<http://webisa.webdatacommons.org/91437134> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/ns/prov#Entity> . <http://webisa.webdatacommons.org/91437134> <http://www.w3.org/ns/prov#wasQuotedFrom> <google.com> . <http://webisa.webdatacommons.org/prov/115715249> <http://www.w3.org/ns/prov#wasDerivedFrom> <http://webisa.webdatacommons.org/91437134> . <http://webisa.webdatacommons.org/91437134> <http://www.w3.org/ns/prov#value> "In various embodiments, volume block device 202 may read a given data block stored in duplicate in logical block devices 204 and 206 by issuing a read operation to one mirror device or the other, for example by alternating devices or defaulting to a particular device." .