Optical Disk

• Optical Disk :-

                                        Laser is used to read and write data on Optical Disk. To save data on disk laser beam creates small holes on disk. Optical drive laser beam able to read the holes on disk. The presence of holes indicates 1 and absent indicates 0. 

Optical technology work fast then a magnetic method. 

• Types of Optical Disk :-

1). CD :-

                

                      A CD ROM an acronym of " Compact Disc Read Only Memory " is a pre-pressed  compact disc that contains data accessible to, but not writable.

 CD ROM are popularly  used to distribute computer software, including video games and multimedia applications, through any data can be stored (up to the capacity limit of a disk.


2). DVD :-

                 DVD ROM stands for " Digital Versatile Disc Read only Memory " and refers to a drive that can read dvd discs. The advent of DVD ROM drives has made it easier for computers users to access large amounts of data as well as providing a medium for watching videos. DVDs can hold many times of the storage of a CD.

 So, Computer applications that required four or five CDs should be consolidated into a single disc. Video and commercial movies could be played on the computer as well. 

Hard Disk

• Hard Disk :-

 

                             Hard disk drive is a type of magnetic disk. It consisit round plates called platter. Data store on platter A head fix on plates to read and write data. Platters usually constructed of aluminum or glass which cannot be bent like floppy disc hence termed as hard disk. A hard disk drive normally has one head per platter with all heads mounted on common rack. The had disk spins the disk as 3600, 5400, and upto 7200 or even more RPM (rotation per minute).  We save a lot of data on hard disk. Hard disk is used in computers to save the important data. 

• Basic Hard Drive Components:

• Disk Platters
• Read/Write head
• Spindle motor
• Head actuator mechanism
• Logic Board
• Cable and Connectors
• Configuration items

• Sector in Hard Disk :-

                          Sector is a section of a tracks which stores a predetermined number of Bytes