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

19 Jul 2010

"Jerome H. Fine" <jhfinedp3k at compsys.to> wrote:

...
  Johnny
Billquist wrote:  
 > >> I suspect that the most likely
possibility is that RTEM and RTEM-11 
> >> are used.
 >
 > Huh? If you are suggesting that they would be the same, I can assure 
 > you they could not.  
 I would not assume anything until I actually had tested the presence or 
 absence of a
 specific "feature". 
What have any features have to do with this?
I'm telling you that RTEM-11 will not, and never have been capable of 
running on a VAX.
If there was a RTEM product for the VAX, it would have to be a separate 
product, with a separate code base from RTEM-11, since you cannot write 
a RT-11 emulator of any kind in PDP-11 mode on a VAX. It will have to be 
VAX code. And thus, it can not be the same product as a RT-11 emulator 
program written to run under RSX.

...
   > A very
common misconception these days seems to be that VAXen with 
 > PDP-1 compatibility could run PDP-11 programs. That is only true in a 
 > very limited sense. Only the basic PDP-11 instruction set is supported 
 > by the VAX, and only the user mode stuff. EMTs, as well as any other 
 > kind of traps, interrupts, and so on, was *not* supported.
 > When you execute an EMT in PDP-11 mode on a VAX, it will trap back to 
 > VAX mode. No possibility to have a PDP-11 trap handler.  
 The absence of a PDP-11 trap handler under VMS compatibility mode on a VAX
 is definitely one possible situation.  However, I suggest that it may 
 also be possible
 for RTEM under VMS on a VAX to handle some of the SJ RT-11 EMT requests. 
Definitely. But the code that catches the trap, and does something will 
have to be VAX code, and not PDP-11 code.

You cannot write a trap handler in PDP-11 code on a VAX, no matter how 
much of the PDP-11 compatibility that exist in the VAX hardware. The 
PDP-11 compatibility mode simple does not extend to that stuff. Period.

...
  > >>
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.
 >
 > It would have to be totally separate products in that case.  
 AGREED!! 
Thank you. Now we can proceed.

...
  > >> 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?
 >
 > I definitely remember (and probably still have some mail somewhere) 
 > from Megan mentioning that she used RTEM-11 for RT-11 work, running on 
 > RSX machines. Possibly even an 11/74.  
 I don't have enough information about RSX to know if RTEM-11 was supported.
 However, ... 
I'm telling you that it is. Just google for it, and you will find the 
documentation from DEC that is still on the net about this product. It's 
actually really simple. Go to "www.google.com". Type in "rtem-11 rsx"
in 
the search field, and hit enter.
The first hit will be 
http://www.google.se/url?sa=t&source=web&cd=1&ved=0CBcQFjAA&…CjH9ifJeDiJ9sf_daeyGX9-A,

which is "RSX-11M Optional Software Cross Reference Table", which lists 
what version of various software is compatible with RSX-11M V4.0 and 
V4.1. Among these, you'll find RTEM-11 V1.0 and V1.1. More "supported" 
than that is hard to get.

...
  > >>
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. 
 >
 > The correct technical term is that RSTS/E have a RT-11 *run time 
 > system*. An RTS in RSTS/E provides an environment under which you can 
 > get a specific behaviour. So you had RTSes for RT-11, RSX, BASIC+, 
 > TECO, DCL and some other stuff. Some RTSes were also KBMs (keyboard 
 > monitors), meaning you could "switch" to them, and get an interactive 
 > command line interpreter with that. But the RTS mostly implemented 
 > system calls. However, there were RTSes which didn't implement any 
 > system calls, and only gave you the basic calls RSTS/E itself 
 > provided, and mostly focused on being a KBM, such as DCL.  
 I apologize for my lack of familiarity with the terminology.  Your 
 description
 is what I was attempting to say. 
:-)

...
  Actually, my testing seems to show that RSTS/E
supports being able to
 run RT-11 programs even if the RT-11 RTS is not activated.  For example:
 RUN  MACRO
 is possible if the RTS is normal RSTS/E or RT-11.  This might be based 
 on the
 file type.  RSTS/E may determine that MACRO.SAV is an RT-11 program and
 support the RT-11 EMT requests.  Or RSTS/E may support naked RT-11 EMT
 requests from any program.  That is something I should test. 
No, you are confusing things, and making wild guesses.
What do you mean by "activated"? There is no activation. If an RTS is 
installed, it will always be used for programs that are marked as 
requiring that RTS. This is an "attribute" of a file. Whenever that file 
is run, it is run under the indicated RTS. If you try to run a program 
that requires an RTS that don't exist I would suspect that you'll get an 
error.

Also, if you type "RUN MACRO", how do you know that you are even running 
the RT-11 version? RSTS/E normally also have an RSX RTS available, and 
an MACRO.TSK, which is MACRO-11 running under the RSX RTS.

There is no RSTS/E RTS, by the way.

...
   > All
exeutable files have an RTS associated with it, and when the 
 > program is run, it is run under that RTS, which then handles all EMTs 
 > and so on when the program executes them.  
 Does the file type trigger the use of that RTS? 
Unless my memory have totally rotted away, the answer is no. The RTS 
associated with a file is an attribute of the file, just like file 
protection. There is a switch to PIP that you can use to check, and set, 
the RTS.
That said, all RTS have a default file extension as well, and I think 
that is used to search for runnable files if you just type "RUN MACRO" 
for example.

...
  I do have a question.  With V7 of RSTS/E, the FIT
program is able to
 copy files from a drive with an RT-11 file structure (such as an RX02)
 to the RSTS/E file structure.  My initial testing with V10.1 of RSTS/E
 shows that (at the very least the distribution which I am using) does not
 have a FIT program.  Is there some other method of making a copy of
 a file on an RX02 with an RT-11 file structure to a device with a RSTS/E
 file structure? 
Either FIT, or some "new" program that does the same thing, I'd guess. 
I'm no expert on RSTS/E, and my experience is old. I mostly ran RSTS/E 
between V7.1 and V9.0, with the majority of my time in the V7-V8 timeframe.

...
  Also, is it possible to run an RT-11 program under a
DEBUG mode?  It
 would be much easier to check out the code if that is possible.  At the
 moment, I can check most of the code under RT-11.  However, the
 portion which runs in a different manner under RSTS/E as opposed to
 RT-11 since RSTS/E does not support all RT-11 EMT requests in the
 same manner as RT-11. 
What do you mean by "debug" mode???

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol