Hi, I have some cards here I want to build a PDP11 from, at the current that's something around an KDF11-A CPU (22bit). Currently I have problems with some Dilog Controller, this is an DQ614 that emulates 4 RL02 Drivers out of two 20MB MFM disks (Microcience HH725). I can install and successfully boot RT11SB.SYS and RT11FB.SYS but not RT11XM oder RT11XB. XXDP2.5 is working fine. Nowhere in the Dilog Documentation is something mentioned about 18 or 16 bit addressing limitations of that controller, the pinout clearly has 22 bits. (http://www.bitsavers.org/pdf/dilog/) I have an RQDX3 with 2 TEAC FD55-GFR-184 Floppies on this system too, I can boot RT11XM oder RT11XB (same files!) from there fine... If I try that from DL0 or DL1 I'll always get a trap to the ODT (0002), regardless if I use the Dilogs own Bootloader or that from an 11/53 or an 11/73 CPU. Does someone here know of that problem? Regards, Holm -- Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, Freiberger Stra?e 42, 09600 Obersch?na, USt-Id: DE253710583 www.tsht.de, info at tsht.de, Fax +49 3731 74200, Mobil: 0172 8790 741