Abstract: A physically compact peripheral bus that provides a long electrical distances between signal branch off points. The compact physical spacing allows a high speed peripheral bus to be used to connect a large number of peripheral devices within a computer system enclosure and yet avoiding the reflections experienced when numerous peripheral branch connections are located near to each other. Branch reflections are reduced by providing an electrically short branch length in conjunction with an electrically long printed wiring path for each signal, while maintaining a physically short connector spacing. The physically-short, electrically-long path is accomplished by a serpentine printed wiring conductor path of many folds for each high speed signal path between adjacent branches. Thus, the SCSI recommended spacing of 0.3 meters is provided in a physical spacing of 0.05 meters.

Abstract: A memory system having both a primary memory and an alternate memory. The alternate memory stores data to be substituted for data stored at memory locations in the primary memory that have defective cells. The alternate memory includes a byte memory and a bit memory. The byte memory stores bytes of data that are to replace bytes having multiple bit errors in the primary memory. The bit memory stores bits to replace single bits in any byte in the primary memory that has a single bit error. A mapping memory controls access to the primary memory and the alternate memory. The memory devices in the primary memory have either all row defects or all column defects in order to reduce the size of the mapping memory.