I'm probably wrong.  But I thought IMS was developed for NASA during the Gemini 
and Apollo time frame.




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------- Original Message -------
On Tuesday, July 25th, 2023 at 2:05 PM, Schmitt, Michael 
<michael.schm...@dxc.com> wrote:


> No, I don’t know of an IMS/TM + DB2 system.
> 
> But then the CICS systems I work with are also not using DB2. They use VSAM!
> 
> And even for IMS/DB, my gut feel is there are a lot more CICS + IMS/DB 
> installations than IMS/TM + IMS/DB.
> 
> 
> Also, CICS is from ~1966, IMS/DC (later renamed to IMS/TM in IMS Version 4) 
> must have been much later than that, but I can't find the date.
> 
> Reason I think I it is much later (late 70's? early 80's?) is because, as I 
> understand it, the reason CICS was designed the way it is was because at the 
> time, the OS it ran on wasn't so great at multitasking. Or maybe didn't do 
> multitasking at all. But IMS/DC was designed at a time when the OS was good 
> at preemptive multitasking between tasks and jobs. Was this MVS?
> 
> 
> -----Original Message-----
> From: IBM Mainframe Discussion List IBM-MAIN@LISTSERV.UA.EDU On Behalf Of 
> David Spiegel
> 
> Sent: Tuesday, July 25, 2023 12:38 PM
> To: IBM-MAIN@LISTSERV.UA.EDU
> Subject: Re: [EXT] Ars Technica: The IBM mainframe: How it runs and why it 
> survives
> 
> Hi Michael,
> I have yet to see a site running IMS/DC and not run IMS/DB.
> Have you actually seen this?
> 
> BTW, the article had more than one technical error. For example, a JCL
> Step name with 9 characters.
> 
> Regards,
> David
> 
> On 2023-07-25 13:16, Schmitt, Michael wrote:
> 
> > The Ars Technica article was discussing CICS as an application server. I 
> > was comparing CICS as an application server to IMS/TM as an application 
> > server. The DBMS is a different issue; there's no reason why IMS/TM must be 
> > used with IMS/DB. You can use IMS/TM with DB2.
> > 
> > The point I was trying to make was that CICS was designed as a cooperative 
> > multitasking system that reproduces all of the OS functions in itself. 
> > IMS/TM (originally IMS/DC) was designed to use the OS to do OS things and 
> > does none of that in itself, so it is much simpler.
> > 
> > -----Original Message-----
> > From: IBM Mainframe Discussion List IBM-MAIN@LISTSERV.UA.EDU On Behalf Of 
> > David Spiegel
> > Sent: Tuesday, July 25, 2023 11:48 AM
> > To: IBM-MAIN@LISTSERV.UA.EDU
> > Subject: Re: [EXT] Ars Technica: The IBM mainframe: How it runs and why it 
> > survives
> > 
> > Hi Michael,
> > You said: "...CICS is to IMS as Windows 3.1 is to Windows 10. ..."
> > You're comparing apples and oranges.
> > (CICS has no native Database portion.)
> > BTW, a lot of the banks, insurance companies etc. are running CICS+DB2.
> > The majority of IMS users need it to support 40+ year old application
> > systems.
> > Which one is the real dinosaur? (Hint: It's not CICS)
> > 
> > Regards,
> > David
> > 
> > On 2023-07-25 10:37, Schmitt, Michael wrote:
> > 
> > > So CICS is no longer doing cooperative multitasking within each AOR, and 
> > > thus requiring CICS versions of OS commands to prevent wait states from 
> > > freezing the entire AOR? A CICS program can do direct GETMAINs, LOADS, 
> > > abends, rather than use CICS commands? CICS no longer requires special 
> > > versions of tools (e.g. debugger, abend dump management) and instead can 
> > > use the same tools as batch programs? A CICS programmer no longer needs 
> > > to learn a long list of CICS commands and EXEC CICS syntax? A CICS region 
> > > no longer contains the storage from all of the transactions currently 
> > > running and is now only one transaction in the region at a time? CICS 
> > > transactions can no longer stomp on each other's memory?
> > > 
> > > Great, I did not know that.
> > > 
> > > IMS/TM uses the operating system for multitasking. There are no IMS/TM 
> > > specific tools. An IMS/TM programmer only needs to know two commands, one 
> > > to get a message and another to send it. IMS transaction abends look 
> > > (almost) exactly like a batch abend. IMS programs have no restrictions on 
> > > OS facilities. An IMS program can even do an STIMER (WAIT) without 
> > > affecting any other transaction processing. Because, it uses the OS to do 
> > > preemptive multitasking, like a modern operating system.
> > > 
> > > -----Original Message-----
> > > From: IBM Mainframe Discussion List IBM-MAIN@LISTSERV.UA.EDU On Behalf Of 
> > > Crawford Robert C (Contractor)
> > > Sent: Tuesday, July 25, 2023 8:14 AM
> > > To: IBM-MAIN@LISTSERV.UA.EDU
> > > Subject: Re: [EXT] Ars Technica: The IBM mainframe: How it runs and why 
> > > it survives
> > > 
> > > Sorry, I worked in a shop that had both and I can tell you CICS is way 
> > > more flexible, modern and performed better.
> > > 
> > > I will give you this: IMS is a great piece of 90's technology.
> > > 
> > > Robert Crawford
> > > Abstract Evolutions LLC
> > > (210) 913-3822
> > > 
> > > -----Original Message-----
> > > From: IBM Mainframe Discussion List IBM-MAIN@LISTSERV.UA.EDU On Behalf Of 
> > > Schmitt, Michael
> > > Sent: Monday, July 24, 2023 11:43 AM
> > > To: IBM-MAIN@LISTSERV.UA.EDU
> > > Subject: [EXT] Ars Technica: The IBM mainframe: How it runs and why it 
> > > survives
> > > 
> > > Ars Technica published a deep-dive explainer of modern IBM mainframes:
> > > 
> > > https://arstechnica.com/information-technology/2023/07/the-ibm-mainframe-how-it-runs-and-why-it-survives/
> > > 
> > > I’d quibble with the application server topic that talks about CICS with 
> > > no mention of IMS/TM. CICS is to IMS as Windows 3.1 is to Windows 10. 😊
> > > 
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