RTEM-11 - test-drb@ccmp.vtda.org

14 Jul 2010

Ethan Dicks <ethan.dicks at gmail.com> wrote:

...
  On 7/14/10, Jerome H. Fine <jhfinedp3k at
compsys.to> wrote:
   In addition, does anyone know  of any systems
currently running
 which support RTEM-11 features which allow RT-11 programs
 to run in that environment?  My assumption is that VMS on a VAX
 supported RTEM-11 at some point, but perhaps (if I am correct)
 the RTEM-11 support was not  continued with
 more recent versions of VMS on the VAX and most definitely VMS on the
 Alpha.  Can anyone comment on these questions?  
 Based on the vague reference at
 http://s-and-b.net/help?key=RTEM~Release_notes&title=VMS Help&referer=
 and what I know of VMS and DEC hardware, I'd think that RTEM-11 would
 require a VAX processor with "compatibility mode", i.e., a "VAX-11"
 processor.  The primary models would be the 11/78x, 11/750, 11/730 and
 11/725 (I don't recall if the VAX 86xx still had "compatibility mode"
 or not, but it should be easy to check).  MicroVAXen and such did not
 have it, and Alpha processors certainly did not have it.

 That being said, I have no experience with RTEM-11, but I would be
 surprised to learn it ran on a machine made after about 1986 or so. 
RTEM might be something else than RTEM-11, which was a software product 
for RSX. Just google for RTEM-11, and you'll find some references for it.

However, I wonder about RTEM for VAX. It's certainly possible, but I 
can't find any other reference to it, and DEC's old SPDs, especially 
those with software version compatiblity matrixes, are usually pretty 
good as a way of finding out what software existed.

As for PDP-11 compatibility in VAXen, yes, the 86x0 machines have that. 
Those were the last, however.

For all other VAXen running VMS, if you wanted to run RSX software, you 
needed a PDP-11 emulator product for VMS, which was available, in 
addition to the RSX additions for VMS, which was also a separate 
product. That thing was supported up until fairly recently, though.
But again, that's for RSX stuff...

	Johnny