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       dat.conf - configuration file for static registration of user-level DAT
       rdma providers


       The DAT (direct access transport)  architecture  supports  the  use  of
       multiple DAT providers within a single consumer application.  Consumers
       implicitly select a provider using the Interface Adapter name parameter
       passed to dat_ia_open().

       The   subsystem   that   maps   Interface  Adapter  names  to  provider
       implementations is known as the DAT registry.  When  a  consumer  calls
       dat_ia_open(),  the  appropriate  provider is found and notified of the
       consumer’s request to access the IA. After  this  point,  all  DAT  API
       calls   acting  on  DAT  objects  are  automatically  directed  to  the
       appropriate provider entry points.

       A persistent, administratively configurable database is used  to  store
       mappings   from   IA  names  to  provider  information.  This  provider
       information includes: the file system  path  to  the  provider  library
       object,   version  information,  and  thread  safety  information.  The
       location and  format  of  the  registry  is  platform  dependent.  This
       database  is  known  as  the  Static  Registry (SR) and is provided via
       entries in the dat.conf file. The process of adding a provider entry is
       termed Static Registration.

Registry File Format

           * All characters after # on a line are ignored (comments).
           * Lines on which there are no characters other than whitespace
             and comments are considered blank lines and are ignored.
           * Non-blank lines must have seven whitespace separated fields.
             These fields may contain whitespace if the field is quoted
             with double quotes. Within fields quoated with double quotes,
             the backslash or qoute are valid escape sequences:
           * Each non-blank line will contain the following fields:
               - The IA Name.
               - The API version of the library:
                 [k|u]major.minor where "major" and "minor" are both integers
                 in decimal format. User-level examples: "u1.2", and "u2.0".
               -       Whether      the      library      is      thread-safe:
               - Whether this is the default section: [default|nondefault]
               - The library image, version included, to be loaded.
               - The vendor id and version of DAPL provider: id.major.minor
               - ia params, IA specific parameters - device name and port
               - platform params, (not used)

Example netdev entries for OpenFabrics rdma_cm providers, both v1.2 and v2.0

               OpenIB-cma u1.2 nonthreadsafe default  dapl.1.2
       "ib0 0" ""
               ofa-v2-ib0  u2.0 nonthreadsafe default dapl.2.0
       "ib0 0" ""

               NOTE: The OpenFabrics providers use <ia_params> to specify  the
       device with one of the following:
                     network  address, network hostname, or netdev name; along
       with port number.

                     The OpenIB- and ofa-v2- IA  names  are  unique  mappings.
       Reserved for OpenFabrics providers.

       The default location for this configuration file is /etc/dat.conf.  The
       file  location  may  be  overridden  with  the   environment   variable


                                 25 March 2008