(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 segment could 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)
