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
