Re: From: "Robert Armstrong" <bob at jfcl.com> Subject: WH-27 Problems (was RE: Heathkit H8's, H9's and H-11's) .... In extended mode the drive could handle 512K diskettes ... So the bottom line is that if you want to run standard RT-11 on the H-11, you have to set the switch to RX-01 mode and you have the equivalent of an RX01 drive. No double density ... ************* I don't think that's correct; the controller in the H-27 (WH-27) is a Z-80 with a Western Digital 1771. The 1771 is most definitely single density only. It's not capable of double density.