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Millennials and Mainframes: How to Bridge the Gap

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Re: Millennials and Mainframes: How to Bridge the Gap

#111

Cloud is initally is a copy of mainframe just a affordable cheaper version. Mainframe aka z/OS is not old it's just like any other software always upgraded only thing is hardware is also upgraded with it. Positive thing about mainframe is if you write a program and if it serves its propose it can run for decades without an issue. Mainframe is made up of TSO CONSOLE, SDSF, CA7(job scheduling), Db2 database, CICS(onlin…

> no data theft or any malware destroying data.

That would only be true if the mainframes never interfaced to any other systems or to any humans. Since the latter can't be the case, and the former hasn't been the case for a long time, this just doesn't hold.

> Why cloud is better ? Pay as you go, this works for all startups and small companies using latest front applications. With mainframes you will be paying from millions to billions to IBM so only large corporates can afford it.

There's an implied false dichotomy here, though, that ignores a decade or two of using commodity hardware, before cloud was viable/popular. It was also pay-as-you-go, just with much larger increments, so it didn't work as well for as small companies. That's still available and is actually cheaper (and carries less vendor lock-in).

Perhaps ironically, large enough companies routinely pay millions to AWS. In theory, they could switch providers, but not if they bought in to any of the vendor-specific services. As you say, cloud is, in many ways, a copy of mainframes.

> If you want to learn a technology that processes massive data. Mainframe is the place.

That may be a stretch, since "massive" isn't what it used to be. Something like all the world's financial transactions might have been massive, in computer terms, 20 years ago, but, today, processors have 1000x the transistor densities, spinning disks have 20x+ the I/O, and SSDs are even faster.

I'd argue that the scientific, physical lab, HPC/supercomputing world is the place for that. The quantities of data produced by the instruments at LLNL's NIF or CERN's LHC would easily overwhelm a mainframe, even after initial processing/filtering.

Re: Millennials and Mainframes: How to Bridge the Gap

#112
post #105
post #99

Earlier quoted context omitted.

Intel leads in x86 performance and comparing performance of System z CPU to x86 is not exactly trivial task as zArchitecture is "uber-CISC" with instructions like "give me SHA256 of this part of memory" that also typically runs on 4+GHz clocks (and the "CPU book" has TDP of several kW). But main part of the performance advantage (be it perceived or real) is incredible memory and IO bandwith combined with large caches…

> On the other hand, you can get rack-mount x86 server with several TB of RAM for fraction of price of mainframe which is exactly the hardware for new applications that would otherwise be best served by mainframe. I expect the largest one of these is still a fraction the size of the largest mainframe, at least for processor power (e.g. 224 cores[0] compared to 1700[1]). Maximum memory, though, is 32TB, which isn't ex…

From my point of view for typical modern bussiness workloads that necessiate large machines (ie. SQL RDBMS or something similar) only thing that you really care about is memory size. On the other hand many "legacy" mainframe workloads are significantly more CPU-bound because the software culture is simply different and brute force is often the way to go.

Re: Millennials and Mainframes: How to Bridge the Gap

#113
post #77

Earlier quoted context omitted.

You have it go the other way, as well. We were running some accounting software on an System i (AS/400, iSeries, like you said whatever IBM calls it this decade), and recently switched to something that runs commodity hardware. Another company that I knew from our user group meeting also switched - the batch processing was so slow, they had to go back to the IBM. Their shipping process just wasn't fast enough otherwi…

> You can run the 5250 at 27x132 This does ring a bell, I think I did discover this eventually ("wide mode", they called it?). And I'm not sure if this is damning with faint praise, but I will admit that the 5250 monospace font kinda grew on me. Interesting to hear that I could have been using Eclipse for RPG; for the PHP side (which was still running on the mainframe via AIX, so I had at least a few Unix tools at my…

Zend has a php product for the IBM i that isn’t too bad - and it runs like you said on a Unix-ish file layout and everything.

Re: Millennials and Mainframes: How to Bridge the Gap

#114
post #101

Earlier quoted context omitted.

Banks and Airline systems go offline all the freaking time. Just the other day I told the post office attendant their system was back online, as the cursor started blinking again. Telltale sign of mainframe style computing.

When you turn off your laptop, does Google go down?

That’s deep man…

https://en.m.wikipedia.org/wiki/If_a_tree_falls_in_a_forest

Re: Millennials and Mainframes: How to Bridge the Gap

#115

Earlier quoted context omitted.

AWS, Google Cloud, and Azure break more often than our mainframes. In this case, the cloud model is a con, essentially the self checkout lane at Walmart. You're paying more for the same ability you had before. "Well, you want redundancy right? Well you're supposed to be redundant across AZs, and then regions, and then you're going to have to have disparate vendors to mitigate sole vendor risks." And then we're right…

Clouds reinvent mainframes. They're still cheaper, run more FOSS, and have more talent available. They're a better form of lockin than mainframes.

> They're still cheaper

Are they, though? Commodity hardware certainly is, but it's not as if cloud providers are charging a small margin on top of that. They're charging a multiple, potentially as large as 10x.

Combined with the parent's proposed need of multi-cloud, that could turn what might otherwise be a few hundred $k of commodity servers into a few $M of cloud costs, which I understand is the OOM the cost of a mainframe.

Re: Millennials and Mainframes: How to Bridge the Gap

#116

Mainframe skills shortage is a complete fabrication, it simply doesn’t exist. In June of this year a local company laid off 850 people, a company with a large mainframe installation (SS&C formerly DST Systems). Hundreds were mainframe programmers. This is after a decade offshoring. There are thousands of former mainframers here. And this is just in Kansas City, Mo. Anecdotal but representative I believe. Mainframes a…

DST!? I still deal with DST(haven't heard SS&C mentioned) in the medical insurance industry every day. Nothing but bad things to say about them.

How would characterize their software and services? Cutting edge modern stuff with engaged knowledgeable support?

Re: Millennials and Mainframes: How to Bridge the Gap

#117
post #28

Ok, maybe this is a silly question, but I am a millennial.... Question: what is a mainframe and why would I want one? In my mind I think of it as a big, but inelastic, compute resource. If that's true, why wouldn't I want to use something horizontally scalable instead?

They DO horizontally scale, just not very cheaply. Reliability above all else is their advantage. There is an entire internet between you and a "5 9s" cloud provider that can screw you. side note; I HATE the trend in the level of abstraction away from hardware. Seems about as short sighted as GP doctors abstracting away human anatomy. They mostly treat illnesses and proscribe medication; why should they need to know…

People are only capable of so much, mentally. As the world is increasingly well understood, it gets increasingly complicated, and individuals require ways to interact with the parts that they don't have time to truly understand.

Re: Millennials and Mainframes: How to Bridge the Gap

#118

Earlier quoted context omitted.

Asking out of complete ignorance: What can a mainframe do that other kinds of machines can't? I barely understand what a mainframe is or why you'd use one over other technologies.

Channel I/O was something I wanted on all my desktops and servers. It helps mainframes get their high utilization ratio and throughput: https://en.m.wikipedia.org/wiki/Channel_I/O

How does this map to the current state of commodity computing?

For example, it seems we already achieved that with disks, once embedded controllers attached to DMA-capabled HBAs became the norm.

A similar thing seems to have happened with NICs, as well as the ability to offload higher-level protocol processing (another mainframe-like feature).

Re: Millennials and Mainframes: How to Bridge the Gap

#119
Modern mainframes are just cloud compute. These are services and microservices written in proprietary programming languages, using possibly-proprietary CPU and RAM. They're equivalent to a few racks of Windows or Linux servers behind load balancers. Or a small fortune in AWS services.

Cray, IBM, et al sell computing nostalgia and laziness. Their biggest product is the need to not rewrite code in an open system.

Re: Millennials and Mainframes: How to Bridge the Gap

#120
post #112
post #105

Earlier quoted context omitted.

> On the other hand, you can get rack-mount x86 server with several TB of RAM for fraction of price of mainframe which is exactly the hardware for new applications that would otherwise be best served by mainframe. I expect the largest one of these is still a fraction the size of the largest mainframe, at least for processor power (e.g. 224 cores[0] compared to 1700[1]). Maximum memory, though, is 32TB, which isn't ex…

From my point of view for typical modern bussiness workloads that necessiate large machines (ie. SQL RDBMS or something similar) only thing that you really care about is memory size. On the other hand many "legacy" mainframe workloads are significantly more CPU-bound because the software culture is simply different and brute force is often the way to go.

> From my point of view for typical modern bussiness workloads that necessiate large machines (ie. SQL RDBMS or something similar) only thing that you really care about is memory size.

That's my general impression, as well, but I have little enough (or inadequately broad) direct experience for that impression to be a strong one.

I've also seen, second-hand (i.e. benchmarks, so not quite real-world) that cache and memory latencies (including inter-CPU/NUMA) can significantly affect OLTP performance.

If that weren't true in practice, then the sheer bandwidth one can deliver from enough SSDs over PCIe rivaling a CPU's memory bandwidth would mean main memory size is much less relevant.

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