From: clubley@remove_me.eisner.decus.org-Earth.UFP   
      
   On 2025-11-07, Dan Cross  wrote:   
   > In article <10eaaqr$2sqg0$1@dont-email.me>,   
   > Simon Clubley   wrote:   
   >>On 2025-10-30, Arne Vajhøj  wrote:   
   >>> On 10/30/2025 9:12 AM, Simon Clubley wrote:   
   >>>> On 2025-10-30, gcalliet  wrote:   
   >>>>> It seems now, because the strategy used by VSI or its investor has been   
   >>>>> for ten years a strategy copied on strategies for legacies OS (like   
   >>>>> z/os...), the option of a VMS revival as an alternate OS solution is   
   >>>>> almost dead.   
   >>>>   
   >>>> z/OS is responsible for keeping a good portion of today's world running.   
   >>>> I would hardly call that a legacy OS.   
   >>>   
   >>> z/OS is still used for a lot of very important systems.   
   >>>   
   >>> But it is also an OS that companies are actively   
   >>> moving away from.   
   >>>   
   >>   
   >>Interesting. I can see how some people on the edges might be considering   
   >>such a move, but at the very core of the z/OS world are companies that   
   >>I thought such a move would be absolutely impossible to consider.   
   >>   
   >>What are they moving to, and how are they satisfying the extremely high   
   >>constraints both on software and hardware availability, failure detection,   
   >>and recovery that z/OS and its underlying hardware provides ?   
   >>   
   >>z/OS has a unique set of capabilities when it comes to the absolutely   
   >>critical this _MUST_ continue working or the country/company dies area.   
   >   
   > I'm curious: what, in your view, are those capabilities?   
   >   
      
   That's a good question. I am hard pressed to identify one single feature,   
   but can identify a range of features, that when combined together, help to   
   produce a solid robust system for mission critical computing.   
      
   For example, I like the predictive failure analysis capabilities (and I wish   
   VMS had something like that).   
      
   I like the multiple levels of hardware failure detection and automatic   
   recovery without system downtime.   
      
   I like the way the hardware and z/OS and layered products software are   
   tightly integrated into a coherent whole.   
      
   I like the way the software was designed with a very tight single-minded   
   focus on providing certain capabilities in highly demanding environments   
   instead of in some undirected rambling evolution.   
      
   I like the way the hardware and software have evolved, in a designed way,   
   to address business needs, without becoming bloated (unlike modern software   
   stacks). A lean system has many less failure points and less points of   
   vulnerability than a bloated system.   
      
   I like the whole CICS transaction functionality and failure recovery model.   
      
   >>Likewise, to replace z/OS, any replacement hardware and software must also   
   >>have the same unique capabilities that z/OS, and the hardware it runs on,   
   >>has. What is the general ecosystem, at both software and hardware level,   
   >>that these people are moving to ?   
   >   
   > I think a bigger issue is lock-in.  We _know_ how to build   
   > performant, reliable, distributed systems.  What we don't seem   
   > able to collectively do is migrate away from 50 years of history   
   > with proprietary technology.  Mainframes work, they're reliable,   
   > and they're low-risk.  It's dealing with the ISAM, CICS, VTAM,   
   > DB2, COBOL extensions, etc, etc, etc, that are slowing migration   
   > off of them because that's migrating to a fundamentally   
   > different model, which is both hard and high-risk.   
   >   
      
   Question: are they low-risk because they were designed to do one thing   
   and to do it very well in extremely demanding environments ?   
      
   Are the replacements higher-risk because they are more of a generic   
   infrastructure and the mission critical workloads need to be force-fitted   
   into them ?   
      
   BTW, what is the general replacement for CICS transaction processing and   
   how does the replacement functionality compare to CICS ?   
      
   > As for the cloud, the number of organizations moving back   
   > on-prem for very good reasons shouldn't be discounted.   
   >   
      
   Yes, and I hope the latest batch of critical system movers do not   
   repeat those same mistakes.   
      
   Simon.   
      
   --   
   Simon Clubley, clubley@remove_me.eisner.decus.org-Earth.UFP   
   Walking destinations on a map are further away than they appear.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)