The hard disk drive, is a component that serves to maintain the dates forever. It is connected to the motherboard from a hard disk controller. This controller manages the disks connected to it. Usually distinguish the following interfaces:
IDE
SCSI
Serial ATA
There are the disks that are called hard disk drive esternal, or that are connected to the computer through a cable taht leads to USB. This disk can be adopted for several reasons: -make backup copies of programs or files on the computer -store data in general -security requirements for to have to have a protection at the hardware level of data. One disk consists of several hard disks, in metal, in glass or ceramic stacked one above the other with a small distance. This disks revolving around an axis in anticlockwise. Reading and writing are made in thanks to of heads, positioned on either side of the plates. This heads are close to the surface and are movable laterrally. The cylinder is the object taht allows us to designate all the data stored vertically on all the disks. The heads of reading/writing are called “inductive”, that is, are able to form a magnetic field. They begin to write data to the disk device, after go to the center. The data are arranged in concentric circles, that are called slopes. The slopes are divided into sectors, where there are the data. The cluster is the minimum area that can occupy a disk file. The first hard disk drive was invented in 1956 from IBM. Later always IBM in 1962 introduced a nwe model “ the 1301”, that were the first hard drives to be marketed. With the years these disks developed increasingly. There was also the birth of the interface SCSI in 1982 and also the birth of the floppy disk created always by IBM.
3 links to other pages in the wiki
http://it.kioskea.net/contents/325-disco-rigido
http://www.mattiolimaikol.altervista.org/index.php?option=com_content&task=view&id=14&Itemid=28
http://it.kioskea.net/contents/486-storia-del-disco-rigido
3 references to online articles that are not on Wikipedia or are referred to by the corresponding Wikipedia article.
http://www.ontrackdatarecovery.it/articolo-storia-hard-disk-55-anni-di-progressi/
http://www.programmifree.com/app/deframmentare.htm
