Optical Storage Mediums :: essays research papers

Optical Storage Mediums The most common way of storing data in a computer is magnetic. We have hard drives and floppy disks (soon making way to the CD-ROM), both of which can store some amount of data. In a disk drive, a read/write head (usually a coil of wire) passes over a spinning disk, generating an electrical current, which defines a bit as either a 1 or a 0. There are limitations to this though, and that is that we can only make the head so small, and the tracks and sectors so close, before the drive starts to suffer from interference from nearby tracks and sectors. What other option do we have to store massive amount of data? We can use light.  Ã‚  Ã‚  Ã‚  Ã‚  Light has its advantages. It is of a short wavelength, so we can place tracks very close together, and the size of the track we use is dependent only on one thing - the color of the light we use. An optical medium typically involves some sort of laser, for laser light does not diverge, so we can pinpoint it to a specific place on the disk. By moving the laser a little bit, we can change tracks on a disk, and this movement is very small, usually less than a hairÕs width. This allows one to store an immense amount of data on one disk. The light does not touch the disk surface, thereby not creating friction, which leads to wear, so the life of an average optical disk is far longer than that of a magnetic medium. Also, it is impossible to Ã’crashÓ an optical disk (in the same sense as crashing a hard drive), since there is a protective layer covering the data areas, and that the Ã’headÓ of the drive can be quite far away from the disk surface (a few millimeters compared to micrometers for a hard drive). If this medium is so superior, then why is it not standard equipment? It is. Most of the new computers have a CD-ROM drive that comes with it. Also, it is only recently that prices have come low enough to actually make them affordable. However, as the acronym states, one cannot write to a CD-ROM disk (unless one gets a CD-Recordable disk and drive). There are products however, that allows one to store and retrieve data on a optical medium. Some of those products are shown in table 1. However, the cost of this is quite high, so it doesnÕt usually make much sense for consumer use yet, unless one loves to transfers 20 megabyte pictures between friends.