Well written.
Sent from Outlook for Android<https://aka.ms/AAb9ysg>
________________________________
From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> on behalf of
Joel C. Ewing <jce.ebe...@cox.net>
Sent: Thursday, August 3, 2023 6:47:37 PM
To: IBM-MAIN@LISTSERV.UA.EDU <IBM-MAIN@LISTSERV.UA.EDU>
Subject: Re: Mainframe Makers.... WAS: Ars Technica: The IBM mainframe: How it
runs and why it survives
There is a synergy that exists between z-architecture hardware and z/OS
that has evolved over many decades.
The hardware is designed with redundancy to detect failures in
components (processors, memory, I/O subsystems, interconnection cables),
correct any resulting data errors where possible, retry a failed
operation using different hardware components where appropriate, vary a
failing component off line, and in many cases allow concurrent repair of
failing components while production continues. Undetected hardware
errors don't happen.
z/OS not only coordinates with the hardware when resources visible to
z/OS are affected by failures and concurrent maintenance, it is also
designed with the philosophy that software failures may occur within
parts of the operating system, either from a hardware failure or a
system software bug. System recovery routines exist to clean up after
such failures, limit what running address spaces are affected, and allow
production to continue in unaffected address spaces.
An explicit part of the design philosophy is that applications running
in different address spaces are isolated: a failure or bug in one
application cannot induce a failure in some different application in a
different address space, or induce a failure in the operating system
itself.
Another important feature of z/OS that requires some hardware
coordination is the System Measurement Facility that gathers measurement
of system activity and resource usage at a level to support performance
tuning or billing based on resource usage.
Aside from fact that z/OS is closed-source and only licensed by IBM to
specific hardware, if you could somehow succeed in running it under
Linux or on non-z hardware, it would lose the reliability, availability,
and serviceability it gets from that hardware/software synergy that
makes it an ideal production platform for critical workloads.
Joel C Ewing
On 8/2/23 22:28, Jon Perryman wrote:
> > On Wednesday, August 2, 2023 at 06:24:15 AM PDT, Rick Troth
> <tro...@gmail.com> wrote:
>
>> I think Jon Perryman first asked us to define mainframe. And I bit!
>> [voice of Leonard Bones McCoy] "Dammit Jon! I'm a software developer,
>> not a field service engineer!"
>> But it really started with Andrew Hudson at Ars Technica getting a
>> number of facts wrong.
> The ARS Technica story made me wonder z/OS people think there is more than a
> design difference between z/OS on z and Linux on Intel. Unix was ported ot
> z/OS. I want to know why people think z/OS couldn't be ported to Linux. There
> are people here who consider the article mostly true. What makes people think
> that is more than a philosophical design difference? Would IBM be relevant if
> it used Linux design philosophy?
>
>
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Joel C. Ewing
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