What a difference a week makes, Six days ago, I was in Berlin at the Citrix Synergy event, today it's Copenhagen for VMware's VMworld and watching Paul Maritz's keynote was a stark contrast to that of his counterpart, Mark Templeman last week.

Maritz gave the air of a man who knows that his company is totally in control of all it surveys.

Templeman gave the impression of a man who knows that he's got a lot of catching up to do - that's why Citrix used Synegy as the springboard for eight new product anouncements, while Vmware kept news of products to a minimum while demonstrating VMware's path towards the virtualised cloud.

That's partly because Vmware released a tranche of products just a month or so ago at VMWorld in the US (although there were also a series of major announcements from Citrix too) but also because VMware is supremely confident of its path.The company boasts more than 190,000 customers - including virtually all of the Fortune 500. That in itself is a stark contrast to Citrix, which last week was pleased to announce that it was in half of the Fortune 500 firms. But VMware has made inroads into more than just the biggest companies: those 190,000 can't all be blue-chip.

Last year, said Maritz, virtual servers overtook physical ones for the first time and the gap between the two is set to widen. It's a virtual world now and VMware is king.

While VMware dictates from a position of strength, there were some similarities with Templeman's Citrix keynote: both companies looked at the challenges of moving cloud services to mobile devices - and in particular, the problems of supporting different sized screens. Both companies talked about the challenges of identities in moving to the cloud, Citrix seemed to have more ambitions here with its desire to incorporate Google identities but VMware's Project Horizon certainly looks an interesting proposition.

However, there are some (ahem) clouds on the horizon. There was noticeably less about desktop virtualisation from VMware than there was from Citrix - we know who's the winner at that little game.

And one big elephant in the room was Microsoft. I tweeted at the start of the keynote when someone mentioned azure that I was surprised that Azure was allowed to be mentioned at a VMware event - I got a quick tweet back from someone at VMware that Azure was not a competitor of VMware. Well, that could have fooled me: Maritz did talk about other cloud platforms but not a whisper about Azure. He spoke about development environments, but not a sausage about .Net. Of course, he's not in the business of talking up his competitors (although Microsoft's not a competitor, remember) but to ignore .Net as a development tool is to ignore a substantial section of the developer community and is a reminder that, despite its total dominance of the space, there's still a little bit of VMware that is anxiously looking over its shoulder.

There's also the issue of cloud portability. Maritz painted a rosy picture of a world where companies could move to on-premise to cloud, back again and then to another cloud provider - all seamlessly, with the same management capabilities and security. The company claims that its vCloud Director offers exactly that. It may be true but we're not really talking about real portability here - this works if all the cloud providers use vCloud Director but not for other products. It's nice for VMware but it's not portability as most of us would understand it.

Maritz was also very keen to talk up open source, although, again this seemed to be a reference to its efforts with SpringSource. No-one will doubt SpringSource credentials here but again, it seems that it's a definition of open that is very much on VMware's terms.

There's little doubt that virtualisation is the way forward for enterprises and that VMware has been hugely influential in this. The company is in its position of strength because it has consistently been the most technically advanced and innovative company pushing virtualisation.

But we're reaching a turning point now. Microsoft has certainly got its act together, after a slow start. Citrix has a coherent message and Red Hat and Oracle are turning their attention to the virtualisation space. VMware is undoubtedly master of the domain for now (hence its confident display at VMworld but the company certainly can't afford to be complacent and assume that that dominance is going to last.<

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