The computer itself is the main source of information for the investigator. In the computer, information is stored on the hard disk. A hard disk drive is a device that can record magnetic data, consisting of one or more rigid discs, read / write heads and mechanical mechanisms protected by a metal casing, hermetically sealed. The storage capacity of a hard disk is normal nowadays thousands of gigabytes. A computer may have one or more hard disks of different types and capacities.