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Hitachi Global Storage to Demo First 12Gb/s SAS SSD

By - Source: HGST | B 23 comments

Hitachi Global Storage Technology (HGST), which was recently acquired by Western Digital, claims to be first with a demonstration of the first 12Gb/s SAS SSD. The company will be unveiling the device at the SCSI Trade Association Technology Showcase, which take place in Santa Clara on May 9.

As the name indicates, the drive is theoretically capable of transferring data at 12 Gb/s - twice the rate of current 6 Gb/s drives - which translates to a total bandwidth of 4.8 GB/s.

“We have successfully achieved interoperability between our 12Gb/s SAS drive and 12Gb/s SAS HBAs and expanders from both LSI and PMC-Sierra,” said Brendan Collins, vice president of HGST product marketing, in a prepared statement. “Meeting these interoperability milestones is critical when preparing the industry for the adoption of a new interface standard."

HGST said that it expects market adoption of 12 Gb SAS drives in 2013.

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  • 18 Hide
    TidalWaveOne , May 2, 2012 12:45 AM
    Since when does 12 Gb/s equal a total bandwidth of 4.8 GB/s? My math must be off (or someone who wrote this piece).
Other Comments
  • 8 Hide
    blazorthon , May 2, 2012 12:36 AM
    Isn't SATA 6Gb/s 600MB/s maximum and SAS 6Gb/s equal to SATA 6Gb/s in bandwidth? So shouldn't SAS and SATA 12Gb/s be 1.2GB/s per port? It should take four such ports to hit 4.8GB/s as a theoretical maximum.
  • 1 Hide
    drwho1 , May 2, 2012 12:42 AM
    are we talking sata 4?
  • Display all 23 comments.
  • 18 Hide
    TidalWaveOne , May 2, 2012 12:45 AM
    Since when does 12 Gb/s equal a total bandwidth of 4.8 GB/s? My math must be off (or someone who wrote this piece).
  • 6 Hide
    tului , May 2, 2012 1:05 AM
    This is SAS 12Gbps, but I would imagine SATA 12Gbps won't be far behind. Given that the current Sandforce SSDs can saturate 6Gbps SATA now it is needed.
  • -4 Hide
    prononbiasedgamerenthusiast , May 2, 2012 1:21 AM
    Sandforce controllers rely on better flash
  • -8 Hide
    cbrunnem , May 2, 2012 1:21 AM
    TidalWaveOneSince when does 12 Gb/s equal a total bandwidth of 4.8 GB/s? My math must be off (or someone who wrote this piece).


    Gb/s is not the same as GB/s
  • 3 Hide
    Anonymous , May 2, 2012 1:29 AM
    this probably refer to sas wide port which consists of 4 ports to achieve 4.8GB/s. For this SSD, i don't think they use wide port, so the theoretically, it can goes as high as 1.2GB/s.
  • 5 Hide
    kinggremlin , May 2, 2012 2:30 AM
    TidalWaveOneSince when does 12 Gb/s equal a total bandwidth of 4.8 GB/s? My math must be off (or someone who wrote this piece).


    As is typically the case with news bits here, this is woefully short on details or expected further explanations.

    Peak performance of 6Gb/s SAS is actually 24Gb/s using link aggragation which basically bundles 4 ports together. Like other current serial interfaces (SATA/USB), for every 10bit packet, 8bits are actually data. So out of the theoretical bus transfer limit of 3GB/s, 2.4GB/s would be the usable data transfer rate. Just double this to get the 4.8GB/s rate quoted in this article for the new 12Gb/s SAS standard.
  • 2 Hide
    alphaalphaalpha , May 2, 2012 2:33 AM
    For everyone who's wondering, SATA has an 8/10 bit encoding (in order to transfer eight bits of data aka one byte, it encodes that eight bits into a ten bit word for improved error correction), so 6Gb/s in SATA means 600MB/s for real data transfer (MB meaning 1000^2 instead of 1024^2), so 6Gb/s means 600MB/s in maximum theoretical transfer bandwidth. SATA also happens to be full duplex, so it's 600MB/s in both ways (to and from the hard drive).

    SATA and SAS have the exact same bandwidths. So, if this is an SAS or a SATA 12Gb/s device, it means that at best, it can transfer at 1.2GB/s. In order for it to have 4.8GB/s, it would need at least four SATA/SAS 12Gb/s ports.

    So yes blazorthon, you're right. Another example of an interface that uses 8/10 encoding is PCIe, that is up until the PCIe 3.0 specification which has a 128/130 bit encoding. IE, a PCIe 2.0 lane has a 5Gb/s connection between the two devices on either end, but only 4Gb/s is actually usable for transferring data between either side because the extra 1Gb/s is used for error correction in the data. PCIe has an 8Gb/s connection, but it's change to a 128/130 bit encoding allows it to have an almost double the bandwidth of PCIe 2.x.

    Yet another common interface that uses 8/10 is USB.
  • -1 Hide
    kronos_cornelius , May 2, 2012 2:38 AM
    Thanks for the discussion on what the speed means commenters. It remains a better choice to just pick a high transfer PCIe SSD since those speeds are well above 600MB/s.
  • 0 Hide
    alphaalphaalpha , May 2, 2012 3:37 AM
    Quote:
    Thanks for the discussion on what the speed means commenters. It remains a better choice to just pick a high transfer PCIe SSD since those speeds are well above 600MB/s.


    Not everyone wants to spend a huge premium for a PCIe drive when it probably won't help most people (not even most consumer SSD users) much more than a SATA SSD does. The whole point of the SSDs is to be far better than a hard drive. Any improvements after that only help greatly for more specific tasks and are usually not justifiable purchases for most consumers.
  • 0 Hide
    madooo12 , May 2, 2012 10:08 AM
    it thought to translate Gb/s to GB/s you should divide by 8 not 10 (number of bits in a byte)?
  • 0 Hide
    enforcer22 , May 2, 2012 10:21 AM
    cbrunnemGb/s is not the same as GB/s


    everyone here seems to know that.

    frozonicGb= Gigabit GB= Gigabyte, a Byte is = 8 bits (Byte is a contraction of two words "By Eight") so, 12Gb/s = 1.5GB/s or 1500000 KB/s


    while not totally accurate this is correct. But i do believe sas uses multi channels so the artical could be correct.
  • -1 Hide
    notsleep , May 2, 2012 11:28 AM
    wow. people still use scsi hard drives?
  • 0 Hide
    ramicio , May 2, 2012 1:03 PM
    notsleepwow. people still use scsi hard drives?


    SAS is not the old SCSI you're thinking of. It's uses the same connectors as SATA. It has tons more features. It recognizes SATA drives. It's full-duplex instead of half (SATA).
  • 0 Hide
    ramicio , May 2, 2012 1:05 PM
    alphaalphaalphaFor everyone who's wondering, SATA has an 8/10 bit encoding (in order to transfer eight bits of data aka one byte, it encodes that eight bits into a ten bit word for improved error correction), so 6Gb/s in SATA means 600MB/s for real data transfer (MB meaning 1000^2 instead of 1024^2), so 6Gb/s means 600MB/s in maximum theoretical transfer bandwidth. SATA also happens to be full duplex, so it's 600MB/s in both ways (to and from the hard drive).SATA and SAS have the exact same bandwidths. So, if this is an SAS or a SATA 12Gb/s device, it means that at best, it can transfer at 1.2GB/s. In order for it to have 4.8GB/s, it would need at least four SATA/SAS 12Gb/s ports.So yes blazorthon, you're right. Another example of an interface that uses 8/10 encoding is PCIe, that is up until the PCIe 3.0 specification which has a 128/130 bit encoding. IE, a PCIe 2.0 lane has a 5Gb/s connection between the two devices on either end, but only 4Gb/s is actually usable for transferring data between either side because the extra 1Gb/s is used for error correction in the data. PCIe has an 8Gb/s connection, but it's change to a 128/130 bit encoding allows it to have an almost double the bandwidth of PCIe 2.x.Yet another common interface that uses 8/10 is USB.


    It's nothing to do with 1,000 vs. 1,024. It's that there are 10 bits per byte instead of 8.
  • -1 Hide
    cirdecus , May 2, 2012 1:29 PM
    blazorthonIsn't SATA 6Gb/s 600MB/s maximum and SAS 6Gb/s equal to SATA 6Gb/s in bandwidth? So shouldn't SAS and SATA 12Gb/s be 1.2GB/s per port? It should take four such ports to hit 4.8GB/s as a theoretical maximum.


    Yeah i was wondering that too :)  6000/8 = 750MB/s maximum for SATA3 so you're only looking at 1.5MB/s for this new 12Gbps speed, not 4.8! Silly Toms!
  • 0 Hide
    yumri , May 2, 2012 2:05 PM
    what i am wondering is how they came up with the super fast adoption of this technology even if it is fully backwards compatible most likely the severs which will be using it will have to have no SAS RAID cards installed as SAS is usually not a standard feature on any motherboard and SAS cards cost a bundle even with that they just upgraded to SAS 6Gbps if they even did that thus the time for them to do another upgrade will be in like another 5 or so years since sever hardware is built to last alot longer then consumer hardware.
    But if the 12Gbps SAS drive is aimed at the consumer market i will be wondering where they are getting consumer boards have a SAS port to hook it up to and even if they do the SAS controller cards are still almost as much as buying another hard drive.
    Very good step in hard drive transfer speed but timing is not that good in the development for it. Also how is it in RAID 3, 5, 6, 8 and 10?
  • 0 Hide
    blazorthon , May 2, 2012 2:31 PM
    yumriwhat i am wondering is how they came up with the super fast adoption of this technology even if it is fully backwards compatible most likely the severs which will be using it will have to have no SAS RAID cards installed as SAS is usually not a standard feature on any motherboard and SAS cards cost a bundle even with that they just upgraded to SAS 6Gbps if they even did that thus the time for them to do another upgrade will be in like another 5 or so years since sever hardware is built to last alot longer then consumer hardware.But if the 12Gbps SAS drive is aimed at the consumer market i will be wondering where they are getting consumer boards have a SAS port to hook it up to and even if they do the SAS controller cards are still almost as much as buying another hard drive.Very good step in hard drive transfer speed but timing is not that good in the development for it. Also how is it in RAID 3, 5, 6, 8 and 10?


    Most servers have SAS connectivity, be it through the motherboard, or through a PCIe RAID card and it's fairly cheap to replace a RAID card if you sell the current one, or at least put it to use somewhere else. It's even better if you just use this drive in new systems instead of upgrading old systems. No SAS drive is aimed at the consumer market. You're not supposed to RAID most SSDs. This has nothing to do with hard drives and is not a hard drive.

    CirdecusYeah i was wondering that too 6000/8 = 750MB/s maximum for SATA3 so you're only looking at 1.5MB/s for this new 12Gbps speed, not 4.8! Silly Toms!


    Divide by ten, not eight. SATA, like many other serial interfaces, uses 8/10 bit encoding and thus each 8 bit byte of data transferred is transferred as a ten bit byte for improved error correction. So, it maxes out at 600MB/s. SAS does the same. That's why no SATA6Gb/s and SAS6Gb/s SSDs can ever breach 600MB/s. A single SAS 12Gb/s port can hit 1.2GB/s as a maximum theoretical transfer speed. Four SAS ports can hit 4.8GB/s in maximum theoretical aggregate throughput.
  • 0 Hide
    WyomingKnott , May 2, 2012 7:29 PM
    On the other hand, the article only refers to interface bandwidth. You need an SSD that can handle data faster than the old interface for this to be really useful. Can the SSD out-perform the existing interfaces?

    Not that I'm knocking the development of the new interface. You need both the interface and the storage for a system to work.
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