There are terms used in this page defined above in the document. Here is a short description. If you hold a node key to N (a node) you can form a segment key to N with an 8 bit data byte of your choosing. Four of those bits are called “lss” (log segment size). The other 4 bits are the number of ‘initial slots’ in the designated node. If that count is n then slots 0 thru n–1 of the node are initial slots. (Such slots define memory. Other slots set rules or are ignored.)