Windows Vista, if the operating system detected corruption in the file system of an NTFS volume, it marked the volume "dirty"; to correct errors on the volume, it had to be taken offline. With self-healing NTFS, an NTFS worker thread is spawned in the background which performs a localized fix-up of damaged data structures, with only the corrupted files/folders remaining unavailable without locking out the entire volume and needing the server to be taken down. S.M.A.R.T. detection techniques were added to help determine when a hard disk may fail. Hyper-V Hyper-V is hypervisor-based virtualization software, forming a core part of Microsoft's virtualization strategy. It virtualizes servers on an operating system's kernel layer. It can be thought of as partitioning a single physical server into multiple small computational partitions. Hyper-V includes the ability to act as a Xen virtualization hypervisor host allowing Xen-enabled guest operating systems to run virtualized. A beta version of Hyper-V shipped with certain x86-64 editions of Windows Server 2008, prior to Microsoft's release of the final version of Hyper-V on 26 June 2008 as a free download. Also, a standalone variant of Hyper-V exists; this variant supports only x86-64 architecture. While the IA-32 editions of Windows Server 2008 cannot run or install Hyper-V, they can run the MMC snap-in for managing Hyper-V. Windows System Resource Manager Windows System Resource Manager (WSRM) is integrated into Windows Server 2008. It provides resource management and can be used to control the amount of resources a process or a user can use based on business priorities. Process Matching Criteria, which is defined by the name, type or owner of the process, enforces restrictions on the resource usage by a process that matches the criteria. CPU time, bandwidth that it can use, number of processors it can be run on, and allocated to a process can be restricted. Restrictions can be set to be imposed only on certain dates as well. Server Manager Server Manager is a new roles-based management tool for Windows Server 2008. It is a combination of Manage Your Server and Security Configuration Wizard from Windows Server 2003. Server Manager is an improvement of the Configure my server dialog that launches by default on Windows Server 2003 machines. However, rather than serve only as a starting point to configuring new roles, Server Manager gathers together all of the operations users would want to conduct on the server, such as,