About SDI and RMI dispatcher:
It is notorious how IBM neglect documentation for the last, hm, five or six years already.
Anyway,
When you are installing SDI for use with ISIM/ISVG, during installation there is a box that you need not to tick, that asks if you need TDI to run as a service. No, you do not need, since you are going to install RMI dispatcher later, which is actually - TDI service (with prettier name).
If you have installed with TDI service - not a big problem. Actually, you may register many TDI services with one SDI installation, if needed.
As others already mentioned, you need to assure that there is no port conflicts between services (RMI Dispatcher is a service, TDI server that may be created during installation is a service, you may want to create more services...)
Every TDI service has its folder, usually under installation folder of SDI itself, and in there is a file called solution.properties, ant ports are in there. I usually move ports 1099, 1098 to other, for other than RMI dispatcher service, and leave this one with defaults.
Mote:
There is another solution.properties file, in SDI installation folder, where you may also want to move ports, since it is used for Configuration Editor GUI, and server that will be started when you run the GUI. If it overlaps with some ports of running services (e.g. RMI dispatcher) the server inside GUI will not start.
If you have installed RMI dispatcher, and there is no Windows service, you may want to try adding it manually: Fix ports in other solution properties files, restart other service if you need, and then go with cmd line into folder where RMI dispather has been installed (usually timsol folder, under SDI installation folder), and execute: ibmdiservice.exe -i
This should create windows service.
More at:
https://www.ibm.com/docs/en/svdi/7.2.0.3?topic=service-installing
Hope this helps,
Mita