VMware is widely expected to announce the next step in its road to its previously announced Virtual Data Center operating system in a webinar on Tuesday, April 21st.\nThe goal is not primarily to explain the little-understood, still unrealized Virtual Data Center Operating System concept that VMware announced last summer, as part of VMware executives' ongoing promotion of the idea that companies should create internal cloud-computing systems for their traditional IT infrastructures, according to sources briefed on the announcement. \nThe intent is to change the positioning and explanations of the VDC-OS in the context of the company's more recent changes in product names and feature sets. The company's focus is changing -- with the impending announcement of vSphere, the upgrade to VMware's core Virtual Infrastructrure 3 (VI-3) product set\u2014to one that encourages customers to virtualize their IT infrastructures within a "private cloud," automate management and provisioning within that cloud, and expand VMware's reach into virtual desktops, according to presentations made at the company's Partner Summit in Florida this week. \nThe new vSphere product set is expected to include the latest version of VMware's hypervisor technology, VMware business partner Unisys told CIO.com's sister publication Network World, earlier this week. \n"The whole focus is about cloud computing and rolling out a platform for cloud and the transition to the operating system for the data center," says one source. "There will be some rebranding around the release of vSphere; it won't be the VDC-OS anymore, but the concept is the same." \nThe company announced this week a reorganization of its reseller channel program that is designed to increase the ability of integrators to sell VMware infrastructure products to small- and mid-sized customers. \nTaken together, the repositioning of vSphere\u2014the new name for the upgrade to VMware's core Virtual Infrastructure 3\u2014the changes are designed to help VMware reinforce its position as the leading virtualization vendor and stave off competition from Microsoft, especially among new adopters of virtualization and mid-sized companies that might be attracted by the lower sticker price of Microsoft's Hyper-V. \nVMware is also prepping for forthcoming technology hooks that it has previously publicly said will let customers "burst up" on demand from their own private clouds to public cloud providers when extra computing capacity is needed. \n"VMware wants to keep people coming to them for virtualization," says Chris Wolf, analyst at The Burton Group, who declined to discuss any of VMware's future plans. "We'll have to see Tuesday if or how they do it. But if you bundle enough stuff together, you can bring it in at a very attractive price when you compare the virtualization platform plus the management applications, and stack that up against what Microsoft can give you." \nToday, IT groups using VMware can control the behavior of applications and virtual machines using the VMware vCenter Server, move or re-provision servers using the vMotion tool, and balance server workloads using the VMware Distributed Resource Scheduler (DRS).\nDRS and the thin-provisioning functions in VMware's vStorage storage-management software, allow operators to devote disk space, CPU cycles, memory and other system resources to specific servers, applications or users manually, according to policy, or on demand. \n\nThat ability to deploy, recall and reallocate system resources based on a company's immediate need or long-term priority gives customers much greater control over the cost and allocation of their IT resources, approximating public cloud-computing environments that are designed to let customers buy just the IT power, storage or bandwidth they need when they need it, according to VMware. \n\nVMware has been campaigning heavily to present its products as cost-efficient, recently offering a money-back guarantee on the professional services portion of a new virtualization contract that fails to save the customer 50 percent on the cost of the hardware required. It has also been heavily promoting a report from the Taneja Group showing that VMware could actually be less expensive that Microsoft's offering, based on the greater number of VMware virtual machines that can run on a single physical host. \nThe guarantee sounds good, says Liam McGlynn, senior analyst with Enterprise Management Associates. But the size of the installations required between 200 and 750 servers the relatively high-end physical servers required, and the potential giveback only in services, not the cost of software, makes the guarantee's practical value questionable, McGlynn says. \nMany analysts have scoffed at the Taneja report, at least partially because users are leery of putting too many eggs in one virtual basket. \nAnother point to keep in mind: Add-on costs for storage, networking and services now equal $11.26 for each dollar spent on VMware software licenses, according to Carl Eschenbach, executive vice president of worldwide field operations at VMware, who used the figure as a way of painting VMware sales as attractive to integrators and resellers. \n"We want to drive customers to be 100 percent virtualized," he told attendees at the company's partner conference this week in Lake Buena Vista, Fla. \n\nVDC-OS remains the fabric that will tie together all a company's IT resources, though the branding is likely to change and the term private cloud computing is likely to be more prominent than VDC-OS. \n\nAt the partner summit, Tod Nielsen, chief operating officer at VMware, described vSphere as a "cloud OS" that can save and apply role- and rules-based compliance or use policies as workloads that can be applied to any part of an IT infrastructure , not just limit the use of disk space, bandwidth or access to specific files. \n\nLater this year, VMware will announce other products and features that will enhance its virtual-desktop capabilities, including centralized management that is integrated with the server-management functions, more sophisticated use of high-bandwidth networks, and improvements in performance for high-demand applications such as video and graphics to virtual desktops over local networks, Nielsen said.