so I gave up on this. I was trying to get this to work to help @gewt load some files, but it turns out this version of Interactive Unix REALLY doesn't like it when you have Big Disks attached.
Like, even if your boot disk is 200mb and it's on controller 1 and you have an unrelated second drive on controller 2 that's 19gb, it'll fail to format the 200mb boot drive. it just hangs.
PLUS it turns out the drive we're trying to mount uses Veritas/VxFS, which is a commercial-only filesystem. Interactive Unix 4.1.1 doesn't have Veritas by default, you'd need to buy it separately. back in 1998.