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The IBM mainframe: How it runs and why it survives

arstechnica.com

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Re: The IBM mainframe: How it runs and why it survives

#51

Post by dralley »

jeffbee wrote: post #39
dralley wrote: post #29

Earlier quoted context omitted.

Getting the same performance out of AWS as a local mainframe is neither trivial nor cheap for a lot of the workloads these systems are running.

Getting stupefying amounts of I/O on AWS is as simple as turning a knob and getting out your credit card. The kind of throughput quoted in the article—48GB/s—is achievable on AWS for $250k/year, list price.

But let's say you want that data compressed and/or encrypted, you're going to need an awful lot of compute to exploit that 48GB/s if it's possible at all.

Whereas on mainframe the service processors can deal with it transparently to the CPU using specialized hardware.

And let's say it's financial transactions - fixed-point decimal arithmetic. On mainframe, that can be hardware accelerated too.

Re: The IBM mainframe: How it runs and why it survives

#52

Post by pdw »

mousetree wrote: post #21

> Today, IBM is the only mainframe manufacturer AFAIK Fujitsu still manufacture mainframes

This is an interesting overview of mainframe vendors and how many customers they might have: https://arcanesciences.com/os2200/app1.html Most of the "dwarves" are now using emulation...

Re: The IBM mainframe: How it runs and why it survives

#53

Post by steveklabnik »

dralley wrote: post #23
mousetree wrote: post #21

> Today, IBM is the only mainframe manufacturer AFAIK Fujitsu still manufacture mainframes

Oxide could probably be considered a "modern mainframe" if you squint. The architecture is of course much different, but server CPUs from the likes of AMD are gradually catching up with the purpose-built stuff in raw power and I/O capabilities.

Yes, like many kinds of comparisons, it really depends on what you mean by the thing. The architecture of Oxide is very different than a mainframe, but the "big computer that's a fully integrated system" vibe is kinda similar.

Re: The IBM mainframe: How it runs and why it survives

#54

Post by pdw »

Hikikomori wrote: post #41
lizknope wrote: post #34

I've never used or even seen a mainframe in 26 years in the tech industry. My brother in law works for a bank and basically the business runs on it. The hardware and software are certainly impressive but does anyone use a mainframe for a new project and not just upgrading or expanding an existing system? I'm in integrated circuit design and we have compute clusters with thousands of CPUs. For some jobs we use a singl…

You'll most likely find it in large companies that operated in the 60s or 70s that haven't switched to anything new, mostly because their core business runs on it. I know of two companies, and at least one still use it, had several summer jobs there. They make sheet metal rolls by flattening out train cart sized hunks of steel, and while the mainframe system didn't run the machines (operators and PLC handled that) it…

That could have been a mainframe, but I think factories are much more likely to be using AS/400 aka IBM i. That runs on regular IBM Power servers these days.

Re: The IBM mainframe: How it runs and why it survives

#55

Post by justapassenger »

mberning wrote: post #18
jmartrican wrote: post #12

Earlier quoted context omitted.

Before we even get to the costs of a migration, what is the reason for the migration?

People may assume that a lot of this mainframe software is "running just fine" but nothing could be farther from the truth. Often you will find that this software was fine when it was written 40-50 years ago, but now it has a lot of deferred maintenance and upgrades which are now a "big problem". Is it a problem that an application that can move millions of dollars is only secured by a strictly 8 character alphanumer…

Updating the software to support stronger passwords or rewrite it from scratch, on a totally different platform?

I don’t think you’re making argument think you’re making.

Re: The IBM mainframe: How it runs and why it survives

#57

Post by colonwqbang »

xahhkakappy11 wrote: post #6
CraigJPerry wrote: post #4

The reason mainframe persists is it's a pretty slick development and deployment environment. A lot things you might cobble together as dependencies - like maybe a database or a message queue, or observability facilities or even deployment strategies like hot-hot deployments - they're all just built in to the platform. That means they're trivial to consume and they're fully supported by one vendor. It's like the world…

Inline SQL is something I've always missed elsewhere. Not sure it's viable when you've got a billion different incompatible databases supported on a platform, so some of the limitations of mainframes have advantages.

Check out C# LINQ, or Haskell postgresql-typed.

https://learn.microsoft.com/en-us/dotnet/csharp/programming-...

https://hackage.haskell.org/package/postgresql-typed-0.6.2.4...

Re: The IBM mainframe: How it runs and why it survives

#58

Post by KennyBlanken »

mberning wrote: post #8
CraigJPerry wrote: post #4

The reason mainframe persists is it's a pretty slick development and deployment environment. A lot things you might cobble together as dependencies - like maybe a database or a message queue, or observability facilities or even deployment strategies like hot-hot deployments - they're all just built in to the platform. That means they're trivial to consume and they're fully supported by one vendor. It's like the world…

It persists in many places due to the deeply ingrained belief that, for one reason or another, it would be technically, practically, or economically impossible to migrate functionality off the mainframe. Somehow the people in charge of these systems have managed to convince large enterprises of this for decades . And now we are in a situation where their long held beliefs have become true because nobody is around tha…

Notice they didn't mention how incredibly outdated all these applications are? Our financial money transfer system is an ancient joke. The IRS has systems that are hopelessly out of date and limited in capabilities. It's really easy and safe to sign a contract for a newer mainframe; porting a legacy app is fraught. Middle-upper management goes for what's safe, not what could torpedo their career.

The hardware might be whiz-bang but the legacy applications are slow, outdated, and extremely hampered in functionality.

In my state, the birth records system is electronic, and so is our RMV. But in order to get a RealID, I had to get a paper copy printed out to bring to the RMV because they can not, or will not, integrate the two systems. Meanwhile other countries have things like electronic ID cards with personal certs so you can electronically sign documents and identify yourself.

The whole thing is a giant puff piece for IBM, reading like a sales presentation transcript.

Re: The IBM mainframe: How it runs and why it survives

#59

Post by sofixa »

jmartrican wrote: post #12
mberning wrote: post #8

Earlier quoted context omitted.

It persists in many places due to the deeply ingrained belief that, for one reason or another, it would be technically, practically, or economically impossible to migrate functionality off the mainframe. Somehow the people in charge of these systems have managed to convince large enterprises of this for decades . And now we are in a situation where their long held beliefs have become true because nobody is around tha…

Before we even get to the costs of a migration, what is the reason for the migration?

Well, for one, lack of capable personnel. Nobody learns IBM Mainframes in school, and most jobs for them want experience. Furthermore, they're not sexy but boring, with paywalled docs and similar shitty "enterprise" techniques, making it so very few people actually want to or manage to learn them. And it's a dead end, career-wise (very few companies use them, so changing jobs isn't as easy as more widely used tech).

So what will happen when in 10 years the last people you have that know how it works are retired?

Not to mention tech debt.

Re: The IBM mainframe: How it runs and why it survives

#60

Post by madmulita »

I believe the real reason for its survivability is the fact that you can pull a tape from the seventies and those binaries will run without any modification. It's not only that you can easily recompile your COBOL from the '70s, the binary is still compatible. You've never been pushed to migrate to another technology. Imagine the effort and 'knowledge' included in those evolved programs. The banks don't even know, and are conscious of it, how many laws and regulations they have encoded in there.

As someone stated in another comment, the software is the impressive part.

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