We are back with our second installment of computer components explained.  Our goal is to break down parts of our computer into easy to under terms for people who do not spend everyday inside their computer.  I know it is hard to believe but some people really just want to use their computers without being intimate with each computer component.  Today, we are going to look at the one component that many people always purchase their computer based upon, their hard drive.  In hard drives the rule is bigger is better, hard drives today are near the terabyte level which for most people is enough hard drive space to last them years.

    Physically, your hard drive is a sealed unit that you can not remove the platters from.  Usually, a typically designed hard drive consists of several spindles that hold the flat platter disks.  Then the platters have a thin coating of a magnetic material.  It is on this magnetic material that your hard drive records data using the binary format of 0 and 1.  The drive then reads the data back by detecting the magnetization on the material.  The magnetic material can be damaged quite easily so modern hard drives are sold as one sealed unit.  This keeps the very thin disks free of any contamination from your fingers oil.

    We are not going to get into the technological reasons or details of how data is read and stored or why drives keep getting smaller because this is introduce your girlfriend, and quite frankly, she will fall asleep if you start talking about sub-micrometre-sized magnetic regions or magnetic gains that are you need micro-microscopes to see.  All you need to explain to explain to your girlfriend is, advances in hard drive technology allow manufacturers to create smaller and smaller platters which can then be layered on top of each other creating hard drives that are either smaller in size or larger in capacity. 

    Currently the highest capacity a single hard drive can reach is 1 terabyte (1000 gigabytes). But hard drive engineers are working hard to shrink the platters and increase the size of the hard drive.   Most hard drives found in desktop computers usually start at around 500 gigabytes while 100 gigabytes are standard for most portable computers today.  Why the difference between the highest capacity and the current standards?  It costs much more money to manufacturer the 1 terabyte drives then 100 gigabytes.  Eventually when the demands we place upon our computers and the manufacturing costs reach equilibrium, the size of the standard hard drive will increase and everyone will have 1 terabyte drives in their computers. 

    All in all, you can explain the purpose of the hard drive as your computers long term memory — the hard drive remembers everything even when it gets turned off (kind of like your girl friend).  Hard drives are no longer limited to computer installations.  As drives get smaller and smaller, the world of hard drive installation possibilities get bigger and bigger.  Next time you purchase a cell phone, child's electronic toy, or even a kitchen timer it may contain a hard drive.