Dennis Boone drb at msu.edu wrote: Looking at the source for vtserver v2.3, the srt0.s file contains the 'mul' instructions. The copy program is aware of the I&D space. It appears the primary purpose of vtserver is to allow the installation/copy of early Unix versions onto RK05's. The source to vtserver appears to be implemented using the early unix version, so it is not really what I need since I cannot modify it to work on my PDP-11/10. The initial vtboot portion of vtserver does work properly on my PDP-11/10. I am able to have the 'copy' program transferred over to the /10 but the processor halts soon after execution begins. The source for vtboot does look like it should work on most machines. I updated the code slightly to make it position independent. I am thinking I will need to write something that will allow me to transfer the disk image over a serial port. I just don't want to re-invent the wheel ;-) My needs are to take a disk image on a host machine and get it transferred over to a PDP-11 via a serial port to be scribbled onto a RK05 disk. Does anyone know of another tool that can do this? I am aware of the TU58 emulator, but that only helps getting something into memory on the PDP-11, but does not help in getting the data onto the RK05. Thank you so much for the information to date! I really appreciate the pointers and discussion. --barrym