Optical Storage Mediums :: essays research papers

Optical Storage MediumsThe most common way of storing selective information in a computer is magnetic. We lease harddrives and floppy disk disks (soon making way to the CD-ROM), both of which sens storesome amount of data. In a disk drive, a read/write head (usually a coil ofwire) passes over a spinning disk, generating an electrical current, whichdefines a bit as either a 1 or a 0. There argon limitations to this though, andthat is that we can only make 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 massive amount of data? Wecan use light.Light has its advantages. It is of a short wavelength, so wecan place tracks very close together, and the sizing of the track we use isdependent only on one thing - the color of the light we use. An optical specialtytypically involves some sort of laser, for laser light does not diverge, so wecan pinpoint it to a spec ific 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 far all-night 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 mold covering the data argonas, 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, then why is itnot standard equipment? It is. Most of the new computers have a CD-ROM drivethat come outs with it. Also, it is only recently that prices have come low enoughto 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.