Computer data storage, often called storage or memory, refers to computer components, devices, and recording media that retain digital data used for computing or for entertainment. Serial Advanced Technology Attachment (SATA), is a computer bus primarily designed for transfer of data between a computer and mass storage devices such as hard disk drives and optical drives. The main advantages over the older parallel ATA interface are faster data transfer, ability to remove or add devices while operating, thinner cables that let air cooling work more efficiently, and more reliable operation with tighter data integrity checks.
To reduce the amount of space used up on the hard disk various off line storage devices, (i.e., they can be physically removed and disconnected), are available like compact disks (CD) and Digital Versatile Video disk (DVD) that store audio and video files. It is possible to have up to 4.37 GB ordinary data or mix DVD-Video and data on a recordable DVD that can be played by most computer or laptop DVD-ROMs.