is flawed. What are your thoughts on the topic?
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