Distributed medical information system. O. Belov, I. Belova National Research Centre for Audiology and Hearing Rehabilitation. Russia Space Research Institute. Russia.

Distributed medical information system. O. Belov, I. Belova National Research Centre for Audiology and Hearing Rehabilitation. Russia Space Research Institute. Russia. This project was started as a fault tolerant solution for a small audiological clinic. Fault tolerance is provided by distributed storage with replication and distributed journalling of transactions.

Thin client Workstation 1Workstation 2 Measurement device SQL Node TCP socket Named pipe Node TCP socket Named pipe Node with restricted capabilities Serial over USB Data in flash memory Custom web application Browser Medical, scientific and administrative applications. (GUI and command- line) Application level Data storage level The bound is a result of code evolution. On this bound we use a simple and human-readable protocol based on SCPI (IEEE488.2) specification => Applications can be very simple.

Thin client Workstation 1Workstation 2 Measurement device SQL Node TCP socket Named pipe Node TCP socket Named pipe Node with restricted capabilities Serial over USB Data in flash memory Custom web application Browser Medical, scientific and administrative applications. (GUI and command- line) This layer provides:  referential integrity,  replication,  distributed searching,  undo-redo stack,  access control,  encryption,  data transmission

Thin client Workstation 1Workstation 2 Measurement device SQL Node TCP socket Named pipe Node TCP socket Named pipe Node with restricted capabilities Serial over USB Data in flash memory Custom web application Browser Medical, scientific and administrative applications. (GUI and command- line) A replication unit is a card. A card can hold:  Electronic Health Record,  Doctor data,  Node description,  Network topology,  Replication rules,  Device description and drivers,  Device calibrations  … The card is a unified representation for all data. There are cards and nothing except cards.

Thin client Workstation 1Workstation 2 Measurement device SQL Node TCP socket Named pipe Node TCP socket Named pipe Node with restricted capabilities Serial over USB Data in flash memory Custom web application Browser Medical, scientific and administrative applications. (GUI and command- line) A replication unit is a card. A card can hold:  Electronic Health Record- is not processed by this level,  Doctor data, - used by node engine,  Node description,- used by node engine,  Network topology, - used by node engine,  Replication rules,- used by node engine,  Device description and drivers,  Device calibrations  … Each type of card has own replication policy. Archetypes and data encoding is not in the scope of this layer.

Thin client Workstation 1Workstation 2 Measurement device SQL Node TCP socket Named pipe Node TCP socket Named pipe Node with restricted capabilities Serial over USB Data in flash memory Custom web application Browser Medical, scientific and administrative applications. (GUI and command- line) Each card has one and only one main instance plus several replicas. If an application wants to modify card, it must obtain the main instance to the own node. There are special rules for some situations...

Card is a header plus a tree of records. Any card and any node has unique identifier. Each record contains one compressed XML document plus 12 indexed fields. Each type of record has several metadata records.  Vocabulary for compression.  Code for visualization,  Templates for hard copy, ... Metadata is distributed together with the card. A lot of implementation details you can find in my poster on the wall. This project is Open Source. Thank you!