The leap was partly pent-up demand from the recession, when apparently people were denying themselves the mainframes they so desperately wanted to buy, the report said.
Some of it is the legitimate usefulness of zEnterprise in data centers crowded with many server hardware architectures and, to a limited extent, integration and management of cloud or virtualization platforms, it said.
Unisys is also pitching mainframe-based cloud service, though mainly to give customers of its ClearPath mainframe systems a test and dev environment.
Somehow I can't see it, though.
Mainframes definitely have lower per-computing-unit costs than other systems, and they're barely even the same species of thing they were even 10 or 15 years ago, when IBM was pushing them for ERP or web serving or security management or data management or whatever the hot technology was at the time.
There are still plenty of legacy apps that run best on (or only on) mainframes, and plenty of companies looking for better performance, lower cost-per-unit and better connectivity or manageability to minimize the pain of supporting them.
I have rarely, if ever, heard praise from those companies of the mainframe as the one thing they would really prefer to buy, given the choice. Far more often they're looking for a way to lifecycle the legacy app out the door, or isolate it in a way that will allow them to not mess with either it or the mainframe any more than they absolutely have to.
IBM has demonstrated how constant reinvention can keep a technology relevant long after all its peers are dust, but there's a limit to how far a single technology can be adapted, even if there's hardly a scrap of the original design left in it.
Users who have to buy mainframes for other reasons may find management and monitoring of apps or systems in clouds and across multiple virtual environments a real advantage. They're not any easier to use in many ways, though, even in roles in which they're supposed to shine.
Those who don't have to buy them can do the same things using systems that don't require the same cost of acquisition, introduction of new (old, actually) technical skills and years-long commitment to a technology that tried to disappear, and possibly should have, decades ago.