Storage of data on a magnetised medium using different patterns of magnetisation is called magnetic storage. In this information is accessed by using one or more read/write heads. Hard disk which is storage media used to store computer data as well as audio and video signals. The term magnetic storage is preferred in case of computing and term magnetic recording is preferable in case of audio and video production. Examples of media storage includes floppy disks, magnetic recording tape, magnetic stripes on credit cards. Purpose of storage device is to hold data when system is turned off it can be used later. Writing data means recording the data the data on the surface of the disk so that we can use that data later. Reading data means retrieving data from the surface and transferring it into the computer memory to use.
Working of diskettes drive include motor that rotates the disk on spindle and having read/write heads also that can move to any spot on the surface. This allow heads to access data randomly rather than sequentially because it skip spot without scanning all the data between. It spin 30 revolution per minute. So the amount of time for one revolution of the diskettes to read/write operation is 0.2 second.
This is the most common storage device for all computers. Hard drives store data in tracks divided into sectors. They are different from diskettes. A metal platter is mounted over a central spindle like a stack of diskettes. Platter is covered with the metal coating and entire unit is contained in sealed chamber. All emphasis in the single unit. Hard drives have become primary storage device for PCs because they are convenient and cost effective. Perform in both speed and capacity. Its support several hundred MBs and more.
Magnetic tape is made up of thin magnetisable coating and it is a medium of magnetic recording. It is a narrow strip of plastic film. Device that record and play audio and video using magnetic tapes are tape recorders. Tape has to write data serially 1 byte after another. This is slower than direct access provided by media such as disk.