There are a number of books describing the packages, and freeware extensions add various new features such as networking support or prepackaged widgets. The TIX extensions in particular provide a useful set of graphical widgets for GUI development. In the MessagingDirect product set, several of the clients and management tools, described in Section 4, contain Tcl interpreters. This section describes how these applications are structured. All MessagingDirect server and management applications link with the MessagingDirect run-time library, which contains X.509 security services, the upper layer protocol stack, and the Directory Access Protocol.
Additional libraries implement cryptography, transport layer services and other functions.
A key advantage of this approach is that it enables MessagingDirect OEMs and Direct Use Customers to develop their own scripts and graphical user interfaces which make use of the library functions. The following picture illustrates the architecture of the MessagingDirect management and client software. For simplicity the Tcl and Tk libraries are not shown. The directory access library is used by clients and management tools which connect with or configure the X.500 Directory services. The library adds commands to a Tcl interpreter for connecting to a directory service, managing directory distinguished names and attributes and invoking operations.