I worked in several shops that had both IMS and CICS. I was always a CICS guy, and know essentially nothing about IMS/DC or IMS/TM...and always wondered why a shop would run both transaction processors.
On Tue, Jul 25, 2023 at 1:11 PM Lionel B. Dyck <[email protected]> wrote: > For history see > https://www.ibm.com/docs/en/zos-basic-skills?topic=now-history-ims-beginnings-nasa > and https://www.informit.com/articles/article.aspx?p=377307&seqNum=2 > > From the 2nd link: > > IMS is still a viable, even unmatched, platform to implement very large > online transaction processing (OLTP) systems and, in combination with Web > Application Server technology, it is the foundation for a new generation of > Web-based, high-workload applications. > > Here are some interesting facts about how IMS is used. > > IMS manages a large percentage of the world's corporate data. > > Over 95% of Fortune 1000 companies use IMS. > IMS manages over 15 million gigabytes of production data. > $2.5 trillion (in US dollars) per day is transferred through IMS by one > customer. > IMS processes over 50 billion transactions per day. > > IMS serves over 200 million users every day. > IMS processes over 100 million transactions per day for one customer. > IMS processes over 120 million transactions per day (7 million per hour) > for another customer. > IMS can process 21,000 transactions per second (over 1 billion per day) > using IMS data sharing and shared queues. > A single IMS has processed over 6000 transactions per second over a single > TCP/IP connection. > > > Lionel B. Dyck <>< > Website: https://www.lbdsoftware.com > Github: https://github.com/lbdyck > > “Worry more about your character than your reputation. Character is what > you are, reputation merely what others think you are.” - - - John Wooden > > -----Original Message----- > From: IBM Mainframe Discussion List <[email protected]> On Behalf > Of Schmitt, Michael > Sent: Tuesday, July 25, 2023 1:05 PM > To: [email protected] > Subject: Re: [EXT] Ars Technica: The IBM mainframe: How it runs and why it > survives > > 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 <[email protected]> On Behalf > Of David Spiegel > Sent: Tuesday, July 25, 2023 12:38 PM > To: [email protected] > 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 <[email protected]> On > > Behalf Of David Spiegel > > Sent: Tuesday, July 25, 2023 11:48 AM > > To: [email protected] > > 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 <[email protected]> On > >> Behalf Of Crawford Robert C (Contractor) > >> Sent: Tuesday, July 25, 2023 8:14 AM > >> To: [email protected] > >> 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 <[email protected]> On > >> Behalf Of Schmitt, Michael > >> Sent: Monday, July 24, 2023 11:43 AM > >> To: [email protected] > >> 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-mainfr > >> ame-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 [email protected] with the message: INFO > >> IBM-MAIN > >> > >> --------------------------------------------------------------------- > >> - For IBM-MAIN subscribe / signoff / archive access instructions, > >> send email to [email protected] with the message: INFO > >> IBM-MAIN > >> > >> > >> > >> --------------------------------------------------------------------- > >> - For IBM-MAIN subscribe / signoff / archive access instructions, > >> send email to [email protected] with the message: INFO > >> IBM-MAIN > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, send > > email to [email protected] with the message: INFO IBM-MAIN > > > > > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, send > > email to [email protected] with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send email > to [email protected] with the message: INFO IBM-MAIN > > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send email > to [email protected] with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > -- Jay Maynard ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
