Abstract: A computer system, bus interface unit employing a memory controller, and method are presented for optimizing the bandwidth data, address, and control transfer rates across a memory bus coupled to an SDRAM system. The SDRAM system is partitioned such that one partition will undergo pre-charge or refresh in the interim between times in which another partition (or a pair of partitions) initiate a burst read. The burst read cycles coincide with an initial column address of the burst, and are spaced a number of cycles equal to the burst length. Proper spacing of the initial column address, or read request, relative to a non-read requested partition ensures data read from the activated partition will be placed on the memory data bus in seamless fashion. That is, there are no non-data transfers occurring between data burst cycles, even though refresh or pre-charge operations are performed on a non-read partition.

Abstract: A method and apparatus for designing a computer system which supports multiple processors of different types. A processor base board is separately connectable to a system board. The processor base board includes a number of connectors for receiving processor boards. The processor boards include a processor and, if necessary, a voltage regulator and voltage level converters. A right angle single edge contact connector is used on a Pentium II board to significantly reduce spacing requirements of adjacent processor boards. A conventional pin grid array type socket is used for a Pentium Pro processor board. A special mapping of bus request signals is disclosed for supporting four Pentium Pro processors or two Pentium II processors without requiring changes to the processor base board.