Abstract: The invention provides an improved digital data processing system, e.g., storage area network (SAN), of the type having a first digital data processor, e.g., a SAN server, and a second digital data processor, e.g., a SAN client, coupled to one another and to one or more storage units, e.g., disk drives. A volume is stored on one or more of the storage devices, with at least two of its blocks residing at locations that are not contiguous with one another. The improvement is characterized, according to aspects of the invention, by transmission from the first to the second digital data processor of one or more addresses. These can constitute, in total, fewer such addresses than would be provided in a canonical map of the volume and, indeed, can comprise (by way of non-limiting example) a start address for each file and/or a portion of the volume on each storage device where the volume resides.

Abstract: The invention provides an improved digital data processing system, e.g., storage area network (SAN), of the type having a first digital data processor, e.g., a SAN server, and a second digital data processor, e.g., a SAN client, coupled to one another and to one or more storage units, e.g., disk drives. A volume is stored on one or more of the storage devices, with at least two of its blocks residing at locations that are not contiguous with one another. The improvement is characterized, according to aspects of the invention, by transmission from the first to the second digital data processor of one or more addresses. These can constitute, in total, fewer such addresses than would be provided in a canonical map of the volume and, indeed, can comprise (by way of non-limiting example) a start address for each file and/or a portion of the volume on each storage device where the volume resides.