Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!nsc!pyramid!infmx!aland
From: aland@infmx.UUCP (Dr. Scump)
Newsgroups: comp.os.misc
Subject: Re: Operating systems
Message-ID: <2467@infmx.UUCP>
Date: 4 Oct 89 06:01:51 GMT
References: <6649@hubcap.clemson.edu| <15064@netnews.upenn.edu>
Reply-To: aland@infmx.UUCP (alan denney)
Organization: INFORMIX Professional Services ("Peace thru Normalization")
Lines: 44

In article <15064@netnews.upenn.edu| ferris@eniac.seas.upenn.edu.UUCP (Richard Ferris) writes:
|I have used two IBM mainframe operating systems: TSO and CMS.
|A friend of mine mentioned that at her computer installation
|they were changing over to MVS as the new operating system.
|Not being very knowledgable about these things, I was wondering
|what is the deal with that OS and whether it is something that
|replaces CMS or runs under it.  Could someone give me a very
|quick explanation?  I would really appreciate it.
|
|Thanks.  RF
|
|Richard T. Ferris
|ferris@eniac.seas.upenn.edu
|University of Pennsylvania

TSO and CMS are *not* operating systems -- they are two different forms
of time-sharing subsystems on IBM mainframes.

TSO, short for Time Sharing Option, usually runs under an MVS variant
such as MVS/SP or MVS/XA or (whatever the new one is, MVS/E-something).
A TSO user is an MVS task and can submit jobs at will.  Privileged TSO
users can even submit operator commands.  (Including shutting down
the system, if s/he knows how.  Scary, huh?)

CMS, short for Conversational Monitor System (?), is a user interface
that is typically run on top of VM.  

Of course, keep in mind that VM is a true Virtual Machine capability,
and you can run *other* operating systems under VM if you desire.
For example, my old company had a massive amount of in-house software
that required extensive conversions to run under MVS/XA.  They did 
the bulk of their testing by running MVS/XA under  VM on a much smaller
mainframe, and still got usable results.

Corrections welcome -- I've been out of that end of the industry for
a couple of years...

--
    Alan S. Denney  @  Informix Software, Inc.    
         {pyramid|uunet}!infmx!aland                 "I want to live!
   --------------------------------------------       as an honest man,
    Disclaimer:  These opinions are mine alone.       to get all I deserve
    If I am caught or killed, the secretary           and to give all I can."
    will disavow any knowledge of my actions.             - S. Vega