<dept>.<accessionnumber>.<bagnumber>/
  `- 0=DISKIMG_ACCN_SIP_0.1
  `- bagit.txt
  `- bag-info.txt
  `- data/
  |  `- images/
  |  |  `- <disk1>/
  |  |  |  `- <disk1>.txt           # Metadata about imaging process
  |  |  |  `- <disk1>.xml           # Metadata about image/FS; like structmap
  |  |  |  `- <disk1>.<format>.<part1>
  |  |  |          ...
  |  |  |  `- <disk1>.<format>.<partn>
  |  |  `- <diskn>/
  |  |     `- <diskn>.txt
  |  |     `- <diskn>.xml
  |  |     `- <diskn>.<format>.<part1>
  |  |             ...
  |  |     `- <diskn>.<format>.<partn>
  |  `- logs/
  |  `- metadata.xml
  `- manifest-<algorithm>.txt
  `- tagmanifest-<algorithm>.txt