| Hard Disk: An Introduction | | | | allowing each head to access almost the entire |
| Hard disk is a non-volatile data storage device that | | | | surface of the platter. Contemporary hard drives use |
| stores electronic data on a magnetic surface layered | | | | a voice coil actuator, which controls the movement |
| onto hard disk platters. Word Hard is use to | | | | of a coil toward or away from a permanent magnet |
| differentiate it from a soft, or floppy disk. Hard disks | | | | based on the amount of current flowing through it. |
| hold more data and can store from 10 to more than | | | | Fundamental structures of all hard disk are same, and |
| 100 gigabytes, whereas most floppies have a | | | | are composed of the same physical features, but |
| maximum storage capacity of 1.4 megabytes and in | | | | their performance depends on the quality of their |
| addition are faster too. Normally term hard disk is | | | | inner components. |
| much familiar with computers only but it is widely | | | | Hard Disk Failure: |
| used as network attached storage for large volume | | | | Hard Disk Failure occurs when a hard disk drive |
| storage. Furthermore, appliance of hard disk drives | | | | malfunctions and the accumulate data cannot be |
| spread out to video recorders, audio players, digital | | | | accessed. It may happen in the course of normal |
| organizers, digital cameras, and even in latest cellular | | | | operation due to an internal or external factor. Disk |
| telephones. | | | | failure varies and the most common is "Head Crash" |
| Reynold Johnson invented the first hard disk in 1955 | | | | where the internal read and write head of a device |
| for IBM 305 computer with fifty 24 inch platters and | | | | touches a platter or magnetic storage surface often |
| total capacity of five million characters, and in 1956 - | | | | grinding away the magnetic surface. Head hover just |
| first commercial hard disk was launched with 5 | | | | micrometers from the platters plane which makes |
| megabyte capacity, the IBM 350 RAMAC disk drive. | | | | such collision a common one. This sort of crash |
| Within time frame of 50 years and rapid progress in | | | | usually invites severe data loss and unprofessional |
| technical enhancement, we have now reached to | | | | data recovery attempts results further damage to |
| latest 2006 - First 750 GB hard drive from (Seagate) | | | | the remaining data. Hard drive also includes other |
| and First 200 GB 2.5" Hard Drive utilizing Perpendicular | | | | controller electronics i.e., semiconductors, valves or |
| recording (Toshiba). | | | | electronic circuits, and major components such as |
| Heart of hard disk consists of four basic components: | | | | Platters, Spindle Motor and Head Actuator. Failure of |
| The Platters: Platters are the actual disks inside the | | | | any these devices may cause a hard diskfailure. |
| drive that store the magnetized data. Conventional | | | | Factors causes disk failure are numerous, yet most |
| platters are made of a light aluminum alloy and | | | | common are power surges, voltage fluctuations, |
| coated with magnetize-able material but latest | | | | electronic malfunction, physical shock, wear and tear, |
| technology uses glass or ceramic platters as they are | | | | corrosion, exposure to high magnetic waves, sharp |
| thinner and also heat resisting. Most drives have at | | | | impact, high temperature exposure etc. |
| least two platters and the larger the storage capacity | | | | The phenomena of hard disk failure is raising higher |
| of the drive, the more platters there are. | | | | and higher; as to increase the read and write speed, |
| The Spindle Motor: Hard disk drive consists of a | | | | today we have latest hard disk rotating amazingly |
| spindle on which the platters spin at a constant RPM. | | | | faster and this immense revolving speed generates |
| Moving along and between the platters on a common | | | | massive centrifugal force, a single adverse cause in |
| arm are read-write heads. The platters in a drive are | | | | the course of normal operation can cause severe |
| divided by disk spacers and are clamped to a | | | | hard disk failure. |
| revolving spindle that turns all the platters in a | | | | Hard Disk Data Recovery: |
| uniform motion. The spindle motor is built right into | | | | Hard disk data recovery is the process of recovering |
| the spindle and rotates the platters at a constant set | | | | the trapped data from the damage hard disk device, |
| rate ranging from 3,600 to 7,200 RPM. | | | | when it can not be accessed in normal circumstance. |
| The Read/Write Heads: Read/write heads read and | | | | Several Techniques are used to retrieving data from |
| write data to the platters, and each head is fixed to | | | | damaged hard disk and techniques vary accordingly. |
| a single actuator shaft so that all the heads move in | | | | It can be done by moving disk drive to a working |
| harmony. Typically, only one of the heads is active at | | | | CPU, or may have to open the disk drive and replace |
| a time either reading or writing data. When not in | | | | parts such as read/write heads, arms and chips and |
| use, the heads are inactive, but when in motion the | | | | sometime the platters have to be removed and |
| spinning of the platters generate air pressure that | | | | placed into another drive. |
| lifts the heads off the platters. The space between | | | | Physical damage can not be repaired by the general |
| the platter and the head is so minute that even one | | | | users, as it requires clean and dust free lab |
| dust particle or a fingerprint could disable the spin. | | | | environment, in addition proper hardware and |
| When the platters cease spinning the heads come to | | | | technical expertise; where under microscopic |
| rest, at a preset position on the heads, called the | | | | examination with proper tool and techniques, the |
| landing zone. | | | | damage drive is put on to observation for data |
| The Head Actuator: All the heads are attached to a | | | | salvaging. |
| single head actuator arm, which moves the heads | | | | In case of worse happening, do consult Data |
| around the platters. The Actuator arm moves the | | | | Recovery Service for saving your important data |
| heads on an arc across the platters as they spin, | | | | trapped within the damage device. |