Computer systems may loose data when a failure occurs within a system. To
counteract such loss of data a backup system may be employed. Common
backup systems make a copy of either of the data on a storage device or
the data, which has changed, on a storage device. The process of backing
up data may involve storing a relatively large amount of data and so is
commonly done infrequently, such as once per day. If a computer's data is
backed up only once per day, several hours of data may be lost if a
computer system fails. Embodiments of the present invention may be used
to prevent this type of data loss by backing up more frequently. In order
to back up more frequently less data at a time is backed up. Instead of
the data undergoing a wholesale backup infrequently, embodiments of the
present invention form a timed log of the storage writes performed by the
computer system. The log provides a running picture of activity to the
computer storage system. By preserving the log, for example storing it at
a remote site through a network connection, the state of the computer can
be recreated with any desired granularity, by using the log entries to
recreate the state of the data within the computer system at any desired
time.