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Thread: The Pesky PWDIS Feature in Newer SATA Specs (and how it relates to PSUS)

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    Default The Pesky PWDIS Feature in Newer SATA Specs (and how it relates to PSUS)

    http://www.tomshardware.com/news/hdd...ure,36146.html

    During our (ongoing) evaluation of a Seasonic Prime Ultra power supply (PSU), we noticed a small detail that previously escaped our attention: the existence of the power disable (PWDIS) feature in HDDs that follow the newer SATA 3.3 (announced on February 16, 2016) and SATA 3.2+ specifications.

    This feature utilizes the third pin (P3) of the SATA connector, which in the older SATA specifications is tied to the first (P1) and second (P2) pins, and all of them carrying the 3.3V rail to the drive in use.

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    We had that discussion some time ago when Jeremy's Seasonic review came out.

    - The spec is stupid, but for some enterprise drives only, not for mainstream. (Thats why they decided on this stupid abuse of 3.3V)
    - So far, I saw only Seasonic include ONE adaptor, no other company doing it
    - Anyone who has such a drive, cut the 3.3V wire (voiding warranty) or use a SATA 2/3 to SATA 1 or a PATA to SATA 1 adaptor

    This is going to be as impactful as MicroSTX or eSATA

    Merry Christmas

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    So the original Cougar CM units were very future proof because they didn't have the 3,3V rail connected on the S-ATA connector...
    Well, wasn't really used much anyway...

    And its a pretty much useless rail...

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    SATA 1 = no 3.3V, SATA 2 got it added, but few manufacturers utilized it. (SATA 1 connectors have 4 cable wires like a PATA)
    Thats why in SATA 3.2 they can mis-use the 3.3V pins as the PWDIS.

    So any SATA 1 PSU is SATA 3(.3), just nobody sells them anymore since 2006 or whenever SATA 2 started. SATA 2's 3.3V got adopted at lightspeed compared to the drop of -5V with ATX12V 1.3!!!

    That is why when SATA 2 was introduced companies highlighted on their collateral if their SATA included 3.3V.

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    And to be more precise, of course you need the 3.3V for PWDIS, so that PATA adaptor renders the feature useless. I just call it SATA 1, which is totallyy misleading but catches the point.

    PWDIS is for datacenters, when you wanna do a hardreset without disconnect.

    For NAS drives nobody needs PWDIS, he has a reset button on the NAS.

    I am just mentally in Christmas mood already

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    I know this is old, but I got bitten by this with a set of Hitachi SAS drives. It took me a while, but I figured out I had to cut that wire to make the drive work.

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    How hard could it possibly be for companies to just start leaving pin 3 open in the SATA connectors for consumer PSUs? It's not like they have to stop supplying 3.3V to pins 1 and 2 or anything, just pin 3...

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