identified storage elements this step is supported by microcode in processing element 105 of storage element mapping controller 110 fig3 is an exemplary implementation of the present invention to effect mapping host read and write commands in a raid system 400 a read or write command is received and includes a host identification number and a logical unit number lun which are used to determine via hosttovolumemaptable 405 a volume number 420 the volume number is then used as an index into another table of volume descriptors namely volumeinfotable 410 each of the entries of the volumeinfotable 410 describes a volume including a starting lba of the particular volume the length size count of the particular volume in terms of logical block addresses lbas and the first mapping segment descriptor msd 425 associated with the particular volume the starting lba and the count length map the volume to a location which starts at the starting lba and ends at the starting lba plus volume span count length the first msd is a pointer to a msd table 415 each of the entries 430 in the msd table 415 include the segment starting lba the segment length count span the raid type the number of members drives and the starting drive.