ferris@eniac.seas.upenn.edu (Richard Ferris) (10/04/89)
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
aland@infmx.UUCP (Dr. Scump) (10/04/89)
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
kevin@msa3b.UUCP (Kevin P. Kleinfelter) (10/04/89)
ferris@eniac.seas.upenn.edu (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 TSO is not really an operating system. It is a terminal monitor program. It provides access to your operating system from a terminal. If you have TSO, chances are pretty good that you have MVS. :-) -- Kevin Kleinfelter @ Management Science America, Inc (404) 239-2347 gatech!nanovx!msa3b!kevin
munck@chance.uucp (Robert Munck) (10/05/89)
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. >... MVS as the new operating system.... >what is ... that OS and whether it ... replaces CMS or runs under it ... > >ferris@eniac.seas.upenn.edu Eniac is a node on the Internet? Jeez, I thought the thing wouldn't even run anymore because they couldn't get the right vacuum tubes. Anyway, your terminology is a bit confused. TSO and CMS are not really OSs in their own right, but subsystems that run under other OSs. CMS was at one time capable of running as an OS on a bare /360, but I believe that ability is long lost. It ran originally as an OS on a virtual machine under CP-40, a virtual machine Control Program running on a /360 mod 40 with a special DAT (Dynamic Address Translation) box that gave the 40 virtual memory. When the /360 mod 67 came along and TSS wasn't quite as wonderful as Big Blue said it would be, CP and CMS were naturals to move to that machine, becoming CP-67/CMS. With their next generation, IBM declared that they had invented virtual memory (surprising the people at Burroughs and various other places) and put CP/CMS on the new machines, eventually renaming it VM/370. The combination of VM and CMS has been greatly loved by IBM customers for nearly a quarter century and hated by large parts of the IBM organization. CMS (originally Cambridge Monitor System, for the IBM Cambridge Scientific Center where it was developed) is as good a program development environment as IBM has, though that's not saying much. TSO (The Slow One) came along a bit later, say late 1960's, as an interactive subsystem under the "main" OS for the /360, MVT. It is fairly universally hated by users and loved by IBM and user management. MVT has become MVS and various other acronyms on the /370 and later generations. TSO is essentially a special user program running on the OS and in tentative communication with interactive terminals. It is rumored that the last attempt to compile a program over 10K lines interactively has been executing on a 6-CPU mainframe in Maryland since late 1987. (TSO is not an especially usable programmer environment). These are, of course, my personal opinions. -- Bob Munck -- Bob <Munck@MITRE.ORG>, linus!munck.UUCP -- MS Z676, MITRE Corporation, McLean, VA 22120 -- 703/883-6688