For any specific, serial hard disk drive that occupies a specific logical position within a personal computer system, A Serial Hard Disk Drive Selector is disclosed that permits the replacement of one physically distinct, permanently mounted serial hard disk drive for another physically distinct, permanently mounted serial hard disk drive within the specific logical position occupied. This Serial Hard Disk Drive Selector simultaneously controls the address/command/data from host to drive connections, the address/command/data from drive to host connections, the ground connections, and the power supply connections of all hard disk drives connected to the Selector. This Serial Hard Disk Drive Selector operates by closing the address, command and control, and data to and from connections, and the power supply connections of the selected serial hard disk drive while opening these connections to all not-selected serial hard disk drives connected to the Serial Hard Disk Drive Selector. The choice of hard disk drive is made prior to booting the computer system and the choice is maintained until the computer system is turned off.