Inside the enterprise: According to IDC, the technology research firm, mainframes account for just 1.7 per cent of IT spending in the UK, and 2.4 per cent in Western Europe.
But these figures underplay the platform's importance. Among companies that use mainframes, big iron runs 60 per cent of their mission-critical applications, and 20 per cent of their open source workloads.
This suggests that, relative to the workloads they handle, mainframes are a highly economical platform. But that assumes, of course, that businesses can afford the considerable initial outlay and that they have the skills to operate and maintain them.
Despite positive research numbers which IBM, in particular, does wheel out from time to time mainframes are no longer the workhorses of computing they once were.
Although IBM still makes them, rival manufacturers have switched to other architectures, especially (Intel) x86, and the concept of connecting up large numbers of small servers, rather than running one, very large, machine. That's exactly how Google, and plenty of other cloud-based services, work.
IBM, though, has not given up the fight. In fact, it has just announced a new mainframe unit, the z13.
This, IBM says, can process a staggering 2.5bn transactions a day, carry out real-time encryption on mobile transactions, and even has built-in support for analytics, removing the need to ship data out to another server to see how the business is doing.
The company is touting the z13 as the first mainframe for the app economy, and says one z13 can handle the equivalent of 100 Cyber Mondays' worth of business.
But if this looks like an attempt by IBM to throw everything it has into the new computer record-breaking processors, encryption, and its open source analytics know how that is not far from the truth. The idea is to create a system rather than a computer.
By integrating analytics, for example, the z13 is able to carry out real-time fraud detection, as well as supporting customisation for e-commerce and m-commerce. IBM's zOS is being upgraded to support in-memory analytics, and its DB2 database will run in memory too.
Then there are the hosting and virtualisation aspects of the mainframe: the z13 can run up to 8,000 virtual servers, and IBM says the new machine is more energy efficient than either x86 hardware or older mainframes.
The total cost of ownership, IBM predicts, will be 32 per cent lower than an x86-based private cloud and a staggering 60 per cent lower than a public cloud although real-world performance will vary, depending on firms' actual workloads.
But people who work with mainframes, at least, are positive about the new system. "The mainframe of today is very different to the mainframe that launched 51 years ago," says Derek Britton, a director at Microfocus. "It consumes less power, has less of an environmental impact, and a lower total cost of ownership there is a huge opportunity here for businesses to use the mainframe to deliver more business value."
IBM, for its part, recently sold its low-end x86 arm to Lenovo. So it will need the new mainframe to shore up declining hardware revenues; the company is set to release its fourth quarter earnings on 20 January.
Stephen Pritchard is a contributing editor at IT Pro.
