File-It-Under: Tech explanation By: D.F.Skin
Its been quite some time since I've done this "Explanation Needed", we get to the point and kick things off with a piece of hardware I bet has heighten your curiosity and that's the inner workings of the hard drive, or to put it simple,How Does It work. Many hardware geeks like myself who's built plenty of computers in the past couple of years pretty much know the overall architecture of the hard drive. But there are plenty of computer owners and tech experts alike who really don't know what goes on inside an actual hard drive. In this installment you'll know about the actual operation of the hard drive and more.
There are three integral parts to the hard drive. There is the platter or we call is the disk which is where data is stored,the voice coil actuator and the read write head.How does the head actually read data? Its all basic mechanical engineering, the head is basically a piece of metal that's wrapped around in wire. Just as the head moves across the magnetic field on the platter,there are changes in magnetism that induces current, this is measured and converted into a binary value,what's binary? well that's a whole new Explanation Needed which I will go into in the near future. Lets keep it simple and say Binary is a code that the computer reads and understands. There are different ways of making the actual hard drive heads and encoding data onto magnetic surface.
The hard drive goes through a series of operations starting with the read write head (head for short) . The head must be able to accurately seek out a magnetic region that is just a few nanometers wide, all while the disk is spinning in a rapid motion,disk in a standard hard drive spins about a thousand revolutions per minute (RPM), the higher the rotational speed the faster the read write /head can retrieve data. You would think that a hard drive has a motor,which it does but its not a normal motor, the hard drive heads move similar to a cone in a speaker when it produces sound. When you apply a little amount of electricity to a wire,there is a certain amount of force being used that moves the hard drive head accurately. There are no moving cogs that actually spins the disk, or little wear and tear--- which is probably the main reason why most hard drives can last a long time.
The data read? Well there is a high amount of density on most standard drives---approximately up to 625 billion bits per square-inch on a 1TB platter. The head must float 5 to 10 nanmeters above the magnetic region on the disk. There are no mechanical fixed head that hangs 10nm above the disk platters,standard drives heads float on a thin layer of air that's created by the rotation of the hard drive. The amazing thing is this sort of technique is very self correcting, meaning if the head rises slightly to much,the drive will lose its buoyancy and fall right back down to its floating height. To get a idea how much separation is the head from the platter, we mention that its 10nm,that's about as thin as an small cookie crumb. As hard drives density increases, the actual floating height of head will get much lower.
To put it in a simplistic format so you can grasp it all,just think of a hard drive as one big compact electric magnet. Its no wonder why if you run an actual magnet to a hard drive,you can cause damage thus lose stored data.