[Info-vax] OT: obscure PDP11 OSes (even more dinosaury)

[Johnny Billquist]

On 2015-06-22 17:51, Jan-Erik Soderholm wrote:
> Browsing around in our development system, I found a MAR
> file with the following as a comment at the top:
>
> ;
> ; FUNCTIONAL DESCRIPTION:
> ;
> ; DOWN_LINE_LOAD.
> ; THE ALLOCATED TT_LINE IS DEALLOCATED. A MAILBOX IS CREATED TO BE
> ; USED TO COMMUNICATE WITH A SUBPROCESS, WHO TAKES CARE OF
> ; THE COMMUNICATION WITH THE PDP-11/23 AND LOADS THE 11/23 WITH
> ; A RSX-11/S SYSTEM...
> ;
>
> So you could "load" a PDP with an RSX system over a serial line!?
> And the VMS system must have had a RSX-11/S "image" available?
>
> Maybe I read to much into that comment, they might just be saying
> that the PDP actualy is running a RSX-11/S system... :-)

No, you understand this right. PDP-11s can downline load RSX-11S. 
RSX-11S is a diskless system that needs a host to boot from.

The host can can be either RSX-11M, RSX-11M-PLUS or VMS.

The loading is done with MOP, and can be done over serial lines using 
DDCMP, or over Ethernet.

	Johnny