Technology Explained: How Does A Hard Drive Work?
The average laptop in the shops for around $500 has somewhere in the
region of 60GB of memory. You see
that figure and think ‘wow – imagine all the movies, songs, images,
files and documents I could save on that baby’, right? But did you ever
think about
how it actually gets stored?
If you were to stack the equivalent capacity of CDs in front of you it
would surely rise to eye-level. You can fit everything
on those CDs onto that hard drive. Truly amazing for an invention that
has its origins in the 1950’s and was first developed as a humble
cassette tape.
How Does a Hard Drive Work – The Basics In order to fully understand a
hard drive you have to know how one works physically. Basically, there
are discs,
one on top of the other spaced a few millimetres apart. These discs are
called platters. Polished to a high mirror shine and incredibly smooth
they can
hold vast amounts of data. Next we have the arm. This writes and reads
data onto the disc. It stretches out over the platter and moves over it
from centre
to edge reading and writing data to the platter through its tiny heads
which hover just over the platter. The arm, on the average domestic
drives can
oscillate around 50 times per second. On many high-spec machines and
those used for complex calculations this figure can rise into the
thousands. Hard
drives use magnetism to store information just like on old cassette
tapes. For that reason, copper heads are used as they are easy to
magnetise and demagnetise
using electricity.
Storage and Operation.
When you save a file, the ‘write’ head on the arm writes the data onto
the platter as it spins at high RPM often
in the region of 4,000. However, it doesn’t just go anywhere as the
computer must be able to locate the file later. It also must not
interfere or indeed
delete any other information already on the drive. For this reason,
platters are separated into different sectors and tracks. The tracks are
the long
circular divisions. They are like ‘tracks’ on music records. Then we
have the different sectors which are small sections of tracks. There are
thousands
of these from centre to edge of the platter. In Operation When you open
a file, program or really anything on your PC, the hard drive must find
it. So
let’s say that you open an image. The CPU will tell the hard drive what
you’re looking for. The hard drive will spin extremely fast and it will find
the image in a nano-second. It will then ‘read’ the image and send it to
the CPU. The time it takes to do this is called the ‘read time’. Then
the CPU
takes over and sends the image on its way to your screen. Let’s say you
edited the image. Well now those changes must be saved. When you click
‘Save’,
all of that information is shot to the CPU which in turn sorts it
(processes it) and sends it to the hard drive for storage. The hard
drive will spin
up and the arm will use its ‘write’ heads to overwrite the previous
image with the new one. Job done. That is what that buzzing disc in your
computer
gets up to all day. friendly word of advice: If you want to look inside
a real hard drive, do so with an old one. There are a few reasons for
this. •exposing
a hard drive to light will damage it and render it as useless. • Once
you pop open that drive, plugs on the screws will snap to tell the
manufacturer
you have been poking around in there. By doing this, your warranty is
void immediately. Many drives actually have this warning printed on the
side. •
They’re expensive and carry a lot of important info so don’t just pop
open the family PC to have a go at it.. and oh by the way, if you've
just used outlook
or some type of email client to read all this, the moment you save this
email, your poor hardDrive mite have to do another few hundred rotations
to find
a proper and appropriate place to save this binary file! -- As long as
forever, i'll stay by your side. i'll be your companion, your friend and
your guide.
www.ruchir89.wordpress.com
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