Sunnyvale, Calif.-based Virsto Software, building on early success in the Microsoft Hyper-V market, is now entering the VMware market with its hypervisor-based storage virtualization software. Virsto for VDI, vSphere Edition, addresses storage costs, performance, and management challenges in virtual desktop environments. The new product for vSphere, officially introduced at VM World this week, delivers scalable virtual machine clones along with thin provisioning for improved virtual desktop density. It can also help reduce the storage cost per virtual desktop, the company said. The product is now in beta testing, with the official release planned for sometime in the fourth quarter.