SAS2 6G Connectors

Elliott, Robert (Server Storage) Elliott at hp.com
Thu Dec 10 12:22:44 PST 2009


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r0912102_f.htm">HTML-formatted message</a>

Cables are divided into two categories:
a) up to 6 m; these cables do not include key 3.
    - All SAS-1 and SAS-2 phys are expected to work with these short cables.
b) 6 m to 10 m; these cables include key 3.
    - SAS-1 phys are not expected to work with these long cables.
    - SAS-2 phys are expected to work with these long cables.
SAS-1 receptacles do not include key slot 3. This prevents long cables from
being attached; only short cables fit.
SAS-2 receptacles include key slot 3. This allows both short and long cables
to be attached.
Possible reasons that a SAS-2 phy might use the SAS-1 receptacle include:
    - the key/key slot definition arrived too late in SAS-2 to make it into
the product release.
    - the phy was not validated with enough other phys for the vendor to be
confident about including the key slot in the product release.	There was a
one-year gap between STA plugfests.
    - the phy is not completely compliant with SAS-2. The transmitter or
receiver might have issues that aren't a problem with 6 m or less.
    - the vendor uses cables and receptacles without keys & key slots,
letting the user plug in combinations that don't work.
From: Felton_Mickey at emc.com [mailto:Felton_Mickey at emc.com]
Sent: Thursday, December 10, 2009 10:29 AM
To: Elliott, Robert (Server Storage); kdbutt at us.ibm.com; t10 at t10.org
Subject: RE: SAS2 6G Connectors
Rob- Did you mean 10m or 6m for key slot 3?
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Elliott,
Robert (Server Storage)
Sent: Wednesday, December 09, 2009 4:12 PM
To: Kevin D Butt; t10 at t10.org
Subject: RE: SAS2 6G Connectors
Only receptacles that support 6 Gbps over a 10 m cable are support to have
that key slot.	If the phy's ability to support 10 m cables at that rate is
questionable, then not including that key slot is safer.
A 10 m cable without that key leaves itself open to being plugged into
receptacles where it won't work reliably.
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Kevin D Butt
Sent: Wednesday, December 09, 2009 2:20 PM
To: t10 at t10.org
Subject: SAS2 6G Connectors
In looking at SAS-2 it appears that all external connectors that support 6G
are supposed to have slot 3 on the connector.  Likewise the cables are
supposed to have key 3 if they are for 6G (i..e, too long for 3G).  Yet when
searching for cables and HBA's on the web, we do not see any cables or HBA's
that have key/slot 3.
Am I missing an understanding here?
Thanks,
Kevin D. Butt
SCSI & Fibre Channel Architect, Tape Firmware
MS 6TYA, 9000 S. Rita Rd., Tucson, AZ 85744
Tel: 520-799-5280
Fax: 520-799-2723 (T/L:321)
Email address: kdbutt at us.ibm.com
http://www-03.ibm.com/servers/storage/



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