Seems like the first "save money on software" shouldn't be there.

That approach is, in scientific computing, at least as old as Beowulf (1994, four years before Google was founded), the prototypical system from which we get the term “beowulf cluster”.

Edit accidentally included runaway thought process...

It's OK to do most things with chunk of normal servers, but when you need to handle very large number of transactions with fast commits, and stuff like eventual consistency is not allowed, it becomes expensive to handle them no matter what.

One of the other big Australian banks (Westpac) has an "exit IBM" project as well, but it isn't complete yet.

There is no information anywhere saying that they moved their critical banking systems and transaction processing.

Unisys always had a smaller mainframe share than IBM, and they stopped making new chips sometime in the 2000s.

For at least ten years the fastest Unisys mainframes have been very big (proprietary) x86 machines running Windows with a Unisys mainframe emulator.

For some time I defined a "serious computer" as something that didn't have ports for keyboard and monitor.

Having said that, the pre-x86 A series were pretty cool. And ran the most user hostile OS ever created, to the point its very name was used for Tron's villain.

Monzo? They're getting bigger now, circa 3M customers. More than First Direct, Starling, Metro Bank.

I personally worked on a project there that involved building new virtualization platforms for not only x86/x86_64 Intel, but also AIX (Power) and Solaris (SPARC).

I was told they did an assessment a year or two ago to price out what it would take to move the business completely off mainframe and onto an x86 stack. It was in the hundreds of millions of dollars to do so because so much other software has been built to interact with and rely on the mainframe over the years that switching off it would be a multi-year effort across every department in the company. So of course that ROI calculation was pretty damn easy and the mainframe isn't going anywhere.

So just... have the new server expose itself over the TN3270/TN5250 protocols, such that these interoperating systems see what they expect to see? (You could even build the new system as a regular REST API or something at its core, and then build the TN3270/TN5250 exposure as a separate gateway service on top, such that it'd be easy to shut it off later if everything finally moves off it one day.)

You don't necessarily need to move the $new project off the legacy hardware, just write it in such a way that you can do easily later.

I'm eliding many details here, but the principle stands.

- Spend $300,000,000 over 10 years moving to a new system, and hope that by the time you've done that it's not obsolete.

- Spend $1,000,000 a year on a system that still works.

You could run the system for 300 years for what it would cost to replace the system.

In spite of the collective wisdom on HN, there aren't a lot of companies in the world with hundreds of millions of dollars sitting around doing nothing. Even ones that work on mainframes.

- Spend $1.5 million maintaining the current system, but as bits get updated keep in mind the system that you'd like to have in 10 15 years time.

You're going to have to replace the system within 300 years anyway, you aren't saving that money, every feature you add that is reliant on the old system is literally technical debt, because eventually you'll have to rewrite it for the new system.

I'm not even saying you need to have a new system in mind, just keep in mind that you will be moving to a new system, so code appropriately.

And it will still be able to run all your programs that were written and tested since the late 20th century, by the kind of organic entity we used to call "human".

Slightly more serious retort: I'm not aware of any brands from 300 years ago, I'd be surprised if any of IBMs customers survive, let alone enough to keep IBM as a going concern.

Btw when you start folding the space time mesh, terahertz figures just become marketing numbers, what you really want to know is how many parsecs it can do the Kessel run in.

You might be, you just don't realize that they're hundreds of years old.

For example, the insurance company Lloyds of London is fairly well-known around the globe. It's 333 years old.

If anything, this is a sign that mainframe users have way too much profit for what should probably be commodity software.

Remember that these are large, public businesses. Explaining to shareholders that profits are going to take a noticeable hit for years because of IT investment that isn't strictly necessary is effectively a non-starter.

I wasn't thinking that. I was thinking more like when you add a new feature, fit it into an API that is portable. Or add a translation layer so the feature can be written how you would like system to be in the future, but it works on your hardware today.

2nd I'd say theres a half life of best practise. Over the 10 20 year tome frame, id expect some of what you were doing is going to become outdated yes, on the same way some of your knowledge over your career will become outdated, or the phone I your pocket will, you wouldn't use that as an argument against education, or buying that phone.

Btw, if its as costly to deal with the interface as with the mainframe directly, that's a win. The interface can move off the mainframe to somewhere cheaper/better.

It doesn't become wrong, it just evolves into another dead-end. The 3270 is an interface, too, but the reason everybody suggests replacing it or augmenting it is precisely because the spartan tooling and mindshare makes it expensive. As XML recedes into history it is likewise becoming more expensive as an interface.

I chose XML vs JSON because I figured it was a transition everybody was somewhat familiar with. And younger programmers have an almost visceral dislike of XML, which I thought might help get the point across--that an interface someone once thought (and probably still thinks) would help ease future interoperability becomes a reason or excuse for future programmers to avoid that integration.

> Btw, if its as costly to deal with the interface as with the mainframe directly, that's a win.

I think the problem is that you don't really know if it's as costly. The error bars on that sort of risk assessment are huge because our industry sucks at accurately predicting migration costs. And it sucks because complex software systems are intrinsically unique. Commercial solutions that claim to be able to capture and control all those dimensions of complexity tend to be sold by vendors with names like IBM and Oracle. Such vendors also pioneered interfaces like SQL, which is both a soaring achievement in terms of capturing complexity behind a beautiful interface while also falling epically short of what's needed to actually reduce long-term integration costs.

But alas, language has changed and these kids won't get off my lawn.

‘Whatever is fitted in any sort to excite the ideas of pain, and danger, that is to say, whatever is in any sort terrible, or is conversant about terrible objects, or operates in a manner analogous to terror, is a source of the sublime; that is, it is productive of the strongest emotion which the mind is capable of feeling.’

What is a problem is that the last time a lot of code was touched may be 5-10 years ago. That code may have started being written 20-40 years ago. It may well have been maintained by people who think "if it was hard to write, it should be hard to read" or "documentation is for the weak". It definitely will have been written when the cost of a gig of memory and storage was many orders of magnitude higher than today (indeed, last time I priced memory for a mainframe, a Z10, it ran to $10,000 a gig); hence terseness in everything from table and column names through stored data and everything else was prized. Dropping from COBOL into assembler is not uncommon for critical path performance.

Making any changes will be a week of coding and three months of working out the what and why of the code, because the last person who worked on it retired a couple of years ago.

It has worked for the past 30 years and hasn't been touched since 20.

Who are the vendors that provide a migration path from mainframe to a set of commodity hardware running an emulator, and subsequently provide continual maintenance and support?

Global 100 company gets IT from other global 100 company

vs

Global 100 company gets IT from small mainframe support shop

there's a question of shareholder liability, being able to adequately sue them for M's of $, expectation they will be around in 20 years, etc.

A single computer with 4 sockets of xeons will outperform a mainframe but will have more downtime.

The mainframe has best possible single thread performance and as much cache as possible, redundancy and parts can be replaced while it's online, but not that many cores.

The cost is very high - when I looked, 1 million per year is the baby version with only 1 CPU enabled and no license to run the cryptographic accelerator and limits on software, etc.

Commodity hardware you buy and use for 5 years, so the amount of good hardware you can buy for the price of owning a mainframe for 5 years is a lot.

For the money, you can buy a lot more CPU, ram, network, storage, etc and hire Kyle Kingsbury to audit your distributed database.

At one point, IBM was selling base-level mainframes for $75,000 (see https://arstechnica.com/information-technology/2013/07/ibm-u...)

It is true though that a 'realistic' configuration is likely to cost north of $1 million, and that none of these numbers include the price of the software.

Another is that the software and hardware designed to turn a baby system into anything useful is astonishingly expensive to people not used to dealing with this end of the market. Enjoy finding that your hypervisor is licensed at 5 figures per core, and that your cores are six figures a pop.

Even if the mainframe never goes down, the entire site will go down (eventually the rack power supply, HVAC, fiber, natural disaster, backhoe, etc. will get you even if your CPUs and RAM are redundant and replaced before they fail), and then either your entire business stops or at least processing for that region stops, or your system is resilient to site failure because you built a distributed system anyway.

If you could rewrite your software to be distributed and handle a node/site going down, you could run a single site on 5 servers that together outperform the mainframe (by a lot) and can be serviced on a whole server basis (though of course, expensive x86 servers also have reliability features), or use really cheap hardware without even redundant power supplies, but have enough of them to not care.

The modern solutions are better than the mainframe, and the only reason to use them is management risk aversion and unwillingness to learn new things.

100 miles will add 5ms (round trip) to your disk flush on commit. So a system like this has the sequential and random IO latencies of a RAID of SSDs but the flush (database commit) times of a 15K RPM spinning rust disk. People lived with mechanical disks, it's ok.

Sync disk replication (in one direction) over a fiber line is not an exclusive feature. Having both sides be active, instead of active and hot standby requires some smarts from the software, but modern distributed databases do that, and if you're careful you can get far with batch sync jobs.

For read-only batch computations you can always add some extra redundancy and partition the problem. So, I don't think it is likely that a mainframe would be useful here.

But we have literally thousands of internally developed applications. We can move thousands of apps the cloud and still have a need to keep thousands on virtual/physical machines. My own apps are stuck on commodity physical hardware for at least the next few years.

The type of applications that can historically been run on mainframes is not really moving to AWS/cloud. Most of what's going to the cloud is what I would consider to be "supporting" applications, not core applications.

My own experience, that of others may differ.

Programmers are taught that database transactions exist so that when you move money from one account to another and crash in the middle, no money is ever created or destroyed. Well, cat picture websites might do that, but banks don't. They reconcile logs at end of day.

> you either spend money on software that deals with the hardware being unreliable...or you spend money on hardware that promises to be highly reliable and save on software.