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Tape backup |
| What It Is | | How It Works | | Types of Tape Drives |
The tape drive copies files from the computer onto tape cartridges. This device is also called a tape backup. The drive can be both external or internal. The external drive is more expensive of course, but can be used with more than one computer. The tape cassettes look like music cassettes that you would buy at a music store. They are used to back up data files on the computer. They also can make a copy of your application program. Most people with tape backups make a copy of their work every day. (Or they should make copies of their work.) Tape backups are also good for storing away rarely used files and data, providing more room on your computer for storage and other applications. Tape backup is also used to transfer large amounts of information between computers.
Tape drives come with specific backup programs to help organize and manage the files stored on the drive. The backup programs can be configured to run automatically. It can also let you backup information at increments (only those files that you have changed) or a full backup that will back up all your files. The incremental backup takes less time of course. The tape drive also can have what is called compression. The compression allows you to squeeze together data so that it can store more information on your tape. In compression, the amount of information compressed is also determined by the type of file that you are backing up. A text file will compress more than a graphics file.
A tape backup uses the same mechanics as the disk but the tape can hold a large amount more than the floppy drive due to its audio tape like capabilities in storage. The W/R surface that is on the disk is Magnetic tape that is wound on two spools exactly like cassette tapes, but what makes the backup tape different than the cassette tape is the Read / Write head or the R/W head. The W/R head is a little different than the W/R head of the floppy drive because of its two R/W heads. The two read heads are there because it can go in two directions, one for reading and one for writing. The reason for this is that the tape is not flat and round like the floppy but is flat and rectangular and continuously winds and unreels back and forth on the tape reels.
When writing to the backup tape the computer sends the file that the user sent to it from FAT and sends it to the RAM or Random Accessed Memory which is a temporary storage unit for the fill, which then sends it to the drives buffer and controller who tells it to run an EC or an Error Correction to find and check all errors to see if it is correction. Once past the EC it goes on to the W/R heads which then aligns the molecules to the correct binary form which is stored until it is accessed by the user. When Reading from the tape the Fat is checked to make sure that the file is there and once that is finished it makes sure that the there are no errors on it. Once past that operation it sends it throughout the buffer in the hardware which sends I to the RAM who then moves it to the desired place determined by the user.
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