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