Difference Between Magnetic Tape and Magnetic Disk

Magnetic tape and magnetic disk both stores the data magnetically. The surface of a magnetic tape and the surface of a magnetic disk are covered with a magnetic material which helps in storing the information magnetically. Both are non-volatile storage. Despite these similarities both differs in many aspects from their appearance to their working, their cost and much more.

The basic difference between magnetic tape and magnetic disk is that magnetic tape is used for backups whereas, magnetic disk are used as secondary storage. Let us discuss some more differences between magnetic tape and magnetic disk with the help of comparison chart shown below.

Content: Magnetic Tape Vs Magnetic Disk

1. Comparison Chart
2. Definition
3. Key Differences
4. Conclusion

Comparison Chart

Basis for Comparison	Magnetic Tape	Magnetic Disk
Basic	Used for backup, and storage of less frequently used information.	Used as a secondary storage.
Physical	Plastic thin, long, narrow strip coated with magnetic material.	Several platters arranged above each other to form a cylinder, each platter has a read-write head.
Use	Idle for sequential access.	Idle for random access.
Access	Slower in data accessing.	Fast in data accessing.
Update	Once data is fed, it can't be updated.	Data can be updated.
Data loss	If the tape is damaged, the data is lost.	In a case of a head crash, the data is lost.
Storage	Typically stores from 20 GB to 200 GB.	From Several hundred GB to Terabytes.
Expense	Magnetic tapes are less expensive.	Magnetic disk is more expensive.

Definition of Magnetic Tape

Magnetic Tapes were introduced in 1928, earlier used as a secondary storage medium. Magnetic tape is a thin long narrow plastic strip coated with the magnetizable substance. The tape is wounded over a spool, and it is wounded or unwounded past a read-write head to read from or write data to the tape.Magnetic Tapes are nonvolatile in nature and hence it holds the large quantity of data permanently. The magnetic tapes store the data sequentially. The random access to magnetic tapes takes more time than magnetic disk because the magnetic tape has to perform forward and rewind operation to locate a correct spot.

Once the read-write head in magnetic tape is positioned correctly, it writes the data with the same speed as that of the magnetic disk. The data transfer speed of the magnetic tape is similar to the magnetic disk. As random access to magnetic tapes is comparatively slower, it was not very useful for secondary storage. Now, the magnetic tapes are used for backups, for storing the data that is less frequently used.

Magnetic tapes are also used in supercomputer centres for holding the large volume of data that is used for scientific research.

Definition of Magnetic Disk

In modern computers, Magnetic Disk is used for secondary storage. Like Magnetic tape, the magnetic disk is also a non-volatile so, its stores the data permanently. The magnetic disk has several flat circular shaped platters which appear like a CD.The diameter of each platter ranges from 1.8 to 5.25 inches.Both inner and outer surfaces of the platter are covered with the magnetic material so that information can be recorded magnetically on the platters. There is a read-write head that moves over the surfaces of each platter. These read-write heads are attached to the disk arm that helps in moving all heads as a single unit.

Each platter surface is divided into circular tracks which are further divided into sectors. The read-write head flies over the platter surface on a thin cushion of air. Though the disk platter is coated with a protective layer, there is always a danger that head will make contact with the disk causing head crash. The Head crash is not repairable the whole magnetic disk is to be replaced.

Conclusion

Magnetic tape was earlier used as secondary storage, but now they are used for backups. Magnetic disks are used as secondary storage for modern computers. Both Magnetic tapes and magnetic disks are the non-volatile storages and both stores the data magnetically.