BAD is destructive to the data on the disk! If there are only four tasks that have read issues you may be able to move just those tasks over from a good version of RSX-11M with Kermit which you mentioned you had. A RD51 drive holds about 10 MB which is about the minimum for a RSX-11M system. The RX50 disks could load a version of Micro RSX which was a pre-GENed RSX-11M system. I used it one time to recover a non-bootable RSX system disk where someone deleted the RSX11M.SYS file that the boot block pointed to. I have not seem those RX50 images of Micro RSX on the internet so far. Since you can read and write the RX50 disks with a PC. Get a copy of PUTR from John Wilson Dbit site http://www.dbit.com/pub/putr/ to be able to write RX50s in RT-11 which can be read in RSX-11M with FLX. Then get a copy of Simh https://github.com/simh/simh Once you have a working Simh PDP-11 emulator (e.g. pdp11.exe) then get a bootable baseline RSX11M disk image ftp://ftp.trailing-edge.com/pub/rsx_dists/rsxm70.dsk.bz2 (Note: this disk image is actually RSX11M V4.8 The Simh will need a configuration file (e.g. sim.ini) that describes the PDP-11 system it is emulating like this: sim> do sim.ini set console log=./console.log set cpu 11/23, 256K set cpu idle set tto 8b set rq0 rd54 attach rq0 rsxm70.dsk sim>show rq sim> show rq RQ address=17772150-17772153, no vector, RQDX3, 4 units RQ0 159MB, not attached, write enabled RD54, autosize, SIMH format RQ1 159MB, not attached, write enabled RD54, autosize, SIMH format RQ2 159MB, not attached, write enabled RD54, autosize, SIMH format RQ3 800KB, not attached, write enabled RX50, autosize, SIMH format sim> b rq0 and it will boot RSX11M where this will bring up a baseline RSX11M system. DU3 should be a virtual RX50 that will create a disk image that can be read with PUTR and moved to a real RX50 or you could use Linux DD to image the RX50. At any rate the emulated RSX11M system will have the tasks that should be compatible on your real PDP-11. You might also be able to kermit from the simulated to the physical PDP-11. At any rate having a virtual RSX11M system to experiment with will help you a great deal in getting your real system running. If this is too complicated, I could try sending you an RX50 disk image with the tasks you need, but I only have RSX11M V4.8 (I mostly use RSX11M+ V4.6) handy so we'd have to try those .TSKs to see if they might work. If you are not getting errors on the disk, then the disk is probably ok and the file system has some corruption. Remember that an RSX11M system should be shut down by running shut up to make sure all files are closed etc. BRU can do disk to disk copies but with only one RD51 and no tape it won't help much. In my RSX work I use a SCSI disk controller like a Emulex UC07 with the SCSI2SD card that emulates unto 4 DU disks on one microSD card. This makes it very easy to move large disk images from Simh on a PC to be bootable RSX disks on the PDP-11. It is easy to back up and very reliable. The SCSI2SD card is only $65 but Qbus SCSI cards are a bit pricey. By the way which CPU is in the PDP-11, a 11/23? Good Luck, Mark