Proposal for T10 consideration - CSMI

Roger Cummings roger.cummings at
Fri Sep 3 11:07:25 PDT 2004

* From the T10 Reflector (t10 at, posted by:
* Roger Cummings <roger.cummings at>
During the SM-HBA Ad Hoc meeting held on August 3, 2004 as part of the T11
Plenary Week in Keystone, CO, a proposal for a "Common Storage Management
Interface (CSMI) for SAS" (see was presented and

CSMI was described as an IOCTL-level interface for SAS Host Bus Adapters.
CSMI will typically be deployed as part of an OS-specific PCI card driver.
CSMI is the first public presentation of a year-long private collaboration
between leading storage interface vendors.

The reaction to this proposal was extremely positive, but the subsequent
discussion highlighted significant differences in scope between CSMI and
SM-HBA. The former is a low-level interface intended to promote commonality
between SAS (and SATA) HBA vendors at the OS driver level, and supports such
functions as firmware download and HBA-based RAID configuration control. The
latter is a library interface intended to allow management applications to
locate multiple HBAs in a system, monitor the resources that they have
discovered, and through those HBAs access the storage network to which they
are connected.

Task Group T11.5 is chartered to address interfaces between management
applications and devices in a storage network. T11.5 is specifically
chartered to "emphasize techniques which are independent of network
topology, platform environment, and infrastructure technology". Thus it made
sense to locate the SM-HBA project in T11.5 as it involves extension of the
current FC-HBA document to address an additional infrastructure technology
(SAS), and to create an architecture within which further technologies may
possibly be supported in the future.

CSMI is both specifically targeted at SAS, and new work unrelated to
previous projects, and thus there seems to be no good reason to locate the
project in the same group as SM-HBA. As T11.5 chair, I would therefore like
to commend the CSMI effort to the attention of T10, and recommend that the
work be carried forward in that TC. I'd also suggest that we maintain an
active liaison between that activity and the SM-HBA project in T11.5 to
ensure that CSMI includes all of the functionality needed to support the
"higher level" SM-HBA definition.


Roger Cummings
Chair, TG T11.5

roger.cummings at

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