Hello Santosh,
The DDS "Global Data Space" concept completely abstracts from location
-- said in other terms, it
makes data available where needed by dealing with network communication if
necessary.
The shared memory, is one of the possible mechanisms used by OpenSplice to
communicate between applications on the same node, yet, to a DDS application
the location on the network is completely transparent w.r.t. the the
availability of data.
I am not sure if you are familiar with tuple-spaces (like Linda or
JavaSpaces). DDS can be seen a a tuple-space with relaxed semantics.
State-driven distributed applications tend to use DDS as a very
high-performance tuple space with relaxed consistency (e.g. eventual
consistency).
However, you can also use DDS (by properly modelling topics and QoS) as a
traditional pub/sub or messaging system. As I explain in these slides
http://www.slideshare.net/Angelo.Corsaro/distributed-events-state-and-commands
you typically need both paradigm to properly model distributed state and
distributed events.
Some good source of information on DDS are available at:
http://www.slideshare.net/Angelo.Corsaro
http://www.prismtech.com/opensplice/resources/white-papers
http://www.prismtech.com/opensplice/resources/articles
http://www.drdobbs.com/architecture-and-design/the-data-distribution-service-for-real-t/222900238
HTH.
Cheers,
Angelo
--
Angelo Corsaro, PhD
Chief Technology Officer
PrismTech
28 rue Jean Rostand | 91400 Orsay | France
T +33 1 69 01 53 54 | M +33 6 42 30 75 65
------------------------------------------------------------------------------------------------------------------
http://icorsaro.net | http://twitter.com/acorsaro |
http://slideshare.net/angelo.corsaro
------------------------------------------------------------------------------------------------------------------
On Oct 18, 2012, at 7:57 AM, Santosh N Dumbre <[email protected]> wrote:
>
> Hi ,
> Please consider a query regarding DDS "Global Data Space" concept -
>
> Is DDS - Global Data Space is similar to "shared memory" concept ?
>
> As I understand, Shared Memory resides on a single machine and processes
> running on that local machine can only access the shared memory.
>
> How the process running on different machine access the shared memory of DDS
> Global Data Space ?
>
> Is there Socket Layer Transport used under the "Global Data Space" access
> APIs ?
> If so, Message Oriented Middlewares also provide wrappers on Socket ,
> then How does DDS provide better performance over socket based Message
> Oriented Middlewares ?
>
> Kindly help my understanding related to DDS - Global Data Space.
> Is there any useful document regarding this ?
>
> Please reply.
>
> Thanks & Reagrds,
> Santosh.
>
>
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