ONTAP implements snapshots by tracking changes to disk-blocks between snapshot operations. Digital images are also available at Snapshots of the Past, which provides archival prints. It was developed to store virtual machine disk images, including snapshots. This avoids the need for exporting and importing images and snapshots between regions. Another property of Git is that it snapshots directory trees of files. Advanced disk arrays often feature cloning, snapshots and remote replication. Pentoo uses rolling releases with periodic ISO snapshots of the latest committed updates. Data is available as live snapshots or a streaming data feed. Only descendant datasets (snapshots and clones) share data encryption keys. Pictures of W. C. Fields and Buzz Aldrin alternated with the snapshots of Led Zeppelin. Compact cameras are intended to be portable (pocketable) and are particularly suitable for casual "snapshots". The video features childhood snapshots of Vandross. This is because application state can be copied across multiple parallel snapshots for high-availability. The aim of Shadow Copy is to create consistent reliable snapshots. The ability to create persistent snapshots was added in Windows Server 2003 onward.