SATA-IO Introduces the SATA v3.2 Specifications
A new revision of the SATA specification has been announced by the SATA-IO, and it comes with some very impressive new specifications.
The SATA-IO (Serial ATA International Organization) has announced the new SATA Revision 3.2 specification. The new standard will carry a number of awaited features.
For starters, the new specification will have support for the SATA Express standard. The SATA Express standard, in short, is the use of a PCIe bus to drive storage devices. While there have been PCIe based storage devices before, the SATA Express standard will unify the system and allow operating systems to get away with only needing one driver to use the devices. SATA Express will also allow devices to run at speeds of up to 2.0 GB/s, as compared to just 6 Gb/s for the SATA3 standard.
"SATA technology continues to evolve to accommodate ever-changing storage industry requirements. The updates featured in the revision 3.2 specification, such as SATA Express and enhancements for emerging solid state hybrid drives, are driven by current market trends. These new features demonstrate SATA-IO's ongoing commitment to providing low-cost, high-performance storage solutions," said Mladen Luksic, SATA-IO President.
mSATA (left) and M.2 (right)
The new standard will also hold the M.2 form factor, which is accepted as the next evolution of mini-PCIe. The M.2 form factor can do more than just accept storage devices. It also accepts WiFi cards, USB cards, WWAN cards, and more. Other features that will be found in the SATA 3.2 specification include DevSleep, USM, Transitional Energy Reporting, Hybrid Information, microSSD, and Rebuild Assist for reconstructing RAID arrays.
SATA-IO will be attending the Flash Memory Summit on August 13 through August 15 in Santa Clara, where we can expect more information to be released.
"SATA Express will also allow devices to run at speeds of up to 2.0 GB/s, as compared to just 6 Gb/s for the SATA3 standard."
- Any comment on SATA port location on motherboard? The current geometry can be inconvenient when a huge graphics card is installed.
2.0GB/S = 20Gb/S (aprox) so it is three and a bit times faster.
No... it doesn't. By using your math we could also say that 80% = 100% (aprox).
8bits in a Byte would be 2GB/s = 16gb/s, making it less than three times faster.
No... it doesn't. By using your math we could also say that 80% = 100% (aprox).
8bits in a Byte would be 2GB/s = 16gb/s, making it less than three times faster.
I believe SATA spec Gb/s is stated in 2^30 bits/s instead of 1x10^9 bits/s. For SATA3.0, 6Gb/s actually does give you 600MB/s taking into account for 8b/10b and some extra headroom. So I'm not surprise that SATAexpress 2GB/s is indeed 20Gb/s.
2.0GB/S = 20Gb/S (aprox) so it is three and a bit times faster.
This might actually be correct if 2GB/s is the actual realisable throughput.
There's about 25% overhead on SATA (which is why SATA III gives you 600 MB/s instead of 750 MB/s that you should get by direct conversion of 6 Gb/s), so if you're getting 2048 MB/s, then the actual interface provides 2048 x 1.25 = 2560 MB/s = 20,480 Mb/s = 20.48 Gb/s.
HOWEVER, since PCIe 3.0 only enables up to 8 Gb/s (GT/s, to be more accurate) and PCIe 4.0 enables 16 GT/s, I think SATA 3.2 enables a 16.38 Gb/s interface (2 GB/s x 8 bits per byte) and not 20 Gb/s.
Pretty sure it's called SATA.
No... it doesn't. By using your math we could also say that 80% = 100% (aprox).
8bits in a Byte would be 2GB/s = 16gb/s, making it less than three times faster.
I believe SATA spec Gb/s is stated in 2^30 bits/s instead of 1x10^9 bits/s. For SATA3.0, 6Gb/s actually does give you 600MB/s taking into account for 8b/10b and some extra headroom. So I'm not surprise that SATAexpress 2GB/s is indeed 20Gb/s.
First of all, binary units are almost never used when talking about communication speed,
The M and G here are metric not binary.
Also,
SATA 3.0 channel speed: 6Gb/s
SATA 3.0 actual data speed: 0.6GB/s not 0.75GB/s because of 8b/10b encoding
PCIe 3.0 channel speed: 8Gb/s per link
PCIe 3.0 actual data speed: 1GB/s per link because it's using the more efficient 128b/130b encoding
SATA Express = 2 lanes PCIe 3.0 = 16Gb/s = 2GB/s
The reason why the usable bandwidth is slightly lower than signaling rate is due to 64b66b encoding which expands each 64bits code word to a 66bits TMDS pattern. There are two reasons for using this encoding: prevent coupling capacitor saturation on differential links my guaranteeing an even distribution of 0s and 1s between bit groups and guaranteeing a minimum number of transitions to help receivers maintain reliable PLL lock on the bitstream.
Lower speed links often used 8b10b coding which yields a larger discrepancy between usable and line rates.
Some link-layer protocol rates are reported based on usable rate while others are reported based on signaling rate. IIRC, 100BaseTX and 1GBaseT/TX are rated based on usable link-layer bits - meaning the line signaling rate is higher - 125Mbps for 100BaseTX which uses 8b10b coding and 1031.25Mbps for 1GBase-TX (yes I know, 1GBase-T won) which uses 64b66b coding as do PCIe and most other high-speed serial links. The good old RS232 rate was based on signaling rate - every extra field you enable on that 115200 is one less bit available for actual data.
If they are going to start emulating SATA on PCIe, they should focus on native PCIe block storage and ditch SATA altogether. Similarly for USB3: if they are going to bring USB up to PCIe specs, might as well quit pussy-footing around and simply allow endpoints to negotiate native PCIe x1 on USB3 ports.
https://en.wikipedia.org/wiki/Serial_ATA