storage device. No quiescing of activity of any kind is required with streamed backups. Both the database and log files are check summed to ensure that no data corruptions exist within the data set during the backup process. Streaming backups may also be incremental backups. Incremental backups are ones in which only the log files are copied and which can be restored along with a previous full backup to bring all databases to a recent state. Shadow copy backups are a new high speed backup method. Shadow copy backups are dramatically faster because the copy is virtually made after a brief period of quiescing an application. As subsequent updates are made to the data, the virtual copy is materialized. In some cases, hardware support for shadow copy backups means that actually saving the virtual copies is unnecessary. Shadow copy backups are always full backups. Restore can be used to apply a single backup, or it can be used to apply a combination of a single full backup with one or more incremental backups. Further, any existing log files can be replayed as well to recreate an entire data set all the way up to the last transaction logged as committed to transaction level 0. Restoration of a backup can be made to any system capable of supporting the original application. It need not be the same machine, or even the same machine configuration. Location of files can be changed as part of the restoration process. Backup and restore to different hardware When an ESENT database is created, the physical disk sector size is stored with the database. The physical sector size is expected to remain consistent between sessions; otherwise, an error is reported. When a physical drive is cloned or restored from a drive image to a drive that uses a different physical sector size (Advanced Format Drives), ESENT will report errors. This is a known issue and Microsoft has hot fixes available. For Windows Vista or Windows Server 2008 see KB2470478. For Windows 7 or Windows Server 2008 R2 see KB982018. History JET Blue was originally developed by Microsoft as a prospective upgrade for the JET Red database engine in Microsoft Access, but was never used in this role. Instead, it went on to be used by Exchange Server, Active Directory, File Replication Service (FRS), Security Configuration Editor, Certificate Services, Windows Internet Name Service (WINS) and a host of