Jerome Fine replies: I agree! While I have not kept track of Unibus prices, Qbus prices usually have an extra zero - on the right of course. And that would probably still be an excellent deal. Unibus prices are probably a bit higher if anything. For some reason, host adapters for both Qbus and Unibus PDP-11 and VAX have held their value for a long time. And now that the supply of most parts is so low, even though demand has fallen, the price seems to be rising. If you also have a standard 8" floppy drive, RX01 or even RX02, then RT-11 allows you to booth MSCP in V5.03 after you boot the floppy. However, PLEASE ask someone who knows about the PDP-11/20 if the Unibus backplane can take the UC17!!! The Unibus backplane sometimes had "interesting" aspects for early models. LIKEWISE!!!!!! Sincerely yours, Jerome Fine -- If you attempted to send a reply and the original e-mail address has been discontinued due a high volume of junk e-mail, then the semi-permanent e-mail address can be obtained by replacing the four characters preceding the 'at' with the four digits of the current year.