loading disk image on PDP-11

B M iamvirtual at gmail.com
Tue Jun 9 16:45:16 CDT 2009

Dennis Boone drb at msu.edu wrote:

> > "I was thinking of using vtserver to transfer the image over a serial
> > line, but the 'copy' program is not compatible with my PDP-11/05 (it
> > uses the 'mul' and 'div' instructions which is not available on my
> > PDP-11/10)."
> I haven't exhaustively searched for such instructions, but a sample
> multiplication found in the C source didn't turn into a mul
> instruction.  You sure this is the cause?
> De

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

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

Thank you so much for the information to date!  I really appreciate
the pointers and discussion.


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