advice wanted on multiple-UDA50 configuration

[Steven Bellovin]

We're considering configuring some new 780s with only RA81 disks.
In particular, we're thinking of getting 4-6 RA81s connected to two
UDA50s, each on a separate UNIBUS.  UNIBUS 0 would also have the
usual communications gear, including some flavor of Ethernet controller.
Any comments on this configuration?  If we were to stick with 4 drives,
does it even make sense to get two controllers, or should we hang them
all on one, on its own UNIBUS?  Any comments or suggestions will be
appreciated.

		--Steve Bellovin
		ulysses!smb

Note:  we already have 8 RA81s on assorted other machines; they've run
well after some infant mortality problems.