
Why on Earth Is IBM Still Making Mainframes? - shubhamjain
https://www.wired.com/2015/01/z13-mainframe/
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dzdt
It is really annoying that the linked article gives statistics only in
completely meaningless forms: "a processor that contains 300 percent more
memory than found on most servers and 100 percent more bandwidth" ... "able to
process 2.5 billion transactions a day." What is a transaction, and what is
processing one? "The concept of a 'mobile transaction' is a bit of marketing-
speak." And no more detailed explanation!

Of course the answer to the rhetorical title question is IBM makes them
because customers buy them. I think the reasons they keep selling are (1)
clients have legacy apps that are very critical and very well tested and run
on mainframe environments and (2) mainframes give higher reliability than
other single-box solutions.

But these points are my take; the article doesn't say anything meaningful!

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alfalfasprout
To answer these questions for you: mainframes are perfect for transactional
workflows. Wait but you haven't told me what a transaction is!!!

So... by a transactional workflow, typically it's going to be some workflow
where you get a request, perform some operations on a database, and then
sometimes return a response. This can be a withdrawal from an ATM, a trade
received by a broker, a new user registering on a website, etc.

Mainframes have CPUs and hardware designed to accelerate and make these
transactions more robust over commodity hardware. An example is with hardware
compression and robust transactional memory when using DB2. It's not uncommon
to see mainframes with decades of uptime. You just don't get that with
commodity hardware.

Mainframes are cheap when you really do have simple transactional workflows
like this at massive scale. Financial institutions are an obvious choice as a
result. Since they're so reliable and you're dealing with a simple node, the
cost savings can be significant.

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dekhn
mainframes are designed for reliable, predictable high throughput. they have
very long software and hardware support cycles. if I ran a business and a
mainframe was the most cost-effective way to do it, I'd use one.

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agumonkey
I was surprised to see what is inside a mainframe. Dedicated IO blocks for
instance. They're not beefed up standard PC.

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dekhn
ummm... precisely! You can basically take a sufficiently provisioned mainframe
and "carve it up" into virtual machines with guaranteed isolation and
performance. This is unlike VMs running on an x86-64 server, where there is a
lot of isolation and performance issues.

~~~
brianwawok
The flip side, is for the cost of 1 mainframe you can often buy 500 linux
PCs.. which end up giving you 100x the CPU and 100x the IO of the mainframe
(with a bit of other challenges like orchestration and such).

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dekhn
sure... but I'd rather have 1 mainframe than 500 PCs. They typically have
higher utilization, the problems don't need to be parallelized, you don't have
to think about your network.

I still use PCs for everything I do, haven't yet found a need for a mainframe
personally.

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kpil
I have 1 mainframe, and which I had 500 PCs...

It's solid engineering, but it's also a lot of branding.

If you have a "golden egg" application that have a lot of internal state so
you can't run it on 10 servers, then a mainframe might be a good solution to
keep it running.

I think the most common reason to have a mainframe is that you happen to have
too many managers that used to be mainframe developers.

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andreiw
IBM didn't quit making servers - it just stepped out of the x86 server market.

That's a big difference.

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svennek
Basic econ 101: they are still profitable...

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cateye
Because nobody ever got fired for buying one.

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venomsnake
Why on Earth has wired writing declined so much?

Better title - Why there is still robust market for mainframes?

IBM makes mainframes because industry needs and wants them. Why such need
arise is the real question. And it is barely scratched in the article.

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gozur88
People have been asking this question for decades, and the answers haven't
changed - 1) mainframes do some things very well in terms of security and
stability and 2) porting software is expensive.

In the mid '90s I was working for a company that bought the "Mainframes are
old technology and we're not an old technology company" line (those industry
broadsheets should really be kept away from management) and set out to replace
the old reliable mainframe with OTS Unix machines. We got the answer to the OP
question and we got it good and hard.

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daly
One reason is the installed base. I worked as systems programmer on mainframes
for years. There are still a lot of them out there running legacy
applications.

