@Article{lawlor:parity,
  author = {F.~D. Lawlor},
  title = {Efficient mass storage parity recovery mechanism},
  journal = {IBM Technical Disclosure Bulletin},
  year = {1981},
  month = {July},
  volume = {24},
  number = {2},
  pages = {986--987},
  keywords = {parallel I/O, disk array, RAID, pario-bib},
  comment = {An early paper, perhaps the earliest, that describes the
  techniques that later became RAID. Lawlor notes how to use parity to recover
  data lost due to disk crash, as in RAID3, addresses the read-before-write
  problem by caching the old data block as well as the new data block, and
  shows how two-dimensional parity can protect against two or more failures.}
}