PHYSICAL PARTITIONING OF LOGICALLY CONTINUOUS BUS

ARRANGEMENTS ARE DISCLOSED FOR PHYSICALLY PARTITIONING A BUS HAVING A WELL DEFINED ARCHITECTURE AS A PHYSICAL ENTITY, WHEREIN THE PARTITIONING IS LOGICALLY TRANSPARENT TO A COMPUTER AND DEVICES WHICH COMMUNICATE THROUGH THE BUS AND SERVES TO AVOID PROBLEMS POTENTIALLY ARISING BECAUSE OF THE SCOPE OF ACTIONS PERMITTED BY THE ARCHITECTURE. A TYPICAL BUS ARCHITECTURE TO WHICH PRESENT ARRANGEMENTS HAVE RELEVANCE IS THAT ASSOCIATED WITH SCSI (SMALL COMPUTER SYSTEM INTERFACE) BUSES. THE POTENTIAL PROBLEMS ALLOWED TO OCCUR ARCHITECTURALLY INVOLVE: (A) EXPOSURES OF DATA SECURITY/INTEGRITY; (B) EXCESSIVE SIGNAL DEGRADATION DUE TO USE OF SIGNAL RATES WHICH ALTHOUGH ALLOWED BY THE ARCHITECTURE ARE INAPPROPRIATE FOR A PARTICULAR BUS LOADING ENVIRONMENT ALSO ALLOWED BY THE ARCHITECTURE; (C) RESTRICTION PREVENTING PARALLEL TRANSFER OF DATA BETWEEN THE COMPUTER AND MULTIPLE STORAGE DEVICES; (D) RESTRICTIONS UNDULY LIMITING THE NUMBER OF DEVICES ATTACHABLE TO ONE LOGICAL BUS PATH (ONE INPUT-OUTPUT CHANNEL OF THE COMPUTER). THE DISCLOSED ARRANGEMENT PARTITIONS THE BUS INTO TWO OR MORE PHYSICAL ENTITIES WHICH TO THE COMPUTER APPEARS AS ONE LOGICAL ENTITY.