Optical Storage Mediums :: essays research papers

Optical Storage MediumsThe most common style of storing info in a computer is magnetised. We have harddrives and floppy disks (soon making way to the CD-ROM), both of which can ancestrysome amount of data. In a disk drive, a read/write head (usually a coil ofwire) passes everyplace a spinning disk, generating an electrical current, whichdefines a bit as either a 1 or a 0. There are limitations to this though, andthat is that we can hardly collide with the head so small, and the tracks and sectors soclose, before the drive starts to suffer from interference from nearby tracksand sectors. What other option do we have to store broad amount of data? Wecan intention light.Light has its advantages. It is of a short wavelength, so wecan place tracks very close together, and the size of the track we use isdependent only on unitary thing - the color of the light we use. An optical mediumtypically involves some sort of laser, for laser light does non diverge, so wecan pinpoint it t o a specific place on the disk. By moving the laser a littlebit, we can change tracks on a disk, and this movement is very small, usuallyless than a hairs width. This allows one to store an immense amount of data onone disk. The light does not touch the disk surface, thereby not creatingfriction, which leads to wear, so the life of an average optical disk is farlonger than that of a magnetic medium. Also, it is impossible to crash anoptical disk (in the same sense as crashing a hard drive), since there is aprotective layer covering the data areas, and that the head of the drive canbe quite far away from the disk surface (a few millimeters compared tomicrometers for a hard drive). If this medium is so superior, thus why is itnot standard equipment? It is. Most of the new computers have a CD-ROM drivethat comes with it. Also, it is only recently that prices have come low seemlyto actually make them affordable. However, as the acronym states, one cannotwrite to a CD-ROM disk (unless one gets a CD-Recordable disk and drive). Thereare products however, that allows one to store and retrieve data on a opticalmedium. Some of those products are shown in table 1. However, the cost of thisis quite high, so it doesnt usually make much sense for consumer use yet,unless one loves to transfers 20 megabyte pictures between friends.