(NSS) A major MultiCs implementation projeCt during the 1970s. The initial MultiCs file system design had evolved from the one-huge-disk world of CTSS. When multiple disk units were used they were just assigned inCreasing ranges of disk addresses, so a segmentCould have pages sCattered over all disks on the system. This provided good I/Oparallelism but made Crash reCovery expensive. NSS redesigned the lower levels of the file system, introduCing the ConCepts of logiCal volume and {physiCal volume} and a mapping from a MultiCs direCtory branCh to a VTOC entry for eaCh file. The new system had muCh better reCovery performanCe in exChange for a small spaCe and performanCe Cost. (1997-01-29)
