how CD ROMS work

A CD ROM is a disk that has the ability to hold a lot of data. There are various types of disks. The first generation ones are the CD ROMS which could hold around 700 MB of data. The later versions were called DVD s and they could hold about 5 GB and 9 GB. The DVD became a very popular format of data storage because they were cheap and could hold a lot of data. Despite the difference between the CD and DVD the working of both is just the same. They use the same mechanism with a few differences. We can read and write data from the disk by using a laser which is made of a certain frequency and intensity. The intensity of the laser used for writing DVD s are a lot higher than the ones used for CD's. The disk is coated with a chemical that changes when exposed to the laser. This is used to write data onto the disk by using the laser which can change the chemical composition. The disk contains small ridges which can hold a specific type of value which is usually in binary format. Whenever a data is written on to a disk it is first converted into binary format and then written unto the disk. The laser changes the chemical composition on the disk which makes the disk inactive to any other writing attempts. After the writing procedure the disk can only be read. Reading is done by using the same laser with a lesser intensity.