Tape Drives and Hard Drives

By: James Walsh

Removable storage media includes devices that are transportable and exist separately from the computer. The reigning monarch of removable storage media, the floppy disk, is now almost history. Its place instead has been taken by optical disks which are today used widely, with capacities ranging from 700 MB to 4.6 GB. These disks in turn are facing heat from another emerging technology the USB drives. These are based on a Flash memory card, with the commonly available ones able to hold up to 8 GB of data.

Tape drives are another prominent removable storage media which is used mostly for taking data backups. The field of non-removable storage media is completely monopolised by hard drives. These are screwed inside a laptop or computer and cannot be transported by the user from one place to another as a matter of routine.

Tape Drives

Tape drives represent an old technology that is time-tested and battle-proven. A tape drive is used along with tape cartridges. The latter are nothing but a cassette of tough plastic inside which exists a long ream of narrow tape wound around a couple of spools. The plastic tape is coated with a thin layer of magnetic paint. This is the actual data-holding surface.

The cartridges are inserted inside the tape drive whose read / write head accesses and modifies digital data on the command of the operating system. Commonly available tape drives have a data holding capacity of up to 80 GB or even more and have for long been the storage media of choice for businesses around the world. This is because these drives are very reliable and offer one of the lowest costs of storage per MB of data compared to other devices. They are also quite small and easy to store for long periods.

Hard Drives

Hard drives are the primary data storage media inside all computers and laptops. They are versatile devices that have also begun to be incorporated in mobile phones, DVD players and digital video cameras. There is no other storage media that even comes close to hard drives in terms of data capacity. Commonly available hard disks have a capacity of 80 GB to 240 GB, though some companies have also introduced those that can store a whopping 1 terabyte of data.

Hard disks have many moving and sophisticated parts inside, but they are still made rugged enough to provide uninterrupted service for many years. Hard disks are non-portable storage media. However, seeing the immense benefit they provide, portable hard disks have also been introduced in the market. These make for great data backup devices and are rapidly becoming popular.


Hard disks and tape drives have been around for decades and are quite popular storage devices. Both use the same principles to store data and offer the same benefits. Both have a magnetic surface on which data is written or modified by a read / write head that carries an electro-magnet. Both last for a number of years and offer very high capacities for data storage despite their small size. Data can be written and re-written over them thousands of times without any problem.


The main difference between a hard disk and tape drive is that the former is fixed inside computers and laptops while the latter is portable media. Though both use a magnetic coating to store data, the mechanisms are quite different. Hard disks have a series of vertical platters that record data on their magnetic surface. The platters spin at a great speed while the read / write head hovering over them moves all over their surface accessing data.

Thus, in a hard drive the data-recording surface as well as the read / write head both are mobile. In a tape drive, data is stored on a magnetic tape which moves past a stationary read/ write head, scraping it. The media is thus in physical contact with the head, which is not the case with a hard disk.

Hard drives offer random data access. They can instantly pick up a data file regardless of where it was stored on the recording surface. Tape drives, on the other hand, afford sequential access. The entire tape has to move past the head to get at the location where the file is stored.

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James Walsh is a freelance writer and copy editor. If you are concerned about data loss and would like more information on Data Recovery see www.fields-data-recovery.co.uk

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