Hard Drives and how they function.

The hard drive was first introduced on September 13, 1956, it required a large housing and 50 24 - inch platters to store 1/2400 as much data as can be fit on today's largest capacity 1 - inch hard drives. IBM makes there HDD in the UK were IBM is located.

A hard drive disk stores information on one or more rigid, flat, disks. The disks are mounted on a spindle, with spaces in between, and a motor on the bottom end of the spindle. It reads and writes the information onto the surface of the disks, the drive uses a small electro-magnet assembly called the head, which is located on the end of the actuator arm. There is one head for each platter surface on the spindle. The disks are spun at a very high speed to allow the head to move quickly over the surface of the disk. Towards the other end of the actuator arm is a pivot point, and near the end is the voice coil, which moves the head. Above and below each voice coil is a rare earth magnet which allows the head to move towards the center of the disk or to the outside of the disk, in a circular pattern.

The disk controller uses a digital-to-analog converter to control the flow of electricity through the voice coil located on the actuator arm. The voice coil acts as an electromagnet that means it produces a magnetic field that interacts with magnetic fields of the magnet located above and below the voice coil. That process causes the voice coil to move the actuator arm, and then the head located on the opposite end of the actuator arm. So as the voice coil is pushed towards one end, the assembly moves the head towards the center, and when the voice coil is pushed towards the other end, the heads move to the outside edge of the disk, or the heads are parked. The digital-to-analog converter allows the disk controller to move the head in tiny steps in either direction.

The disks are made out of a non-magnetic material, they are usually made of aluminum or glass, and are coated with a very thin layer of magnetic material. Old style disks had used iron oxide as the magnetic material, but nowadays the disks use a cobalt-based alloy.

The magnetic surface of each platter is divided into many small sub-micrometre-sized magnetic sections, each of them are used to encode a single binary unit of information. Recent hard drives, these magnetic regions are composed of a few hundred magnetic grains. Each magnetic region forms a magnetic dipole which generates a highly localized magnetic field nearby. The write head magnetizes a magnetic region by generating a strong magnetic field nearby. Early Hard Drives used the same inductor that was used to read the data as an electromagnet to create the field. Later versions of inductive heads included metal in Gap heads and thin film heads. In today's heads, the read and write elements are different things but in close proximity on the head portion of an actuator arm. The read element is typically magnet resisting while the write element is typically thin-film inductive.

Hard disk drives are sealed to prevent dust and other sources of contamination from interfering with the operation of the hard disks heads. The hard drives are not air tight, but rather use an extremely fine air filter, to allow for air inside the hard drive enclosure. The spinning of the disks causes the air to circulate forcing any particles to become trapped on the filter. The spinning of the disks, also allows the hard disk heads to float above the surface of the disk surface using the same air currents.

Using rigid disks and sealing the unit allows much tighter tolerances than in a floppy disk drive. Consequently, hard disk drives can store much more data than floppy disk drives and access and transmit it faster. In 2007, a typical enterprise, workstation HDD might store between 160 GB and 1 TB of data, rotate at 7,200 or 10,000RPM, and have a sequential media transfer rate of over 80 MB/s. The fastest enterprise HDDs spin at 15,000 RPM, and can achieve sequential media transfer speeds up to and beyond 110 MB/s. Mobile, Laptop HDDs, which are physically smaller than their desktop and enterprise counterparts, tend to be slower and have less capacity. In the 1990s, most spun at 4,200 RPM. In 2007, a typical mobile HDD spins at 5,400 RPM, with 7,200 RPM models available for a slight price difference.

Some ways to back up your Hard Drive.

SATA vs. IDE:

SATA is the new the version of HDD's and IDE are the old version of HDD's and. SATA will be the only type of HDD being sold now, brand new.

Ways to back up your Hard Drive:

There are many ways to buy or look for Hard Drives. Like to go to electronic stores that sell computers or you can go online and look on computer websites.

You can buy a portable Hard Drive or do this trick.

http://tutorialninjas.net/2007/09/05/hidden-feature-turn-gmail-into-gspace/

Link:

http://www.pcworld.com/article/id,127104/article.html

http://www.fortunecity.com/marina/reach/435/storage.html

http://en.wikipedia.org/wiki/Hard_disk

http://www.webmasterworld.com/forum105/319.htm

Pics:

http://www.elizajewett.com/images/harddrive.jpg

http://img.clubic.com/photo/00031402.jpg

http://hardwarelogic.com/articles/reviews/misc/Seagate750/HDD_bottom.jpg

http://www.pcdoctor-guide.com/wordpress/images/21%20-%20all_the_parts.jpg