DP4 is designed to run as a service on Windows NT and 2000, NT Terminal Server Edition, Windows 2000 Terminal Services Clients, and servers using Citrix products such as WinFrame or MetaFrame. The installation procedure installs the DP4 service. The service provides the database manager and, optionally, other components such as the network manager - if DP4 network clients are to be used (You do not need the network manager for accessing DP4 via Terminal Server or Citrix clients). DP4 applications and utilities run on a WinFrame or Terminal Server client can access the database manager directly as for stand alone operation. They do this by means of a system of shared memory and semaphores to pass data to and from the database manager. These regions of shared memory and semaphores are created by DP4 servers when they start up, the code to do this is in a DLL, SYSLIBT.DLL. Under regular Windows NT these areas of shared memory and semaphores are immediately accessible to applications for use. This is not so under WinFrame or a Terminal Server, where they are private to the service which created them. For applications to communicate directly with the database manager as opposed to via a DP4 network connection it is necessary to mark SYSLIBT.DLL as being global to the system. This can be done using the register command.
On Windows 2000 or later systemss the register command appears not to work. Instead SYSLIBT.DLL automatically detects that it is running on Windows 2000, and creates the shared objects in a different way that ensures they are global to the system.
If you are installing release 4.619 or earlier of DP4 on Windows NT Terminal Server or Citrix, Installation should be performed in the special "install mode". This ensures that the system will give each client its own copy of the datafit.ini file.