1. A computer implemented method for determining configuration topology of one or more active computer elements in a modular computer system comprising a first node of a configuration, the first node consisting of a first plurality of communicatively coupled computer elements, each element comprising a respective second plurality of first interfaces, each pair of elements of the first plurality of elements communicatively coupled by way of respective first interfaces by way of a respective point-to-point active interconnection, the respective active interconnection interconnecting only the respective pair of elements, each element being separately packaged, the second plurality of first interfaces being greater-than or equal-to the first plurality of communicatively coupled active computer elements, wherein the first plurality of elements comprises one or more clusters, wherein each element consists of any one of a cluster and a storage controller (SC) function, wherein each cluster comprises a plurality of processors, wherein each cluster is configured to communicate with 1 or more other elements based on a coherency value of the respective cluster, the SC function comprising an inclusive directory of cache lines of the first node, the inclusive directory being shared by processors of each cluster of the first node, each SC function configurable to communicate with 1 or more other elements of the first node based on the coherency value of the SC function, wherein each processor of each cluster comprises a private cache, wherein each cluster is further configured to manage cache coherency within all processor caches of the respective cluster for requests, from processors within the respective cluster, that hit in caches of the respective cluster, without interrogating caches not in the respective cluster, wherein the SC function further comprises one or more second interfaces, each second interface configured to communicate with a respective SC function of a second node, the computer implemented method comprising:during system initialization of the computer system, performing, by each respective element of the first node, an operation to identify which other elements are active in the first node, the operation comprising:
determining, by each element, which first interfaces of the respective element are valid first interfaces, wherein each valid first interface of an element has only one active interconnection to only one other element of the first node, wherein each active interconnection is a point-to-point interconnection, wherein each first interface of the respective element not having an active interconnection to another element of the first node is not a valid first interface; and
based on the determining, by each element, which first interfaces of the respective element are valid first interfaces, storing the coherency value by each respective element, the coherency value indicating which first interfaces of the respective element are valid interfaces and which first interfaces of the respective element are not valid interfaces; and
after system initialization, during normal operation, based on the coherency value of the respective cluster, broadcasting, by the respective cluster, cache line fetches to all other active elements of the first node by way of valid interfaces of the respective cluster, the cache line fetches being cache line fetches for cache lines that miss in all caches of the respective cluster, and
after system initialization, during normal operation, using by each element, the respective stored coherency value, of the respective element, to determine which other elements of the first node are to be accessed in the first node.