This is a great enabler, since the data can be instantly modified, deleted, created or copied by the user and even transported a long distance over network wires.

However, there is a major drawback too. The data stored digitally is much easier to lose and destroy than, say, the information contained in a paper file. Data can be lost due to a variety of hardware or software errors. This has necessitated taking a backup of data residing on computers onto other storage media.

A variety of computer backup media today exist, ranging from optical disks on one hand to portable hard disks on the other. However, the most popular data storage media with the corporates even today continues to be the tried and trusted tape drives. These cater to all needs and budgets, with their capacities ranging from 10 or even less gigabytes to a whopping 800 gigabytes. The drive can connect to a computer through a variety of interfaces, such as SCSI, USB, IDE and parallel port.

How Tape Drives Work

Tape drives work on the age-old principle of recording information on a magnetic tape, much like the audio cassettes of yore. A tape drive system consists of two parts – the drive and the cartridge. The latter is a rectangular case made of tough plastic. It encloses a long and thin ream of tape carrying a coat of magnetic paint that is wound around a couple of spools. The cartridge works when it is inserted in the tape drive.

The drive has a motor that begins to spin the tape inside the cartridge at a great speed. The tape runs brushing past a stationary read-and-write head that is made up of an electromagnet. This magnet emits a magnetic field that writes and modifies data on the tape as instructed by the operating system.

Advantages

Tape drives use a technology that has been around for at least half a century. It is a very reliable system with few surprises. The drives offer a very stable media for long-term archival storage of data. Over the years, the tape drive prices have hit rock bottom. These today offer one of the lowest costs per MB of data stored compared to any other media, which makes them the storage devices of choice for companies compared to other alternatives.

The tape drive has matured and its functionality has increased dramatically. It offers quite fast data transfer speeds and a huge capacity. You can buy as many cartridges as you want to keep pace with your data backup needs and use autoloaders and tape libraries to do the job faster and with greater efficiency.

Tape drives are also quite reliable because they spread data over a long ream of magnetic tape. If some part of the tape develops a defect, you do not lose the entire information. You can just cut out the damaged portion, glue the ends together and go on to extract the rest of the data.

Disadvantages

The biggest drawback of tape drives is their sequential data access. The hard disks that store data on a series of vertically arranged platters have a read / write head that can instantly extract any file from anywhere on the data recording surface. This “random access” makes them a perfect candidate for use as primary storage devices inside computers. However, this is not the case with tape drives.

If you want to access a particular file, the tape drive’s motor has to wind the entire length of tape back and forth until the desired location is reached. This fact makes tape drives worthless for use as primary storage devices in computers, but is not of much significance if their only purpose is long-term archival data storage.

Another problem in storing data on tape regularly is that it takes a lot of effort and human intervention. Somebody has to be deputed every evening after office hours who can manually insert tape cartridges in the drive and take a backup. The entire process may consume an hour or even more. Worse, whenever the business premises is hit by a natural or man-made disaster, the tapes carrying the backup get destroyed too, unlike in the case of remote backup where the data is stored far away on servers of the service provider.

Tape drives are also not exactly cheap. If your data storage needs are huge, you will have to buy a dozen or even more tape cartridges, which may come out to be an expensive proposition. Tapes also have to be stored in a cool, dark and dry place away from heat and moisture, which is another hassle.

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James Walsh is a freelance writer and copy editor. For more information on computer crime and Computer Forensics see http://www.fieldsassociates.co.uk