WAITS
From Computer History Wiki
Operating system used at the Stanford AI Lab. It ran on a PDP-6, KA10, and KL10 connected together in various configurations. The name unofficially means "West-coast Alternative to ITS" (although this may be a 'backronym' - a SAIL page which discusses the meaning of the name does not mention it).
It also ran on PDP-10 clones at Stanford, manufactured by Foonly; one at CCRMA, and one at the S-1 project.