Mike Schwab said:
*One thong that helps ImMS is that everything related to a root key isstored together, where as DB2 each segment is a separate database.* Thinging the wrong thong methinks. For starters, a DB2 database can have many tables/tablespaces. From a physical POV an IMS DB can be a single segment or have multiple segments linked by pointers. I've seen models for hierarchical databases implemented in DB2 tables. It's messy and I have to ask why would you do that? Disclaimer...Not a DB2 fan but it pays. On Wed, Jul 26, 2023 at 9:28 AM Mike Schwab <mike.a.sch...@gmail.com> wrote: > One thong that helps ImMS is that everything related to a root key is > stored together, where as DB2 each segment is a separate database. > > On Tue, Jul 25, 2023, 17:58 Attila Fogarasi <fogar...@gmail.com> wrote: > > > IMS/DC predated VTAM (which came in 1974). It was BTAM and later also > > TCAM. IBM MQ started life as a TCAM next generation before being > > redesigned to be store/forward/transform messaging service. That was > more > > than a decade after IMS/DC message queue. As others have said IMS > started > > as a customer initiative, by Rockwell for the Saturn V moon rocket -- > they > > couldn't keep track of the huge bill of materials needed. The IMS > > architecture and internal implementation was always performance > > (instruction path length) and throughput focused. In contrast CICS was > > application services focused, hence a completely different architecture. > > For the first 20 years, IMS was an order of magnitude faster than CICS > once > > IMS Fast Path came along (1977). Over time the same technology (things > > like Data in Memory) was adopted by CICS, so today there is less speed > > difference. Both exploit the system architecture for z very effectively, > > something that other transaction manager solutions such as Tuxedo (now > > Oracle) were never able to do, despite starting 20 years later with a > clean > > slate. Meanwhile there are still IMS application programs running that > > were written 50+ years ago and are fully supported today! > > > > On Wed, Jul 26, 2023 at 4:27 AM Schmitt, Michael < > michael.schm...@dxc.com> > > wrote: > > > > > I wasn't working then 😊, but I think that IMS/DB was developed then, > as > > > the bill of materials database. The question I have is when IMS/DC come > > > along? The online documentation is unclear. > > > > > > > > > The Introduction to IMS says: > > > > > > IBM developed an online component to ICS/DL/I to support data > > > communication access to the databases. The DL/I callable interface was > > > expanded to the online component of the product to enable data > > > communication transparency to the application programs. A message queue > > > function was created to maintain the integrity of data communication > > > messages and to provide for scheduling of the application programs. > > > > > > The online component to ICS/DL/I ultimately became the Data > > Communications > > > (DC) function of IMS, which became the IMS Transaction Manager (IMS TM) > > in > > > IMS Version 4. > > > > > > > > > So *maybe* the original system just allowed some kind of communication > > > access to the database, but not a full screen driven transaction server > > > with a message queue like we know today. > > > > > > > > > > > > While we're on the subject of IMS/TM... > > > > > > Is it true that the MQ Series message queue was based on the IMS/TM > > > message queue? Or is there no connection other than the function they > > > provide. > > > > > > > > > -----Original Message----- > > > From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On > Behalf > > > Of rpinion865 > > > Sent: Tuesday, July 25, 2023 1:09 PM > > > To: IBM-MAIN@LISTSERV.UA.EDU > > > Subject: Re: [EXT] Ars Technica: The IBM mainframe: How it runs and why > > it > > > survives > > > > > > I'm probably wrong. But I thought IMS was developed for NASA during > the > > > Gemini and Apollo time frame. > > > > > > > > > > > > > > > Sent with Proton Mail secure email. > > > > > > ------- 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. > > > 😊 > > > > > > > > > > > > > > > ---------------------------------------------------------------------- > > > > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send > > > email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > > > > > > > > > > > > > ---------------------------------------------------------------------- > > > > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > > > > send email to lists...@listserv.ua.edu with the message: INFO > > > IBM-MAIN > > > > > > > > > > > > > > > ---------------------------------------------------------------------- > > > > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > > > > send email to lists...@listserv.ua.edu with the message: INFO > > > IBM-MAIN > > > > > > > > > ---------------------------------------------------------------------- > > > > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > > > > send email to lists...@listserv.ua.edu with the message: INFO > > > IBM-MAIN > > > > > > > > > > > > ---------------------------------------------------------------------- > > > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > > > send email to lists...@listserv.ua.edu with the message: INFO > > IBM-MAIN > > > > > > > > > > > > > ---------------------------------------------------------------------- > > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > > send email to lists...@listserv.ua.edu with the message: INFO > IBM-MAIN > > > > > > > > > > > > > > > > > ---------------------------------------------------------------------- > > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > > send email to lists...@listserv.ua.edu with the message: INFO > IBM-MAIN > > > > > > ---------------------------------------------------------------------- > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > > > > > > > > > > ---------------------------------------------------------------------- > > > For IBM-MAIN subscribe / signoff / archive access instructions, > > > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > -- Wayne V. Bickerdike ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
