Looks like I'm wrong. Even in 1970 IMS/360 appears to have the same online transaction architecture as today:
http://bitsavers.trailing-edge.com/pdf/ibm/360/ims/SH20-0634-1_IMS_360_Program_Description_Jul70.pdf So why is the CICS architecture so radically different than IMS/TM? Is it the other way around? CICS is the way it is because that way it could achieve higher performance and capacity (i.e. number of simultaneous terminals) than the more direct method IMS used, at least at the time? -----Original Message----- From: Schmitt, Michael Sent: Tuesday, July 25, 2023 1:27 PM To: IBM Mainframe Discussion List <[email protected]> Subject: IMS/Transaction Manager I wasn't working then ๐, 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 <[email protected]> On Behalf Of rpinion865 Sent: Tuesday, July 25, 2023 1:09 PM To: [email protected] 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 <[email protected]> wrote: > No, I donโt 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-mainframe-how-it-runs-and-why-it-survives/ > > > > > > Iโd 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. ๐ > > > > > > ---------------------------------------------------------------------- > > > 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 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
