entry identified by the received index as shown in fig4 hardware is reduced since only one register 80 holding a table size value may be required the table size in register 80 is still compared with the index by comparator 88 to determine if the index is out of bounds of the tpt table segments 102 through 108 each tpt table segment 102 through 108 is the same size this is the table size stored in register 80 divided by the number of tpt table segments in this example embodiment of the present invention each of tpt table segments 102 104 106 108 have a size of the table size in register 80 divided by four since there are four tpt table segments the channel adaptor logic in this example embodiment also contains a register 84 that contains one enable bit for each of tpt table segments 102 through 108 this enable bit may be set by a software making register 84 a programmable register the enable bits inform the channel adaptor hardware whether a particular tpt segment is active software may take advantage of this feature in the channel adaptor as needed disabling all of the supported tpt table segments above the first segment i e segment 102 results in one physically contiguous tpt table in system memory as is used in current systems e g fig2 the channel adaptor embodiment shown in fig4 also supports four base address registers 92 through 98 each register may be programmed to take into account the subtraction of the previous tpt table segments for example the base address contained in register 92 may equal the starting physical address.