[Nextgrid]

Fun and learning.

I doubt there’s a legit use-case for a mainframe even in business environments. All the “reliability” it gives you can be re-implemented on commodity hardware and still come out ahead compared to the costs of buying & maintaining a mainframe.

[badpun]

I wonder how much cheaper it is to implement software for one, huge machine that „just works”, vs the usual way of implementing for a network of distributed machines. Distributed programming is NOT easy, and, even if the hard parts are supposedly implemented by various protocols/frameworks, these solutions constrain the way you can program and also have a ton of „interesting” failure states - just take a look at logs of say Hadoop cluster that’s been running for a while - even though the cluster is supposedly running fine (or is it?), you’ll find various kinds of exceptions related to the distributed model (socket timeouts and whatnot). Not to mention trying to thoroughly understand various eventual consistency models.

On th plus side, we’ve basically moved complexity from hardware to software (it was pioneered by Google, a software company, so no wonder) which increases salaries of software people, at the expense of hardware people. So yay for us I guess.

[bluecmd]

Author here, I agree 100%. It is just a different way of building software, which is why I find these things so interesting. It challenges my worldview and thus I want to learn more about its upsides and downsides.

CICS and IMS definitely made it easy to create scalable software decades ago. It is not that different from the frameworks we have invented to make distributed systems viable that you mention, which I find insanely cool.

One of the cool things of running e.g. Ceph is that it exposes a familiar API (POSIX filesystem) which makes things easy to integrate with. The mainframe is like that but for hardware. VMware has similar things to some degree where your VM can be kept alive across hardware failure, but not really on the same level.

Anyway, I will stop here but I could go on for hours :-)

[ithkuil]

> Anyway, I will stop here but I could go on for hours :-)

Oh please go on for hours; I'd love to hear more. Any format (blog or just semi-structured brain dumps in comment threads) will feed thoughts :-)

[neverartful]

"I doubt there’s a legit use-case for a mainframe even in business environments"

You're incorrect. The most common one is to run legacy software, and not just banks. Insurance, retail, utilities, financial, manufacturing, etc. Some companies have been around before x86 hit the scene and already had significant investments in their in-house computing infrastructure.

[Koshkin]

Using a real mainframe in order to run legacy code is probably the most expensive way to do so I can think of.

[neverartful]

Oh? Even when your environment uses z/OS, z/VM, CICS, DB2, and a whole slew of other IBM and 3rd party products? Do you know that all mainframe software is fully supported when run on a mainframe substitute? I have no idea whether it is or isn't.