I suspect the Girder and Premise plugins have substantially different architectures. I don't know what "buffer" refers to in the Girder plugin. I'll take a wild guess that it may be a fixed-size array to hold M1 resources (zones, outputs, ec). The Premise plugin uses collections so there's no preset ceiling.
My use of the term "Discovery" is very liberal. You can't truly discover all of an M1's resources from scratch. For example, there's no reliable way to learn how many Areas are in use. The plugin requires that you first define how many areas, zones, outputs, PLC devices, etc you wish to monitor. I deemed this approach to be more efficient than polling all possible resources. If you have 32 defined zones, the plugin will only poll 32 instead of the M1's full complement of 208. If you set a resource to zero, it effectively prevents the plugin from "discovering" that resource.
What is "discovered" depends on the resource. For example, for zones it will return with names, state, logical and physical types. It'll be less for outputs and lights. It won't return with a resource's name if its Show Flag is disabled. After predefining the number of resources, one manually-initiated "Discovery" is normally all that is required for the driver to become populated. Afterwards, a Discovery can either be triggered automatically after every RP session (sufficient) or according to a schedule (overkill).
