Introduction to Hard Drives

A hard drive is a hardware device within a computer or external chassis that spins (non solid state drives) a magnetic disk that reads and writes information to and from it.  Below is an illustration of the internal parts of a hard drive.  This is a typical illustration, while most hard drives work identically, they may vary a bit in style and looks.

Hard drives are not typically accessed by the user physically and are normally internal to the computer case.  The exception today, is that if one were to use an external hard drive to carry from place to place or for backup purposes.

In the illustration to the left, you will see that the four main parts of a hard drive are the disk platters, head arm, disk actuator, and the chassis.  For over twenty years now, not much has changed in the thought of how a hard drive works.  The density of how much can be written on the platters have changed tremendously.  I personally remember a 1mb hard drive out of an old IBM word processor with a 8086 cpu.  It was state of the art back then.  Now, we are seeing common place for the 750 gigabyte hard drives.  In the not so distant future this will most likely triple as technology continues to push the barriers and physical limitations of mechanics.

What is not shown in the picture is the connectors and circuit board below.  The introduction of the SATA connector & power connector has been the other large change from the IDE & SCSI connection types.  SATA is much faster in data transfer from the limited ATA 133mbs to SATA's current maximum of 3.0gbs.

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