Okay, I'm back from a DR exercise and have started trying to get this PDP-11/73 working with RT-11. I have a copy of the XXDP formatter now, and trying to format the hard drive gives this error: Unit Cylinders Drive Name 0 1225 RD54 1 RX50 Diskette (UNFORMATABLE) 2 RX50 Diskette (UNFORMATABLE) MSCP Controller Model: 19 Microcode Version: 1 ZRQC SYS FTL ERR 00007 ON UNIT 00 TST 001 SUB 000 PC: 105742 Controller has reported a fatal error in the FORMAT program. Status: FCT write error (check write protect switch) Drive 0 was not formatted successfully. ZRQC EOP 1 1 TOTAL ERRS Since this drive worked fine under VMS before I started the conversion, I am starting to think there is a jumper on either the RQDX3 or the RD54 that has to be changed to use the drive under RT-11, since the write protect switch is NOT enabled (I even toggled it to make sure).