The word ?drive? is usually associated with a device that is used to play the disc ? just like the floppy drive is used for floppy discs, or CD/DVD drives for those discs. In fact, looking at the history of Hard Disks, one would note that it too started out as removable media like these. All HDDs are sealed within their protective metal casing. It all changed in 1980 when Seagate came up with the new version of the smaller HDD.



The Manufacturers

In 1980, Seagate Tech made ST 506, the first 5.25 inches Hard Disk. Its capacity was 5 megabytes. Till date, making Hard Disks remain an arduous task requiring huge technical resources, a high degree of precision, and special atmospherically controlled manufacturing units. As a result, 98% of the world's Hard Disk production is still monopolised by a few big companies ?Seagate, Samsung, Western Digital, and Hitachi, which has taken over the disc manufacturing section of IBM. Fujitsu is another company that makes hard drives, but not for desktops. Toshiba makes 2.5 inch and 1.8 inch notebook discs, specifically with laptops in mind. Between 1985 and 1999, a lot of smaller companies came into the market and went away too, as they could not sustain production. So, it can safely be said that Seagate is the market leader in hard drive manufacturing, followed by Samsung, and then Hitachi and Western Digital.

Types of Hard Disks

Hard Disks can be divided into two groups, according to where they are used, and according to the interface used by them.

A.According to where they are Used:

1.Internal Hard Drives: Most of the hard drives used today are internal drives, i.e., the ones found inside a computer ? from a home pc to a powerful office workstation. Most computers now use a minimum of two Hard Disks within themselves ? one of which is usually kept aside to house all programme files, while the other disk is used for storage and other work. Most hard drives are more or less fast, reliable and offer almost 100% of their space for storage.

2.External Hard Disk Drives: These come with an additional protective casing. Therefore, these can be used by customers who have to travel a lot, or work from multiple computers.

3.Laptop Hard Drives: They are made much in the same way as a pc internal hard drive, but they are more compact in design. Like the ones used in a home computer, laptop hard drives are also of two types ? in-built, and ones that can be quickly installed and removed. It must be mentioned here that many laptop hard drives are designed for a specific model only, and installing them on a different model will fail.

B.HDD s according to Interface:

1.EIDE (Enhanced Integrated Drive Electronics) or ATA drives: These are the most common interfaces used in the market.

2.SATA (Serial Advanced Technical Attachment): This format is gaining popularity fast, since it has several advantages over EIDE. The two greatest benefits of SATA are ? they are much faster ? and have much smaller cables, thus allowing more ?breathing space? inside the computer. The less cluttered the inside of a CPU is, the more chances it has of maintaining an air flow, and not getting overheated.

Data Recovery and the Hard Drive

We store data in the hard drive, precisely because it is supposed to be safer than the other media devices. But, sometimes, data stored in a hard drive that is securely installed in a computer can also be negatively affected. Broadly speaking, there are two ways in which a Hard Disk drive may lose or damage data:

1.Physical Data Loss: The HDD may be physically damaged due to water, humidity, fire, accident, water, or the impact of a fall. It can also be caused by the malfunctioning of other components, like a jammed read or write head, or a motor failure.

2.Logical Data Loss: Here the HDD itself remains unaffected, but the data is lost or corrupt. This happens due to accidental or malicious formatting of a logical partition or the entire disc, overwriting, fragmentation, virus infection and sudden power surge or spike.

To recover data, one may simply install and run a data recovery software available from the net, or approach a professional data recovery firm ? depending on the extent of damage done, and the volume and preciousness of the data.