Can anyone explain me what is the command MCR (sometimes abreviated to
MC). It is quite intriguing to me, namely the message whenever it is
run without arguments:
%DCL-W-ACTIMAGE, error activating image RSX
-CLI-E-IMAGEFNF, image file not found xxxxxx$DKA0:[SYS0.SYSCOMMON.][SYSEXE]RSX.EXE;
RSX? The name RSX rings a bell; something to do with some old PDP-11
operating system? RSX-11? Is that it?
I head that the early VMS versions used PDP-11 software, by the means
of some kind of PDP-11 instruction set emulation with the VAX
processors, but it strikes me that it has reached until today, in
Alpha architecture... Or probably I'm just mixing things up... what a mess!
Cheers,
Rodrigo
--
*** Rodrigo Martins de Matos Ventura <***@isr.ist.utl.pt>
*** Web page: http://www.isr.ist.utl.pt/~yoda
*** Teaching Assistant and PhD Student at ISR:
*** Instituto de Sistemas e Robotica, Polo de Lisboa
*** Instituto Superior Tecnico, Lisboa, PORTUGAL
*** PGP fingerprint = 0119 AD13 9EEE 264A 3F10 31D3 89B3 C6C4 60C6 4585
MCR = "Monitor Console Routines". It was the primary command interface
for the RSX family of operating systems on the PDP-11 (some flavors, such
as RSX-11M+, also had a flavor of DCL). Originally, when the command
"MCR" was used on VMS, it ran the AME (Application Migration Executive)
which ran PDP-11 code in compatibility mode. Now on VMS, "MCR" is the same
thing as saying "RUN SYS$SYSTEM:".
Can anyone explain me what is the command MCR (sometimes abreviated to
MC). It is quite intriguing to me, namely the message whenever it is
%DCL-W-ACTIMAGE, error activating image RSX
-CLI-E-IMAGEFNF, image file not found
xxxxxx$DKA0:[SYS0.SYSCOMMON.][SYSEXE]RSX.EXE;
RSX? The name RSX rings a bell; something to do with some old PDP-11
operating system? RSX-11? Is that it?
I head that the early VMS versions used PDP-11 software, by the means
of some kind of PDP-11 instruction set emulation with the VAX
processors, but it strikes me that it has reached until today, in
Alpha architecture... Or probably I'm just mixing things up... what a mess!
Cheers,
Rodrigo
--
*** Web page: http://www.isr.ist.utl.pt/~yoda
*** Instituto de Sistemas e Robotica, Polo de Lisboa
*** Instituto Superior Tecnico, Lisboa, PORTUGAL
*** PGP fingerprint = 0119 AD13 9EEE 264A 3F10 31D3 89B3 C6C4 60C6 4585
------
+-------------------------------+----------------------------------------+
| Dan O'Reilly | "There are 10 types of people in this |
| Principal Engineer | world: those who understand binary |
| Process Software | and those who don't." |
| http://www.process.com | |
+-------------------------------+----------------------------------------+
Can anyone explain me what is the command MCR (sometimes abreviated to
MC). It is quite intriguing to me, namely the message whenever it is
%DCL-W-ACTIMAGE, error activating image RSX
-CLI-E-IMAGEFNF, image file not found xxxxxx$DKA0:[SYS0.SYSCOMMON.][SYSEXE]RSX.EXE;
RSX? The name RSX rings a bell; something to do with some old PDP-11
operating system? RSX-11? Is that it?
Pretty much. Entering MCR invokes a DCL internal routine which attempts to
run the specified image and passes the rest of the command line to it. The
default image is SYS$SYSTEM:RSX.EXE (or possibly it's RSX if missing with a
default file-spec of SYS$SYSTEM:.EXE, I'm not sure which). If you enter a
parameter, that is the name of the image to be run. So, MC AUTHORIZE will
run the familiar AUTHORIZE utility, while MC SYS$LOGIN:MYIMAGE is needed to
run MYIMAGE which is not in SYS$SYSTEM. RSX.EXE, if present, is an
alternative command-line interpreter, familiar to RSX users. The prompt is
MCR> ...
In early VAXes, PDP compatibility mode was built-in to the hardware. (Later
on, it was emulated in software and an additional layered product was
required - AME?) Native RSX images (subject to certain limitations) would
run just as they would on a PDP-11. Some utilities were provided as
straight copies, and MC(R) was the way to invoke them and pass along the
command line. MC DISP was very similar to SHO PROC/CONT, MC TALK was the
precursor to PHONE. PIP was also provided, although DIRECTORY existed, and
had some useful features, /FR for one.
The most common use for MCR in the last 20 years or so has been as a way of
invoking images and supplying command lines at the same time.
--
Never put off till tomorrow what you can ignore entirely.
Mail john rather than nospam...
Can anyone explain me what is the command MCR (sometimes abreviated to
MC). It is quite intriguing to me, namely the message whenever it is
%DCL-W-ACTIMAGE, error activating image RSX
-CLI-E-IMAGEFNF, image file not found xxxxxx$DKA0:[SYS0.SYSCOMMON.]
[SYSEXE]RSX.EXE;
IIRC that is the Migration Console Routine.
RSX? The name RSX rings a bell; something to do with some old PDP-11
operating system? RSX-11? Is that it?
Yes. VAX is Virtual Address eXtended and was a 32-bit OS built on the
base of RSX-11 from 16-bit PDP-11's. All VAXen had a PDP-11 emulation
mode built into the hardware and DEC promised they would always, but
eventually that became a software emulation add-on.
Everything is now native 32-bit on OpenVMS VAX, but the MCR interface
remains, especially for "foreign" commands.
I head that the early VMS versions used PDP-11 software, by the means
of some kind of PDP-11 instruction set emulation with the VAX
processors, but it strikes me that it has reached until today, in
Alpha architecture... Or probably I'm just mixing things up... what a
mess!
You are not mixing things up, but it is certainly *NOT* a mess. It's
called
backward compatibility and allows things written before 1977 to continue to
work.
Cheers,
Rodrigo
--
*** Web page: http://www.isr.ist.utl.pt/~yoda
*** Instituto de Sistemas e Robotica, Polo de Lisboa
*** Instituto Superior Tecnico, Lisboa, PORTUGAL
*** PGP fingerprint = 0119 AD13 9EEE 264A 3F10 31D3 89B3 C6C4 60C6 4585
And why it is the name for band My Chemical Romance too? I'm not yet another emo kid which stumbled upon here, just I'm curious when I found out accidentally about this band when searching how to use this command.
And why it is the name for band My Chemical Romance too? I'm not yet
another emo kid which stumbled upon here, just I'm curious when I found
out accidentally about this band when searching how to use this command.
MCR The Command was a command well before any of the members of MCR The
Band were born. Maybe go ask them for the origin of the name, if it's
not already been documented?
More for posterity and history around the then-current status of the
MCR command within OpenVMS.
This may well have been the thread that kicked off a discussion or
three within OpenVMS development, around the MCR command and
particularly around its semi-documented status within the OpenVMS
documentation set. There were a few references to the MCR command
scattered around in the manuals and particularly in the examples
published in the documentation set, though the bulk of the MCR-related
command documentation and related baggage had been previously expunged
with the removal of the then-VMS pieces of RSX-11M compatibility mode
at then-VAX/VMS V4.0; when then-VAX/VMS went fully native on VAX.
Whether the then-we OpenVMS development should re-document and
implicitly also then support at least parts of the MCR command—and as
this thread touches upon, the command is somewhat unusual—or whether
then-we should work to further remove the remaining documentation
references to MCR.
As part of this de-documentation effort, a reference to the command and
the RSX-11M compatibility environment would have reasonably been added
into the OpenVMS obsolete features manual, though that manual had
itself been marked obsolete. Go figure.
For reasons of compatibility, the MCR command wouldn't be removed from
the command tables nor from the system, but remaining references to MCR
in the documentation would be removed.
A number of MCR references were then removed from then-opened manuals,
or were queued for removal as the associated and then-closed manuals
were eventually opened and updated and regenerated.
This is one of the areas where OpenVMS documentation falls down badly.
The whole approach was toward printed manuals and stocks and printing
costs, and not toward continuous updates and native-online
documentation. Hence part of my comments around re-thinking the
entirety of the related processes, as well as the tools and the
currently-limited app and tool access available. This is why various
manuals can and variously did end up stale. More often than might be
realized. It wasn't feasible to reprint them, so the updates languished
in source files and/or in bug-tracking databases, and weren't available
to customers. But I digress.
References to MCR in published source code examples would have been the
next targets for further de-documenting the command. There was also
some discussion around the longer-term incremental removal of MCR
references in existing DCL procedures within OpenVMS itself, though
that would have been more aspirational than reality, and only as the
particular DCL was modified for other purposes and other reasons.
There's far too much stale code around in OpenVMS itself and in its
published examples, and it all gets used as examples for newer OpenVMS
and newer customer development, unfortunately. OpenVMS was never very
good at documenting and guiding end-users and ISVs around
security-related programming information, for instance. And OpenVMS
development hasn't been particularly adept at de-documenting and
removing old and outdated bits, at moving folks away from old and
outdated designs, and old approaches. This is probably also related to
why a number of long-term OpenVMS folks haven't recognized the latent
security issues in OpenVMS and in user and third-part apps, too. But I
digress, again.
MCR isn't AFAIK considered documented and—given the retirement of the
RSX-11M compatibility mode kit some years ago—probably also is not
particularly considered supported for customer use, and is probably
best avoided in new DCL procedures and new work. But it almost
certainly won't be removed, and the mainline RUN SYS$SYSTEM behavior
will almost certainly continue to work. This for reasons of
compatibility. Donno. Ask VSI.
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