Since you can keep your service definition in either the WLM couple data set or in MVS™ data sets, it is possible to have multiple, uncoordinated updates. You should decide on a process for updating your service definition.
If you decide to work from the WLM couple data set, installing and extracting the service definition when you need to edit it, you should keep a copy in an MVS data set. The WLM application allows only one user to update an MVS data set at a time. If you do try to edit an MVS data set that is in use, you are locked out, and get a message saying the data set is in use.
If you select the Install option, and someone has done an install since you've extracted, the application displays a pop-up panel asking for confirmation. This way you can prevent inadvertent overwrites of the service definition. Figure 1 shows the Overwrite warning panel.
Overwrite Service Definition
Another service definition was found on the WLM couple data
set.
Service definition name : WLMDEF
Definition installed by : SPFUSER from system SP44
Definition installed on : 1996/04/16 at 22:00:46
Do you want to overwrite this? NO (Yes or No)
F1=Help F2=Split F5=KeysHelp F9=Swap F12=Cancel