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The z15 Represents a Huge Leap for IBM Z

Mainframe computing has been changing and growing for over 60 years, but the IBM z15 is more like a giant leap than a step increment in the IBM Z architecture.

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This is the first post in a new series on the development and rapid change in systems, networks and applications. Mainframes are a great place to start. Since last year’s announcement of the IBM z15, I have been wondering how to put the z15 into its proper place in the progression of large systems. Mainframe computing has been changing and growing for over 60 years, but the z15 is more like a giant leap than a step increment in the IBM Z architecture.

Back Then

This isn’t the place for an engaging history lesson on mainframes because so much is already out there for you to read. One of my favorites is “IBM Mainframes” from an exhibit in the IBM archives. What I remember from my early days with mainframes are important inventions like multiprocessing, multiprogramming, loosely and tightly coupled processors, and virtual storage. These were some of the ideas that my generation sought to understand and use to our advantage.
For us, the study of these monumental ideas was a kind of after-hours avocation. By day, however, we needed any advantage we could find to get our jobs run quickly and to have systems available where we could test our online transactions. Computer resources were highly sought after and we always needed more. That was pretty much the life of a programmer: code, compile then test. Our analysts did the thinking and designing, and our job was to deliver an application that worked.

Utilizing Inventions to Work Productively

To exploit the architecture changes to mainframes (multiprocessing, multiprogramming, loosely and tightly coupled processors and virtual storage), we took specific actions. We looked for ways to target our jobs to run on the most capable systems—those with the most engines so our jobs had a better chance to run quickly. We also looked for ways to run our jobs in the biggest possible address spaces. For our data sets, we used Virtual Storage Access Method over QSAM so we could ask for a large number of buffers (in our JCL) that we could keep in virtual storage. We did this before there was data-in-virtual. There were other tactics we tried in an effort to get our work completed faster.

Inventions Continued

As mainframes developed, so did other systems and approaches. Client server was invented as a way to utilize the growing base of smaller computers, including departmental systems and, later on, desktops. Departmental systems gave way to environments with web servers, database servers, load balancers, switches and routers that used internet protocols and services. This widespread new approach resulted in a web hosting industry to handle the running of commercial websites.
All of this industry innovation was happening concurrently with the continuous modernization of mainframe computers. Really monumental technology emerged from IBM. Virtualized address spaces opened the door to the possibility of virtualized systems, including the OS, software stack and applications. IBM developed multiple ways to create virtualized systems. VM software (now called z/VM) was developed, at first, to provide a way to test new systems. But it became so popular that is was run by customers for other uses.
IBM also developed LPARs as a way to run entire virtualized systems, multiples of them, on the same physical hardware. Today, the z15 has support for up to 85 LPARs, as well as single image multiple data and simultaneous multithreading. Great information is available on this broad topic of virtualization, which is fascinating. Even if you know the topic, revisiting it is useful because virtualization is not a static subject.

The Current State of Z

The z15 continues the continuous improvement activities of the earlier releases, as you can read from the FAQ. For example, the largest IBM z15 is expected to provide approximately 25% more capacity than the largest IBM z14, with some variation based on workload and configuration. A more granular comparison is offered on the “Compare IBM Z Systems” page, where you can read about comparable memory size, configurable cores and such. You can read that z15 is bigger and better, but that is far from the whole story.
IBM Z has more business value than ever. With the z15, it has data privacy and security that’s supported by three features:
1. The new IBM Z Data Privacy Passports enforce security and privacy protections to data not only on IBM Z, but also across platforms. The scope includes a client’s enterprise and hybrid multicloud environments that may be in use.
2. IBM Z Data Privacy for Diagnostics provides clients with the ability to protect sensitive data that may be included in diagnostic dumps. The announcement letter indicates that tagged sensitive data in dumps can be secured and redacted before sending to third-party vendors.
3. A new Crypto Express7S adapter introduced on the IBM z15 has a design and format that have been driven by the adoption of blockchain and other highly secure applications.
With the z15, IBM Z has business continuity and resilience that is supported by two features:
1. New IBM Z Instant Recovery accelerates everything needed to get ready for workload execution. The scope is comprehensive, including planned OS shutdown processing, OS initial program load, and middleware/workload restart and recovery, including the client workload execution that follows, which helps clients catch up for time lost due to the outage.  
2. Enhancements in Geographically Dispersed Parallel Sysplex (GDPS) combined with System Recovery Boost also speed up and streamline the execution of GDPS recovery scripts, which perform reconfiguration actions during various planned and unplanned operational situations
With the z15, IBM Z has three features that support hybrid cloud readiness:
1. IBM Z software offerings combine to help clients integrate and manage cloud environments, including IBM z/OS Container Extensions (zCX), which empowers access to a large ecosystem of open-source and Linux on IBM Z applications      
2. IBM Integrated Accelerator for zEnterprise Data Compression is provided on each processor chip and uses industry-standard compression formats for file compression that can reduce the size of data. This can save storage space and increase data transfer rates. 
3. Ready for the cloud data center, the IBM z15 is housed in a new standardized 19-inch frame that makes it ready for colocation and standardized facilities management. One to four frames may be deployed depending on the configuration of the z15.
With z15, IBM continued to enhance the platform while adding significant new business value. The new level of Z is more like a giant leap than a step increment in the Z architecture.

Next Post

Next post, I’ll continue with this series focused on systems, network and applications.

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