The first level of organization and summary of pixel data is in the form of clusters, which are composed of sequences. At this level, the clusterfinder uses another pair of intertwining tables to store cluster data. These are shown in Figure 4.
Figure 4: Structures used for tabulating TPC cluster data.
The TPCLUSTER table specifies the padrow of the cluster, its ``trustworthiness'' (not currently implemented), the number of hits that have been associated with this cluster by the hitfinder, and a path to the first sequence in a linked list of sequences that form the cluster.
The TPSEQ table simply contains some geographical information, a linked list self-pointer, and a pointer for every sequence to the first pixel of data (in the TPPIXEL table) in the sequence.