On Computing, a hard drive, also called a hard drive , it's a non-volatile data storage device (because the stored contents are not lost even if it is not energized) and that it uses a magnetic recording system to save the digital data.
The hard disk consists of one or more plates or rigid disks joined by the same axis that rotates at high speed inside a sealed metal box, while, on each plate and on each of its faces, there is a reading head located / writing that floats on a thin sheet of air generated by the rotation of the discs.
The first hard drive dates from the year 1956 and it was the IBM company that manufactured it, of course, from that time to this part this type of device has evolved incredibly, greatly multiplying its storage capacity and at the same time has decreased its price.
The characteristics of a hard drive are: mean access time (the average time it takes for the needle to position itself on the track and the desired sector), mean search time (time it takes for the disc to move to the desired track), read / write time (the average time it takes for the disk to read or write new information), medium latency (average time it takes for the needle to position itself in the desired sector), Rotation speed (revolutions per minute of the dishes) and transfer rate (speed with which information is transferred to the computer).
For its part, among the types of connection that a hard disk supports are: IDE, SC SI, SA TA and SAS and regarding the measurements we can find the following: 8 inches, 5.25 inches, 3.5 inches, 2.5 inches, 1.8 inches, 1 inch and 0.85 inches.
As a consequence of the extremely small distance between the heads and the surface of the disc, any contamination that they may suffer can cause damage that undermines their proper functioning.