The administrator defines the metadata (source templates), which are used as the data dictionary. The template tells a subsystem the physical location of the data, the records and fields to extract, and the format in which to present the data to the client.
In addition to acquiring, converting, and managing the data, the subsystem ensures security. When the primary host is an OS/390 system, agents operate through the System Authorization Facility (SAF), interfacing with Resource Access Control Facility (RACF), Advanced Communications Function 2 (ACF2), or Top Secret. The primary host controls exactly which users have permission to access specific files. This level of security extends from the mainframe through the data access servers, and culminates at the data access clients.
Data Access Server
The data access server runs as a service on a Windows NT, 2000, or XP server. The server is responsible for maintaining security of the multiple clients accessing the mainframe, while simultaneously working with the client to ensure client standards compatibility. Client standards are achieved using Microsoft Component Object Model (COM) as the network-abstraction layer.
Data from the mainframe is presented to Windows applications using ADO, ADO.NET, OLE DB, and ASP.NET. This allows numerous Windows programs, including all Microsoft Office products, to directly view data without further manipulation. This approach also allows the client, bridge interfaces, and applications to use standard Windows functions and features.
The data access server provides the join engine that allows access to multiple mainframes. A stored query facility (result template) enables joins to be performed across all mainframe data sources and data locations.
The business impact of this is significant in that it lets enterprises:
- Easily develop new applications (or convert existing open systems applications) to access mainframe data
- Instantly access multiple data sources and present integrated data to requesting applications. This new approach:
- Accesses data instantly and presents it in industry-standard formats
- Lets organizations use their legacy data quickly, easily, and cost-effectively for more accurate strategic decisions
- Leverages investments in mainframe computing.
At organizations that implement this approach, end users may no longer be frustrated that their mainframe data isn’t as easy to use as data from Windows applications. Z