Amanda, previously known as Advanced Maryland Automatic Network Disk Archiver is an open source computer archiving tool that is able to back up data residing on multiple computers on a network. It uses a client–server model, where the server contacts each client to perform a backup at a scheduled time. Amanda supports both tape-based and disk-based backup, and provides some useful functionality not available in other backup products. Amanda supports tape-spanning - i.e. if a backup set does not fit in one tape, it will be split into multiple tapes.