Cloud Computing Technology

As strange as it may sound to many, but people need to get their fact straight – that IBM Mainframes were the first ever Cloud Computing platform built on planet earth. Cloud Computing is probably the most heard about ‘Fancy Tech Term’ in the modern era of Digital Computing. However, most people probably are unaware of the fact that for decades, the IBM Mainframes have been providing organizations with all the benefits that the modern cloud does today. Believe me or not, IBM Mainframes are the first Cloud Computing Platform on earth!

Finding it hard to believe me? Let’s go out and check the facts for ourselves then. Below I specify the various cloud computing benefits and how the IBM Mainframes have already been providing those benefits to enterprises for decades now.


Scalability is a key feature of modern cloud computing. Scalability simply means that you have the flexibility and elasticity to quickly provision resources in the cloud as you need those, and then de-provision/remove the resources when you don’t need them. This sounds to be such a cost-effective feature, right?

And, guess what? The IBM Mainframes were built to scale from their very inception. The IBM Mainframe provides massive scalability with it’s astonishing computation and processing power. Just to provide you with an indication of the computing power of the IBM Mainframe, it can process around 2.5 to 3 billion transactions a day. IBM Mainframes were designed to support hundreds and thousands of users and millions of concurrent transactions. Batch Processing and Message Queue Processing technologies which have been a part of the IBM Mainframes for decades now, lend themselves to asynchronous computational activities and efficiently and fully utilize the CPU capacity. That the IBM Mainframe is a real beast when it comes to a seemingly unlimited computation and processing power speaks volumes about

how scalable a platform the IBM Mainframe has been from the day it appeared on the commercial marketplace.


In very simple terms, virtualization denotes the capability of software simulating hardware and is another key feature of the modern-day cloud computing. With the advent of companies like VMWare, the virtualization technology started hogging the limelight in the mid-2000s. So, in that sense, virtualization is a recent technology in the history of computing when the technology enabled putting a layer of virtual machines on a commodity PC.

However, virtualization technology has been a part and parcel of the IBM Mainframe computing platform since as old as the mid-1960s. Creating logical hardware partitions called LPARs (logical partitions) has been in existence since decades. Virtual memory came into existence in 1965 and Machine virtualization in 1972.

The ability to take advantage of virtualization on the IBM Mainframe enables you to be able to run zLinux on your mainframe while also parallelly running z/OS.

Multi-Tenancy Model

What is a multi-tenancy model and how does it work? Let us consider a very simple example. Consider an apartment building where, say, 100 people, stay. Each one shares the common apartment building infrastructure, but each has his/her own apartment within that apartment building to live in. And, each share his/her own privacy in the respective apartment. When you apply this analogy to cloud computing, multiple users share the same physical infrastructure and/or applications but also enjoy complete privacy and security over their own information. Cloud computing resources are designed to support the multi-tenancy model.

On the IBM Mainframe, LPARs have been doing just that for decades now. LPARs help create distinct computing environments such as separate environments for development, testing and production. Resource allocation and security access control can be set up for a given environment based on the need. As an example, you can build your production environment

to be much more secure and get it an allocation of more resources (more memory allocation, for example) and probably, a higher execution priority as well.

Resource Pooling

Being able to service multiple users from the same physical pool of resources is what is called Resource Pooling. A cloud provider should have a very large and flexible pool of resources to be able to cater to servicing multiple client requirements, ensuring scalability and that resource allocation should, in no way, impact the performances of critical applications. The multiple users that are drawing resources from the same physical resource pool need not have any knowledge of the pool.

On an IBM Mainframe Computer, several different applications execute simultaneously, and each executing work expects consistent execution times and predictable access to databases. On z/OS, the Workload Manager (WLM) component fulfills all these needs by controlling the executing work’s access to the different system resources, based on external specifications/goals set up by the System Administrator. The critical mainframe resources are thus mediated by the WLM and other parts of z/OS, ensuring high system performance. The end users don’t even need to know about these mediations or how they are performed.

Measured Service

The cost model that the cloud service provider charges back to the user is a “pay as you use” model. The user will obviously pay a variable amount to the cloud service provider based on the user’s actual consumption. So, that effectively means that the cloud service provider monitors, measures and reports back to the users their cloud resource usage.

On the IBM Mainframe computing platform, SMF (System Management Facility) can provide a metering capability, which enables a dynamic charge back model. SMF and other repositories provide the opportunity to identify resource utilization on the platform and cap usage or resources that is in line with the user’s agreement.


Now that we have looked at the various cloud computing benefits and compared to see how the IBM Mainframe computing platform has already been, for decades, providing those benefits to the customers, are you pretty much convinced by the fact that the IBM Mainframe computing platform is, in fact, the earliest cloud computing platform to have existed? I am confident that you should be, by now!

My intention here is to not discredit the Cloud Computing technology in any form whatsoever. In fact, I have always believed that we should open our arms to embrace any new form of technology that proves to be beneficial to the entire ecosystem and so is the case with the Cloud Computing technology as well. However, the point that I have tried to establish through this article of mine is that we should not try to look at the IBM Mainframe computing platform to be the one that is trying to keep pace with what the world today calls the latest and greatest “Cloud Computing Technology” but that there always had been a computing

platform in IBM Mainframe that has been effectively carrying out, for decades now, all the tasks that the modern “Cloud Computing Technology” is supposed to do.

I would rather like to call the modern “Cloud Computing Technology” to have evolved from its predecessor, the IBM Mainframe Computing Platform. The IBM Mainframe Computing Platform and the modern “Cloud Computing Technology” can and should coexist.

Subhasish Sarkar is a Senior SQA Engineer, working at BMC Software India Pvt Ltd. He has 12+ years of relevant work experience in different IBM Z Mainframe Technologies. He is passionate and enthusiastic about Technology in general, the IBM Z Mainframe Platform in particular and IMS to be specific. Subhasish Sarkar is an IBM Z Champion (for 2020).
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