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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

#41

Post by Hikikomori »

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 kept track of everything, inventory, logistics and planning. I used it to plan rail shipments, where to put each roll of sheet metal on a train and loaded them up.

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

#42

Post by ElectricalUnion »

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.

I thought such throughput would cost around 30 274 560 USD/year (60 * 60 * 24 * 365 * 48 * 0.02) on data transit fees alone.

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

#43

Post by dboreham »

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…

> I've never used or even seen a mainframe in 26 years in the tech industry.

40 years here. Although in theory I've used a mainframe in college, but it wasn't IBM (Burroughs) and just seemed like "a computer" at the time. I also worked a bit on a terminal emulator for ICL mainframes, so probably at least logged in. So 40 years of saying "I wonder if the mainframe people already have a solution to this?"

Probably mainframes haven't been much used for HPC since the transition to Cray in the 70s.

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

#44

Post by Zigurd »

ElectricalUnion wrote: post #11
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…

> 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. It is never technical or pratical reasons, always economic reasons. To use contemporary vocabulary, you "just" need to replicate a "multi tenant HA cloud environment" to migrate from a mainframe at great cost. > An…

The risk in a reengineering project that comprehensively replaces the mainframe is enough to discourage most people making that decision. It could be a $3M project that pays pack in 4 years after scrapping the mainframe and running out the maintenance contract, or it could go over budget and take forever to pay back. Your IBM rep has undoubtedly run the numbers.

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

#46

Post by jeffbee »

ElectricalUnion wrote: post #42
jeffbee wrote: post #39

Earlier quoted context omitted.

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.

I thought such throughput would cost around 30 274 560 USD/year (60 * 60 * 24 * 365 * 48 * 0.02) on data transit fees alone.

Obviously it would be very foolish to use an AWS storage backend for an application that was not also in AWS.

That said, it is not at all clear to me that the TCO of a maxed-out IBM DS8900F is less than $30 million/year.

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

#47

Post by osullivj »

dboreham wrote: post #43
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…

> I've never used or even seen a mainframe in 26 years in the tech industry. 40 years here. Although in theory I've used a mainframe in college, but it wasn't IBM (Burroughs) and just seemed like "a computer" at the time. I also worked a bit on a terminal emulator for ICL mainframes, so probably at least logged in. So 40 years of saying "I wonder if the mainframe people already have a solution to this?" Probably main…

Also 40 years, 25 in banking. Done several Unix to Z/OS, and Windows to VME integration projects.

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

#48

Post by ooterness »

kkielhofner wrote: post #19

"They’re designed to process large amounts of critical data while maintaining a 99.999 percent uptime—that’s three seconds of outage per year." Very wrong. Five nines is five minutes and 13 seconds of cumulative downtime in a year[0]. Three seconds of downtime in a year is seven nines[1]. [0] - https://uptime.is/five-nines [1] - https://uptime.is/99.99999

Looks like they've updated the article to correct this. It now says, "a bit over five minutes' worth of outage per year".

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

#50

Post by eeegnu »

kkielhofner wrote: post #19

"They’re designed to process large amounts of critical data while maintaining a 99.999 percent uptime—that’s three seconds of outage per year." Very wrong. Five nines is five minutes and 13 seconds of cumulative downtime in a year[0]. Three seconds of downtime in a year is seven nines[1]. [0] - https://uptime.is/five-nines [1] - https://uptime.is/99.99999

I would guess that they did the calculations, but interpreted it as "5 nines after the decimal point", when it's really "5 nines in total".
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