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System Architecture

The defining characteristic of OpenVista is flexibility. Medsphere has innovated at every level of the technology stack to transition VistA from a clinically effective but organizationally beholden tool to one limited neither by environment nor the inclusion of different components.

Client

The VA’s VistA system employs a graphical user interface (GUI) created in Delphi that uses a Remote Procedure Call (RPC) broker to communicate with the MUMPS server. Significantly, the OpenVista client employs either the Microsoft .NET framework or Mono, an open source implementation of Microsoft .NET, to provide modern functionality in a cross-platform graphical user interface (GUI). (Interoperable, language-independent and simple to deploy, the .NET framework is key to OpenVista’s flexible nature.)

The OpenVista architecture enables the client to run natively on Windows or Linux systems. This flexibility allows facilities to leverage current hardware investment, expand resources, and reach a greater clinical user base. Medsphere’s current development path also includes standardizing the OpenVista GUI across all previously character-based VistA applications, as well as new applications developed by Medsphere.

Network

At the network level, VistA’s approach to connecting client and server is an RPC broker that causes actions executed on one computer to also execute on another. Medsphere updates this approach through the use of the OpenVista Bridge, a middleware component that manages interaction between server and client, handles raw communication with the VistA Broker (server), and provides a Binary Remoting interface to the client (the client uses one or the other for a given connection).

The implementation of the OpenVista Bridge gives Medsphere the ability to use on-the-wire encryption for greater levels of security and enables the system to interact with Web-based applications.

Server

The OpenVista server layer uses Java, a platform-independent programming language intended to run anywhere, to give the overall technology improved market viability and extensive commercial market benefits. Through the use of Java, Medsphere preserves the legacy VistA MUMPS code at both the server and application server (see below) levels while enabling the advancement of OpenVista and preserving the longevity of the product. The incorporation of recognized interfacing technology standards such as Health Level 7 (HL7) enables OpenVista to communicate effectively with required third-party applications (e.g., administrative, financial, PACS) in creating a complete, efficient solution.

To read a recent white paper on this topic, click on OVID: From MUMPS to Java.

Database interoperability

Leveraging open-source technologies, Medsphere is developing a database projection technology that will allow customers to view VistA’s hierarchical FileMan (MUMPS-based) database management system as a modern, relational database via a MySQL storage engine. Use of a standard Java Database Connectivity (JDBC) interface enables commercial off-the-shelf (COTS) reporting tools and data warehousing through the use of Structured Query Language (SQL). This greatly expands OpenVista’s ability to provide an organization with data analysis tools, performance metrics, and operational reporting.

Application server

At the Application Server level, Medsphere uses Java technologies to provide OpenVista with more flexibility via an object domain layer. Medsphere developed this Java layer as part of the OpenVista technology stack to realize wider interoperability, develop greater application functionality, and increase development velocity. Through the use of this domain layer, OpenVista applications can seamlessly connect to legacy modules and other Java-based applications, leveraging modern development methodologies and tools. As an example, this tool is used to support interoperability with pharmacy billing systems. Medsphere provides additional flexibility at the Application Server level by giving clients the choice of either InterSystems Caché or Fidelity GT.M, a commercial Open Source solution.

Operating system

Historically, use of the OpenVMS operating system has made VistA dependent on Alpha (VAX) hardware. Medsphere also offers freedom of choice at the OS level by certifying the use of OpenVista on multiple platforms, allowing organizations to choose Linux or Windows operating systems, and hence a wider variety of hardware.

Hardware

Unlike VistA, which is limited to Alpha or Intel Itanium technology, OpenVista runs on any Intel x86 hardware. Medsphere provides recommended sizing guidelines for server-based configurations to support the optimal performance of the OpenVista system. This gives clients a variety of choices, including Hewlett-Packard’s Intel-based products.

Medsphere is hardware-agnostic with regard to compatibility with the OpenVista Bar Code Medication Administration (BCMA) application. Customers can deploy whatever brand of barcode reader they choose. Most barcode readers re literally plug and play and are formatted to read a variety of barcodes. We recommend testing any legacy barcode scanners during implementation. Otherwise, purchase one for testing during implementation to make sure it works properly before the go-live. Typically, scanner ergonomics are more of an issue than specific functionality or compatibility.