|  | 8.11 | Maintaining and Supporting the Network
| 8.11.2 | Demonstrate awareness of standard backup procedures back up media storage practices
Each administrator, maintaining a network, should have a standard backup procedure, which should be implemented nightly. Backup procedures should include tape drives, tape automation, and full, incremental, and differential back ups. DAT and DLT are the two standard types of tape drives. Digital Audio Tape (DAT) provides a complete digital recording method, which was originally used to record audio and video. DAT has a capacity of 24 gigabytes, uses a SCSI connection, and is mostly used for medium sized networks. Digital Linear Tapes (DLT) have a capacity of up to 80 gigabytes and is becoming the more popular method of the three backup standards. Although this method is expensive, it is very fast and reliable. Like DAT, DLT uses a SCSI connection as well. Tape automation is a scheduled routine backup, where a tape backup is scheduled with an average of 20-25 tape rotations. The most common tape backup procedure is the 21-day tape rotation, where rotation is consistent for four days out of the week, Monday through Thursday. There are some rotations scheduled for five days a week as well, Monday through Friday. Storing backup tape offsite is also a good idea in case of a major catastrophe, which will ruin the backed up information. There are three different types of backups: Full, incremental, and differential. Full back up is the process where all the information is backed up. Most companies perform full backups everyday; however, this process requires the most tape out of the three backup processes. Incremental backups back up files, which have been changed since the last incremental or full backup was performed. This process is less time consuming and uses the least amount of tape. In case the database needs to be restored, the last full backup and every incremental tape afterwards would be needed. Differential backup is a process in which those files are backed up which were changed since that last full backup was performed. This type of backup process takes the less tape than a full backup and when restoring the information, only two tapes are required; the last full and differential backup tapes.