Oracle CEO Larry Ellison.

A trio of legacy tech heavyweights will try to prove their cloud cred next week in a series of closely scheduled events. If you didn’t know better, you’d think that Hewlett-Packard, Oracle, and Microsoft are all trying to step on each other’s big cloudy moment.

First up, Hewlett-Packard, which will talk up its public and private cloud game plan at HP Discover in Las Vegas, with CEO Meg Whitman’s keynote slated for Tuesday. Guess what her topic will be? HP’s public cloud went to beta last month and Zorawar “Biri” Singh, HP’s cloud master, is said to have Amazon Web Services in his sights.

Next up is Oracle, which will host an event at its Redwood Shores, Calif. headquarters on Wednesday. There CEO Larry Ellison and Co-president Mark Hurd are expected to provide some details around the company’s oft-promised public cloud and platform as a service play.  Ellison mentioned the PaaS plan at AllThingsD’s D10 conference last week and talked up Oracle’s cloud in general at Oracle OpenWorld last fall.

Microsoft’s big Azure event, hosted by Corporate VP Scott Guthrie,  will be in San Francisco on Thursday, although most of the news  – around its infrastructure-as-a service response to (who else?) Amazon — will probably come out Wednesday. Microsoft launched Windows Azure in February 2010 as a full-fledged platform as a service and then watched Amazon steamroller the public cloud space with its infrastructure as a service.  Microsoft, as has been reported, is expected to announce Azure’s ability to run persistant Linux VMs and other infrastructure as a service functionality. Leading into the event Microsoft disclosed its Azure Active Directory strategy last week.

Satya Nadella, Microsoft’s president of server and tools, will doubtless continue the Azure conversation the following week at TechEd North America and then again at GigaOM’s own Structure Event.

All three of these companies have prodigious resources and all of them have struggled to enter the cloud era — mostly because they — unlike Amazon — have huge legacy software franchises to protect. All of them are after the same thing: Displacing Amazon as the number one cloud provider and to keep the others from doing so.

Stay tuned, it’s going to be an interesting battle.

Ellison photo courtesy of Flickr user Oracle_Photos_Screenshots

Feature photo courtesy of Flickr user Public Domain Photos

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