[Info-vax] Whither VMS?

[xxx]

Bob Eager wrote:
> On Fri, 18 Sep 2009 12:54:14 -0500, Bob Koehler wrote:
> 
>> In article <7hhqleF2u15qvU2 at mid.individual.net>, billg999 at cs.uofs.edu
>> (Bill Gunshannon) writes:
>>> So then, you agree with me that DCL, per se, is not really a part of
>>> the OS as it functions just fine without it.
>>    Nope.  I've never seen a VMS system running without DCL.  Even when
>>    we used VMS in a manner similar to an embedded system it did have an
>>    OPA0, and we used DCL heavily.
> 
> I've seen a VMS system that didn't even have a console.
> 
> It was called an LPS-40.

DCL is the default CLI, and plays a major role in the customary behavior 
of VMS that we all know, but VMS can be run with other CLIs with 
different behaviors.

It was pointed out before that DCL runs in its own private special mode 
(Supervisor) that allows it to play its unique and special role but 
other CLIs can get the job done too.  It is not very easy to discover 
HOW to write a CLI for VMS, but as was mentioned that is another 
story...  As such DCL is "more equal" than other CLIs, but the fact is 
VMS can run under other CLIs too.

   $HELP LOGIN /CLI:

   LOGIN

     /CLI

         /CLI=command-language-interpreter

      Specifies the name of an alternate command language interpreter
      (CLI) to override the default CLI listed in the UAF. The CLI
      you specify must be located in SYS$SYSTEM and have the file type
      .EXE.

      If you do not specify a command interpreter by using the /CLI
      qualifier and you do not have a default CLI listed in the UAF,
      the system supplies the qualifier /CLI=DCL by default.

BTW besides the alternate CLIs that have been mentioned, does anyone 
recall /CLI=MCR back in the early days of VMS?  In fact if you enter MCR 
as a bare command in DCL today it still knows that it should look for 
RSX.EXE.  I think the RSX MCR alternate CLI support (and the supporting 
RSX programs it used) were built into the base VMS distribution in the 
early days and then it was pushed out to a layered product later on 
(Around the time the "/11" stopped being on the end of CPU model numbers 
when they went from hardware support to software support for the PDP-11 
mode I thin)).  I don't know if the yayered product would still work on 
the current versions of VMS.  I do know I kept it on my systems for a 
long time so I could use certain features in the supporting RSX programs 
that did not have equivalents in VMS.

Bob Hassinger