Secondary Storage

 File compression

The process of encoding information using fewer bits or information through use of specific encoding schemes is known as data compression (source coding).The data will be stored more efficiently so that the information can take up less disk or file space as well as may be transmitted in less time. File compression is also a type of data compression that condenses one or more files into a file that has less storage space than the files did separately.

 Head crush

Head crush(disk crash) is defined as the collision of the read-write head with the magnetic recording surface of a hard disk in. It will cause the read/write head to collide with the disk's recording surface if there is misalignment, faulty parts in conjunction with dust, and excessive jostling and temperatures. The drive has to be replaced when the data are rendered unreadable. Program crashes are not destructive to the machine but "head crashes" are destructive to the hardware when the computer stops dead its tracks with a head crush and a regular crush.

              
Internet Hard Drive

Hard drives are the most basis storage medium for laptop and desktop computers. The mechanism that reads and writes data on a hard disk is called Internet Hard Drive. Caching is a technique  which is used by the disk drive to improve the performance.The most commonly used interface standards for passing data between a hard disk are IDE and SCSI. Each laptop will at least have one hard drive. 

 Optical Disc Drive

The disk drive that uses laser light or electromagnetic waves near the light spectrum as part of the process of reading or writing data to or from optical discs is pronounced as Optical Disc Drive(ODD). Optical disks can store a lot of data and information up to 6 gigabytes larger than the most portable magnetic media like floppies. There are few basic types of optical disks, they are CD-ROM,WORM and erasable.CD-ROM is like an audio CD.

Solid-state Storage

A solid-state drive (SSD) is a data storage device that uses solid state memory to store persistent data. An SSD emulates a hard disk drive interface, thus easily replacing it in most applications. It is a nonvolatile, removable storage medium which uses integrated circuits (ICs) rather than magnetic or optical media and is equivalent of large-capacity memory. SSD contains no mechanical parts, making it the main advantage. Data and information that transmit to and from solid-state storage media can be processed at a high speed compare to electromechanical disk drivers.