Distributed Shared Memory on Ericsson Labs


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The Distributed Shared Memory (DSM) service allows you to develop highly interactive and responsive web-based groupwares without having to deal with complicated issues such as networking protocols, database management and concurrency control.

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Distributed Shared Memory on Ericsson Labs

  1. 1. Distributed Shared Memory A labs.ericsson.com APIhttp://labs.ericsson.com/apis/distributed-shared-memory/
  2. 2. ericsson labs APIs Maps & positioning communication security Mobile Mobile SMS Send & Mobile Group Voice Mobile Web Security Oauth2 Location Maps Receive Push Mixer Bootstrap CAPTCHA Framework Web Async Identity Management Key Management Maps Voice Framework Service Web technologies NFC & sensors User & network information Web Web Background Mobile Sensor Mobile Network Tag ToolConnectivity EventSource Service Actuator Link Identification Probe Web Device Mobile Network Distributed Web Real-Time Real- Sensor Networking Connectivity Shared Memory Communication Application Platform Look-up Look- Machine learning Media and graphics Face Cluster Text-to-Speech Text- to- Detector Constructor© Ericsson AB 2010 | Page 2
  3. 3. Distributed shared memory› Distributed Shared Memory enables a distributed in- memory database for JavaScript applications – Get a replica of a DSM storage with a specified address from a DSM server – Register a listener and be notified when data is changes by other users – Modify data locally and synchronize changes in the background with other replicas› Merge conflicts are automatically resolved© Ericsson AB 2010 | Page 3
  4. 4. Why distributed shared memory?› Let web developers focus on developing highly interactive and responsive web-based collaboration software without having to deal with complicated issues such as – networking protocols – database management – concurrency control› Also, using a local replica where data can be modified directly without a lock or blocking improves user experience› Synchronizing application states among multiple clients› Implement group-wares or collaborative web services supporting simultaneous real-time interactions© Ericsson AB 2010 | Page 4
  5. 5. Main Features› Makes it possible for multiple JavaScript clients to address and manipulate the same data at the same› Plain JavaScript Lib (no browser plug-in required)› High performance and low delay› Optimistic replication to resolve merge conflicts› Event-driven (register a listener and be notified when data change)› Support for both ordered arrays/lists and unordered key-value hash tables› Support for both persistent storage (disk) and transient data (RAM)› Automatic garbage collection› Time-to-live (specify how long time a value should be stored)› Possibility to link DSM storages to build graph databases© Ericsson AB 2010 | Page 5
  6. 6. Use casesExamples of usage› E-learning› Tele-care, e.g. remote health care and specialist consultation, remote monitoring etc.› Call center support› Collaborative work, e.g. a shared whiteboard or other collaborative editing systems etc.© Ericsson AB 2010 | Page 6
  7. 7. Merge conflicts are resolved› All clients (and servers) DSM SW contains predefined rules how to resolve conflicts“Adjust” or transformincoming operation tomatch local changes© Ericsson AB 2010 | Page 7
  8. 8. JavaScript API› Simple and easy to use to API// get a replica of hash://simpleTestvar hash = memCtrl.get(“hash://simpleTest”);// update the web page when the replica is clonedhash.onReady = function () { document.getElementById(“myTextfield”).value = hash.get(“myKey”);};// handle changes to the replicahash.onUpdate = function (op) { document.getElementById(“myTextfield”).value = op.value;};// update the local replicahash.set(“myKey”, “myValue”);// send the operation to all other replica clients in the backgroundhash.submit();© Ericsson AB 2010 | Page 8
  9. 9. Example applicationsShared Whiteboards Collaborative Workspaces Shared JavaScript Apps, e.g. a Shared Map Widget© Ericsson AB 2010 | Page 9
  10. 10. © Ericsson AB 2010 | Page 10