Disk staging is a technique in which memory goes through a disk before going to magnetic tape when backing up information on a computer. Depending on the disk, memory can be stored for up to a week without being erased. One reason for using disk staging is that any interruptions when backing up directly to tape can ruin the entire backup, but staging stabilizes the process. It normally also is faster, because disks can be accessed quicker, which makes it easier for the system to perform the entire backup.
Many times when computer data are backed up for long-term archival purposes, the data will be sent directly to magnetic tape. While magnetic tape is very slow, it has a large memory capacity and can be stored for a long time. When disk staging is used, the computer disk acts as an intermediary, and the data first go to the disk. After going through the disk, the data reach the tape.
Operators sometimes will not want to fully perform the backup; instead, they just want to load the data in the disk so it can go to the tape later. Backing up a large amount of data can be tedious for a system, and performing the backup during work hours can dramatically decrease output. If operators decide to back up the system this way, then they commonly have about a week before the backup will disappear from the disk. This depends largely on the disk, because some can hold data longer, while others can only hold data for a day.
Aside from better allocating computer resources, one advantage to using disk staging is that this stabilizes the backup. If the data were sent directly to the tape and an interruption occurred, then the entire backup may become corrupt, forcing operators to perform the backup again from the beginning. When disk staging is used, there already will be data on the disk, and the tape can keep taking from the disk without interruption.
Another reason for using disk staging is that it is faster overall. Magnetic tape is a very slow type of memory, but a disk tends to be much faster. Saving the backup to the disk takes much less time, and because of this, it takes less time to go from disk to tape. If a system restore is needed while the data are on the disk, then this information quickly can be accessed for a faster restore.