24) Reading and Burning Units (CD, DVD, BlueRay). READING UNITS: -CD: The CD-ROM drive allows the use of optical discs with a higher capacity than 3.5-inch floppy disks: up to 700 MB. This is its main advantage, since CD-ROMs have become the standard for distributing operating systems, applications, etc. The use of these units is very widespread, since they also allow to read compact audio discs. -DVD: DVD-ROM drives are apparently the same as CD-ROM drives, they can read both DVD-ROM and CD-ROM discs. They differ from the CD-ROM reading units in that the support used has up to 17 GB capacity, and in the speed of reading the data. The speed is expressed with another number of the "x": 12x, 16x ... But now the x refers to 1.32 MB / s. Thus: 16x = 21.12 MB / s. -BLUERAY: It is a device that mounts in the bays of 5.25 "of the cabinet, basically integrates within itself a special blue laser beam emitter to read the data recorded on a CD (" Compact Disc "), on a DVD (" Disc Versátile Digital ") and the DB (" Blu-ray Disc "), a motor to rotate the disc and a tray to place them.After reading the data, this unit is also responsible for sending them by means of a cable to the main card (Motherboard) to be processed. BURNER UNITS: -CD: CD burner is a device that will record data or any type of information on an empty optical compact disc. There is also the CD Rom device that only does the work to read the compact disc. The CD Rom is an optical disc. The maximum possible memory that can be stored in an empty device is approximately 800 super bytes. The CD burner comes along with the set of a serial bus that can be connected to the system and there will also be a driver software that can be used to burn the Rom. -DVDRW: It can read and record and re-record images, sound and data on discs of several gigabytes of capacity, with a capacity of 650 MB to 9 GB. -BLURAY: The unit opens and closes its tray either through the user by the button assigned to it or from the computer software. Once placed the Blu-ray, DVD, HD-DVD or CD and the tray inside, an internal mechanism couples the disc with the laser beam and the motor begins the turn to read the characteristics of the disc