RTEM-11

[Jerome H. Fine]

 >Johnny Billquist wrote:

> >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...

I suspect that the most likely possibility is that RTEM and RTEM-11 are 
used.

In addition, I also suspect that both Johnny and Ethan are correct in 
that RTEM
was supported under both RSX and VMS on an older VAX which allowed
compatibility mode.

I don''t know if Megan Gentry is still around or perhaps Allison or one 
of the
other DEC fellows.  Perhaps they might at least know something about which
hardware and operating system(s) supported RTEM?

In addition, RSTS/E also supported RT-11 programs via the SWITCH  RT11
capability.  However, only the RT-11 EMTs which are used by a SJ are 
supported
by RSTS/E.  At least there is quite reasonable documentation as well as 
the ability
to test and actually run RT-11 programs under RSTS/E up to the latest 
versions
of RSTS/E.  RT-11 EMTs for mapped RT-11 monitors (RT11XM) are not supported
 not are multi-terminal EMTs.  Also, probably the latest RT-11 EMTs for 
file status
information are also not supported under RSTS/E.

Probably in the same manner as RSTS/E, if RTEM is supported under VMS on an
older VAX, the most likely only the RT-11 EMTs which are used by a SJ are
supported.

Jerome Fine