Many interesting points here, and even if I were interested in contradicting
them I'm too ignorant of hardware to attempt it. But I will at least say that
I'm very, very glad to have multiple algorithmic languages to write in, not
just COBOL. I reluctantly admit that COBOL has important strengths
("reluctant" only because I have a deep dislike of verbosity in coding), but
before I learned COBOL I already was using at least four other languages and
after I (mostly) stopped using it I tacked on some more. Ok, so I'm a software
geek, I admit it. But there are tasks for which I like PL/1, or VBA, or REXX
(or ooRexx), and so on.
"Need"? Maybe not absolutely must have, but they're sure helpful.
Again, not saying I disagree.
---
Bob Bridges, robhbrid...@gmail.com, cell 336 382-7313
/* Somehow or other an extraordinary idea has arisen that the disbelievers in
miracles consider them coldly and fairly, while believers in miracles accept
them only in connection with some dogma. The fact is quite the other way. The
believers in miracles accept them (rightly or wrongly) because they have
evidence for them. The disbelievers in miracles deny them (rightly or wrongly)
because they have a doctrine against them. -G.K. Chesterton, _Orthodoxy_ */
-----Original Message-----
From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Jon
Perryman
Sent: Saturday, July 29, 2023 12:28
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?
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