Some of the VICAR applications link to libraries which you may not have at your site. The library may be proprietary to a vendor (so it doesn't get distributed with VICAR), or it may be simply something you don't need (like our Real-Time telemetry system).
These special libraries are listed below. The abbreviations are used for the link groups, which are described later. You should go through the list and decide which libraries you have, and which you don't. (There are several other link groups that are currently empty that are present for compatibility with VMS.)
Any program that uses one of these libraries will not link at your site if the library doesn't exist. The VICAR build procedures account for this by allowing you to omit programs that link to libraries you don't have. The mechanism for doing this is called a link group.
Every program belongs to one and only one link group. If a program used the SPICE library, it would be in the SPICE link group. Due to a peculiarity in CMS (which maintains these groups for us), programs which would fall into more than one group get their own group which is a combination of the two. So, DTR contains only programs that link to Datatrieve, DTR_SPICE contains programs that link to both DTR and SPICE, etc.
The current link groups are (note that many of these groups are currently not used):
A typical external site may use only the EASY group, or more likely EASY, FPS, RDM_SHR_IMG, and RDM.
To find out which programs are in a link group, simply look at the file imake_obj.p2prog in $P2TOP, or imake_obj.p3prog in $P3TOP. All programs belonging to the group will be listed in that file. It would be a good idea to scan through the programs in the link groups you aren't using to see if any of the programs are needed at your site. If they are, you should look into getting the appropriate library.
The list of groups you want to build is used as an argument to the application build procedure. Take note of which groups you want; it'll be needed later.