Technical
The client layer
Constitutes the system’s user interface, and Profdoc supports a multitude of different client applications such as 32-bit Windows clients, .NET applications, PDAs or Web applications. The standard client is a 32-bit Windows client.
The client’s connection to Profdoc is “stateless” which means that the client is disconnected form the underlying layers except when underlying functions are actually used. This creates excellent scalability for large installations by avoiding the allocation of permanent system resources on the server side.
Three middle layers - Data access, Manager, Façade
Are separate components compiled to run on 32-bit Windows and managed by COM+. ADO record set is used as information carrier between the logical layers. >
The façade layer provides a component library for each client application in a manner that fits with each client, i.e. the façade layer can be made with different technology/interface for different types of clients.
The manager layer contains components that provide business logic.
The data-access layer contains components to read and write information to and from a data source, and thereby provides an abstraction layer for a database. The three middle layers can be distributed on multiple computers for load balancing and scalability. Standard, off-the-shelf tools are available for this.
The data-storage layer
contains the actual data storage part of the system. The standard database is Microsoft SQL Server (or MSDE for free distribution and smaller installations). SQL Server has many features like 24-hour operation, online-backup, multi-CPU support, clustering etc.
COM+ is a standard, off-the-shelf software which today is included in every Windows computer. COM+ provides a runtime environment for all the system’s components and enables the components/objects to communicate with each other in a distributed system. Furthermore, COM+ provides security settings (on process and component level), object pooling, activation, queuing, threaded transactions with multiple data sources (Resource Managers) etc.
Plans are under way to migrate Profdoc to a .NET framework platform, where the components will be managed by the .NET Enterprise Services (as opposed to COM+) and where the .NET common language runtime is used instead of 32-bit Windows.
