Just as the hard disk drive works on the principle of magnetism, the optical disk drive works on the principle of optics. The optical disk drive is used to read and write digital data on compact disks(CD), Digital versatile disc (DVD), and blue ray disks. This is one device that can be used as both input (read data in) and output device (writes data out).
Some of you might be thinking that optical drives are obsolete and the new laptops are designed without any optical drives. To some extent this is true but you cannot discard them altogether since these optical drives are still used for various important purposes.
Applications of optical drives
Apart from installing the operating systems the optical drives to date are still used to read old backups in organizations. The optical discs are more secure since the data contained in CDs, DVDs, or blue ray disks cannot be infected with the virus. So it is still the preferred option to take backups.
Another need to use the optical drive today is the availability of many movies and games on optical discs. But yes, you can download the same from the internet but that will consume so much time and bandwidth which will not be worth it since the movies and games are available in CDS or DVDs at a much cheaper price.
Technology used
A laser beam is used to read or write data on optical media disks. To read or write CDs, DVDs, or blue rays, laser beams of different wavelengths are used. There are three components involved in reading the data. The laser beam itself, a lens that guides this laser beam, and a photo-diode that will receive the light reflected from the optical disc. The same lens can be used to read/write CDs or DVDs but a different lens is used to read blue-ray discs.
As far as the rotational mechanism is concerned, the optical discs maintain constant angular velocity abbreviated as CAV. The optical drive consists of two motors. A brushless DC motor is used to rotate or spin the optical disc and a stepper motor is used to move the lens in a linear motion.
Speed of optical drives
You might have noticed that DVD writers or Blu-Ray drives are marked with 4x, 16x, or 32x. These are the speed capacities of optical drives. Typically, 16x means the optical drive can work at 16 times the speed of the base speed.
CD, DVD, and Blue-ray, all have different base speeds as mentioned in the table below.
| Disc Type | Base speed |
| CD | 150 Kb/s |
| DVD | 1.38Mb/s |
| Blue Ray | 6.74 Mb/s |
Computer connectivity
On desktop computers, there is a 5.25” bay on the front side. The optical drive is connected to the motherboard through two interfaces. On is the 4-pin power connector that comes with SMPS and a SATA, IDE, or SCSI cable for data transfer.
The optical drives also come with a USB port which is found on external optical drives and a PCMCIA interface for laptop connectivity.
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