To me, mainframe denotes one large computer that is expandable to handle volumes of tasks and data that require hundreds if not thousands of PC-class systems to handle, with an emphasis on reliability, availability, and serviceability. It's not just CPU power or number of cores, but the ability to connect thousands of volumes of data and access them simultaneously, and move that data from point A to point B efficiently. It's also a mindset: instead of "just reboot it", RAS demands an effort be made to find the cause of every problem and fix it.
Yes, it needs specialized skills and tools, but then so does that datacenter that PC types say "oh, just slide another rack row of blade servers in" about. There are jobs mainframes do well, and that's why there are still so many in service. On Mon, Jul 31, 2023 at 5:41 AM P H < 000004843e86df79-dmarc-requ...@listserv.ua.edu> wrote: > IBM's definition of mainframe (Source: DICTIONARY OF IBM & COMPUTING > TERMINOLOGY) > > mainframe n. A computer, usually in a computer center, with extensive > capabilities and > resources to which other computers may be connected so that they can share > facilities. > Originally referred to the central processing unit of a large computer, > which occupied the largest or central frame (rack). > > In case of IBM z, a single component doesn't doesn't make it a mainframe. > It's the whole system i.e. microprocessor, cache, memory, I/O Subsystem, > PR/SM, microcode/firmware, instruction set , RAS, Security etc etc etc. > > I suggest, comparison of individual components of IBM z with individual > components of other technologies is not valid. > > ________________________________ > From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> on behalf > of Jon Perryman <jperr...@pacbell.net> > Sent: 29 July 2023 17:28 > To: IBM-MAIN@LISTSERV.UA.EDU <IBM-MAIN@LISTSERV.UA.EDU> > Subject: Definition of mainframe? Was: Ars Technica > > Can anyone provide the definition of MAINFRAME? The ARS Technica article > is complete nonsense because the mainframe is a state of mind and nothing > to do with reality. Can anyone prove me wrong? > https://arstechnica.com/information-technology/2023/07/the-ibm-mainframe-how-it-runs-and-why-it-survives/ > . > > The IBM z16 is just 4 motherboards containing 16 CPU and many PCIe slots. > Linux will run on an IBM z16. Is a PC also mainframe? Forget zPDT because I > suspect it still uses a PCIe zCPU card. I can't say with any certainty, but > I suspect that z/OS will run on a PC by using Hercules. What is the > definition of MAINFRAME? > > 1. CPU does not make a mainframe: The smallest IBM z16 (39 user cores of > the 64 cores) is the same as an AMD Ryzen 4.2Ghz CPU (64 user cores of 64 > cores). The largest IBM z16 (200 user cores of the 256 cores) is the same > as 4 AMD Ryzen CPU on 1 motherboard (256 user cores of the 256 cores). Both > are CISC CPU (AMD uses X86 instructions versus IBM z instructions). IBM > Telum (5.2Ghz) has a slightly faster clock than AMD Ryzen (4.2Ghz) but is > offset by the 25% extra user cores. IBM z16 has 4 motherboards for 16 CPU > and the same AMD Ryzen would need 1 motherboard for 4 CPU. > > 2. Hardware does not make a mainframe. IBM z16 has PCIe and ram which are > also on every modern motherboard. IBM z16 chooses not to include other > hardware (e.g. SATA, IDE, WIFI and more). Motherboards choose not to have > 1,600 PCIe slots. IBM could allow PCIe graphics cards, mice, keyboards and > more. Essentially, IBM z16 and AMD Ryzen can implement the same hardware if > there was enough customer demand. > > 3. OS does not make a mainframe. Linux running on z16 doesn't make it > mainframe Linux. There's nothing stopping Linux from taking advantage of > every z16 hardware feature (e.g. 1,600 PCIe slots) but no one is willing to > build the Linux software. IBM hasn't duplicated z/OS software features in > Linux. > > 4. Software does not make a mainframe. IBM sells DB2 for Linux and DB2 for > z/OS. DB2 for Linux runs on all hardware including z16. With Linux, you can > still run DB2 on z16 but large customers choose DB2 for z/OS. > > ASK YOURSELF: Other than design philosophy, name 1 fundamental difference > between IBM z16, AMD Ryzen and the software. > > ASK YOURSELF: Since design philosophy is the only difference, name the > philosophy that makes a mainframe. > > Despite the story's false claims for z/OS relevance, it is ignorance in > the Linux community that makes IBM z/OS relevant. Specifically, it's the > lack of design in Linux. Consider DB2 for Linux and DB2 for z/OS which are > the same product both from IBM and available on an IBM z16. Linux people > tell you they provide the same results, but they ignore the intrinsic > capabilities of z/OS design. DB2 for Linux supports high availability and > large databases but it requires knowledge of big data solutions, Linux > clustering solutions and more. Add a computer to the cluster and you must > replicate the master disk. Take a computer offline from the cluster, then > it must re-sync or replicate the master disk. DB2 on z/OS does not > experience these problems because of z/OS shared dasd and dasd mirroring. > > ASK YOURSELF: Name 1 brilliant feature design that originated directly > from Linux or Unix. Please don't use features that originated from IBM > (e.g. databases, SQL, HTML, Cloud and more). > > Brilliant feature design exposes very little. For instance, does anyone > know the problems solved by z/OS shared dasd and dasd mirroring. Linux > people on the other hand can easily name those problems solved if you > mention clustering solutions and big data solutions. I've personally seen > one sysplex split between 2 sites 40 KM apart using line of site satellite > dishes for communication, yet z/OS app programmers were informed. In other > words, IBM designs for the 21st century. > > ASK YOURSELF: Name 1 brilliant unnoticed Linux feature. Name several > brilliant unnoticed z/OS features. > > The story claims Linux feature design is similar to z/OS feature design. > For example, the story claims Unix filesystems provide the same > functionality as z/OS datasets. A filesystem is the equivalent of one PDS/e > (even in Linux). In fact, z/OS Unix filesystems were built from PDS/e > functionality. A filesystem is a container file containing the files in a > Unix filesystem. You may have a filesystem using 10 disks but that's not > any different than a single z/OS PDS/e file with 10 full disk extents. Like > PDS/e members, files in a filesystem are randomly placed in the filesystem. > > ASK YOURSELF: Name 1 fundamental difference between a PDS/e and a Unix > filesystem. > > ASK YOURSELF: Name the z/OS Unix feature that sort of fixes the > fundamental design flaw with Unix filesystems just described? > > I suspect most people won't think about each user having a unique > filesystem using automount to make their filesystem available. Typical Unix > uses one file system with all users having directories in the /user > directory. The mediocre design philosophy extends past Linux and enters > into the programmer mentality. > > ASK YOURSELF: Name 1 z/OS application programmer that uses bTree, big-O, > clustering, big data and various other techniques required for Linux. > > ASK YOURSELF: Name 1 reason why Twitter could not have been easily written > in Cobol on z/OS. Excluding the user interfaces (e.g. phone app, Windows > app, web browser app, ...). I'm not saying I would be willing but it's > doable without additional effort. > > As many complained, the article says z/OS requires hundreds to thousands > to support it. Twitter went from 7,000 employees to 2,000. Since it did not > fall apart, the real question: do Linux developers understand how to create > a well-designed application? z/OS applications programmers are business > line experts whereas Linux applications programmers are computer experts > who create programs for the business line. Exactly what makes them a > computer expert? > > The story falsely claims Cobol is an ancient language. Big data, > clustering and more are hidden by z/OS. VSAM is simple and efficient to use > in Cobol but Linux programmers must use databases for the same purpose. > > ASK YOURSELF: Other than programmer self esteem, why do business > programmers need languages more complicated than Cobol? > > The story falsely claims z/OS needs xWindows & bitmapping. z/OS supports > xWindows & bitmapping. The author doesn't understand that xWindows is not > used for general access of a multi-user environment (servers) regardless of > platform. MS Windows and Mac don't use xWindows. For Linux servers, the > only people using xWindows from these machines are sysadmins. Android is > the largest Linux distro but no platform (even z/OS) does not build > xWindows programs because there are so many different phone sizes. > > ASK YOURSELF: Name 1 company that uses xWindows except for Linux desktops > and Linux workstations. > > ASK YOURSELF: Name 1 company whose programmers use their IDE (development > environment e.g. VSCode) from common servers. > > The story mentions IMS & CICS but forgets to mention the Unix & Linux > equivalents that stemmed from IMS & CICS concepts. Surely people have heard > of SAP, Peoplesoft, web servers and other such products. > > Our worlds are colliding. z/OS should be smashing Linux but Linux survives > on people's desire to be computer experts instead of business line experts. > Google management thinks it's cheaper to spend $4,000 for each of their > 5,500,000 servers than $4,000,000 for each IBM z16 computer needed. You get > what you pay for. > > ASK YOURSELF: Are people delusional when they call the mainframe a > dinosaur when it's more advanced than the most advanced workstations and > servers? > > What is the definition of mainframe? > > ---------------------------------------------------------------------- > 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 > -- Jay Maynard ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
