Difference Between A Hard Disk And A Hard Drive?

Difference Between A Hard Disk And A Hard Drive?

By Victor Epand

Many people are confused about the difference between a hard drive and a hard disk, and even what these are within a computer. Very simply, a hard disk is a physical disk which can be used to store a large amount of information using magnetic patterns, in a similar way to audio cassettes and video tapes, except that a hard disk is quite a lot smaller, and yet can store an incredible amount of information. In fact, hard disks tend to be a collection of several disks all stacked done above the other like a multi storey car park.

A hard drive, on the other hand, is the whole unit in which a hard disk is just one part. The hard disk, or the different layers or platters which make up a hard disk, requires turning. This means that there is a small motor built into the hard drive unit. A very small head needs to read the magnetic patterns on the disk, a little like the stylus from an old record player. The difference, however, apart from being in terms of scale, is that the head which reads a hard disk never actually touches the surface, but hovers a fraction of a millimeter above it.

If the head of a hard disk actually touched the disk surface itself whilst it was spinning, the result would be disastrous, almost certainly damaging the data irreparably, and possibly wrecking the hard disk completely.

A good analogy is to imagine the planet earth as the hard disk. On this sort of scale, the head reading the surface would be just one foot above the ground. You can easily see just how close the head must be to the hard disk when you consider how much smaller the disk is than the planet earth, and therefore how more minuscule the distance between the disk surface and the head must be.

Continuing this analogy, if it were the head which revolved, rather than the disk, then it would be travelling so quickly that it would circumnavigate the earth completely and be back to its starting position once every twelve seconds. Needless to say, the speeds are phenomenal, and when you consider how close it is to the ground, the danger inherent in the head touching the ground at that speed would be utterly disastrous.

A single speck of dust coming between the head and the hard disk would be like a mountain in the way of our analogous head, and clearly cause for complete failure. This is why the hard disk, the motors, the heads and the other components which make up the complete hard drive unit are all enclosed in a special case which is vacuum sealed. This makes sure that there is no possible way in which dust can enter this unit.

The hard disk is the main storage space on any computer, and usually contains all of the data and programmes needed for the computer to run, including the operating system itself, such as Microsoft Windows, Mac OS or Linux.

About the Author : Victor Epand is an expert consultant for computer parts and suits & ties. Shop here to find hard disks, operating systems, formal suits & ties, and computer parts in Canada.

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