1. A machine-implemented data compression/decompression method comprising: (a) within a computer, segmenting a data containing address space for a memory associated with the computer to thereby define a plurality of segments where each segment contains a consecutively addressable sequence of data containing tiles and each tile contains at least one symbol occurring in a predefined alphabet; (b) within the memory, recording a first expression of a corresponding first boundary approximating plot that extends across the data containing address space where the first plot cuts through end tiles of two or more of said segments and where the first plot further lays to one side or another or on a predefined reference point of each tile it cuts through and the positioning of the reference point relative to the first plot deterministically indicates in accordance with a predefined system convention whether the cut-through tile is to be deemed as being wholly disposed to one side or the other of a segmentation boundary represented by the first boundary approximating plot; (c) within the computer, beginning or discontinuing a compressing or decompressing walk through a first of said segments in response to a machine determination that a corresponding first end tile of the first segment has a reference point lying to one side or another or on the first boundary approximating plot; and (d) within the computer, beginning or discontinuing a continuation of said compressing or decompressing walk through a second of said segments in response to a machine determination that a corresponding second end tile of the second segment has a reference point lying to one side or another or on the first boundary approximating plot, where the first and second segments are spaced apart address-wise from each other in said data containing address space.