In computers, tape is an external storage medium, usually both readable and writable, consisting of a loop of flexible celluloid-like material that can store data in the form of tiny magnetic fields that can be read and also erased. The magnetic tape is housed in a plastic cartridge similar to that of an audio or video cassette. Because the tapes, which are recorded by a device called a tape drive, are portable and inexpensive to purchase, tape is often used for backing up or archiving data. A drawback of tape is that it can only be accessed by starting at the beginning and rolling through the tape until the desired data is located.
The most commonly quoted figure for the archival life of magnetic tape is 30 years. There are ways to minimize the chances of a tape backup's failing in the first place. Here are a few tips for managing tape from SearchStorage expert Rick Cook:
Verify your tape backups. Most backup software will automatically do a quick "read-after-write" verification and will offer optional full verification. The latter is both more thorough and more time-consuming, roughly doubling the backup time, but if your files are crucial, it makes sense to do a full verification regularly.
Store one backup tape off site. This will ensure your files are preserved if your site experiences a fire, flood or other disaster. Some companies swap backup tapes with other offices. With some smaller businesses, it often makes sense for one employee to take the backup tape home with him. Another option is using an off-site storage firm that provides fire-protected storage facilities for print and digital media as well as tape.
Store your tapes properly. With backup tapes on site, keep them stored in a stable environment, without extreme temperatures, humidity or electromagnetism. Do not, for instance, store the tapes in a safe on the opposite side of the wall from a large generator, whose electrical fields can wreck havoc with the data on them.
Rotate tapes. Use more than one backup tape. Instead of using the same tape time after time, rotate through multiple tapes. You can use any of a number of different systems for this. With the odd/even system, you use one tape on one day, a second tape the next day, reuse the first tape on day three, and so on. With the five-day rotation system, you use a different tape for each day of the workweek.
Track the "expiry date." Backup tapes are typically rated to be used from 5,000 to 500,000 times, depending on the type of tape. Tape backup software typically will keep track of the tapes, regardless of the rotation system.
Maintain your equipment. Clean your tape backup drive periodically, following directions in its manual regarding frequency. Consider having an authorized maintenance person from the manufacturer of the tape backup drive or from a third-party repair firm check the alignment of the drive every 12 to 18 months. Most businesses just send the drive back to the manufacturer when it begins to have problems, but if a drive has problems, so can the backup tapes.
Do regular checkups. Periodically test the backup tapes and restore procedures. You can, for instance, restore the data on them to a different server or to a different partition or folder on the same server where the original information is stored.
Dispose of old tapes properly. Once you have migrated or retired old tape media, make sure to dispose of it properly. Visit the manufacturer's Web site to learn how. Simply throwing your old tapes in the dumpster is no longer an option.